magnum/src/Magnum/Test/MeshGLTest.cpp

/*
    This file is part of Magnum.

    Copyright © 2010, 2011, 2012, 2013, 2014, 2015
              Vladimír Vondruš <mosra@centrum.cz>

    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
    to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense,
    and/or sell copies of the Software, and to permit persons to whom the
    Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included
    in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
    DEALINGS IN THE SOFTWARE.
*/

#include "Magnum/AbstractShaderProgram.h"
#include "Magnum/Buffer.h"
#include "Magnum/Color.h"
#include "Magnum/ColorFormat.h"
#include "Magnum/Framebuffer.h"
#include "Magnum/Image.h"
#include "Magnum/Mesh.h"
#include "Magnum/MeshView.h"
#include "Magnum/Renderbuffer.h"
#include "Magnum/RenderbufferFormat.h"
#include "Magnum/Shader.h"
#include "Magnum/Math/Matrix.h"
#include "Magnum/Math/Vector4.h"
#include "Magnum/Test/AbstractOpenGLTester.h"

namespace Magnum { namespace Test {

/* Tests also MeshView class. */

struct MeshGLTest: AbstractOpenGLTester {
    explicit MeshGLTest();

    void construct();
    void constructCopy();
    void constructMove();
    void wrap();

    void label();

    #ifndef MAGNUM_TARGET_GLES2
    void addVertexBufferUnsignedInt();
    void addVertexBufferInt();
    #endif
    void addVertexBufferFloat();
    #ifndef MAGNUM_TARGET_GLES
    void addVertexBufferDouble();
    #endif
    #ifndef MAGNUM_TARGET_GLES2
    void addVertexBufferVectorNui();
    void addVertexBufferVectorNi();
    #endif
    void addVertexBufferVectorN();
    #ifndef MAGNUM_TARGET_GLES
    void addVertexBufferVectorNd();
    #endif
    void addVertexBufferMatrixNxN();
    #ifndef MAGNUM_TARGET_GLES
    void addVertexBufferMatrixNxNd();
    #endif
    #ifndef MAGNUM_TARGET_GLES2
    void addVertexBufferMatrixMxN();
    #endif
    #ifndef MAGNUM_TARGET_GLES
    void addVertexBufferMatrixMxNd();
    #endif

    #ifndef MAGNUM_TARGET_GLES2
    void addVertexBufferUnsignedIntWithUnsignedShort();
    void addVertexBufferUnsignedIntWithShort();
    void addVertexBufferIntWithUnsignedShort();
    void addVertexBufferIntWithShort();
    #endif
    /* Other Float types omitted (covered by addVertexBufferNormalized()) */
    void addVertexBufferFloatWithHalfFloat();
    #ifndef MAGNUM_TARGET_GLES
    void addVertexBufferFloatWithDouble();
    void addVertexBufferVector3WithUnsignedInt10f11f11fRev();
    #endif
    #ifndef MAGNUM_TARGET_GLES2
    void addVertexBufferVector4WithUnsignedInt2101010Rev();
    void addVertexBufferVector4WithInt2101010Rev();
    #endif

    void addVertexBufferLessVectorComponents();
    void addVertexBufferNormalized();
    #ifndef MAGNUM_TARGET_GLES
    void addVertexBufferBGRA();
    #endif

    void addVertexBufferMultiple();
    void addVertexBufferMultipleGaps();

    void setIndexBuffer();
    void setIndexBufferRange();
    void setIndexBufferUnsignedInt();

    #ifndef MAGNUM_TARGET_GLES
    void setBaseVertex();
    #endif
    void setInstanceCount();
    void setInstanceCountIndexed();
    #ifndef MAGNUM_TARGET_GLES
    void setInstanceCountBaseInstance();
    void setInstanceCountBaseInstanceIndexed();
    void setInstanceCountBaseVertex();
    void setInstanceCountBaseVertexBaseInstance();
    #endif

    void addVertexBufferInstancedFloat();
    #ifndef MAGNUM_TARGET_GLES2
    void addVertexBufferInstancedInteger();
    #endif
    #ifndef MAGNUM_TARGET_GLES
    void addVertexBufferInstancedDouble();
    #endif

    void multiDraw();
    void multiDrawIndexed();
    #ifndef MAGNUM_TARGET_GLES
    void multiDrawBaseVertex();
    #endif
};

MeshGLTest::MeshGLTest() {
    addTests({&MeshGLTest::construct,
              &MeshGLTest::constructCopy,
              &MeshGLTest::constructMove,
              &MeshGLTest::wrap,

              &MeshGLTest::label,

              #ifndef MAGNUM_TARGET_GLES2
              &MeshGLTest::addVertexBufferUnsignedInt,
              &MeshGLTest::addVertexBufferInt,
              #endif
              &MeshGLTest::addVertexBufferFloat,
              #ifndef MAGNUM_TARGET_GLES
              &MeshGLTest::addVertexBufferDouble,
              #endif
              #ifndef MAGNUM_TARGET_GLES2
              &MeshGLTest::addVertexBufferVectorNui,
              &MeshGLTest::addVertexBufferVectorNi,
              #endif
              &MeshGLTest::addVertexBufferVectorN,
              #ifndef MAGNUM_TARGET_GLES
              &MeshGLTest::addVertexBufferVectorNd,
              #endif
              &MeshGLTest::addVertexBufferMatrixNxN,
              #ifndef MAGNUM_TARGET_GLES
              &MeshGLTest::addVertexBufferMatrixNxNd,
              #endif
              #ifndef MAGNUM_TARGET_GLES2
              &MeshGLTest::addVertexBufferMatrixMxN,
              #endif
              #ifndef MAGNUM_TARGET_GLES
              &MeshGLTest::addVertexBufferMatrixMxNd,
              #endif

              #ifndef MAGNUM_TARGET_GLES2
              &MeshGLTest::addVertexBufferUnsignedIntWithUnsignedShort,
              &MeshGLTest::addVertexBufferUnsignedIntWithShort,
              &MeshGLTest::addVertexBufferIntWithUnsignedShort,
              &MeshGLTest::addVertexBufferIntWithShort,
              #endif
              &MeshGLTest::addVertexBufferFloatWithHalfFloat,
              #ifndef MAGNUM_TARGET_GLES
              &MeshGLTest::addVertexBufferFloatWithDouble,
              &MeshGLTest::addVertexBufferVector3WithUnsignedInt10f11f11fRev,
              #endif
              #ifndef MAGNUM_TARGET_GLES2
              &MeshGLTest::addVertexBufferVector4WithUnsignedInt2101010Rev,
              &MeshGLTest::addVertexBufferVector4WithInt2101010Rev,
              #endif

              &MeshGLTest::addVertexBufferLessVectorComponents,
              &MeshGLTest::addVertexBufferNormalized,
              #ifndef MAGNUM_TARGET_GLES
              &MeshGLTest::addVertexBufferBGRA,
              #endif

              &MeshGLTest::addVertexBufferMultiple,
              &MeshGLTest::addVertexBufferMultipleGaps,

              &MeshGLTest::setIndexBuffer,
              &MeshGLTest::setIndexBufferRange,
              &MeshGLTest::setIndexBufferUnsignedInt,

              #ifndef MAGNUM_TARGET_GLES
              &MeshGLTest::setBaseVertex,
              #endif
              &MeshGLTest::setInstanceCount,
              &MeshGLTest::setInstanceCountIndexed,
              #ifndef MAGNUM_TARGET_GLES
              &MeshGLTest::setInstanceCountBaseInstance,
              &MeshGLTest::setInstanceCountBaseInstanceIndexed,
              &MeshGLTest::setInstanceCountBaseVertex,
              &MeshGLTest::setInstanceCountBaseVertexBaseInstance,
              #endif

              &MeshGLTest::addVertexBufferInstancedFloat,
              #ifndef MAGNUM_TARGET_GLES2
              &MeshGLTest::addVertexBufferInstancedInteger,
              #endif
              #ifndef MAGNUM_TARGET_GLES
              &MeshGLTest::addVertexBufferInstancedDouble,
              #endif

