[GL] Enabled GL_EXT_framebuffer_object extension in GL 2.x backend.

- Added GL_EXT_framebuffer_object as substitute for GL_ARB_framebuffer_object in GL.
- Removed HasNativeVAO(): VAOs are always required in GL 3+, but they are excluded for GL 2.x compatibility profile.

sources/Renderer/OpenGL/Command/GLCommandExecutor.cpp

@@ -326,7 +326,7 @@ static std::size_t ExecuteGLCommand(const GLOpcode opcode, const void* pc, GLSta
  case GLOpcodeDrawArraysInstanced:
  {
  auto cmd = reinterpret_cast<const GLCmdDrawArraysInstanced*>(pc);
- #if !LLGL_GL_ENABLE_OPENGL2X
+ #if LLGL_GLEXT_DRAW_INSTANCED
  glDrawArraysInstanced(cmd->mode, cmd->first, cmd->count, cmd->instancecount);
  #endif
  return sizeof(*cmd);
@@ -370,7 +370,7 @@ static std::size_t ExecuteGLCommand(const GLOpcode opcode, const void* pc, GLSta
  case GLOpcodeDrawElementsInstanced:
  {
  auto cmd = reinterpret_cast<const GLCmdDrawElementsInstanced*>(pc);
- #if !LLGL_GL_ENABLE_OPENGL2X
+ #if LLGL_GLEXT_DRAW_INSTANCED
  glDrawElementsInstanced(cmd->mode, cmd->count, cmd->type, cmd->indices, cmd->instancecount);
  #endif
  return sizeof(*cmd);

sources/Renderer/OpenGL/Command/GLImmediateCommandBuffer.cpp

@@ -634,7 +634,7 @@ void GLImmediateCommandBuffer::DrawIndexed(std::uint32_t numIndices, std::uint32
 
 void GLImmediateCommandBuffer::DrawInstanced(std::uint32_t numVertices, std::uint32_t firstVertex, std::uint32_t numInstances)
 {
- #if !LLGL_GL_ENABLE_OPENGL2X
+ #if LLGL_GLEXT_DRAW_INSTANCED
  LLGL_FLUSH_MEMORY_BARRIERS();
  glDrawArraysInstanced(
  GetDrawMode(),
@@ -661,7 +661,7 @@ void GLImmediateCommandBuffer::DrawInstanced(std::uint32_t numVertices, std::uin
 
 void GLImmediateCommandBuffer::DrawIndexedInstanced(std::uint32_t numIndices, std::uint32_t numInstances, std::uint32_t firstIndex)
 {
- #if !LLGL_GL_ENABLE_OPENGL2X
+ #if LLGL_GLEXT_DRAW_INSTANCED
  LLGL_FLUSH_MEMORY_BARRIERS();
  glDrawElementsInstanced(
  GetDrawMode(),

sources/Renderer/OpenGL/Ext/GLExtensionRegistry.cpp

@@ -15,11 +15,28 @@ namespace LLGL
 
 static std::array<bool, static_cast<std::size_t>(GLExt::Count)> g_registeredExtensions { { false } };
 
-void RegisterExtension(GLExt extension)
+static void RegisterExtensionInternal(GLExt extension)
 {
  g_registeredExtensions[static_cast<std::size_t>(extension)] = true;
 }
 
+void RegisterExtension(GLExt extension)
+{
+ #if LLGL_GL_ENABLE_OPENGL2X
+ switch (extension)
+ {
+ case GLExt::EXT_framebuffer_object:
+ RegisterExtensionInternal(GLExt::ARB_framebuffer_object); // Substitute EXT_framebuffer_object with ARB_framebuffer_object
+ break;
+ default:
+ RegisterExtensionInternal(extension);
+ break;
+ }
+ #else // LLGL_GL_ENABLE_OPENGL2X
+ RegisterExtensionInternal(extension);
+ #endif // /LLGL_GL_ENABLE_OPENGL2X
+}
+
 bool HasExtension(const GLExt extension)
 {
  return g_registeredExtensions[static_cast<std::size_t>(extension)];
@@ -30,11 +47,6 @@ bool HasNativeSamplers()
  return HasExtension(GLExt::ARB_sampler_objects);
 }
 
