Saving index buffer pointer only if not using VAOs.

With VAOs it is not used anyway, might remove the member variable for
platforms with mandatory VAO support altogether.

src/IndexedMesh.cpp

@@ -24,12 +24,6 @@ namespace Magnum {
 IndexedMesh::BindIndexBufferImplementation IndexedMesh::bindIndexBufferImplementation = &IndexedMesh::bindIndexBufferImplementationDefault;
 IndexedMesh::BindIndexedImplementation IndexedMesh::bindIndexedImplementation = &IndexedMesh::bindIndexedImplementationDefault;
 
-IndexedMesh* IndexedMesh::setIndexBuffer(Buffer* buffer) {
-    _indexBuffer = buffer;
-    (this->*bindIndexBufferImplementation)();
-    return this;
-}
-
 void IndexedMesh::draw() {
     if(!_indexCount) return;
 
@@ -41,8 +35,6 @@ void IndexedMesh::draw() {
 }
 
 void IndexedMesh::bind() {
-    CORRADE_ASSERT(!_indexCount || _indexBuffer, "IndexedMesh: index buffer must be added if index count is non-zero", );
-
     Mesh::bind();
     (this->*bindIndexedImplementation)();
 }
@@ -61,11 +53,13 @@ void IndexedMesh::initializeContextBasedFunctionality(Context* context) {
     #endif
 }
 
-void IndexedMesh::bindIndexBufferImplementationDefault() {}
+void IndexedMesh::bindIndexBufferImplementationDefault(Buffer* buffer) {
+    _indexBuffer = buffer;
+}
 
-void IndexedMesh::bindIndexBufferImplementationVAO() {
+void IndexedMesh::bindIndexBufferImplementationVAO(Buffer* buffer) {
     bindVAO(vao);
-    _indexBuffer->bind(Buffer::Target::ElementArray);
+    buffer->bind(Buffer::Target::ElementArray);
 }
 
 void IndexedMesh::bindIndexedImplementationDefault() {

src/IndexedMesh.h

@@ -83,12 +83,16 @@ class MAGNUM_EXPORT IndexedMesh: public Mesh {
 
         /**
          * @brief Set index buffer
+         * @return Pointer to self (for method chaining)
          *
          * @see setIndexCount(), setIndexType(), MeshTools::compressIndices(),
          *      @fn_gl{BindVertexArray}, @fn_gl{BindBuffer} (if
          *      @extension{APPLE,vertex_array_object} is available)
          */
-        IndexedMesh* setIndexBuffer(Buffer* buffer);
+        inline IndexedMesh* setIndexBuffer(Buffer* buffer) {
+            (this->*bindIndexBufferImplementation)(buffer);
+            return this;
+        }
 
         /**
          * @brief Draw the mesh
@@ -140,10 +144,10 @@ class MAGNUM_EXPORT IndexedMesh: public Mesh {
 
         void MAGNUM_LOCAL bind();
 
-        typedef void(IndexedMesh::*BindIndexBufferImplementation)();
-        void MAGNUM_LOCAL bindIndexBufferImplementationDefault();
-        void MAGNUM_LOCAL bindIndexBufferImplementationVAO();
-        static MAGNUM_LOCAL BindIndexBufferImplementation bindIndexBufferImplementation;
+        typedef void(IndexedMesh::*BindIndexBufferImplementation)(Buffer*);
+        void MAGNUM_LOCAL bindIndexBufferImplementationDefault(Buffer* buffer);
+        void MAGNUM_LOCAL bindIndexBufferImplementationVAO(Buffer* buffer);
+        static BindIndexBufferImplementation bindIndexBufferImplementation;
 
         typedef void(IndexedMesh::*BindIndexedImplementation)();
         void MAGNUM_LOCAL bindIndexedImplementationDefault();