              &MeshGLTest::multiDraw,
              &MeshGLTest::multiDrawIndexed,
              #ifndef MAGNUM_TARGET_GLES
              &MeshGLTest::multiDrawBaseVertex
              #endif
              });
}

void MeshGLTest::construct() {
    {
        const Mesh mesh;

        MAGNUM_VERIFY_NO_ERROR();

        #ifndef MAGNUM_TARGET_GLES
        if(Context::current()->isExtensionSupported<Extensions::GL::ARB::vertex_array_object>())
        #elif defined(MAGNUM_TARGET_GLES2)
        if(Context::current()->isExtensionSupported<Extensions::GL::OES::vertex_array_object>())
        #endif
        {
            CORRADE_VERIFY(mesh.id() > 0);
        }
    }

    MAGNUM_VERIFY_NO_ERROR();
}

void MeshGLTest::constructCopy() {
    CORRADE_VERIFY(!(std::is_constructible<Mesh, const Mesh&>{}));
    CORRADE_VERIFY(!(std::is_assignable<Mesh, const Mesh&>{}));
}

void MeshGLTest::constructMove() {
    Mesh a;
    const Int id = a.id();

    MAGNUM_VERIFY_NO_ERROR();

    #ifndef MAGNUM_TARGET_GLES
    if(Context::current()->isExtensionSupported<Extensions::GL::ARB::vertex_array_object>())
    #elif defined(MAGNUM_TARGET_GLES2)
    if(Context::current()->isExtensionSupported<Extensions::GL::OES::vertex_array_object>())
    #endif
    {
        CORRADE_VERIFY(id > 0);
    }

    Mesh b(std::move(a));

    CORRADE_COMPARE(a.id(), 0);
    CORRADE_COMPARE(b.id(), id);

    Mesh c;
    const Int cId = c.id();
    c = std::move(b);

    MAGNUM_VERIFY_NO_ERROR();

    #ifndef MAGNUM_TARGET_GLES
    if(Context::current()->isExtensionSupported<Extensions::GL::ARB::vertex_array_object>())
    #elif defined(MAGNUM_TARGET_GLES2)
    if(Context::current()->isExtensionSupported<Extensions::GL::OES::vertex_array_object>())
    #endif
    {
        CORRADE_VERIFY(cId > 0);
    }

    CORRADE_COMPARE(b.id(), cId);
    CORRADE_COMPARE(c.id(), id);
}

void MeshGLTest::wrap() {
    #ifndef MAGNUM_TARGET_GLES
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::vertex_array_object>())
    #elif defined(MAGNUM_TARGET_GLES2)
    if(!Context::current()->isExtensionSupported<Extensions::GL::OES::vertex_array_object>())
    #endif
    {
        CORRADE_SKIP(Extensions::GL::ARB::vertex_array_object::string() + std::string{" is not supported."});
    }

    GLuint id;
    glGenVertexArrays(1, &id);

    /* Releasing won't delete anything */
    {
        auto mesh = Mesh::wrap(id, ObjectFlag::DeleteOnDestruction);
        CORRADE_COMPARE(mesh.release(), id);
    }

    /* ...so we can wrap it again */
    Mesh::wrap(id);
    glDeleteVertexArrays(1, &id);
}

void MeshGLTest::label() {
    /* No-Op version is tested in AbstractObjectGLTest */
    if(!Context::current()->isExtensionSupported<Extensions::GL::KHR::debug>() &&
       !Context::current()->isExtensionSupported<Extensions::GL::EXT::debug_label>())
        CORRADE_SKIP("Required extension is not available");

    Mesh mesh;

    CORRADE_COMPARE(mesh.label(), "");
    MAGNUM_VERIFY_NO_ERROR();

    mesh.setLabel("MyMesh");
    MAGNUM_VERIFY_NO_ERROR();

    CORRADE_COMPARE(mesh.label(), "MyMesh");
}

namespace {
    struct FloatShader: AbstractShaderProgram {
        explicit FloatShader(const std::string& type, const std::string& conversion);
    };

    #ifndef MAGNUM_TARGET_GLES2
    struct IntegerShader: AbstractShaderProgram {
        explicit IntegerShader(const std::string& type);
    };
    #endif

    #ifndef MAGNUM_TARGET_GLES
    struct DoubleShader: AbstractShaderProgram {
        explicit DoubleShader(const std::string& type, const std::string& outputType, const std::string& conversion);
    };
    #endif

    struct Checker {
        Checker(AbstractShaderProgram&& shader, RenderbufferFormat format, Mesh& mesh);

        template<class T> T get(ColorFormat format, ColorType type);

        Renderbuffer renderbuffer;
        Framebuffer framebuffer;
    };
}

#ifndef DOXYGEN_GENERATING_OUTPUT
FloatShader::FloatShader(const std::string& type, const std::string& conversion) {
    /* We need special version for ES3, because GLSL in ES2 doesn't support
       rectangle matrices */
    #ifndef MAGNUM_TARGET_GLES
    Shader vert(Version::GL210, Shader::Type::Vertex);
    Shader frag(Version::GL210, Shader::Type::Fragment);
    #elif defined(MAGNUM_TARGET_GLES2)
    Shader vert(Version::GLES200, Shader::Type::Vertex);
    Shader frag(Version::GLES200, Shader::Type::Fragment);
    #else
    Shader vert(Version::GLES300, Shader::Type::Vertex);
    Shader frag(Version::GLES300, Shader::Type::Fragment);
    #endif

    vert.addSource(
        #if !defined(MAGNUM_TARGET_GLES) || defined(MAGNUM_TARGET_GLES2)
        "attribute mediump " + type + " value;\n"
        "varying mediump " + type + " valueInterpolated;\n"
        #else
        "in mediump " + type + " value;\n"
        "out mediump " + type + " valueInterpolated;\n"
        #endif
        "void main() {\n"
        "    valueInterpolated = value;\n"
        "    gl_Position = vec4(0.0, 0.0, 0.0, 1.0);\n"
        "}\n");

    #if !defined(MAGNUM_TARGET_GLES) || defined(MAGNUM_TARGET_GLES2)
    frag.addSource("varying mediump " + type + " valueInterpolated;\n"
                   "void main() { gl_FragColor = " + conversion + "; }\n");
    #else
    frag.addSource("in mediump " + type + " valueInterpolated;\n"
                   "out mediump vec4 result;\n"
                   "void main() { result = " + conversion + "; }\n");
    #endif

    CORRADE_INTERNAL_ASSERT_OUTPUT(Shader::compile({vert, frag}));

    attachShaders({vert, frag});

    bindAttributeLocation(0, "value");

    CORRADE_INTERNAL_ASSERT_OUTPUT(link());
}

#ifndef MAGNUM_TARGET_GLES2
IntegerShader::IntegerShader(const std::string& type) {
    #ifndef MAGNUM_TARGET_GLES
    Shader vert(Version::GL300, Shader::Type::Vertex);
    Shader frag(Version::GL300, Shader::Type::Fragment);
    #else
    Shader vert(Version::GLES300, Shader::Type::Vertex);
    Shader frag(Version::GLES300, Shader::Type::Fragment);
    #endif

    vert.addSource("in mediump " + type + " value;\n"
                   "flat out mediump " + type + " valueInterpolated;\n"
                   "void main() {\n"
                   "    valueInterpolated = value;\n"
                   "    gl_Position = vec4(0.0, 0.0, 0.0, 1.0);\n"
                   "}\n");
    frag.addSource("flat in mediump " + type + " valueInterpolated;\n"
                   "out mediump " + type + " result;\n"
                   "void main() { result = valueInterpolated; }\n");

    CORRADE_INTERNAL_ASSERT_OUTPUT(Shader::compile({vert, frag}));

    attachShaders({vert, frag});

    bindAttributeLocation(0, "value");

