diff --git a/examples/protonect/include/libfreenect2/depth_packet_stream_parser.h b/examples/protonect/include/libfreenect2/depth_packet_stream_parser.h
index 7773cadc4..7258d3685 100644
--- a/examples/protonect/include/libfreenect2/depth_packet_stream_parser.h
+++ b/examples/protonect/include/libfreenect2/depth_packet_stream_parser.h
@@ -68,6 +68,7 @@ class LIBFREENECT2_API DepthPacketStreamParser : public DataCallback
 
   uint32_t current_sequence_;
   uint32_t current_subsequence_;
+  uint32_t processed_packets_;
 };
 
 } /* namespace libfreenect2 */
diff --git a/examples/protonect/src/command_transaction.cpp b/examples/protonect/src/command_transaction.cpp
index 716dd32e2..ec81d109e 100644
--- a/examples/protonect/src/command_transaction.cpp
+++ b/examples/protonect/src/command_transaction.cpp
@@ -29,6 +29,8 @@
 
 #include <stdint.h>
 
+#define WRITE_LIBUSB_ERROR(__RESULT) libusb_error_name(__RESULT) << " " << libusb_strerror((libusb_error)__RESULT)
+
 namespace libfreenect2
 {
 namespace protocol
@@ -135,7 +137,7 @@ CommandTransaction::ResultCode CommandTransaction::send(const CommandBase& comma
 
   if(r != LIBUSB_SUCCESS)
   {
-    LOG_ERROR << "bulk transfer failed! libusb error " << r << ": " << libusb_error_name(r);
+    LOG_ERROR << "bulk transfer failed: " << WRITE_LIBUSB_ERROR(r);
     code = Error;
   }
 
@@ -157,7 +159,7 @@ void CommandTransaction::receive(CommandTransaction::Result& result)
 
   if(r != LIBUSB_SUCCESS)
   {
-    LOG_ERROR << "bulk transfer failed! libusb error " << r << ": " << libusb_error_name(r);
+    LOG_ERROR << "bulk transfer failed: " << WRITE_LIBUSB_ERROR(r);
     result.code = Error;
   }
 }
diff --git a/examples/protonect/src/depth_packet_stream_parser.cpp b/examples/protonect/src/depth_packet_stream_parser.cpp
index a90f1ed70..a3ddfa097 100644
--- a/examples/protonect/src/depth_packet_stream_parser.cpp
+++ b/examples/protonect/src/depth_packet_stream_parser.cpp
@@ -33,6 +33,7 @@ namespace libfreenect2
 
 DepthPacketStreamParser::DepthPacketStreamParser() :
     processor_(noopProcessor<DepthPacket>()),
+    processed_packets_(-1),
     current_sequence_(0),
     current_subsequence_(0)
 {
@@ -79,7 +80,7 @@ void DepthPacketStreamParser::onDataReceived(unsigned char* buffer, size_t in_le
 
     if(wb.length + in_length > wb.capacity)
     {
-      LOG_ERROR << "subpacket too large";
+      LOG_DEBUG << "subpacket too large";
       wb.length = 0;
       return;
     }
@@ -91,7 +92,7 @@ void DepthPacketStreamParser::onDataReceived(unsigned char* buffer, size_t in_le
     {
       if(footer->length != wb.length)
       {
-        LOG_ERROR << "image data too short!";
+        LOG_DEBUG << "image data too short!";
       }
       else
       {
@@ -110,15 +111,26 @@ void DepthPacketStreamParser::onDataReceived(unsigned char* buffer, size_t in_le
               packet.buffer_length = buffer_.back().length;
 
               processor_->process(packet);
+
+              processed_packets_++;
+              if (processed_packets_ == 0)
+                processed_packets_ = current_sequence_;
+              int diff = current_sequence_ - processed_packets_;
+              const int interval = 30;
+              if (current_sequence_ % interval == 0 && diff != 0)
+              {
+                LOG_INFO << diff << " of " << interval << " packets were lost";
+                processed_packets_ = current_sequence_;
+              }
             }
             else
             {
-              LOG_WARNING << "skipping depth packet";
+              LOG_DEBUG << "skipping depth packet";
             }
           }
           else
           {
-            LOG_ERROR << "not all subsequences received " << current_subsequence_;
+            LOG_DEBUG << "not all subsequences received " << current_subsequence_;
           }
 
           current_sequence_ = footer->sequence;
@@ -132,7 +144,7 @@ void DepthPacketStreamParser::onDataReceived(unsigned char* buffer, size_t in_le
 
         if(footer->subsequence * footer->length > fb.length)
         {
-          LOG_ERROR << "front buffer too short! subsequence number is " << footer->subsequence;
+          LOG_DEBUG << "front buffer too short! subsequence number is " << footer->subsequence;
         }
         else
         {
diff --git a/examples/protonect/src/flextGL.c b/examples/protonect/src/flextGL.c
index a462628b3..5828eff44 100644
--- a/examples/protonect/src/flextGL.c
+++ b/examples/protonect/src/flextGL.c
@@ -1,46 +1,11 @@
-/* WARNING: This file was automatically generated */
-/* Do not edit. */
-
 #include "flextGL.h"
 #include "GLFW/glfw3.h"
 
-#include <stdio.h>
-
-
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-
-void flextLoadOpenGLFunctions(OpenGLBindings *bindings);
-
-int flextInit(GLFWwindow* window, OpenGLBindings *bindings)
-{
-  
-    int major = glfwGetWindowAttrib(window, GLFW_CONTEXT_VERSION_MAJOR);
-    int minor = glfwGetWindowAttrib(window, GLFW_CONTEXT_VERSION_MINOR);
-
-    flextLoadOpenGLFunctions(bindings);
-    
-    /* --- Check for minimal version and profile --- */
-
-    if (major * 10 + minor < 33) {
-        fprintf(stderr, "Error: OpenGL version 3.3 not supported.\n");
-        fprintf(stderr, "       Your version is %d.%d.\n", major, minor);
-        fprintf(stderr, "       Try updating your graphics driver.\n");
-        return GL_FALSE;
-    }
-
-
-    /* --- Check for extensions --- */
-
-
-    return GL_TRUE;
-}
-
-
-
-void flextLoadOpenGLFunctions(OpenGLBindings *bindings)
+void flextInit(OpenGLBindings *bindings)
 {
     /* --- Function pointer loading --- */
 
@@ -305,59 +270,6 @@ void flextLoadOpenGLFunctions(OpenGLBindings *bindings)
     bindings->glGetActiveUniformBlockName = (PFNGLGETACTIVEUNIFORMBLOCKNAME_PROC*)glfwGetProcAddress("glGetActiveUniformBlockName");
     bindings->glUniformBlockBinding = (PFNGLUNIFORMBLOCKBINDING_PROC*)glfwGetProcAddress("glUniformBlockBinding");
 