-bool HasNativeVAO()
-{
- return HasExtension(GLExt::ARB_vertex_array_object);
-}
-
 
 } // /namespace LLGL
 

sources/Renderer/OpenGL/Ext/GLExtensionRegistry.h

@@ -116,6 +116,9 @@ enum class GLExt
  /* Intel sepcific extensions (INTEL) */
  INTEL_conservative_rasterization, // no procedures
 
+ /* Substitute extensions for GL 2.x only - do *not* used in HasExtension() calls! */
+ EXT_framebuffer_object,
+
  /* Enumeration entry counter */
  Count,
 };
@@ -130,9 +133,6 @@ bool HasExtension(const GLExt extension);
 // Returns ture if GL_ARB_sampler_objects is supported. Shortcut for 'HasExtension(GLExt::ARB_sampler_objects)'.
 bool HasNativeSamplers();
 
-// Returns true if GL_ARB_vertex_array_object is supported. Shortcut for 'HasExtension(GLExt::ARB_vertex_array_object)'.
-bool HasNativeVAO();
-
 
 } // /namespace LLGL
 

sources/Renderer/OpenGL/GLTypes.cpp

@@ -946,7 +946,7 @@ GLenum ToTextureCubeMap(std::uint32_t arrayLayer)
 
 GLenum ToColorAttachment(std::uint32_t attachmentIndex)
 {
- #if !LLGL_GL_ENABLE_OPENGL2X
+ #if LLGL_GLEXT_FRAMEBUFFER_OBJECT
  if (attachmentIndex < LLGL_MAX_NUM_COLOR_ATTACHMENTS)
  {
  static const GLenum g_drawBuffers[] =

sources/Renderer/OpenGL/OpenGL.h

@@ -26,6 +26,10 @@
 
 #else // LLGL_WEBGL
 
+#if GL_ARB_framebuffer_object || GL_EXT_framebuffer_object || GL_ES_VERSION_2_0 || GL_ES_VERSION_3_0
+# define LLGL_GLEXT_FRAMEBUFFER_OBJECT 1
+#endif
+
 #if !LLGL_GL_ENABLE_OPENGL2X
 
 #if GL_ARB_vertex_array_object || GL_ES_VERSION_3_0
@@ -36,6 +40,10 @@
 # define LLGL_GLEXT_SAMPLER_OBJECTS 1
 #endif
 
+#if GL_ARB_draw_instanced || GL_ES_VERSION_3_0
+# define LLGL_GLEXT_DRAW_INSTANCED 1
+#endif
+
 #if GL_ARB_separate_shader_objects || GL_ES_VERSION_3_1
 # define LLGL_GLEXT_SEPARATE_SHADER_OBJECTS 1
 #elif GL_EXT_separate_shader_objects
@@ -195,27 +203,6 @@
 # define LLGL_USE_NULL_FRAGMENT_SHADER 1
 #endif
 
-#if LLGL_GL_ENABLE_OPENGL2X
-# define glGenFramebuffers glGenFramebuffersEXT
-# define glDeleteFramebuffers glDeleteFramebuffersEXT
-# define glBindFramebuffer glBindFramebufferEXT
-# define glBindRenderbuffer glBindRenderbufferEXT
-# define glBlitFramebuffer glBlitFramebufferEXT
-# define glFramebufferTexture1D glFramebufferTexture1DEXT
-# define glFramebufferTexture2D glFramebufferTexture2DEXT
-# define glFramebufferTexture3D glFramebufferTexture3DEXT
-# define glFramebufferRenderbuffer glFramebufferRenderbufferEXT
-# define glCheckFramebufferStatus glCheckFramebufferStatusEXT
-# define glGenRenderbuffers glGenRenderbuffersEXT
-# define glDeleteRenderbuffers glDeleteRenderbuffersEXT
-# define glRenderbufferStorage glRenderbufferStorageEXT
-# define glRenderbufferStorageMultisample glRenderbufferStorageMultisampleEXT
-# define glGetRenderbufferParameteriv glGetRenderbufferParameterivEXT
-# define glGetFramebufferAttachmentParameteriv glGetFramebufferAttachmentParameterivEXT
-# define glGenerateMipmap glGenerateMipmapEXT
-#endif
-
-
 #endif