    CORRADE_INTERNAL_ASSERT_OUTPUT(link());
}
#endif

#ifndef MAGNUM_TARGET_GLES
DoubleShader::DoubleShader(const std::string& type, const std::string& outputType, const std::string& conversion) {
    Shader vert(Version::GL410, Shader::Type::Vertex);
    Shader frag(Version::GL410, Shader::Type::Fragment);

    vert.addSource("in " + type + " value;\n"
                   "out " + outputType + " valueInterpolated;\n"
                   "void main() {\n"
                   "    valueInterpolated = " + conversion + ";\n"
                   "    gl_Position = vec4(0.0, 0.0, 0.0, 1.0);\n"
                   "}\n");
    frag.addSource("in " + outputType + " valueInterpolated;\n"
                   "out " + outputType + " result;\n"
                   "void main() { result = valueInterpolated; }\n");

    CORRADE_INTERNAL_ASSERT_OUTPUT(Shader::compile({vert, frag}));

    attachShaders({vert, frag});

    bindAttributeLocation(0, "value");

    CORRADE_INTERNAL_ASSERT_OUTPUT(link());
}
#endif

Checker::Checker(AbstractShaderProgram&& shader, RenderbufferFormat format, Mesh& mesh): framebuffer({{}, Vector2i(1)}) {
    renderbuffer.setStorage(format, Vector2i(1));
    framebuffer.attachRenderbuffer(Framebuffer::ColorAttachment(0), renderbuffer);

    framebuffer.bind();
    mesh.setPrimitive(MeshPrimitive::Points)
        .setCount(2);

    /* Skip first vertex so we test also offsets */
    MeshView(mesh)
        .setCount(1)
        .setBaseVertex(mesh.baseVertex())
        .setInstanceCount(mesh.instanceCount())
        #ifndef MAGNUM_TARGET_GLES
        .setBaseInstance(mesh.baseInstance())
        #endif
        .setIndexRange(1)
        .draw(shader);
}

template<class T> T Checker::get(ColorFormat format, ColorType type) {
    return framebuffer.read({{}, Vector2i{1}}, {format, type}).data<T>()[0];
}
#endif

#ifndef MAGNUM_TARGET_GLES2
void MeshGLTest::addVertexBufferUnsignedInt() {
    #ifndef MAGNUM_TARGET_GLES
    if(!Context::current()->isExtensionSupported<Extensions::GL::EXT::gpu_shader4>())
        CORRADE_SKIP(Extensions::GL::EXT::gpu_shader4::string() + std::string(" is not available."));
    #endif

    typedef Attribute<0, UnsignedInt> Attribute;

    constexpr UnsignedInt data[] = { 0, 157, 35681 };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 4, Attribute());

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(IntegerShader("uint"), RenderbufferFormat::R32UI, mesh)
        .get<UnsignedInt>(ColorFormat::RedInteger, ColorType::UnsignedInt);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, 35681);
}

void MeshGLTest::addVertexBufferInt() {
    #ifndef MAGNUM_TARGET_GLES
    if(!Context::current()->isExtensionSupported<Extensions::GL::EXT::gpu_shader4>())
        CORRADE_SKIP(Extensions::GL::EXT::gpu_shader4::string() + std::string(" is not available."));
    #endif

    typedef Attribute<0, Int> Attribute;

    constexpr Int data[] = { 0, 457931, 27530 };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 4, Attribute());

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(IntegerShader("int"), RenderbufferFormat::R32I, mesh)
        .get<Int>(ColorFormat::RedInteger, ColorType::Int);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, 27530);
}
#endif

void MeshGLTest::addVertexBufferFloat() {
    typedef Attribute<0, Float> Attribute;

    const Float data[] = { 0.0f, -0.7f, Math::normalize<Float, UnsignedByte>(96) };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 4, Attribute());

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(FloatShader("float", "vec4(valueInterpolated, 0.0, 0.0, 0.0)"),
        #ifndef MAGNUM_TARGET_GLES2
        RenderbufferFormat::RGBA8,
        #else
        RenderbufferFormat::RGBA4,
        #endif
        mesh).get<UnsignedByte>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, 96);
}

#ifndef MAGNUM_TARGET_GLES
void MeshGLTest::addVertexBufferDouble() {
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::vertex_attrib_64bit>())
        CORRADE_SKIP(Extensions::GL::ARB::vertex_attrib_64bit::string() + std::string(" is not available."));

    typedef Attribute<0, Double> Attribute;

    const Double data[] = { 0.0, -0.7, Math::normalize<Double, UnsignedShort>(45828) };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 8, Attribute());

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(DoubleShader("double", "float", "float(value)"),
        RenderbufferFormat::R16, mesh).get<UnsignedShort>(ColorFormat::Red, ColorType::UnsignedShort);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, 45828);
}
#endif

#ifndef MAGNUM_TARGET_GLES2
void MeshGLTest::addVertexBufferVectorNui() {
    #ifndef MAGNUM_TARGET_GLES
    if(!Context::current()->isExtensionSupported<Extensions::GL::EXT::gpu_shader4>())
        CORRADE_SKIP(Extensions::GL::EXT::gpu_shader4::string() + std::string(" is not available."));
    #endif

    typedef Attribute<0, Vector3ui> Attribute;

    constexpr Vector3ui data[] = { {}, {37448, 547686, 156}, {27592, 157, 25} };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 3*4, Attribute());

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(IntegerShader("uvec3"), RenderbufferFormat::RGBA32UI, mesh)
        .get<Vector3ui>(ColorFormat::RGBAInteger, ColorType::UnsignedInt);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, Vector3ui(27592, 157, 25));
}

void MeshGLTest::addVertexBufferVectorNi() {
    #ifndef MAGNUM_TARGET_GLES
    if(!Context::current()->isExtensionSupported<Extensions::GL::EXT::gpu_shader4>())
        CORRADE_SKIP(Extensions::GL::EXT::gpu_shader4::string() + std::string(" is not available."));
    #endif

    typedef Attribute<0, Vector2i> Attribute;

    constexpr Vector2i data[] = { {}, {-37448, 547686}, {27592, -157} };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 2*4, Attribute());

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(IntegerShader("ivec2"), RenderbufferFormat::RG32I, mesh)
        .get<Vector2i>(ColorFormat::RGInteger, ColorType::Int);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, Vector2i(27592, -157));
}
#endif

void MeshGLTest::addVertexBufferVectorN() {
    typedef Attribute<0, Vector3> Attribute;

    const Vector3 data[] = { {}, {0.0f, -0.9f, 1.0f}, Math::normalize<Vector3>(Color3ub(96, 24, 156)) };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 3*4, Attribute());

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(FloatShader("vec3", "vec4(valueInterpolated, 0.0)"),
        #ifndef MAGNUM_TARGET_GLES2
        RenderbufferFormat::RGBA8,
        #else
        RenderbufferFormat::RGBA4,
        #endif
        mesh).get<Color3ub>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, Color3ub(96, 24, 156));
}

#ifndef MAGNUM_TARGET_GLES
void MeshGLTest::addVertexBufferVectorNd() {
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::vertex_attrib_64bit>())
        CORRADE_SKIP(Extensions::GL::ARB::vertex_attrib_64bit::string() + std::string(" is not available."));

    typedef Attribute<0, Vector4d> Attribute;

    const Vector4d data[] = {
        {}, {0.0, -0.9, 1.0, 1.25},
        Math::normalize<Vector4d>(Math::Vector4<UnsignedShort>(315, 65201, 2576, 12))
    };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 4*8, Attribute());

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(DoubleShader("dvec4", "vec4", "vec4(value)"),
        RenderbufferFormat::RGBA16, mesh).get<Math::Vector4<UnsignedShort>>(ColorFormat::RGBA, ColorType::UnsignedShort);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, Math::Vector4<UnsignedShort>(315, 65201, 2576, 12));
}
#endif

void MeshGLTest::addVertexBufferMatrixNxN() {
    typedef Attribute<0, Matrix3x3> Attribute;

    const Matrix3x3 data[] = {
        {},
        Matrix3x3::fromDiagonal({0.0f, -0.9f, 1.0f}),
        Matrix3x3::fromDiagonal(Math::normalize<Vector3>(Color3ub(96, 24, 156)))
    };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 3*3*4, Attribute());