-    /* GL_VERSION_3_2 */
-
-    bindings->glDrawElementsBaseVertex = (PFNGLDRAWELEMENTSBASEVERTEX_PROC*)glfwGetProcAddress("glDrawElementsBaseVertex");
-    bindings->glDrawRangeElementsBaseVertex = (PFNGLDRAWRANGEELEMENTSBASEVERTEX_PROC*)glfwGetProcAddress("glDrawRangeElementsBaseVertex");
-    bindings->glDrawElementsInstancedBaseVertex = (PFNGLDRAWELEMENTSINSTANCEDBASEVERTEX_PROC*)glfwGetProcAddress("glDrawElementsInstancedBaseVertex");
-    bindings->glMultiDrawElementsBaseVertex = (PFNGLMULTIDRAWELEMENTSBASEVERTEX_PROC*)glfwGetProcAddress("glMultiDrawElementsBaseVertex");
-    bindings->glProvokingVertex = (PFNGLPROVOKINGVERTEX_PROC*)glfwGetProcAddress("glProvokingVertex");
-    bindings->glFenceSync = (PFNGLFENCESYNC_PROC*)glfwGetProcAddress("glFenceSync");
-    bindings->glIsSync = (PFNGLISSYNC_PROC*)glfwGetProcAddress("glIsSync");
-    bindings->glDeleteSync = (PFNGLDELETESYNC_PROC*)glfwGetProcAddress("glDeleteSync");
-    bindings->glClientWaitSync = (PFNGLCLIENTWAITSYNC_PROC*)glfwGetProcAddress("glClientWaitSync");
-    bindings->glWaitSync = (PFNGLWAITSYNC_PROC*)glfwGetProcAddress("glWaitSync");
-    bindings->glGetInteger64v = (PFNGLGETINTEGER64V_PROC*)glfwGetProcAddress("glGetInteger64v");
-    bindings->glGetSynciv = (PFNGLGETSYNCIV_PROC*)glfwGetProcAddress("glGetSynciv");
-    bindings->glGetInteger64i_v = (PFNGLGETINTEGER64I_V_PROC*)glfwGetProcAddress("glGetInteger64i_v");
-    bindings->glGetBufferParameteri64v = (PFNGLGETBUFFERPARAMETERI64V_PROC*)glfwGetProcAddress("glGetBufferParameteri64v");
-    bindings->glFramebufferTexture = (PFNGLFRAMEBUFFERTEXTURE_PROC*)glfwGetProcAddress("glFramebufferTexture");
-    bindings->glTexImage2DMultisample = (PFNGLTEXIMAGE2DMULTISAMPLE_PROC*)glfwGetProcAddress("glTexImage2DMultisample");
-    bindings->glTexImage3DMultisample = (PFNGLTEXIMAGE3DMULTISAMPLE_PROC*)glfwGetProcAddress("glTexImage3DMultisample");
-    bindings->glGetMultisamplefv = (PFNGLGETMULTISAMPLEFV_PROC*)glfwGetProcAddress("glGetMultisamplefv");
-    bindings->glSampleMaski = (PFNGLSAMPLEMASKI_PROC*)glfwGetProcAddress("glSampleMaski");
-
-    /* GL_VERSION_3_3 */
-
-    bindings->glBindFragDataLocationIndexed = (PFNGLBINDFRAGDATALOCATIONINDEXED_PROC*)glfwGetProcAddress("glBindFragDataLocationIndexed");
-    bindings->glGetFragDataIndex = (PFNGLGETFRAGDATAINDEX_PROC*)glfwGetProcAddress("glGetFragDataIndex");
-    bindings->glGenSamplers = (PFNGLGENSAMPLERS_PROC*)glfwGetProcAddress("glGenSamplers");
-    bindings->glDeleteSamplers = (PFNGLDELETESAMPLERS_PROC*)glfwGetProcAddress("glDeleteSamplers");
-    bindings->glIsSampler = (PFNGLISSAMPLER_PROC*)glfwGetProcAddress("glIsSampler");
-    bindings->glBindSampler = (PFNGLBINDSAMPLER_PROC*)glfwGetProcAddress("glBindSampler");
-    bindings->glSamplerParameteri = (PFNGLSAMPLERPARAMETERI_PROC*)glfwGetProcAddress("glSamplerParameteri");
-    bindings->glSamplerParameteriv = (PFNGLSAMPLERPARAMETERIV_PROC*)glfwGetProcAddress("glSamplerParameteriv");
-    bindings->glSamplerParameterf = (PFNGLSAMPLERPARAMETERF_PROC*)glfwGetProcAddress("glSamplerParameterf");
-    bindings->glSamplerParameterfv = (PFNGLSAMPLERPARAMETERFV_PROC*)glfwGetProcAddress("glSamplerParameterfv");
-    bindings->glSamplerParameterIiv = (PFNGLSAMPLERPARAMETERIIV_PROC*)glfwGetProcAddress("glSamplerParameterIiv");
-    bindings->glSamplerParameterIuiv = (PFNGLSAMPLERPARAMETERIUIV_PROC*)glfwGetProcAddress("glSamplerParameterIuiv");
-    bindings->glGetSamplerParameteriv = (PFNGLGETSAMPLERPARAMETERIV_PROC*)glfwGetProcAddress("glGetSamplerParameteriv");
-    bindings->glGetSamplerParameterIiv = (PFNGLGETSAMPLERPARAMETERIIV_PROC*)glfwGetProcAddress("glGetSamplerParameterIiv");
-    bindings->glGetSamplerParameterfv = (PFNGLGETSAMPLERPARAMETERFV_PROC*)glfwGetProcAddress("glGetSamplerParameterfv");
-    bindings->glGetSamplerParameterIuiv = (PFNGLGETSAMPLERPARAMETERIUIV_PROC*)glfwGetProcAddress("glGetSamplerParameterIuiv");
-    bindings->glQueryCounter = (PFNGLQUERYCOUNTER_PROC*)glfwGetProcAddress("glQueryCounter");
-    bindings->glGetQueryObjecti64v = (PFNGLGETQUERYOBJECTI64V_PROC*)glfwGetProcAddress("glGetQueryObjecti64v");
-    bindings->glGetQueryObjectui64v = (PFNGLGETQUERYOBJECTUI64V_PROC*)glfwGetProcAddress("glGetQueryObjectui64v");
-    bindings->glVertexAttribDivisor = (PFNGLVERTEXATTRIBDIVISOR_PROC*)glfwGetProcAddress("glVertexAttribDivisor");
-    bindings->glVertexAttribP1ui = (PFNGLVERTEXATTRIBP1UI_PROC*)glfwGetProcAddress("glVertexAttribP1ui");
-    bindings->glVertexAttribP1uiv = (PFNGLVERTEXATTRIBP1UIV_PROC*)glfwGetProcAddress("glVertexAttribP1uiv");
-    bindings->glVertexAttribP2ui = (PFNGLVERTEXATTRIBP2UI_PROC*)glfwGetProcAddress("glVertexAttribP2ui");
-    bindings->glVertexAttribP2uiv = (PFNGLVERTEXATTRIBP2UIV_PROC*)glfwGetProcAddress("glVertexAttribP2uiv");
-    bindings->glVertexAttribP3ui = (PFNGLVERTEXATTRIBP3UI_PROC*)glfwGetProcAddress("glVertexAttribP3ui");
-    bindings->glVertexAttribP3uiv = (PFNGLVERTEXATTRIBP3UIV_PROC*)glfwGetProcAddress("glVertexAttribP3uiv");
-    bindings->glVertexAttribP4ui = (PFNGLVERTEXATTRIBP4UI_PROC*)glfwGetProcAddress("glVertexAttribP4ui");
-    bindings->glVertexAttribP4uiv = (PFNGLVERTEXATTRIBP4UIV_PROC*)glfwGetProcAddress("glVertexAttribP4uiv");
-
 }
 
 /* ----------------------- Extension flag definitions ---------------------- */
diff --git a/examples/protonect/src/flextGL.h b/examples/protonect/src/flextGL.h
index 3da3d1c9c..807d742fc 100644
--- a/examples/protonect/src/flextGL.h
+++ b/examples/protonect/src/flextGL.h
@@ -1,6 +1,3 @@
-/* WARNING: This file was automatically generated */
-/* Do not edit. */
-
 #ifndef __gl_h_
 #define __gl_h_
 
@@ -840,92 +837,6 @@ typedef struct __GLsync *GLsync;
 #define GL_UNIFORM_BLOCK_REFERENCED_BY_FRAGMENT_SHADER 0x8A46
 #define GL_INVALID_INDEX 0xFFFFFFFFu
 
