Support for indexed primitive queries.

Amazing how it all still fits my original design without needing to
rewrite half of the API.

doc/opengl-mapping.dox

@@ -52,7 +52,7 @@ OpenGL function                         | Matching API
 --------------------------------------- | ------------
 @fn_gl{BeginConditionalRender}, `glEndConditionalRender()` | @ref SampleQuery::beginConditionalRender(), \n @ref SampleQuery::endConditionalRender()
 @fn_gl{BeginQuery}, `glEndQuery()`      | @ref PrimitiveQuery::begin(), \n @ref SampleQuery::begin(), \n @ref TimeQuery::begin(), \n @ref AbstractQuery::end()
-@fn_gl{BeginQueryIndexed}, `glEndQueryIndexed()` | |
+@fn_gl{BeginQueryIndexed}, `glEndQueryIndexed()` | @ref PrimitiveQuery::begin(UnsignedInt), \n @ref PrimitiveQuery::end()
 @fn_gl{BeginTransformFeedback}, `glEndTransformFeedback()` | @ref TransformFeedback::begin(), @ref TransformFeedback::end()
 @fn_gl{BindAttribLocation}              | @ref AbstractShaderProgram::bindAttributeLocation()
 @fn_gl{BindBuffer}                      | not needed, handled internally in @ref Buffer and elsewhere

doc/opengl-support.dox

@@ -132,7 +132,7 @@ GLSL 4.00                                   | done
 @extension{ARB,tessellation_shader}         | missing some limit queries and patch parameter specification function
 @extension{ARB,texture_buffer_object_rgb32} | done
 @extension{ARB,transform_feedback2}         | missing transform feedback draw
-@extension{ARB,transform_feedback3}         | only advanced interleaving
+@extension{ARB,transform_feedback3}         | missing indexed properties query
 
 @subsection opengl-support-41 OpenGL 4.1
 

src/Magnum/AbstractQuery.h

@@ -183,6 +183,9 @@ class MAGNUM_EXPORT AbstractQuery: public AbstractObject {
         void begin(GLenum target);
         #endif
 
+        GLuint _id;
+        GLenum _target;
+
     private:
         #ifndef MAGNUM_TARGET_WEBGL
         AbstractQuery& setLabelInternal(Containers::ArrayView<const char> label);
@@ -193,8 +196,6 @@ class MAGNUM_EXPORT AbstractQuery: public AbstractObject {
         void MAGNUM_LOCAL createImplementationDSA();
         #endif
 
-        GLuint _id;
-        GLenum _target;
         ObjectFlags _flags;
 };
 

src/Magnum/CMakeLists.txt

@@ -151,6 +151,7 @@ endif()
 if(NOT TARGET_GLES2)
     list(APPEND Magnum_SRCS
         BufferImage.cpp
+        PrimitiveQuery.cpp
         TextureArray.cpp
         TransformFeedback.cpp
 

src/Magnum/PrimitiveQuery.cpp

@@ -0,0 +1,69 @@
+/*
+    This file is part of Magnum.
+
+    Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016
+              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 "PrimitiveQuery.h"
+
+namespace Magnum {
+
+void PrimitiveQuery::begin() {
+    #ifndef MAGNUM_TARGET_GLES
+    _index = 0;
+    #endif
+    AbstractQuery::begin();
+}
+
+#ifdef MAGNUM_BUILD_DEPRECATED
+void PrimitiveQuery::begin(const Target target) {
+    #ifndef MAGNUM_TARGET_GLES
+    _index = 0;
+    #endif
+    AbstractQuery::begin(GLenum(target));
+}
+#endif
+
+#ifndef MAGNUM_TARGET_GLES
+void PrimitiveQuery::begin(const UnsignedInt index) {
+    #ifdef MAGNUM_BUILD_DEPRECATED
+    CORRADE_INTERNAL_ASSERT(_target);
+    #endif
+
+    glBeginQueryIndexed(_target, _index = index, _id);
+}
+#endif
+
+void PrimitiveQuery::end() {
+    #ifdef MAGNUM_BUILD_DEPRECATED
+    CORRADE_INTERNAL_ASSERT(_target);
+    #endif
+
+    #ifndef MAGNUM_TARGET_GLES
+    if(!_index) glEndQuery(_target);
+    else glEndQueryIndexed(_target, _index);
+    #else
+    AbstractQuery::end();
+    #endif
+}
+
+}

