From 2879a62b0874588386fcf909884bde66d2b4b5cf Mon Sep 17 00:00:00 2001
From: granzuglia <guido.ranzuglia@isti.cnr.it>
Date: Thu, 20 Sep 2012 07:08:09 +0000
Subject: [PATCH] - some additional check on OpenGL symbol availability
 (changes Spat approved)

---
 wrap/glw/context.h | 61 ++++++++++++++++++++++++++++++----------------
 1 file changed, 40 insertions(+), 21 deletions(-)

diff --git a/wrap/glw/context.h b/wrap/glw/context.h
index 5fc55d45..b1044ebb 100644
--- a/wrap/glw/context.h
+++ b/wrap/glw/context.h
@@ -45,9 +45,13 @@ class Context : public detail::NonCopyable
 
 		bool acquire(void)
 		{
+			//
 			this->release();
+			//
 			this->initializeTargets();
+			//
 			this->m_acquired = true;
+			(void)glGetError();
 			return this->m_acquired;
 		}
 
@@ -57,6 +61,7 @@ class Context : public detail::NonCopyable
 			this->m_acquired = false;
 			this->terminateTargets();
 			this->invalidateReferencesToAllObjects();
+			(void)glGetError();
 		}
 
 		bool isAcquired(void) const
@@ -436,37 +441,51 @@ class Context : public detail::NonCopyable
 		}
 
 		void initializeTargets(void)
-		{
+		{	
 			this->initializeTarget<BoundVertexBuffer,        VertexBufferBindingParams        >(VertexBufferBindingParams        ()       );
-			this->initializeTarget<BoundIndexBuffer,         IndexBufferBindingParams         >(IndexBufferBindingParams         ()       );
-			this->initializeTarget<BoundPixelPackBuffer,     PixelPackBufferBindingParams     >(PixelPackBufferBindingParams     ()       );
-			this->initializeTarget<BoundPixelUnpackBuffer,   PixelUnpackBufferBindingParams   >(PixelUnpackBufferBindingParams   ()       );
-			this->initializeTarget<BoundRenderbuffer,        RenderbufferBindingParams        >(RenderbufferBindingParams        ()       );
-			this->initializeTarget<BoundVertexShader,        VertexShaderBindingParams        >(VertexShaderBindingParams        ()       );
-			this->initializeTarget<BoundGeometryShader,      GeometryShaderBindingParams      >(GeometryShaderBindingParams      ()       );
-			this->initializeTarget<BoundFragmentShader,      FragmentShaderBindingParams      >(FragmentShaderBindingParams      ()       );
-			this->initializeTarget<BoundProgram,             ProgramBindingParams             >(ProgramBindingParams             ()       );
-			this->initializeTarget<BoundReadFramebuffer,     ReadFramebufferBindingParams     >(ReadFramebufferBindingParams     ()       );
-			this->initializeTarget<BoundDrawFramebuffer,     DrawFramebufferBindingParams     >(DrawFramebufferBindingParams     ()       );
+			this->initializeTarget<BoundIndexBuffer,         IndexBufferBindingParams         >(IndexBufferBindingParams         ()       );			
+			this->initializeTarget<BoundPixelPackBuffer,     PixelPackBufferBindingParams     >(PixelPackBufferBindingParams     ()       );			
+			this->initializeTarget<BoundPixelUnpackBuffer,   PixelUnpackBufferBindingParams   >(PixelUnpackBufferBindingParams   ()       );			
+			this->initializeTarget<BoundRenderbuffer,        RenderbufferBindingParams        >(RenderbufferBindingParams        ()       );			
+			this->initializeTarget<BoundVertexShader,        VertexShaderBindingParams        >(VertexShaderBindingParams        ()       );			
+			this->initializeTarget<BoundGeometryShader,      GeometryShaderBindingParams      >(GeometryShaderBindingParams      ()       );			
+			this->initializeTarget<BoundFragmentShader,      FragmentShaderBindingParams      >(FragmentShaderBindingParams      ()       );			
+			this->initializeTarget<BoundProgram,             ProgramBindingParams             >(ProgramBindingParams             ()       );			
+			this->initializeTarget<BoundReadFramebuffer,     ReadFramebufferBindingParams     >(ReadFramebufferBindingParams     ()       );			
+			this->initializeTarget<BoundDrawFramebuffer,     DrawFramebufferBindingParams     >(DrawFramebufferBindingParams     ()       );			
 			this->initializeTarget<BoundReadDrawFramebuffer, ReadDrawFramebufferBindingParams >(ReadDrawFramebufferBindingParams ()       );
 
 			{
-				GLint uniformBuffers = 0;
-				glGetIntegerv(GL_MAX_UNIFORM_BUFFER_BINDINGS, &uniformBuffers);
-				this->m_maxUniformBuffers = int(uniformBuffers);
-				for (int i=0; i<this->m_maxUniformBuffers; ++i)
+				this->m_maxUniformBuffers = 0;
+				if (GLEW_ARB_uniform_buffer_object)
 				{
-					this->initializeTarget<BoundUniformBuffer, UniformBufferBindingParams>(UniformBufferBindingParams(GLuint(i), 0, 0));
+					GLint uniformBuffers = 0;
+					
+					glGetIntegerv(GL_MAX_UNIFORM_BUFFER_BINDINGS, &uniformBuffers);
+					GLenum err = glGetError();
+					const GLubyte* errr = gluErrorString(err);
+					assert(err == GL_NO_ERROR);
+					this->m_maxUniformBuffers = int(uniformBuffers);
+					for (int i=0; i<this->m_maxUniformBuffers; ++i)
+					{
+						
+						this->initializeTarget<BoundUniformBuffer, UniformBufferBindingParams>(UniformBufferBindingParams(GLuint(i), 0, 0));
+						
+					}
 				}
 			}
 
 			{
-				GLint feedbackBuffers = 0;
-				glGetIntegerv(GL_MAX_TRANSFORM_FEEDBACK_SEPARATE_ATTRIBS, &feedbackBuffers);
-				this->m_maxFeedbackBuffers = int(feedbackBuffers);
-				for (int i=0; i<this->m_maxFeedbackBuffers; ++i)
+				this->m_maxFeedbackBuffers = 0;
+				if (GLEW_EXT_transform_feedback)
 				{
-					this->initializeTarget<BoundFeedbackBuffer, FeedbackBufferBindingParams>(FeedbackBufferBindingParams(GLuint(i), 0, 0));
+					GLint feedbackBuffers = 0;
+					glGetIntegerv(GL_MAX_TRANSFORM_FEEDBACK_SEPARATE_ATTRIBS, &feedbackBuffers);
+					this->m_maxFeedbackBuffers = int(feedbackBuffers);
+					for (int i=0; i<this->m_maxFeedbackBuffers; ++i)
+					{
+						this->initializeTarget<BoundFeedbackBuffer, FeedbackBufferBindingParams>(FeedbackBufferBindingParams(GLuint(i), 0, 0));
+					}
 				}
 			}