Account for missing glVertexArrayVertexAttribDivisorEXT.

This function was added to ARB_instanced_arrays spec very late and thus
some implementations don't provide it (one case being AMD drivers on
Linux). If that function is not available, the non-DSA VAO specification
is used instead.

src/Magnum/Implementation/MeshState.cpp

@@ -137,7 +137,16 @@ MeshState::MeshState(Context& context, std::vector<std::string>& extensions): cu
         drawArraysInstancedImplementation = nullptr;
         drawElementsInstancedImplementation = nullptr;
     }
+    #endif
 
+    #ifndef MAGNUM_TARGET_GLES
+    /* Partial EXT_DSA implementation of vertex attrib divisor */
+    if(context.isExtensionSupported<Extensions::GL::EXT::direct_state_access>()) {
+        if(glVertexArrayVertexAttribDivisorEXT)
+            vertexAttribDivisorImplementation = &Mesh::vertexAttribDivisorImplementationDSAEXT;
+        else vertexAttribDivisorImplementation = &Mesh::vertexAttribDivisorImplementationVAO;
+    } else vertexAttribDivisorImplementation = nullptr;
+    #elif defined(MAGNUM_TARGET_GLES2)
     /* Instanced arrays implementation on ES2 */
     if(context.isExtensionSupported<Extensions::GL::ANGLE::instanced_arrays>()) {
         /* Extension added above */

src/Magnum/Implementation/MeshState.h

@@ -46,7 +46,7 @@ struct MeshState {
     void(Mesh::*attributeLPointerImplementation)(const Mesh::LongAttribute&);
     #endif
     #endif
-    #ifdef MAGNUM_TARGET_GLES2
+    #if !defined(MAGNUM_TARGET_GLES) || defined(MAGNUM_TARGET_GLES2)
     void(Mesh::*vertexAttribDivisorImplementation)(GLuint, GLuint);
     #endif
     void(Mesh::*bindIndexBufferImplementation)(Buffer&);

src/Magnum/Mesh.cpp

@@ -406,7 +406,8 @@ void Mesh::attributePointerImplementationDSAEXT(const GenericAttribute& attribut
     _created = true;
     glEnableVertexArrayAttribEXT(_id, attribute.location);
     glVertexArrayVertexAttribOffsetEXT(_id, attribute.buffer->id(), attribute.location, attribute.size, attribute.type, attribute.normalized, attribute.stride, attribute.offset);
-    if(attribute.divisor) glVertexArrayVertexAttribDivisorEXT(_id, attribute.location, attribute.divisor);
+    if(attribute.divisor)
+        (this->*Context::current()->state().mesh->vertexAttribDivisorImplementation)(attribute.location, attribute.divisor);
 }
 #endif
 
@@ -442,7 +443,8 @@ void Mesh::attributePointerImplementationDSAEXT(const IntegerAttribute& attribut
     _created = true;
     glEnableVertexArrayAttribEXT(_id, attribute.location);
     glVertexArrayVertexAttribIOffsetEXT(_id, attribute.buffer->id(), attribute.location, attribute.size, attribute.type, attribute.stride, attribute.offset);
-    if(attribute.divisor) glVertexArrayVertexAttribDivisorEXT(_id, attribute.location, attribute.divisor);
+    if(attribute.divisor)
+        (this->*Context::current()->state().mesh->vertexAttribDivisorImplementation)(attribute.location, attribute.divisor);
 }
 #endif
 
@@ -472,7 +474,8 @@ void Mesh::attributePointerImplementationDSAEXT(const LongAttribute& attribute)
     _created = true;
     glEnableVertexArrayAttribEXT(_id, attribute.location);
     glVertexArrayVertexAttribLOffsetEXT(_id, attribute.buffer->id(), attribute.location, attribute.size, attribute.type, attribute.stride, attribute.offset);
-    if(attribute.divisor) glVertexArrayVertexAttribDivisorEXT(_id, attribute.location, attribute.divisor);
+    if(attribute.divisor)
+        (this->*Context::current()->state().mesh->vertexAttribDivisorImplementation)(attribute.location, attribute.divisor);
 }
 
 void Mesh::vertexAttribPointer(const LongAttribute& attribute) {
@@ -483,7 +486,15 @@ void Mesh::vertexAttribPointer(const LongAttribute& attribute) {
 }
 #endif
 
-#ifdef MAGNUM_TARGET_GLES2
+#ifndef MAGNUM_TARGET_GLES
+void Mesh::vertexAttribDivisorImplementationVAO(const GLuint index, const GLuint divisor) {
+    bindVAO();
+    glVertexAttribDivisor(index, divisor);
+}
+void Mesh::vertexAttribDivisorImplementationDSAEXT(const GLuint index, const GLuint divisor) {
+    glVertexArrayVertexAttribDivisorEXT(_id, index, divisor);
+}
+#elif defined(MAGNUM_TARGET_GLES2)
 void Mesh::vertexAttribDivisorImplementationANGLE(const GLuint index, const GLuint divisor) {
     #if !defined(CORRADE_TARGET_EMSCRIPTEN) && !defined(CORRADE_TARGET_NACL)
     glVertexAttribDivisorANGLE(index, divisor);
@@ -493,7 +504,6 @@ void Mesh::vertexAttribDivisorImplementationANGLE(const GLuint index, const GLui
     CORRADE_ASSERT_UNREACHABLE();
     #endif
 }
-
 void Mesh::vertexAttribDivisorImplementationEXT(const GLuint index, const GLuint divisor) {
     #if !defined(CORRADE_TARGET_EMSCRIPTEN) && !defined(CORRADE_TARGET_NACL)
     glVertexAttribDivisorEXT(index, divisor);
@@ -503,7 +513,6 @@ void Mesh::vertexAttribDivisorImplementationEXT(const GLuint index, const GLuint
     CORRADE_ASSERT_UNREACHABLE();
     #endif
 }
-
 void Mesh::vertexAttribDivisorImplementationNV(const GLuint index, const GLuint divisor) {
     #if !defined(CORRADE_TARGET_EMSCRIPTEN) && !defined(CORRADE_TARGET_NACL)
     glVertexAttribDivisorNV(index, divisor);

src/Magnum/Mesh.h

@@ -981,7 +981,10 @@ class MAGNUM_EXPORT Mesh: public AbstractObject {
         void MAGNUM_LOCAL vertexAttribPointer(const LongAttribute& attribute);
         #endif
 
-        #ifdef MAGNUM_TARGET_GLES2
+        #ifndef MAGNUM_TARGET_GLES
+        void MAGNUM_LOCAL vertexAttribDivisorImplementationVAO(GLuint index, GLuint divisor);
+        void MAGNUM_LOCAL vertexAttribDivisorImplementationDSAEXT(GLuint index, GLuint divisor);
+        #elif defined(MAGNUM_TARGET_GLES2)
         void MAGNUM_LOCAL vertexAttribDivisorImplementationANGLE(GLuint index, GLuint divisor);
         void MAGNUM_LOCAL vertexAttribDivisorImplementationEXT(GLuint index, GLuint divisor);
         void MAGNUM_LOCAL vertexAttribDivisorImplementationNV(GLuint index, GLuint divisor);