-/* GL_VERSION_3_2 */
-
-#define GL_CONTEXT_CORE_PROFILE_BIT 0x00000001
-#define GL_CONTEXT_COMPATIBILITY_PROFILE_BIT 0x00000002
-#define GL_LINES_ADJACENCY 0x000A
-#define GL_LINE_STRIP_ADJACENCY 0x000B
-#define GL_TRIANGLES_ADJACENCY 0x000C
-#define GL_TRIANGLE_STRIP_ADJACENCY 0x000D
-#define GL_PROGRAM_POINT_SIZE 0x8642
-#define GL_MAX_GEOMETRY_TEXTURE_IMAGE_UNITS 0x8C29
-#define GL_FRAMEBUFFER_ATTACHMENT_LAYERED 0x8DA7
-#define GL_FRAMEBUFFER_INCOMPLETE_LAYER_TARGETS 0x8DA8
-#define GL_GEOMETRY_SHADER 0x8DD9
-#define GL_GEOMETRY_VERTICES_OUT 0x8916
-#define GL_GEOMETRY_INPUT_TYPE 0x8917
-#define GL_GEOMETRY_OUTPUT_TYPE 0x8918
-#define GL_MAX_GEOMETRY_UNIFORM_COMPONENTS 0x8DDF
-#define GL_MAX_GEOMETRY_OUTPUT_VERTICES 0x8DE0
-#define GL_MAX_GEOMETRY_TOTAL_OUTPUT_COMPONENTS 0x8DE1
-#define GL_MAX_VERTEX_OUTPUT_COMPONENTS 0x9122
-#define GL_MAX_GEOMETRY_INPUT_COMPONENTS 0x9123
-#define GL_MAX_GEOMETRY_OUTPUT_COMPONENTS 0x9124
-#define GL_MAX_FRAGMENT_INPUT_COMPONENTS 0x9125
-#define GL_CONTEXT_PROFILE_MASK 0x9126
-#define GL_DEPTH_CLAMP 0x864F
-#define GL_QUADS_FOLLOW_PROVOKING_VERTEX_CONVENTION 0x8E4C
-#define GL_FIRST_VERTEX_CONVENTION 0x8E4D
-#define GL_LAST_VERTEX_CONVENTION 0x8E4E
-#define GL_PROVOKING_VERTEX 0x8E4F
-#define GL_TEXTURE_CUBE_MAP_SEAMLESS 0x884F
-#define GL_MAX_SERVER_WAIT_TIMEOUT 0x9111
-#define GL_OBJECT_TYPE 0x9112
-#define GL_SYNC_CONDITION 0x9113
-#define GL_SYNC_STATUS 0x9114
-#define GL_SYNC_FLAGS 0x9115
-#define GL_SYNC_FENCE 0x9116
-#define GL_SYNC_GPU_COMMANDS_COMPLETE 0x9117
-#define GL_UNSIGNALED 0x9118
-#define GL_SIGNALED 0x9119
-#define GL_ALREADY_SIGNALED 0x911A
-#define GL_TIMEOUT_EXPIRED 0x911B
-#define GL_CONDITION_SATISFIED 0x911C
-#define GL_WAIT_FAILED 0x911D
-#define GL_TIMEOUT_IGNORED 0xFFFFFFFFFFFFFFFFull
-#define GL_SYNC_FLUSH_COMMANDS_BIT 0x00000001
-#define GL_SAMPLE_POSITION 0x8E50
-#define GL_SAMPLE_MASK 0x8E51
-#define GL_SAMPLE_MASK_VALUE 0x8E52
-#define GL_MAX_SAMPLE_MASK_WORDS 0x8E59
-#define GL_TEXTURE_2D_MULTISAMPLE 0x9100
-#define GL_PROXY_TEXTURE_2D_MULTISAMPLE 0x9101
-#define GL_TEXTURE_2D_MULTISAMPLE_ARRAY 0x9102
-#define GL_PROXY_TEXTURE_2D_MULTISAMPLE_ARRAY 0x9103
-#define GL_TEXTURE_BINDING_2D_MULTISAMPLE 0x9104
-#define GL_TEXTURE_BINDING_2D_MULTISAMPLE_ARRAY 0x9105
-#define GL_TEXTURE_SAMPLES 0x9106
-#define GL_TEXTURE_FIXED_SAMPLE_LOCATIONS 0x9107
-#define GL_SAMPLER_2D_MULTISAMPLE 0x9108
-#define GL_INT_SAMPLER_2D_MULTISAMPLE 0x9109
-#define GL_UNSIGNED_INT_SAMPLER_2D_MULTISAMPLE 0x910A
-#define GL_SAMPLER_2D_MULTISAMPLE_ARRAY 0x910B
-#define GL_INT_SAMPLER_2D_MULTISAMPLE_ARRAY 0x910C
-#define GL_UNSIGNED_INT_SAMPLER_2D_MULTISAMPLE_ARRAY 0x910D
-#define GL_MAX_COLOR_TEXTURE_SAMPLES 0x910E
-#define GL_MAX_DEPTH_TEXTURE_SAMPLES 0x910F
-#define GL_MAX_INTEGER_SAMPLES 0x9110
-
-/* GL_VERSION_3_3 */
-
-#define GL_VERTEX_ATTRIB_ARRAY_DIVISOR 0x88FE
-#define GL_SRC1_COLOR 0x88F9
-#define GL_ONE_MINUS_SRC1_COLOR 0x88FA
-#define GL_ONE_MINUS_SRC1_ALPHA 0x88FB
-#define GL_MAX_DUAL_SOURCE_DRAW_BUFFERS 0x88FC
-#define GL_ANY_SAMPLES_PASSED 0x8C2F
-#define GL_SAMPLER_BINDING 0x8919
-#define GL_RGB10_A2UI 0x906F
-#define GL_TEXTURE_SWIZZLE_R 0x8E42
-#define GL_TEXTURE_SWIZZLE_G 0x8E43
-#define GL_TEXTURE_SWIZZLE_B 0x8E44
-#define GL_TEXTURE_SWIZZLE_A 0x8E45
-#define GL_TEXTURE_SWIZZLE_RGBA 0x8E46
-#define GL_TIME_ELAPSED 0x88BF
-#define GL_TIMESTAMP 0x8E28
-#define GL_INT_2_10_10_10_REV 0x8D9F
-
 /* --------------------------- FUNCTION PROTOTYPES --------------------------- */
 
     
@@ -1257,59 +1168,6 @@ typedef void (APIENTRY PFNGLGETACTIVEUNIFORMBLOCKIV_PROC (GLuint program, GLuint
 typedef void (APIENTRY PFNGLGETACTIVEUNIFORMBLOCKNAME_PROC (GLuint program, GLuint uniformBlockIndex, GLsizei bufSize, GLsizei * length, GLchar * uniformBlockName));
 typedef void (APIENTRY PFNGLUNIFORMBLOCKBINDING_PROC (GLuint program, GLuint uniformBlockIndex, GLuint uniformBlockBinding));
     
-/* GL_VERSION_3_2 */
-  
-typedef void (APIENTRY PFNGLDRAWELEMENTSBASEVERTEX_PROC (GLenum mode, GLsizei count, GLenum type, const void * indices, GLint basevertex));
-typedef void (APIENTRY PFNGLDRAWRANGEELEMENTSBASEVERTEX_PROC (GLenum mode, GLuint start, GLuint end, GLsizei count, GLenum type, const void * indices, GLint basevertex));
-typedef void (APIENTRY PFNGLDRAWELEMENTSINSTANCEDBASEVERTEX_PROC (GLenum mode, GLsizei count, GLenum type, const void * indices, GLsizei instancecount, GLint basevertex));
-typedef void (APIENTRY PFNGLMULTIDRAWELEMENTSBASEVERTEX_PROC (GLenum mode, const GLsizei * count, GLenum type, const void *const* indices, GLsizei drawcount, const GLint * basevertex));
-typedef void (APIENTRY PFNGLPROVOKINGVERTEX_PROC (GLenum mode));
-typedef GLsync (APIENTRY PFNGLFENCESYNC_PROC (GLenum condition, GLbitfield flags));
-typedef GLboolean (APIENTRY PFNGLISSYNC_PROC (GLsync sync));
-typedef void (APIENTRY PFNGLDELETESYNC_PROC (GLsync sync));
-typedef GLenum (APIENTRY PFNGLCLIENTWAITSYNC_PROC (GLsync sync, GLbitfield flags, GLuint64 timeout));
-typedef void (APIENTRY PFNGLWAITSYNC_PROC (GLsync sync, GLbitfield flags, GLuint64 timeout));
-typedef void (APIENTRY PFNGLGETINTEGER64V_PROC (GLenum pname, GLint64 * data));
-typedef void (APIENTRY PFNGLGETSYNCIV_PROC (GLsync sync, GLenum pname, GLsizei bufSize, GLsizei * length, GLint * values));
-typedef void (APIENTRY PFNGLGETINTEGER64I_V_PROC (GLenum target, GLuint index, GLint64 * data));
-typedef void (APIENTRY PFNGLGETBUFFERPARAMETERI64V_PROC (GLenum target, GLenum pname, GLint64 * params));
-typedef void (APIENTRY PFNGLFRAMEBUFFERTEXTURE_PROC (GLenum target, GLenum attachment, GLuint texture, GLint level));
-typedef void (APIENTRY PFNGLTEXIMAGE2DMULTISAMPLE_PROC (GLenum target, GLsizei samples, GLenum internalformat, GLsizei width, GLsizei height, GLboolean fixedsamplelocations));
-typedef void (APIENTRY PFNGLTEXIMAGE3DMULTISAMPLE_PROC (GLenum target, GLsizei samples, GLenum internalformat, GLsizei width, GLsizei height, GLsizei depth, GLboolean fixedsamplelocations));
-typedef void (APIENTRY PFNGLGETMULTISAMPLEFV_PROC (GLenum pname, GLuint index, GLfloat * val));
-typedef void (APIENTRY PFNGLSAMPLEMASKI_PROC (GLuint maskNumber, GLbitfield mask));
-    
-/* GL_VERSION_3_3 */
-  
-typedef void (APIENTRY PFNGLBINDFRAGDATALOCATIONINDEXED_PROC (GLuint program, GLuint colorNumber, GLuint index, const GLchar * name));
-typedef GLint (APIENTRY PFNGLGETFRAGDATAINDEX_PROC (GLuint program, const GLchar * name));
-typedef void (APIENTRY PFNGLGENSAMPLERS_PROC (GLsizei count, GLuint * samplers));
-typedef void (APIENTRY PFNGLDELETESAMPLERS_PROC (GLsizei count, const GLuint * samplers));
-typedef GLboolean (APIENTRY PFNGLISSAMPLER_PROC (GLuint sampler));
-typedef void (APIENTRY PFNGLBINDSAMPLER_PROC (GLuint unit, GLuint sampler));
-typedef void (APIENTRY PFNGLSAMPLERPARAMETERI_PROC (GLuint sampler, GLenum pname, GLint param));
-typedef void (APIENTRY PFNGLSAMPLERPARAMETERIV_PROC (GLuint sampler, GLenum pname, const GLint * param));
-typedef void (APIENTRY PFNGLSAMPLERPARAMETERF_PROC (GLuint sampler, GLenum pname, GLfloat param));
-typedef void (APIENTRY PFNGLSAMPLERPARAMETERFV_PROC (GLuint sampler, GLenum pname, const GLfloat * param));
-typedef void (APIENTRY PFNGLSAMPLERPARAMETERIIV_PROC (GLuint sampler, GLenum pname, const GLint * param));
-typedef void (APIENTRY PFNGLSAMPLERPARAMETERIUIV_PROC (GLuint sampler, GLenum pname, const GLuint * param));
-typedef void (APIENTRY PFNGLGETSAMPLERPARAMETERIV_PROC (GLuint sampler, GLenum pname, GLint * params));
-typedef void (APIENTRY PFNGLGETSAMPLERPARAMETERIIV_PROC (GLuint sampler, GLenum pname, GLint * params));
-typedef void (APIENTRY PFNGLGETSAMPLERPARAMETERFV_PROC (GLuint sampler, GLenum pname, GLfloat * params));
-typedef void (APIENTRY PFNGLGETSAMPLERPARAMETERIUIV_PROC (GLuint sampler, GLenum pname, GLuint * params));
-typedef void (APIENTRY PFNGLQUERYCOUNTER_PROC (GLuint id, GLenum target));
-typedef void (APIENTRY PFNGLGETQUERYOBJECTI64V_PROC (GLuint id, GLenum pname, GLint64 * params));
-typedef void (APIENTRY PFNGLGETQUERYOBJECTUI64V_PROC (GLuint id, GLenum pname, GLuint64 * params));
-typedef void (APIENTRY PFNGLVERTEXATTRIBDIVISOR_PROC (GLuint index, GLuint divisor));
-typedef void (APIENTRY PFNGLVERTEXATTRIBP1UI_PROC (GLuint index, GLenum type, GLboolean normalized, GLuint value));
-typedef void (APIENTRY PFNGLVERTEXATTRIBP1UIV_PROC (GLuint index, GLenum type, GLboolean normalized, const GLuint * value));
-typedef void (APIENTRY PFNGLVERTEXATTRIBP2UI_PROC (GLuint index, GLenum type, GLboolean normalized, GLuint value));
-typedef void (APIENTRY PFNGLVERTEXATTRIBP2UIV_PROC (GLuint index, GLenum type, GLboolean normalized, const GLuint * value));
-typedef void (APIENTRY PFNGLVERTEXATTRIBP3UI_PROC (GLuint index, GLenum type, GLboolean normalized, GLuint value));
-typedef void (APIENTRY PFNGLVERTEXATTRIBP3UIV_PROC (GLuint index, GLenum type, GLboolean normalized, const GLuint * value));
-typedef void (APIENTRY PFNGLVERTEXATTRIBP4UI_PROC (GLuint index, GLenum type, GLboolean normalized, GLuint value));
-typedef void (APIENTRY PFNGLVERTEXATTRIBP4UIV_PROC (GLuint index, GLenum type, GLboolean normalized, const GLuint * value));
-        
 struct OpenGLBindings
 {
     
