magnum/doc/snippets/MagnumTrade.cpp

/*
    This file is part of Magnum.

    Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019,
                2020 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 <unordered_map>
#include <Corrade/Containers/Optional.h>
#include <Corrade/Utility/Directory.h>
#include <Corrade/Utility/Resource.h>

#include "Magnum/FileCallback.h"
#include "Magnum/ImageView.h"
#include "Magnum/Mesh.h"
#include "Magnum/PixelFormat.h"
#include "Magnum/Animation/Player.h"
#include "Magnum/Math/Color.h"
#include "Magnum/Math/Swizzle.h"
#include "Magnum/MeshTools/Interleave.h"
#include "Magnum/MeshTools/Transform.h"
#include "Magnum/Trade/AbstractImporter.h"
#include "Magnum/Trade/AnimationData.h"
#include "Magnum/Trade/ImageData.h"
#include "Magnum/Trade/MaterialData.h"
#include "Magnum/Trade/MeshData.h"
#include "Magnum/Trade/ObjectData2D.h"
#include "Magnum/Trade/MeshObjectData3D.h"
#include "Magnum/Trade/PbrClearCoatMaterialData.h"
#include "Magnum/Trade/PbrSpecularGlossinessMaterialData.h"
#include "Magnum/Trade/PbrMetallicRoughnessMaterialData.h"
#include "Magnum/Trade/PhongMaterialData.h"
#ifdef MAGNUM_TARGET_GL
#include "Magnum/GL/Texture.h"
#include "Magnum/GL/Mesh.h"
#include "Magnum/MeshTools/Compile.h"
#include "Magnum/Shaders/Phong.h"
#endif
#ifdef MAGNUM_TARGET_VK
#include "Magnum/Vk/Vulkan.h"
#endif

#ifdef MAGNUM_BUILD_DEPRECATED
#define _MAGNUM_NO_DEPRECATED_MESHDATA /* So it doesn't yell here */

#include "Magnum/Trade/MeshData2D.h"
#include "Magnum/Trade/MeshData3D.h"
#endif

#define DOXYGEN_IGNORE(...) __VA_ARGS__

using namespace Magnum;
using namespace Magnum::Math::Literals;

int main() {

{
/* [AbstractImporter-usage] */
PluginManager::Manager<Trade::AbstractImporter> manager;
Containers::Pointer<Trade::AbstractImporter> importer =
    manager.loadAndInstantiate("AnyImageImporter");
if(!importer || !importer->openFile("image.png"))
    Fatal{} << "Can't open image.png with AnyImageImporter";

Containers::Optional<Trade::ImageData2D> image = importer->image2D(0);
if(!image) Fatal{} << "Importing the image failed";

// use the image ...
/* [AbstractImporter-usage] */
}

#if defined(CORRADE_TARGET_UNIX) || (defined(CORRADE_TARGET_WINDOWS) && !defined(CORRADE_TARGET_WINDOWS_RT))
{
Containers::Pointer<Trade::AbstractImporter> importer;
/* [AbstractImporter-usage-callbacks] */
struct Data {
    std::unordered_map<std::string,
        Containers::Array<const char, Utility::Directory::MapDeleter>> files;
} data;

importer->setFileCallback([](const std::string& filename,
    InputFileCallbackPolicy policy, Data& data)
        -> Containers::Optional<Containers::ArrayView<const char>>
    {
        auto found = data.files.find(filename);

        /* Discard the memory mapping, if not needed anymore */
        if(policy == InputFileCallbackPolicy::Close) {
            if(found != data.files.end()) data.files.erase(found);
            return {};
        }

        /* Load if not there yet */
        if(found == data.files.end()) found = data.files.emplace(
            filename, Utility::Directory::mapRead(filename)).first;

        return Containers::arrayView(found->second);
    }, data);

importer->openFile("scene.gltf"); // memory-maps all files
/* [AbstractImporter-usage-callbacks] */
}
#endif