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(FloatShader("mat3",
        "vec4(valueInterpolated[0][0], valueInterpolated[1][1], valueInterpolated[2][2], 0.0)"),
        RenderbufferFormat::RGBA8, mesh).get<Color3ub>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, Color3ub(96, 24, 156));
}

#ifndef MAGNUM_TARGET_GLES
void MeshGLTest::addVertexBufferMatrixNxNd() {
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::vertex_attrib_64bit>())
        CORRADE_SKIP(Extensions::GL::ARB::vertex_attrib_64bit::string() + std::string(" is not available."));

    typedef Attribute<0, Matrix3x3d> Attribute;

    const Matrix3x3d data[] = {
        {},
        Matrix3x3d::fromDiagonal({0.0, -0.9, 1.0}),
        Matrix3x3d::fromDiagonal(Math::normalize<Vector3d>(Math::Vector3<UnsignedShort>(315, 65201, 2576)))
    };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 3*3*8, Attribute());

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(DoubleShader("dmat3", "vec4",
        "vec4(value[0][0], value[1][1], value[2][2], 0.0)"),
        RenderbufferFormat::RGBA16, mesh).get<Math::Vector3<UnsignedShort>>(ColorFormat::RGB, ColorType::UnsignedShort);

    MAGNUM_VERIFY_NO_ERROR();

    {
        CORRADE_EXPECT_FAIL("Somehow only first two values are extracted");
        CORRADE_COMPARE(value, Math::Vector3<UnsignedShort>(315, 65201, 2576));
    }
    /* This is wrong, but check if it's still the right wrong */
    CORRADE_COMPARE(value, Math::Vector3<UnsignedShort>(315, 65201, 0));
}
#endif

#ifndef MAGNUM_TARGET_GLES2
void MeshGLTest::addVertexBufferMatrixMxN() {
    typedef Attribute<0, Matrix3x4> Attribute;

    const Matrix3x4 data[] = {
        {},
        Matrix3x4::fromDiagonal({0.0f, -0.9f, 1.0f}),
        Matrix3x4::fromDiagonal(Math::normalize<Vector3>(Color3ub(96, 24, 156)))
    };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 3*4*4, Attribute());

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(FloatShader("mat3x4",
        "vec4(valueInterpolated[0][0], valueInterpolated[1][1], valueInterpolated[2][2], 0.0)"),
        RenderbufferFormat::RGBA8, mesh).get<Color3ub>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, Color3ub(96, 24, 156));
}
#endif

#ifndef MAGNUM_TARGET_GLES
void MeshGLTest::addVertexBufferMatrixMxNd() {
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::vertex_attrib_64bit>())
        CORRADE_SKIP(Extensions::GL::ARB::vertex_attrib_64bit::string() + std::string(" is not available."));

    typedef Attribute<0, Matrix3x4d> Attribute;

    const Matrix3x4d data[] = {
        {},
        Matrix3x4d::fromDiagonal({0.0f, -0.9f, 1.0f}),
        Matrix3x4d::fromDiagonal(Math::normalize<Vector3d>(Math::Vector3<UnsignedShort>(315, 65201, 2576)))
    };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 3*4*8, Attribute());

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(DoubleShader("dmat3x4", "vec4",
        "vec4(value[0][0], value[1][1], value[2][2], 0.0)"),
        RenderbufferFormat::RGBA16, mesh).get<Math::Vector3<UnsignedShort>>(ColorFormat::RGB, ColorType::UnsignedShort);

    MAGNUM_VERIFY_NO_ERROR();

    {
        CORRADE_EXPECT_FAIL("Somehow only first two values are extracted");
        CORRADE_COMPARE(value, Math::Vector3<UnsignedShort>(315, 65201, 2576));
    }
    /* This is wrong, but check if it's still the right wrong */
    CORRADE_COMPARE(value, Math::Vector3<UnsignedShort>(315, 65201, 0));
}
#endif

#ifndef MAGNUM_TARGET_GLES2
void MeshGLTest::addVertexBufferUnsignedIntWithUnsignedShort() {
    #ifndef MAGNUM_TARGET_GLES
    if(!Context::current()->isExtensionSupported<Extensions::GL::EXT::gpu_shader4>())
        CORRADE_SKIP(Extensions::GL::EXT::gpu_shader4::string() + std::string(" is not available."));
    #endif

    typedef Attribute<0, UnsignedInt> Attribute;

    constexpr UnsignedShort data[] = { 0, 49563, 16583 };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 2, Attribute(Attribute::DataType::UnsignedShort));

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(IntegerShader("uint"), RenderbufferFormat::R16UI, mesh)
        .get<UnsignedShort>(ColorFormat::RedInteger, ColorType::UnsignedShort);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, 16583);
}

void MeshGLTest::addVertexBufferUnsignedIntWithShort() {
    #ifndef MAGNUM_TARGET_GLES
    if(!Context::current()->isExtensionSupported<Extensions::GL::EXT::gpu_shader4>())
        CORRADE_SKIP(Extensions::GL::EXT::gpu_shader4::string() + std::string(" is not available."));
    #endif

    typedef Attribute<0, UnsignedInt> Attribute;

    constexpr Short data[] = { 0, 24563, 16583 };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 2, Attribute(Attribute::DataType::Short));

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(IntegerShader("uint"), RenderbufferFormat::R16I, mesh)
        .get<Short>(ColorFormat::RedInteger, ColorType::Short);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, 16583);
}

void MeshGLTest::addVertexBufferIntWithUnsignedShort() {
    #ifndef MAGNUM_TARGET_GLES
    if(!Context::current()->isExtensionSupported<Extensions::GL::EXT::gpu_shader4>())
        CORRADE_SKIP(Extensions::GL::EXT::gpu_shader4::string() + std::string(" is not available."));
    #endif

    typedef Attribute<0, Int> Attribute;

    constexpr UnsignedShort data[] = { 0, 49563, 16583 };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 2, Attribute(Attribute::DataType::UnsignedShort));

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(IntegerShader("int"), RenderbufferFormat::R16UI, mesh)
        .get<UnsignedShort>(ColorFormat::RedInteger, ColorType::UnsignedShort);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, 16583);
}

void MeshGLTest::addVertexBufferIntWithShort() {
    #ifndef MAGNUM_TARGET_GLES
    if(!Context::current()->isExtensionSupported<Extensions::GL::EXT::gpu_shader4>())
        CORRADE_SKIP(Extensions::GL::EXT::gpu_shader4::string() + std::string(" is not available."));
    #endif

    typedef Attribute<0, Int> Attribute;

    constexpr Short data[] = { 0, 24563, -16583 };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 2, Attribute(Attribute::DataType::Short));

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(IntegerShader("int"), RenderbufferFormat::R16I, mesh)
        .get<Short>(ColorFormat::RedInteger, ColorType::Short);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, -16583);
}
#endif

void MeshGLTest::addVertexBufferFloatWithHalfFloat() {
    #ifndef MAGNUM_TARGET_GLES
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::half_float_vertex>())
        CORRADE_SKIP(Extensions::GL::ARB::half_float_vertex::string() + std::string(" is not supported."));
    #elif defined(MAGNUM_TARGET_GLES2)
    if(!Context::current()->isExtensionSupported<Extensions::GL::OES::vertex_half_float>())
        CORRADE_SKIP(Extensions::GL::OES::vertex_half_float::string() + std::string(" is not supported."));
    #endif

    typedef Attribute<0, Float> Attribute;

    Buffer buffer;
    buffer.setData({nullptr, 6}, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 2, Attribute(Attribute::DataType::HalfFloat));

    MAGNUM_VERIFY_NO_ERROR();
    /* Won't test the actual values */
}

#ifndef MAGNUM_TARGET_GLES
void MeshGLTest::addVertexBufferFloatWithDouble() {
    typedef Attribute<0, Float> Attribute;

    const Double data[] = { 0.0, -0.7, Math::normalize<Double, UnsignedByte>(186) };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 8, Attribute(Attribute::DataType::Double));

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(FloatShader("float", "vec4(valueInterpolated, 0.0, 0.0, 0.0)"),
        RenderbufferFormat::RGBA8, mesh).get<UnsignedByte>(ColorFormat::RGBA, ColorType::UnsignedShort);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, 186);
}

void MeshGLTest::addVertexBufferVector3WithUnsignedInt10f11f11fRev() {
    #ifndef MAGNUM_TARGET_GLES
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::vertex_type_10f_11f_11f_rev>())
        CORRADE_SKIP(Extensions::GL::ARB::vertex_type_10f_11f_11f_rev::string() + std::string(" is not available."));
    #endif

    typedef Attribute<0, Vector3> Attribute;

    Buffer buffer;
    buffer.setData({nullptr, 12}, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 4, Attribute(Attribute::DataType::UnsignedInt10f11f11fRev));

    MAGNUM_VERIFY_NO_ERROR();
    /* Won't test the actual values */
}
#endif

#ifndef MAGNUM_TARGET_GLES2
void MeshGLTest::addVertexBufferVector4WithUnsignedInt2101010Rev() {
    #ifndef MAGNUM_TARGET_GLES
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::vertex_type_2_10_10_10_rev>())
        CORRADE_SKIP(Extensions::GL::ARB::vertex_type_2_10_10_10_rev::string() + std::string(" is not available."));
    #endif

    typedef Attribute<0, Vector4> Attribute;

    Buffer buffer;
    buffer.setData({nullptr, 12}, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 4, Attribute(Attribute::DataType::UnsignedInt2101010Rev));

    MAGNUM_VERIFY_NO_ERROR();
    /* Won't test the actual values */
}

void MeshGLTest::addVertexBufferVector4WithInt2101010Rev() {
    #ifndef MAGNUM_TARGET_GLES
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::vertex_type_2_10_10_10_rev>())
        CORRADE_SKIP(Extensions::GL::ARB::vertex_type_2_10_10_10_rev::string() + std::string(" is not available."));
    #endif

    typedef Attribute<0, Vector4> Attribute;

    Buffer buffer;
    buffer.setData({nullptr, 12}, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 4, Attribute(Attribute::DataType::Int2101010Rev));

    MAGNUM_VERIFY_NO_ERROR();
    /* Won't test the actual values */
}
#endif

void MeshGLTest::addVertexBufferLessVectorComponents() {
    typedef Attribute<0, Vector4> Attribute;

    const Vector3 data[] = {
        {}, {0.0f, -0.9f, 1.0f},
        Math::normalize<Vector3>(Color3ub(96, 24, 156))
    };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 3*4, Attribute(Attribute::Components::Three));

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(FloatShader("vec4", "valueInterpolated"),
        #ifndef MAGNUM_TARGET_GLES2
        RenderbufferFormat::RGBA8,
        #else
        RenderbufferFormat::RGBA4,
        #endif
        mesh).get<Color4ub>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, Color4ub(96, 24, 156, 255));
}

void MeshGLTest::addVertexBufferNormalized() {
    typedef Attribute<0, Vector3> Attribute;

    constexpr Color3ub data[] = { {}, {0, 128, 64}, {32, 156, 228} };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 3, Attribute(Attribute::DataType::UnsignedByte, Attribute::DataOption::Normalized));

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(FloatShader("vec3", "vec4(valueInterpolated, 0.0)"),
        #ifndef MAGNUM_TARGET_GLES2
        RenderbufferFormat::RGBA8,
        #else
        RenderbufferFormat::RGBA4,
        #endif
        mesh).get<Color3ub>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, Color3ub(32, 156, 228));
}

#ifndef MAGNUM_TARGET_GLES
void MeshGLTest::addVertexBufferBGRA() {
    #ifndef MAGNUM_TARGET_GLES
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::vertex_array_bgra>())
        CORRADE_SKIP(Extensions::GL::ARB::vertex_array_bgra::string() + std::string(" is not available."));
    #endif

    typedef Attribute<0, Vector4> Attribute;

    constexpr Color4ub data[] = { {}, {0, 128, 64, 161}, {96, 24, 156, 225} };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 4, Attribute(Attribute::Components::BGRA, Attribute::DataType::UnsignedByte, Attribute::DataOption::Normalized));

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(FloatShader("vec4", "valueInterpolated"),
        RenderbufferFormat::RGBA8, mesh).get<Color4ub>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, Color4ub(156, 24, 96, 225));
}
#endif

namespace {
    struct MultipleShader: AbstractShaderProgram {
        typedef Attribute<0, Vector3> Position;
        typedef Attribute<1, Vector3> Normal;
        typedef Attribute<2, Vector2> TextureCoordinates;

        explicit MultipleShader();
    };
}

#ifndef DOXYGEN_GENERATING_OUTPUT
MultipleShader::MultipleShader() {
    #ifndef MAGNUM_TARGET_GLES
    Shader vert(Version::GL210, Shader::Type::Vertex);
    Shader frag(Version::GL210, Shader::Type::Fragment);
    #else
    Shader vert(Version::GLES200, Shader::Type::Vertex);
    Shader frag(Version::GLES200, Shader::Type::Fragment);
    #endif

    vert.addSource("attribute mediump vec4 position;\n"
                   "attribute mediump vec3 normal;\n"
                   "attribute mediump vec2 textureCoordinates;\n"
                   "varying mediump vec4 valueInterpolated;\n"
                   "void main() {\n"
                   "    valueInterpolated = position + vec4(normal, 0.0) + vec4(textureCoordinates, 0.0, 0.0);\n"
                   "    gl_Position = vec4(0.0, 0.0, 0.0, 1.0);\n"
                   "}\n");
    frag.addSource("varying mediump vec4 valueInterpolated;\n"
                   "void main() { gl_FragColor = valueInterpolated; }\n");

    CORRADE_INTERNAL_ASSERT_OUTPUT(Shader::compile({vert, frag}));

    attachShaders({vert, frag});

    bindAttributeLocation(Position::Location, "position");
    bindAttributeLocation(Normal::Location, "normal");
    bindAttributeLocation(TextureCoordinates::Location, "textureCoordinates");

    CORRADE_INTERNAL_ASSERT_OUTPUT(link());
}
#endif

void MeshGLTest::addVertexBufferMultiple() {
    const Float data[] = {
        0.0f, /* Offset */

        /* First attribute */
        0.3f, 0.1f, 0.5f,
            0.4f, 0.0f, -0.9f,
                1.0f, -0.5f,

        /* Second attribute */
        Math::normalize<Float, UnsignedByte>(64),
            Math::normalize<Float, UnsignedByte>(17),
                Math::normalize<Float, UnsignedByte>(56),
        Math::normalize<Float, UnsignedByte>(15),
            Math::normalize<Float, UnsignedByte>(164),
                Math::normalize<Float, UnsignedByte>(17),
        Math::normalize<Float, UnsignedByte>(97),
            Math::normalize<Float, UnsignedByte>(28)
    };

    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 1*4, MultipleShader::Position(),
        MultipleShader::Normal(), MultipleShader::TextureCoordinates());

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(MultipleShader(),
        #ifndef MAGNUM_TARGET_GLES2
        RenderbufferFormat::RGBA8,
        #else
        RenderbufferFormat::RGBA4,
        #endif
        mesh).get<Color4ub>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, Color4ub(64 + 15 + 97, 17 + 164 + 28, 56 + 17, 255));
}

void MeshGLTest::addVertexBufferMultipleGaps() {
     const Float data[] = {
        0.0f, 0.0f, 0.0f, 0.0f, /* Offset */

        /* First attribute */
        0.3f, 0.1f, 0.5f, 0.0f,
            0.4f, 0.0f, -0.9f, 0.0f,
                1.0f, -0.5f, 0.0f, 0.0f,