@@ -1573,58 +1431,6 @@ struct OpenGLBindings
   PFNGLGETACTIVEUNIFORMBLOCKNAME_PROC* glGetActiveUniformBlockName;
   PFNGLUNIFORMBLOCKBINDING_PROC* glUniformBlockBinding;
     
-  /* GL_VERSION_3_2 */
-
-  PFNGLDRAWELEMENTSBASEVERTEX_PROC* glDrawElementsBaseVertex;
-  PFNGLDRAWRANGEELEMENTSBASEVERTEX_PROC* glDrawRangeElementsBaseVertex;
-  PFNGLDRAWELEMENTSINSTANCEDBASEVERTEX_PROC* glDrawElementsInstancedBaseVertex;
-  PFNGLMULTIDRAWELEMENTSBASEVERTEX_PROC* glMultiDrawElementsBaseVertex;
-  PFNGLPROVOKINGVERTEX_PROC* glProvokingVertex;
-  PFNGLFENCESYNC_PROC* glFenceSync;
-  PFNGLISSYNC_PROC* glIsSync;
-  PFNGLDELETESYNC_PROC* glDeleteSync;
-  PFNGLCLIENTWAITSYNC_PROC* glClientWaitSync;
-  PFNGLWAITSYNC_PROC* glWaitSync;
-  PFNGLGETINTEGER64V_PROC* glGetInteger64v;
-  PFNGLGETSYNCIV_PROC* glGetSynciv;
-  PFNGLGETINTEGER64I_V_PROC* glGetInteger64i_v;
-  PFNGLGETBUFFERPARAMETERI64V_PROC* glGetBufferParameteri64v;
-  PFNGLFRAMEBUFFERTEXTURE_PROC* glFramebufferTexture;
-  PFNGLTEXIMAGE2DMULTISAMPLE_PROC* glTexImage2DMultisample;
-  PFNGLTEXIMAGE3DMULTISAMPLE_PROC* glTexImage3DMultisample;
-  PFNGLGETMULTISAMPLEFV_PROC* glGetMultisamplefv;
-  PFNGLSAMPLEMASKI_PROC* glSampleMaski;
-    
-  /* GL_VERSION_3_3 */
-
-  PFNGLBINDFRAGDATALOCATIONINDEXED_PROC* glBindFragDataLocationIndexed;
-  PFNGLGETFRAGDATAINDEX_PROC* glGetFragDataIndex;
-  PFNGLGENSAMPLERS_PROC* glGenSamplers;
-  PFNGLDELETESAMPLERS_PROC* glDeleteSamplers;
-  PFNGLISSAMPLER_PROC* glIsSampler;
-  PFNGLBINDSAMPLER_PROC* glBindSampler;
-  PFNGLSAMPLERPARAMETERI_PROC* glSamplerParameteri;
-  PFNGLSAMPLERPARAMETERIV_PROC* glSamplerParameteriv;
-  PFNGLSAMPLERPARAMETERF_PROC* glSamplerParameterf;
-  PFNGLSAMPLERPARAMETERFV_PROC* glSamplerParameterfv;
-  PFNGLSAMPLERPARAMETERIIV_PROC* glSamplerParameterIiv;
-  PFNGLSAMPLERPARAMETERIUIV_PROC* glSamplerParameterIuiv;
-  PFNGLGETSAMPLERPARAMETERIV_PROC* glGetSamplerParameteriv;
-  PFNGLGETSAMPLERPARAMETERIIV_PROC* glGetSamplerParameterIiv;
-  PFNGLGETSAMPLERPARAMETERFV_PROC* glGetSamplerParameterfv;
-  PFNGLGETSAMPLERPARAMETERIUIV_PROC* glGetSamplerParameterIuiv;
-  PFNGLQUERYCOUNTER_PROC* glQueryCounter;
-  PFNGLGETQUERYOBJECTI64V_PROC* glGetQueryObjecti64v;
-  PFNGLGETQUERYOBJECTUI64V_PROC* glGetQueryObjectui64v;
-  PFNGLVERTEXATTRIBDIVISOR_PROC* glVertexAttribDivisor;
-  PFNGLVERTEXATTRIBP1UI_PROC* glVertexAttribP1ui;
-  PFNGLVERTEXATTRIBP1UIV_PROC* glVertexAttribP1uiv;
-  PFNGLVERTEXATTRIBP2UI_PROC* glVertexAttribP2ui;
-  PFNGLVERTEXATTRIBP2UIV_PROC* glVertexAttribP2uiv;
-  PFNGLVERTEXATTRIBP3UI_PROC* glVertexAttribP3ui;
-  PFNGLVERTEXATTRIBP3UIV_PROC* glVertexAttribP3uiv;
-  PFNGLVERTEXATTRIBP4UI_PROC* glVertexAttribP4ui;
-  PFNGLVERTEXATTRIBP4UIV_PROC* glVertexAttribP4uiv;
 };
 
 typedef struct OpenGLBindings OpenGLBindings;
@@ -1641,20 +1447,13 @@ typedef struct OpenGLBindings OpenGLBindings;
 #define GL_VERSION_2_1
 #define GL_VERSION_3_0
 #define GL_VERSION_3_1
-#define GL_VERSION_3_2
-#define GL_VERSION_3_3
 
 /* ---------------------- Flags for optional extensions ---------------------- */
 
-
-
-struct GLFWwindow;
-typedef struct GLFWwindow GLFWwindow;
-
-int flextInit(GLFWwindow* window, OpenGLBindings *bindings);
+void flextInit(OpenGLBindings *bindings);
 
 #define FLEXT_MAJOR_VERSION 3
-#define FLEXT_MINOR_VERSION 3
+#define FLEXT_MINOR_VERSION 1
 #define FLEXT_CORE_PROFILE 1
 
 #ifdef __cplusplus
diff --git a/examples/protonect/src/libfreenect2.cpp b/examples/protonect/src/libfreenect2.cpp
index 88d52b225..a441e11ba 100644
--- a/examples/protonect/src/libfreenect2.cpp
+++ b/examples/protonect/src/libfreenect2.cpp
@@ -28,6 +28,7 @@
 #include <vector>
 #include <algorithm>
 #include <libusb.h>
+#define WRITE_LIBUSB_ERROR(__RESULT) libusb_error_name(__RESULT) << " " << libusb_strerror((libusb_error)__RESULT)
 
 #include <libfreenect2/libfreenect2.hpp>
 
@@ -101,13 +102,16 @@ class Freenect2DeviceImpl : public Freenect2Device
 struct PrintBusAndDevice
 {
   libusb_device *dev_;
+  int status_;
 
-  PrintBusAndDevice(libusb_device *dev) : dev_(dev) {}
+  PrintBusAndDevice(libusb_device *dev, int status = 0) : dev_(dev), status_(status) {}
 };
 
 std::ostream &operator<<(std::ostream &out, const PrintBusAndDevice& dev)
 {
   out << "@" << int(libusb_get_bus_number(dev.dev_)) << ":" << int(libusb_get_device_address(dev.dev_));
+  if (dev.status_)
+    out << " " << WRITE_LIBUSB_ERROR(dev.status_);
   return out;
 }
 
@@ -130,26 +134,39 @@ class Freenect2Impl
   UsbDeviceVector enumerated_devices_;
   DeviceVector devices_;
 