{
Containers::Pointer<Trade::AbstractImporter> importer;
Int materialIndex;
/* [AbstractImporter-usage-cast] */
Containers::Pointer<Trade::ObjectData3D> data = importer->object3D(12);
if(data && data->instanceType() == Trade::ObjectInstanceType3D::Mesh) {
    auto& mesh = static_cast<Trade::MeshObjectData3D&>(*data);

    materialIndex = mesh.material();
    // ...
}
/* [AbstractImporter-usage-cast] */
static_cast<void>(materialIndex);
}

{
Containers::Pointer<Trade::AbstractImporter> importer;
/* [AbstractImporter-setFileCallback] */
importer->setFileCallback([](const std::string& filename,
    InputFileCallbackPolicy, void*) {
        Utility::Resource rs("data");
        return Containers::optional(rs.getRaw(filename));
    });
/* [AbstractImporter-setFileCallback] */
}

{
Containers::Pointer<Trade::AbstractImporter> importer;
/* [AbstractImporter-setFileCallback-template] */
struct Data {
    std::unordered_map<std::string, Containers::Array<char>> files;
} data;

importer->setFileCallback([](const std::string& filename,
    InputFileCallbackPolicy, Data& data)
        -> Containers::Optional<Containers::ArrayView<const char>>
    {
        auto found = data.files.find(filename);
        if(found == data.files.end()) {
            if(!Utility::Directory::exists(filename))
                return Containers::NullOpt;
            found = data.files.emplace(filename, Utility::Directory::read(filename)).first;
        }
        return Containers::ArrayView<const char>{found->second};
    }, data);
/* [AbstractImporter-setFileCallback-template] */
}

{
UnsignedInt id{};
Containers::Pointer<Trade::AbstractImporter> importer;
/* [AnimationData-usage] */

Containers::Optional<Trade::AnimationData> data = importer->animation(id);

Animation::Player<Float> player;
Containers::Array<Vector3> positions; /* Translations for all objects */
for(UnsignedInt i = 0; i != data->trackCount(); ++i) {
    if(data->trackTargetType(i) == Trade::AnimationTrackTargetType::Translation3D) {
        CORRADE_INTERNAL_ASSERT(data->trackType(i) ==
            Trade::AnimationTrackType::Vector3);
        player.add(data->track<Vector3>(i), positions[data->trackTarget(i)]);
    }

    // similarly for rotation / scaling ...
}

Containers::Array<char> animationData = data->release(); /* Take ownership */
/* [AnimationData-usage] */
}

{
Trade::AnimationData data{nullptr, {}};
/* [AnimationData-usage-mutable] */
for(UnsignedInt i = 0; i != data.trackCount(); ++i) {
    if(data.trackTargetType(i) != Trade::AnimationTrackTargetType::Translation3D)
        continue;
    /* Check prerequisites */
    if(!(data.dataFlags() & Trade::DataFlag::Mutable) ||
       data.trackType(i) != Trade::AnimationTrackType::Vector2)
        Fatal{} << "Oops";

    MeshTools::transformVectorsInPlace(Matrix4::scaling(Vector3::yScale(-1.0f)),
        data.mutableTrack<Vector3>(i).values());
}
/* [AnimationData-usage-mutable] */
}

{
/* [ImageData-construction] */
Containers::Array<char> data;
Trade::ImageData2D image{PixelFormat::RGB8Unorm, {32, 32}, std::move(data)};
/* [ImageData-construction] */
}

{
/* [ImageData-construction-compressed] */
Containers::Array<char> data;
Trade::ImageData2D image{CompressedPixelFormat::Bc1RGBUnorm,
    {32, 32}, std::move(data)};
/* [ImageData-construction-compressed] */
}

#ifdef MAGNUM_TARGET_GL
{
/* [ImageData-usage] */
Containers::Pointer<Trade::AbstractImporter> importer;
Containers::Optional<Trade::ImageData2D> image = importer->image2D(0);
if(!image) Fatal{} << "Oopsie!";

GL::Texture2D texture;
// ...
if(!image->isCompressed())
    texture.setSubImage(0, {}, *image);
else
    texture.setCompressedSubImage(0, {}, *image);
/* [ImageData-usage] */
}
#endif

