GL: remove one function pointer indirection for certain glDraw calls.

The extension-epcific code paths can reference the GL APIs directly, no
need to go through another function.

src/Magnum/GL/Implementation/MeshState.cpp

@@ -159,8 +159,8 @@ MeshState::MeshState(Context& context, ContextState& contextState, std::vector<s
     if(context.isExtensionSupported<Extensions::ANGLE::instanced_arrays>()) {
         extensions.push_back(Extensions::ANGLE::instanced_arrays::string());
 
-        drawArraysInstancedImplementation = &Mesh::drawArraysInstancedImplementationANGLE;
+        drawArraysInstancedImplementation = glDrawArraysInstancedANGLE;
-        drawElementsInstancedImplementation = &Mesh::drawElementsInstancedImplementationANGLE;
+        drawElementsInstancedImplementation = glDrawElementsInstancedANGLE;
     }
     #ifndef MAGNUM_TARGET_WEBGL
     else if(context.isExtensionSupported<Extensions::EXT::instanced_arrays>() ||
@@ -169,8 +169,8 @@ MeshState::MeshState(Context& context, ContextState& contextState, std::vector<s
             Extensions::EXT::instanced_arrays::string() :
             Extensions::EXT::draw_instanced::string());
 
-        drawArraysInstancedImplementation = &Mesh::drawArraysInstancedImplementationEXT;
+        drawArraysInstancedImplementation = glDrawArraysInstancedEXT;
-        drawElementsInstancedImplementation = &Mesh::drawElementsInstancedImplementationEXT;
+        drawElementsInstancedImplementation = glDrawElementsInstancedEXT;
 
     } else if(context.isExtensionSupported<Extensions::NV::instanced_arrays>() ||
               context.isExtensionSupported<Extensions::NV::draw_instanced>()) {
@@ -178,8 +178,8 @@ MeshState::MeshState(Context& context, ContextState& contextState, std::vector<s
             Extensions::NV::instanced_arrays::string() :
             Extensions::NV::draw_instanced::string());
 
-        drawArraysInstancedImplementation = &Mesh::drawArraysInstancedImplementationNV;
+        drawArraysInstancedImplementation = glDrawArraysInstancedNV;
-        drawElementsInstancedImplementation = &Mesh::drawElementsInstancedImplementationNV;
+        drawElementsInstancedImplementation = glDrawElementsInstancedNV;
     }
     #endif
     else {

src/Magnum/GL/Implementation/MeshState.h

@@ -54,8 +54,8 @@ struct MeshState {
     void(Mesh::*unbindImplementation)();
 
     #ifdef MAGNUM_TARGET_GLES2
-    void(Mesh::*drawArraysInstancedImplementation)(GLint, GLsizei, GLsizei);
+    void(APIENTRY *drawArraysInstancedImplementation)(GLenum, GLint, GLsizei, GLsizei);
-    void(Mesh::*drawElementsInstancedImplementation)(GLsizei, GLintptr, GLsizei);
+    void(APIENTRY *drawElementsInstancedImplementation)(GLenum, GLsizei, GLenum, const void*, GLsizei);
     #endif
 
     #ifdef MAGNUM_TARGET_GLES

src/Magnum/GL/Mesh.cpp

@@ -467,10 +467,11 @@ void Mesh::drawInternal(Int count, Int baseVertex, Int instanceCount, GLintptr i
             #endif
             {
                 #ifndef MAGNUM_TARGET_GLES2
-                glDrawArraysInstanced(GLenum(_primitive), baseVertex, count, instanceCount);
+                glDrawArraysInstanced
                 #else
-                (this->*state.drawArraysInstancedImplementation)(baseVertex, count, instanceCount);
+                state.drawArraysInstancedImplementation
                 #endif
+                    (GLenum(_primitive), baseVertex, count, instanceCount);
             }
 