+  bool initialized;
+
   Freenect2Impl(void *usb_context) :
     managed_usb_context_(usb_context == 0),
     usb_context_(reinterpret_cast<libusb_context *>(usb_context)),
+    initialized(false),
     has_device_enumeration_(false)
   {
+    if (libusb_get_version()->nano < 10952)
+    {
+      LOG_ERROR << "Your libusb does not support large iso buffer!";
+      return;
+    }
+
     if(managed_usb_context_)
     {
       int r = libusb_init(&usb_context_);
-      // TODO: error handling
       if(r != 0)
       {
-        LOG_ERROR << "failed to create usb context!";
+        LOG_ERROR << "failed to create usb context: " << WRITE_LIBUSB_ERROR(r);
+        return;
       }
     }
 
     usb_event_loop_.start(usb_context_);
+    initialized = true;
   }
 
   ~Freenect2Impl()
   {
+    if (!initialized)
+      return;
+
     clearDevices();
     clearDeviceEnumeration();
 
@@ -165,11 +182,17 @@ class Freenect2Impl
 
   void addDevice(Freenect2DeviceImpl *device)
   {
+    if (!initialized)
+      return;
+
     devices_.push_back(device);
   }
 
   void removeDevice(Freenect2DeviceImpl *device)
   {
+    if (!initialized)
+      return;
+
     DeviceVector::iterator it = std::find(devices_.begin(), devices_.end(), device);
 
     if(it != devices_.end())
@@ -184,6 +207,9 @@ class Freenect2Impl
 
   bool tryGetDevice(libusb_device *usb_device, Freenect2DeviceImpl **device)
   {
+    if (!initialized)
+      return false;
+
     for(DeviceVector::iterator it = devices_.begin(); it != devices_.end(); ++it)
     {
       if((*it)->isSameUsbDevice(usb_device))
@@ -198,6 +224,9 @@ class Freenect2Impl
 
   void clearDevices()
   {
+    if (!initialized)
+      return;
+
     DeviceVector devices(devices_.begin(), devices_.end());
 
     for(DeviceVector::iterator it = devices.begin(); it != devices.end(); ++it)
@@ -213,6 +242,9 @@ class Freenect2Impl
 
   void clearDeviceEnumeration()
   {
+    if (!initialized)
+      return;
+
     // free enumerated device pointers, this should not affect opened devices
     for(UsbDeviceVector::iterator it = enumerated_devices_.begin(); it != enumerated_devices_.end(); ++it)
     {
@@ -225,6 +257,9 @@ class Freenect2Impl
 
   void enumerateDevices()
   {
+    if (!initialized)
+      return;
+
     LOG_INFO << "enumerating devices...";
     libusb_device **device_list;
     int num_devices = libusb_get_device_list(usb_context_, &device_list);
@@ -277,14 +312,14 @@ class Freenect2Impl
               }
               else
               {
-                LOG_ERROR << "failed to get serial number of Kinect v2 " << PrintBusAndDevice(dev) << "!";
+                LOG_ERROR << "failed to get serial number of Kinect v2: " << PrintBusAndDevice(dev, r);
               }
 
               libusb_close(dev_handle);
             }
             else
             {
-              LOG_ERROR << "failed to open Kinect v2 " << PrintBusAndDevice(dev) << "!";
+              LOG_ERROR << "failed to open Kinect v2: " << PrintBusAndDevice(dev, r);
             }
           }
         }
@@ -300,6 +335,9 @@ class Freenect2Impl
 
   int getNumDevices()
   {
+    if (!initialized)
+      return 0;
+
     if(!has_device_enumeration_)
     {
       enumerateDevices();
@@ -654,6 +692,9 @@ int Freenect2::enumerateDevices()
 
 std::string Freenect2::getDeviceSerialNumber(int idx)
 {
+  if (!impl_->initialized)
+    return std::string();
+
   return impl_->enumerated_devices_[idx].serial;
 }
 
@@ -701,7 +742,7 @@ Freenect2Device *Freenect2::openDevice(int idx, const PacketPipeline *pipeline,
 
   if(r != LIBUSB_SUCCESS)
   {
-    LOG_ERROR << "failed to open Kinect v2 " << PrintBusAndDevice(dev.dev) << "!";
+    LOG_ERROR << "failed to open Kinect v2: " << PrintBusAndDevice(dev.dev, r);
     delete pipeline;
 
     return device;
@@ -740,7 +781,7 @@ Freenect2Device *Freenect2::openDevice(int idx, const PacketPipeline *pipeline,
     }
     else if(r != LIBUSB_SUCCESS)
     {
-      LOG_ERROR << "failed to reset Kinect v2 " << PrintBusAndDevice(dev.dev) << "!";
+      LOG_ERROR << "failed to reset Kinect v2: " << PrintBusAndDevice(dev.dev, r);
       delete pipeline;
 
       return device;
@@ -755,7 +796,7 @@ Freenect2Device *Freenect2::openDevice(int idx, const PacketPipeline *pipeline,
     delete device;
     device = 0;
 
-    LOG_ERROR << "failed to open Kinect v2 " << PrintBusAndDevice(dev.dev) << "!";
+    LOG_ERROR << "failed to open Kinect v2: " << PrintBusAndDevice(dev.dev);
   }
 
   return device;
diff --git a/examples/protonect/src/opengl_depth_packet_processor.cpp b/examples/protonect/src/opengl_depth_packet_processor.cpp
index e42b0f73b..1710cd859 100644
--- a/examples/protonect/src/opengl_depth_packet_processor.cpp
+++ b/examples/protonect/src/opengl_depth_packet_processor.cpp
@@ -32,10 +32,17 @@
 #include <GLFW/glfw3.h>
 
 #include <fstream>
-
+#include <string>
+#include <map>
+#include <cstdlib>
 
 #include <stdint.h>
 
+#define CHECKGL() do { \
+for (GLenum glerror = glGetError(); glerror != GL_NO_ERROR; glerror = glGetError()) \
+  LOG_ERROR << "line " << __LINE__ << ": GL error " << glerror; \
+} while(0)
+
 namespace libfreenect2
 {
 
@@ -117,31 +124,66 @@ bool loadBufferFromFile(const std::string& filename, unsigned char *buffer, size
 
 struct ShaderProgram : public WithOpenGLBindings
 {
+  typedef std::map<std::string, int> FragDataMap;
+  FragDataMap frag_data_map_;
   GLuint program, vertex_shader, fragment_shader;
 
   char error_buffer[2048];
 
+  std::string defines;
+  bool is_mesa_checked;
+
   ShaderProgram() :
     program(0),
+    is_mesa_checked(false),
     vertex_shader(0),
     fragment_shader(0)
   {
   }
 
+  void checkMesaBug()
+  {
+    if (is_mesa_checked)
+      return;
+    is_mesa_checked = true;
+    std::string ren((const char*)glGetString(GL_RENDERER));
+    std::string ver((const char*)glGetString(GL_VERSION));
+    if (ren.find("Mesa DRI Intel") == 0)
+    {
+      size_t mesa_pos = ver.rfind("Mesa ");
+      if (mesa_pos != std::string::npos)
+      {
+        double mesa_ver = atof(ver.substr(mesa_pos + 5).c_str());
+        if (mesa_ver < 10.3)
+        {
+          defines += "#define MESA_BUGGY_BOOL_CMP\n";
+          LOG_WARNING << "Working around buggy boolean instructions in your Mesa driver. Mesa DRI 10.3+ is recommended.";
+        }
+      }
+    }
+  }
+
   void setVertexShader(const std::string& src)
   {
-    const char* src_ = src.c_str();
-    int length_ = src.length();
+    checkMesaBug();
+    const GLchar *sources[] = {"#version 140\n", defines.c_str(), src.c_str()};
     vertex_shader = gl()->glCreateShader(GL_VERTEX_SHADER);
-    gl()->glShaderSource(vertex_shader, 1, &src_, &length_);
+    gl()->glShaderSource(vertex_shader, 3, sources, NULL);
+    CHECKGL();
   }
 
   void setFragmentShader(const std::string& src)
   {
-    const char* src_ = src.c_str();
-    int length_ = src.length();
+    checkMesaBug();
+    const GLchar *sources[] = {"#version 140\n", defines.c_str(), src.c_str()};
     fragment_shader = gl()->glCreateShader(GL_FRAGMENT_SHADER);
-    gl()->glShaderSource(fragment_shader, 1, &src_, &length_);
+    gl()->glShaderSource(fragment_shader, 3, sources, NULL);
+    CHECKGL();
+  }
+
+  void bindFragDataLocation(const std::string &name, int output)
+  {
+    frag_data_map_[name] = output;
   }
 
   void build()
@@ -172,6 +214,11 @@ struct ShaderProgram : public WithOpenGLBindings
     gl()->glAttachShader(program, vertex_shader);
     gl()->glAttachShader(program, fragment_shader);
 
+    for(FragDataMap::iterator it = frag_data_map_.begin(); it != frag_data_map_.end(); ++it)
+    {
+      gl()->glBindFragDataLocation(program, it->second, it->first.c_str());
+    }
+
     gl()->glLinkProgram(program);
 
     gl()->glGetProgramiv(program, GL_LINK_STATUS, &status);
@@ -181,6 +228,7 @@ struct ShaderProgram : public WithOpenGLBindings
       gl()->glGetProgramInfoLog(program, sizeof(error_buffer), NULL, error_buffer);
       LOG_ERROR << "failed to link shader program!" << std::endl << error_buffer;
     }
+    CHECKGL();
   }
 
