Add initial support for NV_path_rendering extension to gpu command buffer

gpu/command_buffer/service/gles2_cmd_decoder.cc

 // 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.
 
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
 
 #include <stdio.h>
 
 #include <algorithm>
 #include <list>
@@ skipping 969 matching lines @@
   void DoReleaseTexImage2DCHROMIUM(
       GLenum target,
       GLint image_id);
 
   void DoTraceEndCHROMIUM(void);
 
   void DoDrawBuffersEXT(GLsizei count, const GLenum* bufs);
 
   void DoLoseContextCHROMIUM(GLenum current, GLenum other);
 
+  void DoMatrixLoadfCHROMIUM(GLenum matrix_mode, const GLfloat* matrix);
+  void DoMatrixLoadIdentityCHROMIUM(GLenum matrix_mode);
+
   // Creates a Program for the given program.
   Program* CreateProgram(
       GLuint client_id, GLuint service_id) {
     return program_manager()->CreateProgram(client_id, service_id);
   }
 
   // Gets the program info for the given program. Returns NULL if none exists.
   Program* GetProgram(GLuint client_id) {
     return program_manager()->GetProgram(client_id);
   }
@@ skipping 9641 matching lines @@
     group_->set_draw_buffer(bufs[0]);
   }
 }
 
 void GLES2DecoderImpl::DoLoseContextCHROMIUM(GLenum current, GLenum other) {
   group_->LoseContexts(other);
   reset_status_ = current;
   current_decoder_error_ = error::kLostContext;
 }
 
+void GLES2DecoderImpl::DoMatrixLoadfCHROMIUM(GLenum matrix_mode,
+                                             const GLfloat* matrix) {
+  DCHECK(matrix_mode == GL_PATH_PROJECTION_CHROMIUM ||
+         matrix_mode == GL_PATH_MODELVIEW_CHROMIUM);
+  if (!features().chromium_path_rendering) {
+    LOCAL_SET_GL_ERROR(GL_INVALID_OPERATION,
+                       "glMatrixLoadfCHROMIUM",
+                       "function not available");
+    return;
+  }
+
+  GLfloat* target_matrix = matrix_mode == GL_PATH_PROJECTION_CHROMIUM
+                               ? state_.projection_matrix
+                               : state_.modelview_matrix;
+  memcpy(target_matrix, matrix, sizeof(GLfloat) * 16);
+  glMatrixLoadfEXT(matrix_mode, matrix);

[vmiura, 2014/08/25 19:42:22]

We're using GL_PATH_MODELVIEW_CHROMIUM/GL_PATH_PROJECTION_CHROMIUM directly with
glMatrixLoadfEXT.

Could you comment here, and in gl2chromium.h/gl_bindings.h that:
  GL_PATH_MODELVIEW_CHROMIUM == GL_MODELVIEW
  GL_PATH_PROJECTION_CHROMIUM == GL_PROJECTION

[Kimmo Kinnunen, 2014/08/26 06:48:33]

Done.

I added comments here and in gl_bindings.h and in the commit message. I left
gl2chromium.h out because it didn't seem to fit there, hope it's ok.

The thing to note is that conceptually the trick you noticed is done in the
extension spec, not in the patch. In the patch, GL_PATH_MODELVIEW_CHROMIUM
actually corresponds to GL_PATH_MODELVIEW_NV, similarly to
glSomePathFuncCHROMIUM corresponds to glSomePathFuncNV. 

The gl headers in chromium do not yet have the GL_PATH_MODELVIEW_NV, so it can
not, unfortunately, be documented by compile-time assertions.

+}
+
+void GLES2DecoderImpl::DoMatrixLoadIdentityCHROMIUM(GLenum matrix_mode) {
+  DCHECK(matrix_mode == GL_PATH_PROJECTION_CHROMIUM ||
+         matrix_mode == GL_PATH_MODELVIEW_CHROMIUM);
+  if (!features().chromium_path_rendering) {
+    LOCAL_SET_GL_ERROR(GL_INVALID_OPERATION,
+                       "glMatrixLoadIdentityCHROMIUM",
+                       "function not available");
+    return;
+  }
+
+  static GLfloat kIdentityMatrix[16] = {1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f,
+                                        0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f,
+                                        0.0f, 0.0f, 0.0f, 1.0f};
+
+  GLfloat* target_matrix = matrix_mode == GL_PATH_PROJECTION_CHROMIUM
+                               ? state_.projection_matrix
+                               : state_.modelview_matrix;
+  memcpy(target_matrix, kIdentityMatrix, sizeof(kIdentityMatrix));
+  glMatrixLoadIdentityEXT(matrix_mode);
+}
+
 bool GLES2DecoderImpl::ValidateAsyncTransfer(
     const char* function_name,
     TextureRef* texture_ref,
     GLenum target,
     GLint level,
     const void * data) {
   // We only support async uploads to 2D textures for now.
   if (GL_TEXTURE_2D != target) {
     LOCAL_SET_GL_ERROR_INVALID_ENUM(function_name, target, "target");
     return false;
@@ skipping 296 matching lines @@
   }
 }
 
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.
 #include "gpu/command_buffer/service/gles2_cmd_decoder_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu