Use NV_draw_buffers to implement EXT_draw_buffers

ui/gl/generate_bindings.py

 #!/usr/bin/env python
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """code generator for GL/GLES extension wrangler."""
 
 import optparse
 import os
 import collections
@@ skipping 198 matching lines @@
 { 'return_type': 'void',
   'names': ['glDisableVertexAttribArray'],
   'arguments': 'GLuint index', },
 { 'return_type': 'void',
   'names': ['glDrawArrays'],
   'arguments': 'GLenum mode, GLint first, GLsizei count', },
 { 'return_type': 'void',
   'names': ['glDrawBuffer'],
   'arguments': 'GLenum mode', },
 { 'return_type': 'void',
-  'names': ['glDrawBuffersARB', 'glDrawBuffersEXT'],
+  'names': ['glDrawBuffersARB', 'glDrawBuffersEXT', 'glDrawBuffers'],

[Zhenyao Mo, 2014/10/09 17:51:32]

I thought the NV extension function is glDrawBuffersNV? That's not defined in
any header files in chromium code base.  How does it magically map from
glDrawBuffersNV to glDrawBuffers?

[oetuaho-nv, 2014/10/10 07:42:15]

The intention is not to use glDrawBuffersNV, which has somewhat different
behavior, but to use glDrawBuffers from GLES3.0. NV_draw_buffers is used only to
enable ESSL 1.0 shaders to reference multiple render targets, the rest will work
according to GLES3.0 API, where DrawBuffers works the same way as in
EXT_draw_buffers.

Should I maybe add more explanation on this, maybe as a comment in
feature_info.cc?

   'arguments': 'GLsizei n, const GLenum* bufs', },
 { 'return_type': 'void',
   'names': ['glDrawElements'],
   'arguments':
       'GLenum mode, GLsizei count, GLenum type, const void* indices', },
 { 'return_type': 'void',
   'names': ['glEGLImageTargetTexture2DOES'],
   'arguments': 'GLenum target, GLeglImageOES image', },
 { 'return_type': 'void',
   'names': ['glEGLImageTargetRenderbufferStorageOES'],
@@ skipping 1849 matching lines @@
 
   source_file = open(os.path.join(directory, 'gl_bindings_autogen_mock.cc'),
                      'wb')
   GenerateMockBindingsSource(source_file, GL_FUNCTIONS)
   source_file.close()
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))