{
Trade::ImageData2D data{PixelFormat::RGB8Unorm, {}, nullptr};
/* [ImageData-usage-mutable] */
if(data.isCompressed() ||
   data.format() != PixelFormat::RGB8Unorm ||
   !(data.dataFlags() & Trade::DataFlag::Mutable))
    Fatal{} << ":(";

for(auto&& row: data.mutablePixels<Color3ub>())
    for(Color3ub& pixel: row)
        pixel = Math::gather<'b', 'g', 'r'>(pixel);
/* [ImageData-usage-mutable] */
}

{
/* [MaterialAttributeData-name] */
Trade::MaterialAttributeData a{
    Trade::MaterialAttribute::DiffuseColor, 0x3bd267ff_rgbaf};
Trade::MaterialAttributeData b{"DiffuseColor", 0x3bd267ff_rgbaf};
/* [MaterialAttributeData-name] */
}

{
/* [MaterialData-usage] */
Trade::MaterialData data = DOXYGEN_IGNORE(Trade::MaterialData{{}, {}});

// Assumes the attribute exists
Float roughness = data.attribute<Float>(Trade::MaterialAttribute::Roughness);

// Optional access
Color4 color = data.attributeOr(Trade::MaterialAttribute::BaseColor,
                                0x3bd267ff_rgbaf);
if(Containers::Optional<UnsignedInt> texture =
   data.tryAttribute<UnsignedInt>(Trade::MaterialAttribute::BaseColorTexture))
{
    // ...
}
/* [MaterialData-usage] */
static_cast<void>(roughness);
static_cast<void>(color);
}

{
Trade::MaterialData data{{}, {}};
/* [MaterialData-usage-types] */
/* Prefer a specular/roughness workflow, if present */
if(data.types() & Trade::MaterialType::PbrSpecularGlossiness) {
    const auto& pbr = data.as<Trade::PbrSpecularGlossinessMaterialData>();

    Color4 diffuse = pbr.diffuseColor();
    Color4 specular = pbr.specularColor();
    Float glossiness = pbr.glossiness();

    DOXYGEN_IGNORE(static_cast<void>(diffuse), static_cast<void>(specular), static_cast<void>(glossiness);)

/* Otherwise use metallic/roughness (or defaults if no attributes present) */
} else {
    const auto& pbr = data.as<Trade::PbrMetallicRoughnessMaterialData>();

    Color4 base = pbr.baseColor();
    Float metalness = pbr.metalness();
    Float roughness = pbr.roughness();

    DOXYGEN_IGNORE(static_cast<void>(base), static_cast<void>(metalness), static_cast<void>(roughness);)
}
/* [MaterialData-usage-types] */
}

{
/* [MaterialData-usage-packing] */
Trade::PbrMetallicRoughnessMaterialData data = DOXYGEN_IGNORE(Trade::PbrMetallicRoughnessMaterialData{{}, {}});

/* Use a shader that accepts a single packed metallic/roughness texture.
   Querying any texture attributes will give the same values for both metalness
   and roughness. */
if(data.hasMetallicRoughnessTexture()) {
    UnsignedInt metallicRoughness = data.metalnessTexture();

    DOXYGEN_IGNORE(static_cast<void>(metallicRoughness);)

/* Supply texture channels separately */
} else {
    UnsignedInt metalness = data.metalnessTexture();
    UnsignedInt roughness = data.roughnessTexture();
    Trade::MaterialTextureSwizzle metalnessSwizzle = data.metalnessTextureSwizzle();
    Trade::MaterialTextureSwizzle roughnessSwizzle = data.roughnessTextureSwizzle();

    DOXYGEN_IGNORE(static_cast<void>(metalness), static_cast<void>(roughness), static_cast<void>(metalnessSwizzle), static_cast<void>(roughnessSwizzle);)
}
/* [MaterialData-usage-packing] */
}