        /* Second attribute */
        Math::normalize<Float, UnsignedByte>(64),
            Math::normalize<Float, UnsignedByte>(17),
                Math::normalize<Float, UnsignedByte>(56), 0.0f,
        Math::normalize<Float, UnsignedByte>(15),
            Math::normalize<Float, UnsignedByte>(164),
                Math::normalize<Float, UnsignedByte>(17), 0.0f,
        Math::normalize<Float, UnsignedByte>(97),
            Math::normalize<Float, UnsignedByte>(28), 0.0f, 0.0f
    };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .addVertexBuffer(buffer, 4*4,
        MultipleShader::Position(), 1*4,
        MultipleShader::Normal(), 1*4,
        MultipleShader::TextureCoordinates(), 2*4);

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(MultipleShader(),
        #ifndef MAGNUM_TARGET_GLES2
        RenderbufferFormat::RGBA8,
        #else
        RenderbufferFormat::RGBA4,
        #endif
        mesh).get<Color4ub>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, Color4ub(64 + 15 + 97, 17 + 164 + 28, 56 + 17, 255));
}

namespace {
    const Float indexedVertexData[] = {
        0.0f, /* Offset */

        /* First vertex */
        Math::normalize<Float, UnsignedByte>(64),
            Math::normalize<Float, UnsignedByte>(17),
                Math::normalize<Float, UnsignedByte>(56),
        Math::normalize<Float, UnsignedByte>(15),
            Math::normalize<Float, UnsignedByte>(164),
                Math::normalize<Float, UnsignedByte>(17),
        Math::normalize<Float, UnsignedByte>(97),
            Math::normalize<Float, UnsignedByte>(28),

        /* Second vertex */
        0.3f, 0.1f, 0.5f,
            0.4f, 0.0f, -0.9f,
                1.0f, -0.5f
    };

    const Float indexedVertexDataBaseVertex[] = {
        0.0f, 0.0f, /* Offset */

        /* First vertex */
        0.0f, 0.0f, 0.0f,
            0.0f, 0.0f, 0.0f,
                0.0f, 0.0f,

        /* Second vertex */
        0.0f, 0.0f, 0.0f,
            0.0f, 0.0f, 0.0f,
                0.0f, 0.0f,

        /* Third vertex */
        Math::normalize<Float, UnsignedByte>(64),
            Math::normalize<Float, UnsignedByte>(17),
                Math::normalize<Float, UnsignedByte>(56),
        Math::normalize<Float, UnsignedByte>(15),
            Math::normalize<Float, UnsignedByte>(164),
                Math::normalize<Float, UnsignedByte>(17),
        Math::normalize<Float, UnsignedByte>(97),
            Math::normalize<Float, UnsignedByte>(28),

        /* Fourth vertex */
        0.3f, 0.1f, 0.5f,
            0.4f, 0.0f, -0.9f,
                1.0f, -0.5f
    };

    constexpr Color4ub indexedResult(64 + 15 + 97, 17 + 164 + 28, 56 + 17, 255);
}

void MeshGLTest::setIndexBuffer() {
    Buffer vertices;
    vertices.setData(indexedVertexData, BufferUsage::StaticDraw);

    constexpr UnsignedShort indexData[] = { 2, 1, 0 };
    Buffer indices{Buffer::TargetHint::ElementArray};
    indices.setData(indexData, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.addVertexBuffer(vertices, 1*4,  MultipleShader::Position(),
                         MultipleShader::Normal(), MultipleShader::TextureCoordinates())
        .setIndexBuffer(indices, 2, Mesh::IndexType::UnsignedShort);

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(MultipleShader{},
        #ifndef MAGNUM_TARGET_GLES2
        RenderbufferFormat::RGBA8,
        #else
        RenderbufferFormat::RGBA4,
        #endif
        mesh).get<Color4ub>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, indexedResult);
}

void MeshGLTest::setIndexBufferRange() {
    Buffer vertices;
    vertices.setData(indexedVertexData, BufferUsage::StaticDraw);

    constexpr UnsignedShort indexData[] = { 2, 1, 0 };
    Buffer indices{Buffer::TargetHint::ElementArray};
    indices.setData(indexData, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.addVertexBuffer(vertices, 1*4,  MultipleShader::Position(),
                         MultipleShader::Normal(), MultipleShader::TextureCoordinates())
        .setIndexBuffer(indices, 2, Mesh::IndexType::UnsignedShort, 0, 1);

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(MultipleShader{},
        #ifndef MAGNUM_TARGET_GLES2
        RenderbufferFormat::RGBA8,
        #else
        RenderbufferFormat::RGBA4,
        #endif
        mesh).get<Color4ub>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, indexedResult);
}

void MeshGLTest::setIndexBufferUnsignedInt() {
    #ifdef MAGNUM_TARGET_GLES2
    if(!Context::current()->isExtensionSupported<Extensions::GL::OES::element_index_uint>())
        CORRADE_SKIP(Extensions::GL::OES::element_index_uint::string() + std::string(" is not available."));
    #endif

    Buffer vertices;
    vertices.setData(indexedVertexData, BufferUsage::StaticDraw);

    constexpr UnsignedInt indexData[] = { 2, 1, 0 };
    Buffer indices{Buffer::TargetHint::ElementArray};
    indices.setData(indexData, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.addVertexBuffer(vertices, 1*4,  MultipleShader::Position(),
                         MultipleShader::Normal(), MultipleShader::TextureCoordinates())
        .setIndexBuffer(indices, 4, Mesh::IndexType::UnsignedInt);

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(MultipleShader{},
        #ifndef MAGNUM_TARGET_GLES2
        RenderbufferFormat::RGBA8,
        #else
        RenderbufferFormat::RGBA4,
        #endif
        mesh).get<Color4ub>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, indexedResult);
}

#ifndef MAGNUM_TARGET_GLES
void MeshGLTest::setBaseVertex() {
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::draw_elements_base_vertex>())
        CORRADE_SKIP(Extensions::GL::ARB::draw_elements_base_vertex::string() + std::string(" is not available."));

    Buffer vertices;
    vertices.setData(indexedVertexDataBaseVertex, BufferUsage::StaticDraw);

    constexpr UnsignedShort indexData[] = { 2, 1, 0 };
    Buffer indices{Buffer::TargetHint::ElementArray};
    indices.setData(indexData, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(2)
        .addVertexBuffer(vertices, 2*4,  MultipleShader::Position(),
                         MultipleShader::Normal(), MultipleShader::TextureCoordinates())
        .setIndexBuffer(indices, 2, Mesh::IndexType::UnsignedShort);

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(MultipleShader{}, RenderbufferFormat::RGBA8,
        mesh).get<Color4ub>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, indexedResult);
}
#endif

void MeshGLTest::setInstanceCount() {
    /* Verbatim copy of addVertexBufferFloat() with added extension check and
       setInstanceCount() call. It would just render three times the same
       value. I'm too lazy to invent proper test case, so I'll just check that
       it didn't generate any error and rendered something */

    #ifndef MAGNUM_TARGET_GLES
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::draw_instanced>())
        CORRADE_SKIP(Extensions::GL::ARB::draw_instanced::string() + std::string(" is not available."));
    #elif defined(MAGNUM_TARGET_GLES2)
    if(!Context::current()->isExtensionSupported<Extensions::GL::ANGLE::instanced_arrays>() && !Context::current()->isExtensionSupported<Extensions::GL::EXT::draw_instanced>() && !Context::current()->isExtensionSupported<Extensions::GL::NV::draw_instanced>())
        CORRADE_SKIP("Required extension is not available.");
    #endif

    typedef Attribute<0, Float> Attribute;

    const Float data[] = { 0.0f, -0.7f, Math::normalize<Float, UnsignedByte>(96) };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .setInstanceCount(3)
        .addVertexBuffer(buffer, 4, Attribute());