src/Magnum/PrimitiveQuery.h

@@ -63,18 +63,19 @@ UnsignedInt primitiveCount = q.result<UnsignedInt>();
 @requires_gl30 Extension @extension{EXT,transform_feedback}
 @requires_gles30 Only sample queries are available in OpenGL ES 2.0.
 @requires_webgl20 Queries are not available in WebGL 1.0.
-@todo glBeginQueryIndexed
 @todo @extension{ARB,transform_feedback_overflow_query}
 */
-class PrimitiveQuery: public AbstractQuery {
+class MAGNUM_EXPORT PrimitiveQuery: public AbstractQuery {
     public:
         /** @brief Query target */
         enum class Target: GLenum {
             #ifndef MAGNUM_TARGET_GLES2
             /**
              * Count of primitives generated from vertex shader or geometry
-             * shader. Use @ref result<UnsignedInt>() or @ref result<Int>() to
-             * retrieve the result.
+             * shader. When used with @ref begin(UnsignedInt), the index must
+             * be lower than @ref TransformFeedback::maxVertexStreams(). Use
+             * @ref result<UnsignedInt>() or @ref result<Int>() to retrieve the
+             * result.
              * @requires_gles30 Not defined in OpenGL ES 2.0.
              * @requires_es_extension Extension @es_extension{ANDROID,extension_pack_es31a}/
              *      @es_extension{EXT,geometry_shader}
@@ -88,7 +89,9 @@ class PrimitiveQuery: public AbstractQuery {
             #endif
 
             /**
-             * Count of primitives written to transform feedback buffer. Use
+             * Count of primitives written to transform feedback buffer. When
+             * used with @ref begin(UnsignedInt), the index must be lower than
+             * @ref TransformFeedback::maxVertexStreams(). Use
              * @ref result<UnsignedInt>() or @ref result<Int>() to retrieve the
              * result.
              */
@@ -140,18 +143,49 @@ class PrimitiveQuery: public AbstractQuery {
          */
         explicit PrimitiveQuery(NoCreateT) noexcept: AbstractQuery{NoCreate, GLenum(Target::TransformFeedbackPrimitivesWritten)} {}
 
+        /**
+         * @brief Begin query
+         *
+         * Begins counting until @ref end() is called. Equivalent to calling
+         * @ref begin(UnsignedInt) with @p index set to `0`.
+         * @see @fn_gl{BeginQuery}
+         */
+        void begin();
+
         #ifdef MAGNUM_BUILD_DEPRECATED
         /**
-         * @copybrief AbstractQuery::begin()
+         * @copybrief begin()
          * @deprecated Use @ref begin() instead.
          */
-        CORRADE_DEPRECATED("use begin() instead") void begin(Target target) {
-            AbstractQuery::begin(GLenum(target));
-        }
+        CORRADE_DEPRECATED("use begin() instead") void begin(Target target);
+        #endif
 
-        using AbstractQuery::begin;
+        #ifndef MAGNUM_TARGET_GLES
+        /**
+         * @brief Begin indexed query
+         *
+         * Begins counting until @ref end() is called.
+         * @see @fn_gl{BeginQueryIndexed}
+         * @requires_gl40 Extension @extension{ARB,transform_feedback3}
+         * @requires_gl Indexed queries are not available in OpenGL ES or WebGL.
+         */
+        void begin(UnsignedInt index);
         #endif
 
+        /**
+         * @brief End query
+         *
+         * Ends the non-indexed or indexed query started with @ref begin() or
+         * @ref begin(UnsignedInt). The result can be then retrieved by calling
+         * @ref result().
+         * @see @fn_gl{EndQuery}, @fn_gl2{EndQueryIndexed,BeginQueryIndexed}
+         * @requires_gl40 Extension @extension{ARB,transform_feedback3} for
+         *      indexed queries
+         * @requires_gl Indexed queries are not available in OpenGL ES or
+         *      WebGL.
+         */
+        void end();
+
         /* Overloads to remove WTF-factor from method chaining order */
         #if !defined(DOXYGEN_GENERATING_OUTPUT) && !defined(MAGNUM_TARGET_WEBGL)
         PrimitiveQuery& setLabel(const std::string& label) {
@@ -166,6 +200,10 @@ class PrimitiveQuery: public AbstractQuery {
 
     private:
         explicit PrimitiveQuery(GLuint id, Target target, ObjectFlags flags) noexcept: AbstractQuery{id, GLenum(target), flags} {}
+
+        #ifndef MAGNUM_TARGET_GLES
+        GLuint _index{};
+        #endif
 };
 
 }

src/Magnum/Test/PrimitiveQueryGLTest.cpp

@@ -48,6 +48,7 @@ struct PrimitiveQueryGLTest: AbstractOpenGLTester {
 
     #ifndef MAGNUM_TARGET_GLES
     void primitivesGenerated();
+    void primitivesGeneratedIndexed();
     #endif
     void transformFeedbackPrimitivesWritten();
 };
@@ -58,6 +59,7 @@ PrimitiveQueryGLTest::PrimitiveQueryGLTest() {
 
               #ifndef MAGNUM_TARGET_GLES
               &PrimitiveQueryGLTest::primitivesGenerated,
+              &PrimitiveQueryGLTest::primitivesGeneratedIndexed,
               #endif
               &PrimitiveQueryGLTest::transformFeedbackPrimitivesWritten});
 }
@@ -158,6 +160,67 @@ void PrimitiveQueryGLTest::primitivesGenerated() {
     CORRADE_VERIFY(availableAfter);
     CORRADE_COMPARE(count, 3);
 }
+
+void PrimitiveQueryGLTest::primitivesGeneratedIndexed() {
+    if(!Context::current().isExtensionSupported<Extensions::GL::ARB::transform_feedback3>())
+        CORRADE_SKIP(Extensions::GL::ARB::transform_feedback3::string() + std::string(" is not available."));
+
+    /* Bind some FB to avoid errors on contexts w/o default FB */
+    Renderbuffer color;
+    color.setStorage(RenderbufferFormat::RGBA8, Vector2i{32});
+    Framebuffer fb{{{}, Vector2i{32}}};
+    fb.attachRenderbuffer(Framebuffer::ColorAttachment{0}, color)
+      .bind();
+
+    struct MyShader: AbstractShaderProgram {
+        typedef Attribute<0, Vector2> Position;
+
+        explicit MyShader() {
+            Shader vert(
+                #ifndef CORRADE_TARGET_APPLE
+                Version::GL210
+                #else
+                Version::GL310
+                #endif
+                , Shader::Type::Vertex);
+
+            CORRADE_INTERNAL_ASSERT_OUTPUT(vert.addSource(
+                "#if __VERSION__ >= 130\n"
+                "#define attribute in\n"
+                "#endif\n"
+                "attribute vec4 position;\n"
+                "void main() {\n"
+                "    gl_Position = position;\n"
+                "}\n").compile());
+
+            attachShader(vert);
+            bindAttributeLocation(Position::Location, "position");
+            CORRADE_INTERNAL_ASSERT_OUTPUT(link());
+        }
+    } shader;
+
+    Buffer vertices;
+    vertices.setData({nullptr, 9*sizeof(Vector2)}, BufferUsage::StaticDraw);
+
+    Mesh mesh;
+    mesh.setPrimitive(MeshPrimitive::Triangles)
+        .setCount(9)
+        .addVertexBuffer(vertices, 0, MyShader::Position());
+
+    MAGNUM_VERIFY_NO_ERROR();
+
+    PrimitiveQuery q{PrimitiveQuery::Target::PrimitivesGenerated};
+    q.begin(0);
+
+    Renderer::enable(Renderer::Feature::RasterizerDiscard);
+    mesh.draw(shader);
+
+    q.end();
+    const UnsignedInt count = q.result<UnsignedInt>();
+
+    MAGNUM_VERIFY_NO_ERROR();
+    CORRADE_COMPARE(count, 3);
+}
 #endif
 
 void PrimitiveQueryGLTest::transformFeedbackPrimitivesWritten() {