{
Trade::MaterialData data{{}, {}};
/* [MaterialData-usage-layers] */
if(data.hasLayer(Trade::MaterialLayer::ClearCoat)) {
    Float clearCoatFactor = data.attributeOr(Trade::MaterialLayer::ClearCoat,
        Trade::MaterialAttribute::LayerFactor, 1.0f);
    Float clearCoatRoughness = data.attributeOr(Trade::MaterialLayer::ClearCoat,
        Trade::MaterialAttribute::Roughness, 0.0f);

    DOXYGEN_IGNORE(static_cast<void>(clearCoatFactor), static_cast<void>(clearCoatRoughness);)
}
/* [MaterialData-usage-layers] */
}

{
Trade::MaterialData data{{}, {}};
/* [MaterialData-usage-layers-types] */
if(data.types() & Trade::MaterialType::PbrClearCoat) {
    const auto& clearCoat = data.as<Trade::PbrClearCoatMaterialData>();

    Float clearCoatFactor = clearCoat.layerFactor();
    Float clearCoatRoughness = clearCoat.roughness();

    DOXYGEN_IGNORE(static_cast<void>(clearCoatFactor), static_cast<void>(clearCoatRoughness);)
}
/* [MaterialData-usage-layers-types] */
}

{
/* [MaterialData-populating] */
Trade::MaterialData data{Trade::MaterialType::PbrMetallicRoughness, {
    {Trade::MaterialAttribute::DoubleSided, true},
    {Trade::MaterialAttribute::BaseColor, 0x3bd267ff_srgbaf},
    {Trade::MaterialAttribute::BaseColorTexture, 17u},
    {Trade::MaterialAttribute::TextureMatrix, Matrix3::scaling({0.5f, 1.0f})}
}};
/* [MaterialData-populating] */
}

{
/* [MaterialData-populating-non-owned] */
using namespace Containers::Literals;

constexpr Trade::MaterialAttributeData attributes[]{
    {"DoubleSided"_s, true},
    {"BaseColor"_s, Color4{0.043735f, 0.64448f, 0.135633f, 1.0f}},
    {"BaseColorTexture"_s, 5u},
    {"TextureMatrix"_s, Matrix3{{0.5f, 0.0f, 0.0f},
                                {0.0f, 1.0f, 0.0f},
                                {0.0f, 0.0f, 1.0f}}}
};

Trade::MaterialData data{Trade::MaterialType::Phong, {}, attributes};
/* [MaterialData-populating-non-owned] */
}

#ifdef MAGNUM_TARGET_GL
{
GL::Texture2D baseColorTexture;
/* [MaterialData-populating-custom] */
Trade::MaterialData data{Trade::MaterialType::PbrMetallicRoughness, {
    {Trade::MaterialAttribute::BaseColor, 0x3bd267ff_srgbaf},
    {Trade::MaterialAttribute::TextureMatrix, Matrix3::scaling({0.5f, 1.0f})},
    {"baseColorTexturePointer", &baseColorTexture},
    {"highlightColor", 0x00ffff_srgbf},
    {"name", "Canary Green Plastic, really ugly"}
}};

// Retrieving the texture pointer
GL::Texture2D* texture = data.attribute<GL::Texture2D*>("baseColorTexturePointer");
/* [MaterialData-populating-custom] */
static_cast<void>(texture);
}
#endif

{
/* [MaterialData-populating-layers] */
Trade::MaterialData data{
    Trade::MaterialType::PbrMetallicRoughness|Trade::MaterialType::PbrClearCoat,
    {
        {Trade::MaterialAttribute::BaseColor, 0xffcc33_srgbf},
        {Trade::MaterialAttribute::MetallicRoughnessTexture, 0u},

        {Trade::MaterialLayer::ClearCoat},
        {Trade::MaterialAttribute::LayerFactorTexture, 1u},
        {Trade::MaterialAttribute::RoughnessTexture,  1u},
        {Trade::MaterialAttribute::RoughnessTextureSwizzle,
            Trade::MaterialTextureSwizzle::G}
    },

    {2, 6}
};
/* [MaterialData-populating-layers] */
}

{
UnsignedInt a, b, c, d, sandTile, grassTile, rockTile;
/* [MaterialData-populating-layers-custom] */
Trade::MaterialData proceduralLandscape{
    Trade::MaterialTypes{}, // Doesn't match any builtin material type
    {
        // Rock layer
        {Trade::MaterialAttribute::LayerFactorTexture, a},
        {Trade::MaterialAttribute::BaseColorTexture, rockTile},

        // Sand layer
        {Trade::MaterialAttribute::LayerFactorTexture, b},
        {"blendType", "mix"},
        {Trade::MaterialAttribute::BaseColorTexture, sandTile},

        // Grass layer
        {Trade::MaterialAttribute::LayerFactorTexture, c},
        {"blendType", "overlay"},
        {"strandLengthTexture", d},
        {Trade::MaterialAttribute::BaseColorTexture, grassTile},
    },

    // There's no base material, everything is in layers
    {0, 2, 5, 9}
};
/* [MaterialData-populating-layers-custom] */
}

{
/* [MeshIndexData-usage] */
Containers::ArrayView<const UnsignedShort> indices;

Trade::MeshIndexData data{indices};
/* [MeshIndexData-usage] */
}

{
Vector3 normal;
Vector4 tangent;
/* [MeshAttribute-bitangent-from-tangent] */
Vector3 bitangent = Math::cross(normal, tangent.xyz())*tangent.w();
/* [MeshAttribute-bitangent-from-tangent] */
static_cast<void>(bitangent);
}

{
/* [MeshAttributeData-usage] */
Containers::StridedArrayView1D<const Vector3> positions;

Trade::MeshAttributeData data{Trade::MeshAttribute::Position, positions};
/* [MeshAttributeData-usage] */
}

{
/* [MeshAttributeData-usage-offset-only] */
struct Vertex {
    Vector3 position;
    Vector4 color;
};

/* Layout defined statically, 15 vertices in total */
constexpr Trade::MeshAttributeData positions{Trade::MeshAttribute::Position,
    VertexFormat::Vector3, offsetof(Vertex, position), 15, sizeof(Vertex)};
constexpr Trade::MeshAttributeData colors{Trade::MeshAttribute::Color,
    VertexFormat::Vector4, offsetof(Vertex, color), 15, sizeof(Vertex)};

/* Actual data populated later */
Containers::Array<char> vertexData{15*sizeof(Vertex)};
// ...
Trade::MeshData{MeshPrimitive::Triangles, std::move(vertexData),
    {positions, colors}};
/* [MeshAttributeData-usage-offset-only] */
}

#ifdef MAGNUM_TARGET_VK
{
Containers::StridedArrayView1D<const void> data;
/* [MeshAttributeData-custom-vertex-format] */
Trade::MeshAttributeData normals{Trade::MeshAttribute::Normal,
    vertexFormatWrap(VK_FORMAT_B10G11R11_UFLOAT_PACK32),
    data};
/* [MeshAttributeData-custom-vertex-format] */
}
#endif

#ifdef MAGNUM_TARGET_GL
{
Trade::MeshData data{MeshPrimitive::Points, 0};
/* [MeshData-usage] */
/* Check that we have at least positions and normals */
GL::Mesh mesh{data.primitive()};
if(!data.hasAttribute(Trade::MeshAttribute::Position) ||
   !data.hasAttribute(Trade::MeshAttribute::Normal))
    Fatal{} << "Oh well";

/* Interleave vertex data */
GL::Buffer vertices;
vertices.setData(MeshTools::interleave(data.positions3DAsArray(),
                                       data.normalsAsArray()));
mesh.addVertexBuffer(std::move(vertices), 0,
    Shaders::Phong::Position{}, Shaders::Phong::Normal{});

/* Set up an index buffer, if the mesh is indexed*/
if(data.isIndexed()) {
    GL::Buffer indices;
    indices.setData(data.indicesAsArray());
    mesh.setIndexBuffer(std::move(indices), 0, MeshIndexType::UnsignedInt)
        .setCount(data.indexCount());
} else mesh.setCount(data.vertexCount());
/* [MeshData-usage] */
}

{
Trade::MeshData data{MeshPrimitive::Points, 0};
GL::Mesh mesh{data.primitive()};
/* [MeshData-usage-advanced] */
/* Upload the original packed vertex data */
GL::Buffer vertices;
vertices.setData(data.vertexData());

/* Set up the position and normal attributes */
mesh.addVertexBuffer(vertices,
    data.attributeOffset(Trade::MeshAttribute::Position),
    data.attributeStride(Trade::MeshAttribute::Position),
    GL::DynamicAttribute{Shaders::Phong::Position{},
        data.attributeFormat(Trade::MeshAttribute::Position)});
mesh.addVertexBuffer(vertices,
    data.attributeOffset(Trade::MeshAttribute::Normal),
    data.attributeStride(Trade::MeshAttribute::Normal),
    GL::DynamicAttribute{Shaders::Phong::Normal{},
        data.attributeFormat(Trade::MeshAttribute::Normal)});

// Set up other attributes ...

/* Upload the original packed index data */
if(data.isIndexed()) {
    GL::Buffer indices;
    indices.setData(data.indexData());
    mesh.setIndexBuffer(std::move(indices), 0, data.indexType())
        .setCount(data.indexCount());
} else mesh.setCount(data.vertexCount());
/* [MeshData-usage-advanced] */
}

{
Trade::MeshData data{MeshPrimitive::Points, 0};
/* [MeshData-usage-compile] */
GL::Mesh mesh = MeshTools::compile(data);
/* [MeshData-usage-compile] */
}
#endif

{
Trade::MeshData data{MeshPrimitive::Points, 0};
/* [MeshData-usage-mutable] */
/* Check prerequisites */
if(!(data.vertexDataFlags() & Trade::DataFlag::Mutable) ||
   !data.hasAttribute(Trade::MeshAttribute::Position) ||
   data.attributeFormat(Trade::MeshAttribute::Position) != VertexFormat::Vector3)
    Fatal{} << "Oh well";

/* Scale the mesh two times */
MeshTools::transformPointsInPlace(Matrix4::scaling(Vector3{2.0f}),
    data.mutableAttribute<Vector3>(Trade::MeshAttribute::Position));
/* [MeshData-usage-mutable] */
}

{
std::size_t vertexCount{}, indexCount{};
/* [MeshData-populating] */
struct Vertex {
    Vector3 position;
    Vector4 color;
};

Containers::Array<char> indexData{indexCount*sizeof(UnsignedShort)};
Containers::Array<char> vertexData{vertexCount*sizeof(Vertex)};
// …
auto vertices = Containers::arrayCast<const Vertex>(vertexData);
auto indices = Containers::arrayCast<const UnsignedShort>(indexData);

Trade::MeshData data{MeshPrimitive::Triangles,
    std::move(indexData), Trade::MeshIndexData{indices},
    std::move(vertexData), {
        Trade::MeshAttributeData{Trade::MeshAttribute::Position,
            Containers::StridedArrayView1D<const Vector3>{vertices,
                &vertices[0].position, vertexCount, sizeof(Vertex)}},
        Trade::MeshAttributeData{Trade::MeshAttribute::Color,
            Containers::StridedArrayView1D<const Vector4>{vertices,
                &vertices[0].color, vertexCount, sizeof(Vertex)}}
    }};
/* [MeshData-populating] */
}

{
struct Vertex {
    Vector3 position;
    Vector4 color;
};
/* [MeshData-populating-non-owned] */
const UnsignedShort indices[] {
    0, 1, 2,
    2, 1, 3,
    3, 4, 5,
    5, 4, 6
};
Vertex vertices[7];