         /* Indexed mesh with base vertex */
@@ -503,10 +504,11 @@ void Mesh::drawInternal(Int count, Int baseVertex, Int instanceCount, GLintptr i
             #endif
             {
                 #ifndef MAGNUM_TARGET_GLES2
-                glDrawElementsInstanced(GLenum(_primitive), count, GLenum(_indexType), reinterpret_cast<GLvoid*>(indexOffset), instanceCount);
+                glDrawElementsInstanced
                 #else
-                (this->*state.drawElementsInstancedImplementation)(count, indexOffset, instanceCount);
+                state.drawElementsInstancedImplementation
                 #endif
+                    (GLenum(_primitive), count, GLenum(_indexType), reinterpret_cast<GLvoid*>(indexOffset), instanceCount);
             }
         }
     }
@@ -871,34 +873,4 @@ void Mesh::unbindImplementationDefault() {
 
 void Mesh::unbindImplementationVAO() {}
 
-#ifdef MAGNUM_TARGET_GLES2
-void Mesh::drawArraysInstancedImplementationANGLE(const GLint baseVertex, const GLsizei count, const GLsizei instanceCount) {
-    glDrawArraysInstancedANGLE(GLenum(_primitive), baseVertex, count, instanceCount);
-}
-
-#ifndef MAGNUM_TARGET_WEBGL
-void Mesh::drawArraysInstancedImplementationEXT(const GLint baseVertex, const GLsizei count, const GLsizei instanceCount) {
-    glDrawArraysInstancedEXT(GLenum(_primitive), baseVertex, count, instanceCount);
-}
-
-void Mesh::drawArraysInstancedImplementationNV(const GLint baseVertex, const GLsizei count, const GLsizei instanceCount) {
-    glDrawArraysInstancedNV(GLenum(_primitive), baseVertex, count, instanceCount);
-}
-#endif
-
-void Mesh::drawElementsInstancedImplementationANGLE(const GLsizei count, const GLintptr indexOffset, const GLsizei instanceCount) {
-    glDrawElementsInstancedANGLE(GLenum(_primitive), count, GLenum(_indexType), reinterpret_cast<GLvoid*>(indexOffset), instanceCount);
-}
-
-#ifndef MAGNUM_TARGET_WEBGL
-void Mesh::drawElementsInstancedImplementationEXT(const GLsizei count, const GLintptr indexOffset, const GLsizei instanceCount) {
-    glDrawElementsInstancedEXT(GLenum(_primitive), count, GLenum(_indexType), reinterpret_cast<GLvoid*>(indexOffset), instanceCount);
-}
-
-void Mesh::drawElementsInstancedImplementationNV(const GLsizei count, const GLintptr indexOffset, const GLsizei instanceCount) {
-    glDrawElementsInstancedNV(GLenum(_primitive), count, GLenum(_indexType), reinterpret_cast<GLvoid*>(indexOffset), instanceCount);
-}
-#endif
-#endif
-
 }}

src/Magnum/GL/Mesh.h

@@ -1133,20 +1133,6 @@ class MAGNUM_GL_EXPORT Mesh: public AbstractObject {
         void MAGNUM_GL_LOCAL unbindImplementationDefault();
         void MAGNUM_GL_LOCAL unbindImplementationVAO();
 
-        #ifdef MAGNUM_TARGET_GLES2
-        void MAGNUM_GL_LOCAL drawArraysInstancedImplementationANGLE(GLint baseVertex, GLsizei count, GLsizei instanceCount);
-        #ifndef MAGNUM_TARGET_WEBGL
-        void MAGNUM_GL_LOCAL drawArraysInstancedImplementationEXT(GLint baseVertex, GLsizei count, GLsizei instanceCount);
-        void MAGNUM_GL_LOCAL drawArraysInstancedImplementationNV(GLint baseVertex, GLsizei count, GLsizei instanceCount);
-        #endif
-
-        void MAGNUM_GL_LOCAL drawElementsInstancedImplementationANGLE(GLsizei count, GLintptr indexOffset, GLsizei instanceCount);
-        #ifndef MAGNUM_TARGET_WEBGL
-        void MAGNUM_GL_LOCAL drawElementsInstancedImplementationEXT(GLsizei count, GLintptr indexOffset, GLsizei instanceCount);
-        void MAGNUM_GL_LOCAL drawElementsInstancedImplementationNV(GLsizei count, GLintptr indexOffset, GLsizei instanceCount);
-        #endif
-        #endif
-
         /* _id, _primitive, _flags set from constructors */
         GLuint _id;
         MeshPrimitive _primitive;