   GLint getAttributeLocation(const std::string& name)
@@ -194,6 +242,7 @@ struct ShaderProgram : public WithOpenGLBindings
     if(idx == -1) return;
 
     gl()->glUniform1i(idx, value);
+    CHECKGL();
   }
 
   void setUniform(const std::string& name, GLfloat value)
@@ -202,6 +251,7 @@ struct ShaderProgram : public WithOpenGLBindings
     if(idx == -1) return;
 
     gl()->glUniform1f(idx, value);
+    CHECKGL();
   }
 
   void setUniformVector3(const std::string& name, GLfloat value[3])
@@ -210,6 +260,7 @@ struct ShaderProgram : public WithOpenGLBindings
     if(idx == -1) return;
 
     gl()->glUniform3fv(idx, 1, value);
+    CHECKGL();
   }
 
   void setUniformMatrix3(const std::string& name, GLfloat value[9])
@@ -218,11 +269,13 @@ struct ShaderProgram : public WithOpenGLBindings
     if(idx == -1) return;
 
     gl()->glUniformMatrix3fv(idx, 1, false, value);
+    CHECKGL();
   }
 
   void use()
   {
     gl()->glUseProgram(program);
+    CHECKGL();
   }
 };
 
@@ -262,10 +315,19 @@ struct Texture : public WithOpenGLBindings
   {
     gl()->glActiveTexture(unit);
     glBindTexture(GL_TEXTURE_RECTANGLE, texture);
+    CHECKGL();
   }
 
   void allocate(size_t new_width, size_t new_height)
   {
+    GLint max_size;
+    glGetIntegerv(GL_MAX_RECTANGLE_TEXTURE_SIZE, &max_size);
+    if (new_width > max_size || new_height > max_size)
+    {
+      LOG_ERROR << "GL_MAX_RECTANGLE_TEXTURE_SIZE is too small: " << max_size;
+      exit(-1);
+    }
+
     width = new_width;
     height = new_height;
     size = height * width * bytes_per_pixel;
@@ -278,6 +340,7 @@ struct Texture : public WithOpenGLBindings
     glTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
     glTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     glTexImage2D(GL_TEXTURE_RECTANGLE, 0, FormatT::InternalFormat, width, height, 0, FormatT::Format, FormatT::Type, 0);
+    CHECKGL();
   }
 
   void upload()
@@ -285,6 +348,7 @@ struct Texture : public WithOpenGLBindings
     bindToUnit(GL_TEXTURE0);
     glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
     glTexSubImage2D(GL_TEXTURE_RECTANGLE, /*level*/0, /*xoffset*/0, /*yoffset*/0, width, height, FormatT::Format, FormatT::Type, data);
+    CHECKGL();
   }
 
   void download()
@@ -295,6 +359,7 @@ struct Texture : public WithOpenGLBindings
   void downloadToBuffer(unsigned char *data)
   {
     glReadPixels(0, 0, width, height, FormatT::Format, FormatT::Type, data);
+    CHECKGL();
   }
 
   void flipY()
@@ -344,10 +409,10 @@ struct OpenGLDepthPacketProcessorImpl : public WithOpenGLBindings, public WithPe
   Texture<U16C1> input_data;
 
   Texture<F32C4> stage1_debug;
-  Texture<F32C3> stage1_data[3];
+  Texture<F32C4> stage1_data[3];
   Texture<F32C1> stage1_infrared;
 
-  Texture<F32C3> filter1_data[2];
+  Texture<F32C4> filter1_data[2];
   Texture<U8C1> filter1_max_edge_test;
   Texture<F32C4> filter1_debug;
 
@@ -434,19 +499,41 @@ struct OpenGLDepthPacketProcessorImpl : public WithOpenGLBindings, public WithPe
     debug.gl(b);
   }
 
+  static void glfwErrorCallback(int error, const char* description)
+  {
+    LOG_ERROR << "GLFW error " << error << " " << description;
+  }
+
+  void checkFBO(GLenum target)
+  {
+    GLenum status = gl()->glCheckFramebufferStatus(target);
+    if (status != GL_FRAMEBUFFER_COMPLETE)
+    {
+      LOG_ERROR << "incomplete FBO " << status;
+      exit(-1);
+    }
+    CHECKGL();
+  }
+
   void initialize()
   {
     ChangeCurrentOpenGLContext ctx(opengl_context_ptr);
     
-    OpenGLBindings *b = new OpenGLBindings();
-    if (flextInit(opengl_context_ptr, b) == 0)
-    {
-        LOG_ERROR << "Failed to initialize flextGL.";
+    int major = glfwGetWindowAttrib(opengl_context_ptr, GLFW_CONTEXT_VERSION_MAJOR);
+    int minor = glfwGetWindowAttrib(opengl_context_ptr, GLFW_CONTEXT_VERSION_MINOR);
+
+    if (major * 10 + minor < 31) {
+        LOG_ERROR << "OpenGL version 3.1 not supported.";
+        LOG_ERROR << "Your version is " << major << "." << minor;
+        LOG_ERROR << "Try updating your graphics driver.";
         exit(-1);
     }
+
+    OpenGLBindings *b = new OpenGLBindings();
+    flextInit(b);
     gl(b);
 
-    input_data.allocate(352, 424 * 10);
+    input_data.allocate(352, 424 * 9);
 
     for(int i = 0; i < 3; ++i)
       stage1_data[i].allocate(512, 424);
@@ -469,24 +556,39 @@ struct OpenGLDepthPacketProcessorImpl : public WithOpenGLBindings, public WithPe
 
     stage1.setVertexShader(loadShaderSource(shader_folder + "default.vs"));
     stage1.setFragmentShader(loadShaderSource(shader_folder + "stage1.fs"));
+    stage1.bindFragDataLocation("Debug", 0);
+    stage1.bindFragDataLocation("A", 1);
+    stage1.bindFragDataLocation("B", 2);
+    stage1.bindFragDataLocation("Norm", 3);
+    stage1.bindFragDataLocation("Infrared", 4);
     stage1.build();
 
     filter1.setVertexShader(loadShaderSource(shader_folder + "default.vs"));
     filter1.setFragmentShader(loadShaderSource(shader_folder + "filter1.fs"));
+    filter1.bindFragDataLocation("Debug", 0);
+    filter1.bindFragDataLocation("FilterA", 1);
+    filter1.bindFragDataLocation("FilterB", 2);
+    filter1.bindFragDataLocation("MaxEdgeTest", 3);
     filter1.build();
 
     stage2.setVertexShader(loadShaderSource(shader_folder + "default.vs"));
     stage2.setFragmentShader(loadShaderSource(shader_folder + "stage2.fs"));
+    stage2.bindFragDataLocation("Debug", 0);
+    stage2.bindFragDataLocation("Depth", 1);
+    stage2.bindFragDataLocation("DepthAndIrSum", 2);
     stage2.build();
 
     filter2.setVertexShader(loadShaderSource(shader_folder + "default.vs"));
     filter2.setFragmentShader(loadShaderSource(shader_folder + "filter2.fs"));
+    filter2.bindFragDataLocation("Debug", 0);
+    filter2.bindFragDataLocation("FilterDepth", 1);
     filter2.build();
 
     if(do_debug)
     {
       debug.setVertexShader(loadShaderSource(shader_folder + "default.vs"));
       debug.setFragmentShader(loadShaderSource(shader_folder + "debug.fs"));
+      debug.bindFragDataLocation("Debug", 0);
       debug.build();
     }
 
@@ -503,6 +605,7 @@ struct OpenGLDepthPacketProcessorImpl : public WithOpenGLBindings, public WithPe
     gl()->glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT2, GL_TEXTURE_RECTANGLE, stage1_data[1].texture, 0);
     gl()->glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT3, GL_TEXTURE_RECTANGLE, stage1_data[2].texture, 0);
     gl()->glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT4, GL_TEXTURE_RECTANGLE, stage1_infrared.texture, 0);
+    checkFBO(GL_DRAW_FRAMEBUFFER);
 
     gl()->glGenFramebuffers(1, &filter1_framebuffer);
     gl()->glBindFramebuffer(GL_DRAW_FRAMEBUFFER, filter1_framebuffer);
@@ -514,6 +617,7 @@ struct OpenGLDepthPacketProcessorImpl : public WithOpenGLBindings, public WithPe
     gl()->glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, GL_TEXTURE_RECTANGLE, filter1_data[0].texture, 0);
     gl()->glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT2, GL_TEXTURE_RECTANGLE, filter1_data[1].texture, 0);
     gl()->glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT3, GL_TEXTURE_RECTANGLE, filter1_max_edge_test.texture, 0);
+    checkFBO(GL_DRAW_FRAMEBUFFER);
 
     gl()->glGenFramebuffers(1, &stage2_framebuffer);
     gl()->glBindFramebuffer(GL_DRAW_FRAMEBUFFER, stage2_framebuffer);
@@ -524,6 +628,7 @@ struct OpenGLDepthPacketProcessorImpl : public WithOpenGLBindings, public WithPe
     if(do_debug) gl()->glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_RECTANGLE, stage2_debug.texture, 0);
     gl()->glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, GL_TEXTURE_RECTANGLE, stage2_depth.texture, 0);
     gl()->glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT2, GL_TEXTURE_RECTANGLE, stage2_depth_and_ir_sum.texture, 0);
+    checkFBO(GL_DRAW_FRAMEBUFFER);
 
     gl()->glGenFramebuffers(1, &filter2_framebuffer);
     gl()->glBindFramebuffer(GL_DRAW_FRAMEBUFFER, filter2_framebuffer);
@@ -533,6 +638,7 @@ struct OpenGLDepthPacketProcessorImpl : public WithOpenGLBindings, public WithPe
 
     if(do_debug) gl()->glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_RECTANGLE, filter2_debug.texture, 0);
     gl()->glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, GL_TEXTURE_RECTANGLE, filter2_depth.texture, 0);
+    checkFBO(GL_DRAW_FRAMEBUFFER);
 
     Vertex bl = {-1.0f, -1.0f, 0.0f, 0.0f }, br = { 1.0f, -1.0f, 512.0f, 0.0f }, tl = {-1.0f, 1.0f, 0.0f, 424.0f }, tr = { 1.0f, 1.0f, 512.0f, 424.0f };
     Vertex vertices[] = {
@@ -545,13 +651,14 @@ struct OpenGLDepthPacketProcessorImpl : public WithOpenGLBindings, public WithPe
     gl()->glBindBuffer(GL_ARRAY_BUFFER, square_vbo);
     gl()->glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
 
-    GLint position_attr = stage1.getAttributeLocation("Position");
+    GLint position_attr = stage1.getAttributeLocation("InputPosition");
     gl()->glVertexAttribPointer(position_attr, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (GLvoid*)0);
     gl()->glEnableVertexAttribArray(position_attr);
 
-    GLint texcoord_attr = stage1.getAttributeLocation("TexCoord");
+    GLint texcoord_attr = stage1.getAttributeLocation("InputTexCoord");
     gl()->glVertexAttribPointer(texcoord_attr, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (GLvoid*)(2 * sizeof(float)));
     gl()->glEnableVertexAttribArray(texcoord_attr);
+    CHECKGL();
   }
 
   void deinitialize()
@@ -619,6 +726,7 @@ struct OpenGLDepthPacketProcessorImpl : public WithOpenGLBindings, public WithPe
 
     gl()->glBindVertexArray(square_vao);
     glDrawArrays(GL_TRIANGLES, 0, 6);
+    CHECKGL();
 
     if(ir != 0)
     {
@@ -652,6 +760,7 @@ struct OpenGLDepthPacketProcessorImpl : public WithOpenGLBindings, public WithPe
 
     stage2.use();
     updateShaderParametersForProgram(stage2);
+    CHECKGL();
 
     if(config.EnableBilateralFilter)
     {
@@ -672,6 +781,7 @@ struct OpenGLDepthPacketProcessorImpl : public WithOpenGLBindings, public WithPe
 
     gl()->glBindVertexArray(square_vao);
     glDrawArrays(GL_TRIANGLES, 0, 6);
+    CHECKGL();
 
     if(config.EnableEdgeAwareFilter)
     {
@@ -705,6 +815,7 @@ struct OpenGLDepthPacketProcessorImpl : public WithOpenGLBindings, public WithPe
         *depth = stage2_depth.downloadToNewFrame();
       }
     }
+    CHECKGL();
 
     if(do_debug)
     {
@@ -732,6 +843,7 @@ struct OpenGLDepthPacketProcessorImpl : public WithOpenGLBindings, public WithPe
 
       glDrawArrays(GL_TRIANGLES, 0, 6);
     }
+    CHECKGL();
 
     params_need_update = false;
   }
@@ -741,6 +853,10 @@ OpenGLDepthPacketProcessor::OpenGLDepthPacketProcessor(void *parent_opengl_conte
 {
   GLFWwindow* parent_window = (GLFWwindow *)parent_opengl_context_ptr;
 
+  GLFWerrorfun prev_func = glfwSetErrorCallback(&OpenGLDepthPacketProcessorImpl::glfwErrorCallback);
+  if (prev_func)
+    glfwSetErrorCallback(prev_func);
+
   // init glfw - if already initialized nothing happens
   if (glfwInit() == GL_FALSE)
   {
@@ -751,11 +867,11 @@ OpenGLDepthPacketProcessor::OpenGLDepthPacketProcessor(void *parent_opengl_conte
   // setup context
   glfwDefaultWindowHints();
   glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
-  glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
+  glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 1);
   #ifdef __APPLE__
     glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
   #endif
-  glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
+  glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_ANY_PROFILE);
   glfwWindowHint(GLFW_VISIBLE, debug ? GL_TRUE : GL_FALSE);
 
   GLFWwindow* window = glfwCreateWindow(1024, 848, "OpenGLDepthPacketProcessor", 0, parent_window);
@@ -914,7 +1030,7 @@ void OpenGLDepthPacketProcessor::process(const DepthPacket &packet)
 
   glfwMakeContextCurrent(impl_->opengl_context_ptr);
 
-  std::copy(packet.buffer, packet.buffer + packet.buffer_length, impl_->input_data.data);
+  std::copy(packet.buffer, packet.buffer + packet.buffer_length/10*9, impl_->input_data.data);
   impl_->input_data.upload();
   impl_->run(has_listener ? &ir : 0, has_listener ? &depth : 0);
 
diff --git a/examples/protonect/src/shader/debug.fs b/examples/protonect/src/shader/debug.fs
index 34dac1298..226e9d216 100644
--- a/examples/protonect/src/shader/debug.fs
+++ b/examples/protonect/src/shader/debug.fs
@@ -1,16 +1,12 @@
-#version 330
-
 uniform sampler2DRect Data;
 
-in VertexData {
-    vec2 TexCoord;
-} FragmentIn;
+in vec2 TexCoord;
 
-layout(location = 0) out vec4 Color;
+out vec4 Color;
 
 void main(void)
 {
-  ivec2 uv = ivec2(FragmentIn.TexCoord.x, FragmentIn.TexCoord.y);
+  ivec2 uv = ivec2(TexCoord.x, TexCoord.y);
   
   Color = texelFetch(Data, uv);
-}
\ No newline at end of file
+}
diff --git a/examples/protonect/src/shader/default.vs b/examples/protonect/src/shader/default.vs
index 8cb838b5a..f8c02096c 100644
--- a/examples/protonect/src/shader/default.vs
+++ b/examples/protonect/src/shader/default.vs
@@ -1,14 +1,10 @@
-#version 330
+in vec2 InputPosition;
+in vec2 InputTexCoord;
 
-in vec2 Position;
-in vec2 TexCoord;
-
-out VertexData {
-  vec2 TexCoord;
-} VertexOut;
+out vec2 TexCoord;
 
 void main(void)
 {
-  gl_Position = vec4(Position, 0.0, 1.0);
-  VertexOut.TexCoord = TexCoord;
-}
\ No newline at end of file
+  gl_Position = vec4(InputPosition, 0.0, 1.0);
+  TexCoord = InputTexCoord;
+}
diff --git a/examples/protonect/src/shader/filter1.fs b/examples/protonect/src/shader/filter1.fs
index 2fb526f6b..50e1d5dae 100644
--- a/examples/protonect/src/shader/filter1.fs
+++ b/examples/protonect/src/shader/filter1.fs
@@ -1,5 +1,3 @@
-#version 330
-
 struct Parameters
 {
   float ab_multiplier;
@@ -40,14 +38,12 @@ uniform sampler2DRect Norm;
 
 uniform Parameters Params;
 
-in VertexData {
-    vec2 TexCoord;
-} FragmentIn;
+in vec2 TexCoord;
 
-layout(location = 0) out vec4 Debug;
-layout(location = 1) out vec3 FilterA;
-layout(location = 2) out vec3 FilterB;
-layout(location = 3) out uint MaxEdgeTest;
+/*layout(location = 0)*/ out vec4 Debug;
+/*layout(location = 1)*/ out vec3 FilterA;
+/*layout(location = 2)*/ out vec3 FilterB;
+/*layout(location = 3)*/ out uint MaxEdgeTest;
 
 void applyBilateralFilter(ivec2 uv)
 {
@@ -115,7 +111,7 @@ void applyBilateralFilter(ivec2 uv)
 
 void main(void)
 {
-  ivec2 uv = ivec2(FragmentIn.TexCoord.x, FragmentIn.TexCoord.y);
+  ivec2 uv = ivec2(TexCoord.x, TexCoord.y);
     
   applyBilateralFilter(uv);
   
@@ -123,4 +119,4 @@ void main(void)
   float i = min(dot(norm, vec3(0.333333333  * Params.ab_multiplier * Params.ab_output_multiplier)), 65535.0);
   