Trade::MeshData data{MeshPrimitive::Triangles,
    Trade::DataFlags{}, indices, Trade::MeshIndexData{indices},
    Trade::DataFlag::Mutable, vertices, {
        Trade::MeshAttributeData{Trade::MeshAttribute::Position,
            Containers::StridedArrayView1D<const Vector3>{
                Containers::arrayView(vertices), &vertices[0].position,
                Containers::arraySize(vertices), sizeof(Vertex)}},
        Trade::MeshAttributeData{Trade::MeshAttribute::Color,
            Containers::StridedArrayView1D<const Vector4>{
                Containers::arrayView(vertices), &vertices[0].color,
                Containers::arraySize(vertices), sizeof(Vertex)}}
    }};
/* [MeshData-populating-non-owned] */
}

{
/* [MeshData-populating-custom] */
/* Each face can consist of 15 triangles at most, triangleCount says how many
   indices in triangleIds are valid */
struct Face {
    UnsignedShort triangleIds[15];
    UnsignedByte triangleCount;
};

constexpr Trade::MeshAttribute TriangleIds = Trade::meshAttributeCustom(0x01);
constexpr Trade::MeshAttribute TriangleCount = Trade::meshAttributeCustom(0x02);

Containers::Array<char> vertexData;
auto faces = Containers::arrayCast<const Face>(vertexData);

Trade::MeshData data{MeshPrimitive::Faces, std::move(vertexData), {
    Trade::MeshAttributeData{TriangleIds,
        Containers::StridedArrayView2D<const UnsignedShort>{faces,
            &faces[0].triangleIds[0],
            {faces.size(), 15},
            {sizeof(Face), sizeof(UnsignedShort)}}},
    Trade::MeshAttributeData{TriangleCount,
        Containers::StridedArrayView1D<const UnsignedByte>{faces,
            &faces[0].triangleCount, faces.size(), sizeof(Face)}}
}};
/* [MeshData-populating-custom] */

/* [MeshData-populating-custom-retrieve] */
Containers::StridedArrayView2D<const UnsignedShort> triangleIds =
    data.attribute<UnsignedShort[]>(TriangleIds);
Containers::StridedArrayView1D<const UnsignedByte> triangleCounts =
    data.attribute<UnsignedByte>(TriangleCount);
/* [MeshData-populating-custom-retrieve] */
static_cast<void>(triangleIds);
static_cast<void>(triangleCounts);
}

#ifdef MAGNUM_BUILD_DEPRECATED
{
CORRADE_IGNORE_DEPRECATED_PUSH
Trade::MeshData2D& foo();
Trade::MeshData2D& data = foo();
/* [MeshData2D-transform] */
Matrix3 transformation =
    Matrix3::translation({3.0f, -2.0f})*
    Matrix3::scaling(Vector2{2.0f})*
    Matrix3::rotation(45.0_degf);
MeshTools::transformPointsInPlace(transformation, data.positions(0));
/* [MeshData2D-transform] */
CORRADE_IGNORE_DEPRECATED_POP
}
#endif

{
Trade::ObjectData2D& baz();
Trade::ObjectData2D& data = baz();
/* [ObjectData2D-transformation] */
Matrix3 transformation =
    Matrix3::from(data.rotation().toMatrix(), data.translation())*
    Matrix3::scaling(data.scaling());
/* [ObjectData2D-transformation] */
static_cast<void>(transformation);
}

#ifdef MAGNUM_BUILD_DEPRECATED
{
CORRADE_IGNORE_DEPRECATED_PUSH
Trade::MeshData3D& bar();
Trade::MeshData3D& data = bar();
/* [MeshData3D-transform] */
Matrix4 transformation =
    Matrix4::translation({3.0f, 1.5f, -2.0f})*
    Matrix4::rotationX(45.0_degf);
MeshTools::transformPointsInPlace(transformation, data.positions(0));
MeshTools::transformVectorsInPlace(transformation, data.normals(0));
/* [MeshData3D-transform] */
CORRADE_IGNORE_DEPRECATED_POP
}
#endif

{
Trade::ObjectData3D& fizz();
Trade::ObjectData3D& data = fizz();
/* [ObjectData3D-transformation] */
Matrix4 transformation =
    Matrix4::from(data.rotation().toMatrix(), data.translation())*
    Matrix4::scaling(data.scaling());
/* [ObjectData3D-transformation] */
static_cast<void>(transformation);
}

}