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(FloatShader("float", "vec4(valueInterpolated, 0.0, 0.0, 0.0)"),
        #ifndef MAGNUM_TARGET_GLES2
        RenderbufferFormat::RGBA8,
        #else
        RenderbufferFormat::RGBA4,
        #endif
        mesh).get<UnsignedByte>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, 96);
}

void MeshGLTest::setInstanceCountIndexed() {
    /* Verbatim copy of setIndexBuffer() with added extension check and
       setInstanceCount() call. It would just render three times the same
       value. I'm too lazy to invent proper test case, so I'll just check that
       it didn't generate any error and rendered something */

    #ifndef MAGNUM_TARGET_GLES
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::draw_instanced>())
        CORRADE_SKIP(Extensions::GL::ARB::draw_instanced::string() + std::string(" is not available."));
    #elif defined(MAGNUM_TARGET_GLES2)
    if(!Context::current()->isExtensionSupported<Extensions::GL::ANGLE::instanced_arrays>() && !Context::current()->isExtensionSupported<Extensions::GL::EXT::draw_instanced>() && !Context::current()->isExtensionSupported<Extensions::GL::NV::draw_instanced>())
        CORRADE_SKIP("Required extension is not available.");
    #endif

    Buffer vertices;
    vertices.setData(indexedVertexData, BufferUsage::StaticDraw);

    constexpr UnsignedShort indexData[] = { 2, 1, 0 };
    Buffer indices{Buffer::TargetHint::ElementArray};
    indices.setData(indexData, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setInstanceCount(3)
        .addVertexBuffer(vertices, 1*4,  MultipleShader::Position(),
                         MultipleShader::Normal(), MultipleShader::TextureCoordinates())
        .setIndexBuffer(indices, 2, Mesh::IndexType::UnsignedShort);

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(MultipleShader{},
        #ifndef MAGNUM_TARGET_GLES2
        RenderbufferFormat::RGBA8,
        #else
        RenderbufferFormat::RGBA4,
        #endif
        mesh).get<Color4ub>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, indexedResult);
}

#ifndef MAGNUM_TARGET_GLES
void MeshGLTest::setInstanceCountBaseInstance() {
    /* Verbatim copy of setInstanceCount() with additional extension check and
       setBaseInstance() call. It would just render three times the same
       value. I'm too lazy to invent proper test case, so I'll just check that
       it didn't generate any error and rendered something */

    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::draw_instanced>())
        CORRADE_SKIP(Extensions::GL::ARB::draw_instanced::string() + std::string(" is not available."));
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::base_instance>())
        CORRADE_SKIP(Extensions::GL::ARB::base_instance::string() + std::string(" is not available."));

    typedef Attribute<0, Float> Attribute;

    const Float data[] = { 0.0f, -0.7f, Math::normalize<Float, UnsignedByte>(96) };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(1)
        .setInstanceCount(3)
        .setBaseInstance(72)
        .addVertexBuffer(buffer, 4, Attribute());

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(FloatShader("float", "vec4(valueInterpolated, 0.0, 0.0, 0.0)"),
        RenderbufferFormat::RGBA8,
        mesh).get<UnsignedByte>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, 96);
}

void MeshGLTest::setInstanceCountBaseInstanceIndexed() {
    /* Verbatim copy of setInstanceCountIndexed() with additional extension
       check and setBaseInstance() call. It would just render three times the
       same value. I'm too lazy to invent proper test case, so I'll just check
       that it didn't generate any error and rendered something */

    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::draw_instanced>())
        CORRADE_SKIP(Extensions::GL::ARB::draw_instanced::string() + std::string(" is not available."));
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::base_instance>())
        CORRADE_SKIP(Extensions::GL::ARB::base_instance::string() + std::string(" is not available."));

    Buffer vertices;
    vertices.setData(indexedVertexData, BufferUsage::StaticDraw);

    constexpr UnsignedShort indexData[] = { 2, 1, 0 };
    Buffer indices{Buffer::TargetHint::ElementArray};
    indices.setData(indexData, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setInstanceCount(3)
        .setBaseInstance(72)
        .addVertexBuffer(vertices, 1*4,  MultipleShader::Position(),
                         MultipleShader::Normal(), MultipleShader::TextureCoordinates())
        .setIndexBuffer(indices, 2, Mesh::IndexType::UnsignedShort);

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(MultipleShader{}, RenderbufferFormat::RGBA8,
        mesh).get<Color4ub>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, indexedResult);
}

void MeshGLTest::setInstanceCountBaseVertex() {
    /* Verbatim copy of setBaseVertex() with additional extension check and
       setInstanceCount() call. It would just render three times the same
       value. I'm too lazy to invent proper test case, so I'll just check
       that it didn't generate any error and rendered something */

    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::draw_instanced>())
        CORRADE_SKIP(Extensions::GL::ARB::draw_instanced::string() + std::string(" is not available."));
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::draw_elements_base_vertex>())
        CORRADE_SKIP(Extensions::GL::ARB::draw_elements_base_vertex::string() + std::string(" is not available."));

    Buffer vertices;
    vertices.setData(indexedVertexDataBaseVertex, BufferUsage::StaticDraw);

    constexpr UnsignedShort indexData[] = { 2, 1, 0 };
    Buffer indices{Buffer::TargetHint::ElementArray};
    indices.setData(indexData, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(2)
        .setInstanceCount(3)
        .addVertexBuffer(vertices, 2*4,  MultipleShader::Position(),
                         MultipleShader::Normal(), MultipleShader::TextureCoordinates())
        .setIndexBuffer(indices, 2, Mesh::IndexType::UnsignedShort);

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(MultipleShader{}, RenderbufferFormat::RGBA8,
        mesh).get<Color4ub>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, indexedResult);
}

void MeshGLTest::setInstanceCountBaseVertexBaseInstance() {
    /* Verbatim copy of setInstanceCountBaseVertex() with added extension check
       and setBaseInstance() call. It would just render three times the same
       value. I'm too lazy to invent proper test case, so I'll just check
       that it didn't generate any error and rendered something */

    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::draw_instanced>())
        CORRADE_SKIP(Extensions::GL::ARB::draw_instanced::string() + std::string(" is not available."));
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::draw_elements_base_vertex>())
        CORRADE_SKIP(Extensions::GL::ARB::draw_elements_base_vertex::string() + std::string(" is not available."));
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::base_instance>())
        CORRADE_SKIP(Extensions::GL::ARB::base_instance::string() + std::string(" is not available."));

    Buffer vertices;
    vertices.setData(indexedVertexDataBaseVertex, BufferUsage::StaticDraw);

    constexpr UnsignedShort indexData[] = { 2, 1, 0 };
    Buffer indices{Buffer::TargetHint::ElementArray};
    indices.setData(indexData, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(2)
        .setInstanceCount(3)
        .setBaseInstance(72)
        .addVertexBuffer(vertices, 2*4,  MultipleShader::Position(),
                         MultipleShader::Normal(), MultipleShader::TextureCoordinates())
        .setIndexBuffer(indices, 2, Mesh::IndexType::UnsignedShort);

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(MultipleShader{}, RenderbufferFormat::RGBA8,
        mesh).get<Color4ub>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, indexedResult);
}
#endif

void MeshGLTest::addVertexBufferInstancedFloat() {
    #ifndef MAGNUM_TARGET_GLES
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::draw_instanced>())
        CORRADE_SKIP(Extensions::GL::ARB::draw_instanced::string() + std::string(" is not available."));
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::instanced_arrays>())
        CORRADE_SKIP(Extensions::GL::ARB::instanced_arrays::string() + std::string(" is not available."));
    #elif defined(MAGNUM_TARGET_GLES2)
    if(!Context::current()->isExtensionSupported<Extensions::GL::ANGLE::instanced_arrays>() && !Context::current()->isExtensionSupported<Extensions::GL::EXT::instanced_arrays>() && !Context::current()->isExtensionSupported<Extensions::GL::NV::instanced_arrays>())
        CORRADE_SKIP("Required instancing extension is not available.");
    if(!Context::current()->isExtensionSupported<Extensions::GL::ANGLE::instanced_arrays>() && !Context::current()->isExtensionSupported<Extensions::GL::EXT::draw_instanced>() && !Context::current()->isExtensionSupported<Extensions::GL::NV::draw_instanced>())
        CORRADE_SKIP("Required drawing extension is not available.");
    #endif

    typedef Attribute<0, Float> Attribute;

    const Float data[] = {
        0.0f,   /* Offset */
                /* Base vertex is ignored for instanced arrays */
        -0.7f,  /* First instance */
        0.3f,   /* Second instance */
        Math::normalize<Float, UnsignedByte>(96) /* Third instance */
    };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setInstanceCount(3)
        .addVertexBufferInstanced(buffer, 1, 4, Attribute{});