   Debug = vec4(vec3(i, i, i) / 65535.0, 1);
-}
\ No newline at end of file
+}
diff --git a/examples/protonect/src/shader/filter2.fs b/examples/protonect/src/shader/filter2.fs
index 03355e4a7..d1618a0ea 100644
--- a/examples/protonect/src/shader/filter2.fs
+++ b/examples/protonect/src/shader/filter2.fs
@@ -1,5 +1,3 @@
-#version 330
-
 struct Parameters
 {
   float ab_multiplier;
@@ -39,12 +37,10 @@ uniform usampler2DRect MaxEdgeTest;
 
 uniform Parameters Params;
 
-in VertexData {
-    vec2 TexCoord;
-} FragmentIn;
+in vec2 TexCoord;
 
-layout(location = 0) out vec4 Debug;
-layout(location = 1) out float FilterDepth;
+/*layout(location = 0)*/ out vec4 Debug;
+/*layout(location = 1)*/ out float FilterDepth;
 
 void applyEdgeAwareFilter(ivec2 uv)
 {
@@ -126,7 +122,7 @@ void applyEdgeAwareFilter(ivec2 uv)
 
 void main(void)
 {
-  ivec2 uv = ivec2(FragmentIn.TexCoord.x, FragmentIn.TexCoord.y);
+  ivec2 uv = ivec2(TexCoord.x, TexCoord.y);
   
   applyEdgeAwareFilter(uv);
   
diff --git a/examples/protonect/src/shader/stage1.fs b/examples/protonect/src/shader/stage1.fs
index d2fcd0e78..cb6473401 100644
--- a/examples/protonect/src/shader/stage1.fs
+++ b/examples/protonect/src/shader/stage1.fs
@@ -1,5 +1,3 @@
-#version 330
-
 struct Parameters
 {
   float ab_multiplier;
@@ -43,16 +41,14 @@ uniform sampler2DRect ZTable;
 
 uniform Parameters Params;
 
-in VertexData {
-    vec2 TexCoord;
-} FragmentIn;
-
-layout(location = 0) out vec4 Debug;
+in vec2 TexCoord;
 
-layout(location = 1) out vec3 A;
-layout(location = 2) out vec3 B;
-layout(location = 3) out vec3 Norm;
-layout(location = 4) out float Infrared;
+/*layout(location = 0)*/ out vec4 Debug;
+/*                    */
+/*layout(location = 1)*/ out vec3 A;
+/*layout(location = 2)*/ out vec3 B;
+/*layout(location = 3)*/ out vec3 Norm;
+/*layout(location = 4)*/ out float Infrared;
 
 #define M_PI 3.1415926535897932384626433832795
 
@@ -97,7 +93,7 @@ vec2 processMeasurementTriple(in ivec2 uv, in usampler2DRect p0table, in int off
 
 void main(void)
 {
-  ivec2 uv = ivec2(FragmentIn.TexCoord.x, FragmentIn.TexCoord.y);
+  ivec2 uv = ivec2(TexCoord.x, TexCoord.y);
     
   bool valid_pixel = 0.0 < texelFetch(ZTable, uv).x;
   bvec3 saturated = bvec3(valid_pixel);
@@ -106,6 +102,9 @@ void main(void)
   vec2 ab1 = processMeasurementTriple(uv, P0Table1, 3, Params.ab_multiplier_per_frq.y, saturated.y);
   vec2 ab2 = processMeasurementTriple(uv, P0Table2, 6, Params.ab_multiplier_per_frq.z, saturated.z);
   
+#ifdef MESA_BUGGY_BOOL_CMP
+  valid_pixel = valid_pixel ? true : false;
+#endif
   bvec3 invalid_pixel = bvec3(!valid_pixel);
   
   A    = mix(vec3(ab0.x, ab1.x, ab2.x), vec3(0.0), invalid_pixel);
diff --git a/examples/protonect/src/shader/stage2.fs b/examples/protonect/src/shader/stage2.fs
index a06c28f13..c31472cca 100644
--- a/examples/protonect/src/shader/stage2.fs
+++ b/examples/protonect/src/shader/stage2.fs
@@ -1,5 +1,3 @@
-#version 330
-
 struct Parameters
 {
   float ab_multiplier;
@@ -41,19 +39,17 @@ uniform sampler2DRect ZTable;
 
 uniform Parameters Params;
 
-in VertexData {
-    vec2 TexCoord;
-} FragmentIn;
+in vec2 TexCoord;
 
-layout(location = 0) out vec4 Debug;
-layout(location = 1) out float Depth;
-layout(location = 2) out vec2 DepthAndIrSum;
+/*layout(location = 0)*/ out vec4 Debug;
+/*layout(location = 1)*/ out float Depth;
+/*layout(location = 2)*/ out vec2 DepthAndIrSum;
 
 #define M_PI 3.1415926535897932384626433832795
 
 void main(void)
 {
-  ivec2 uv = ivec2(FragmentIn.TexCoord.x, FragmentIn.TexCoord.y);
+  ivec2 uv = ivec2(TexCoord.x, TexCoord.y);
       
   vec3 a = texelFetch(A, uv).xyz;
   vec3 b = texelFetch(B, uv).xyz;
@@ -156,4 +152,4 @@ void main(void)
   DepthAndIrSum = vec2(Depth, ir_sum);
   
   Debug = vec4(vec3(Depth / Params.max_depth), 1.0);
-}
\ No newline at end of file
+}
diff --git a/examples/protonect/src/transfer_pool.cpp b/examples/protonect/src/transfer_pool.cpp
index dfe70921e..31b36f143 100644
--- a/examples/protonect/src/transfer_pool.cpp
+++ b/examples/protonect/src/transfer_pool.cpp
@@ -27,6 +27,8 @@
 #include <libfreenect2/usb/transfer_pool.h>
 #include <libfreenect2/logging.h>
 
+#define WRITE_LIBUSB_ERROR(__RESULT) libusb_error_name(__RESULT) << " " << libusb_strerror((libusb_error)__RESULT)
+
 namespace libfreenect2
 {
 namespace usb
@@ -84,8 +86,10 @@ void TransferPool::submit(size_t num_parallel_transfers)
   if(transfers_.size() < num_parallel_transfers)
   {
     LOG_ERROR << "too few idle transfers!";
+    return;
   }
 
+  size_t failcount = 0;
   for(size_t i = 0; i < num_parallel_transfers; ++i)
   {
     libusb_transfer *transfer = transfers_[i].transfer;
@@ -95,10 +99,14 @@ void TransferPool::submit(size_t num_parallel_transfers)
 
     if(r != LIBUSB_SUCCESS)
     {
-      LOG_ERROR << "failed to submit transfer: " << libusb_error_name(r);
+      LOG_ERROR << "failed to submit transfer: " << WRITE_LIBUSB_ERROR(r);
       transfers_[i].setStopped(true);
+      failcount++;
     }
   }
+
+  if (failcount == num_parallel_transfers)
+    LOG_ERROR << "all submissions failed. Try debugging with environment variable: LIBUSB_DEBUG=4.";
 }
 
 void TransferPool::cancel()
@@ -109,7 +117,7 @@ void TransferPool::cancel()
 
     if(r != LIBUSB_SUCCESS && r != LIBUSB_ERROR_NOT_FOUND)
     {
-      LOG_ERROR << "failed to cancel transfer: " << libusb_error_name(r);
+      LOG_ERROR << "failed to cancel transfer: " << WRITE_LIBUSB_ERROR(r);
     }
   }
 
@@ -186,7 +194,7 @@ void TransferPool::onTransferComplete(TransferPool::Transfer* t)
 
   if(r != LIBUSB_SUCCESS)
   {
-    LOG_ERROR << "failed to submit transfer: " << libusb_error_name(r);
+    LOG_ERROR << "failed to submit transfer: " << WRITE_LIBUSB_ERROR(r);
     t->setStopped(true);
   }
 }
diff --git a/examples/protonect/src/usb_control.cpp b/examples/protonect/src/usb_control.cpp
index 00e3e5da6..8cbdda148 100644
--- a/examples/protonect/src/usb_control.cpp
+++ b/examples/protonect/src/usb_control.cpp
@@ -188,7 +188,7 @@ UsbControl::~UsbControl()
 }
 
 #define CHECK_LIBUSB_RESULT(__CODE, __RESULT) if((__CODE = (__RESULT == LIBUSB_SUCCESS ? Success : Error)) == Error) LOG_ERROR
-#define WRITE_LIBUSB_ERROR(__RESULT) "libusb error " << __RESULT << ": " << libusb_error_name(__RESULT)
+#define WRITE_LIBUSB_ERROR(__RESULT) libusb_error_name(__RESULT) << " " << libusb_strerror((libusb_error)__RESULT) << ". Try debugging with environment variable: export LIBUSB_DEBUG=4 ."
 
 UsbControl::ResultCode UsbControl::setConfiguration()
 {
diff --git a/examples/protonect/viewer.cpp b/examples/protonect/viewer.cpp
index 71801f702..6b086228b 100644
--- a/examples/protonect/viewer.cpp
+++ b/examples/protonect/viewer.cpp
@@ -22,7 +22,7 @@ void Viewer::initialize()
     window = glfwCreateWindow(1280, 800, "Viewer", 0, NULL);
     glfwMakeContextCurrent(window);
     OpenGLBindings *b = new OpenGLBindings();
-    flextInit(window, b);
+    flextInit(b);
     gl(b);
 
     std::string vertexshadersrc = ""