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(FloatShader("float", "vec4(valueInterpolated, 0.0, 0.0, 0.0)"),
        #ifndef MAGNUM_TARGET_GLES2
        RenderbufferFormat::RGBA8,
        #else
        RenderbufferFormat::RGBA4,
        #endif
        mesh).get<UnsignedByte>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, 96);
}

#ifndef MAGNUM_TARGET_GLES2
void MeshGLTest::addVertexBufferInstancedInteger() {
    #ifndef MAGNUM_TARGET_GLES
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::draw_instanced>())
        CORRADE_SKIP(Extensions::GL::ARB::draw_instanced::string() + std::string(" is not available."));
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::instanced_arrays>())
        CORRADE_SKIP(Extensions::GL::ARB::instanced_arrays::string() + std::string(" is not available."));
    if(!Context::current()->isExtensionSupported<Extensions::GL::EXT::gpu_shader4>())
        CORRADE_SKIP(Extensions::GL::EXT::gpu_shader4::string() + std::string(" is not available."));
    #endif

    typedef Attribute<0, UnsignedInt> Attribute;

    constexpr UnsignedInt data[] = {
        0,      /* Offset */
                /* Base vertex is ignored for instanced arrays */
        157,    /* First instance */
        25,     /* Second instance */
        35681   /* Third instance */
    };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setInstanceCount(3)
        .addVertexBufferInstanced(buffer, 1, 4, Attribute{});

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(IntegerShader("uint"), RenderbufferFormat::R32UI, mesh)
        .get<UnsignedInt>(ColorFormat::RedInteger, ColorType::UnsignedInt);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, 35681);
}
#endif

#ifndef MAGNUM_TARGET_GLES
void MeshGLTest::addVertexBufferInstancedDouble() {
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::draw_instanced>())
        CORRADE_SKIP(Extensions::GL::ARB::draw_instanced::string() + std::string(" is not available."));
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::instanced_arrays>())
        CORRADE_SKIP(Extensions::GL::ARB::instanced_arrays::string() + std::string(" is not available."));
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::vertex_attrib_64bit>())
        CORRADE_SKIP(Extensions::GL::ARB::vertex_attrib_64bit::string() + std::string(" is not available."));

    typedef Attribute<0, Double> Attribute;

    const Double data[] = {
        0.0,    /* Offset */
                /* Base vertex is ignored for instanced arrays */
        -0.7,   /* First instance */
        0.3,    /* Second instance */
        Math::normalize<Double, UnsignedShort>(45828) /* Third instance */
    };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setInstanceCount(3)
        .addVertexBufferInstanced(buffer, 1, 8, Attribute{});

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = Checker(DoubleShader("double", "float", "float(value)"),
        RenderbufferFormat::R16, mesh).get<UnsignedShort>(ColorFormat::Red, ColorType::UnsignedShort);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, 45828);
}
#endif

namespace {
    struct MultiChecker {
        MultiChecker(AbstractShaderProgram&& shader, Mesh& mesh);

        template<class T> T get(ColorFormat format, ColorType type);

        Renderbuffer renderbuffer;
        Framebuffer framebuffer;
    };
}

#ifndef DOXYGEN_GENERATING_OUTPUT
MultiChecker::MultiChecker(AbstractShaderProgram&& shader, Mesh& mesh): framebuffer({{}, Vector2i(1)}) {
    renderbuffer.setStorage(
        #ifndef MAGNUM_TARGET_GLES2
        RenderbufferFormat::RGBA8,
        #else
        RenderbufferFormat::RGBA4,
        #endif
        Vector2i(1));
    framebuffer.attachRenderbuffer(Framebuffer::ColorAttachment(0), renderbuffer);

    framebuffer.bind();
    mesh.setPrimitive(MeshPrimitive::Points)
        .setCount(2);

    /* Skip first vertex so we test also offsets */
    MeshView a(mesh);
    a.setCount(1)
     .setBaseVertex(mesh.baseVertex());

    MeshView b(mesh);
    b.setCount(1);
    if(mesh.isIndexed()) {
        b.setBaseVertex(mesh.baseVertex())
         .setIndexRange(1);
    } else b.setBaseVertex(1);

    MeshView::draw(shader, {a, b});
}

template<class T> T MultiChecker::get(ColorFormat format, ColorType type) {
    return framebuffer.read({{}, Vector2i{1}}, {format, type}).data<T>()[0];
}
#endif

void MeshGLTest::multiDraw() {
    #ifdef MAGNUM_TARGET_GLES
    if(!Context::current()->isExtensionSupported<Extensions::GL::EXT::multi_draw_arrays>())
        Debug() << Extensions::GL::EXT::multi_draw_arrays::string() << "not supported, using fallback implementation";
    #endif

    typedef Attribute<0, Float> Attribute;

    const Float data[] = { 0.0f, -0.7f, Math::normalize<Float, UnsignedByte>(96) };
    Buffer buffer;
    buffer.setData(data, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.addVertexBuffer(buffer, 4, Attribute());

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = MultiChecker(FloatShader("float", "vec4(valueInterpolated, 0.0, 0.0, 0.0)"),
        mesh).get<UnsignedByte>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, 96);
}

void MeshGLTest::multiDrawIndexed() {
    #ifdef MAGNUM_TARGET_GLES
    if(!Context::current()->isExtensionSupported<Extensions::GL::EXT::multi_draw_arrays>())
        Debug() << Extensions::GL::EXT::multi_draw_arrays::string() << "not supported, using fallback implementation";
    #endif

    Buffer vertices;
    vertices.setData(indexedVertexData, BufferUsage::StaticDraw);

    constexpr UnsignedShort indexData[] = { 2, 1, 0 };
    Buffer indices{Buffer::TargetHint::ElementArray};
    indices.setData(indexData, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.addVertexBuffer(vertices, 1*4,  MultipleShader::Position(),
                         MultipleShader::Normal(), MultipleShader::TextureCoordinates())
        .setIndexBuffer(indices, 2, Mesh::IndexType::UnsignedShort);

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = MultiChecker(MultipleShader{}, mesh).get<Color4ub>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, indexedResult);
}

#ifndef MAGNUM_TARGET_GLES
void MeshGLTest::multiDrawBaseVertex() {
    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::draw_elements_base_vertex>())
        CORRADE_SKIP(Extensions::GL::ARB::draw_elements_base_vertex::string() + std::string(" is not available."));

    Buffer vertices;
    vertices.setData(indexedVertexDataBaseVertex, BufferUsage::StaticDraw);

    constexpr UnsignedShort indexData[] = { 2, 1, 0 };
    Buffer indices{Buffer::TargetHint::ElementArray};
    indices.setData(indexData, BufferUsage::StaticDraw);

    Mesh mesh;
    mesh.setBaseVertex(2)
        .addVertexBuffer(vertices, 2*4,  MultipleShader::Position(),
                         MultipleShader::Normal(), MultipleShader::TextureCoordinates())
        .setIndexBuffer(indices, 2, Mesh::IndexType::UnsignedShort);

    MAGNUM_VERIFY_NO_ERROR();

    const auto value = MultiChecker(MultipleShader{}, mesh).get<Color4ub>(ColorFormat::RGBA, ColorType::UnsignedByte);

    MAGNUM_VERIFY_NO_ERROR();
    CORRADE_COMPARE(value, indexedResult);
}
#endif

}}

CORRADE_TEST_MAIN(Magnum::Test::MeshGLTest)