Use client side arrays for GL_STREAM_DRAW attributes

Certain GPU/drivers are slow when using constantly changing
vertex buffers. They also run out of memory as the pipeline
the buffers so while a buffer is in used being drawn to they
can't delete it immediately when you upload new data to the 
buffer.

This is an attempt to work around that issue seemlessly by
using client side arrays for buffers marked as GL_STREAM_DRAW

BUG=178093


Review URL: https://chromiumcodereview.appspot.com/12494005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@186416 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 18 insertions, 3 deletions

diff --git a/gpu/command_buffer/build_gles2_cmd_buffer.py b/gpu/command_buffer/build_gles2_cmd_buffer.py
index e826abd..a408db7 100755
--- a/gpu/command_buffer/build_gles2_cmd_buffer.py
+++ b/gpu/command_buffer/build_gles2_cmd_buffer.py
@@ -1176,6 +1176,7 @@ _PEPPER_INTERFACES = [
 #               when they can not be automatically determined.
 # pepper_interface: The pepper interface that is used for this extension
 # invalid_test: False if no invalid test needed.
+# shadowed:     True = the value is shadowed so no glGetXXX call will be made.
 
 _FUNCTION_INFO = {
   'ActiveTexture': {
@@ -1563,7 +1564,13 @@ _FUNCTION_INFO = {
     'decoder_func': 'DoGetBooleanv',
     'gl_test_func': 'glGetBooleanv',
   },
-  'GetBufferParameteriv': {'type': 'GETn', 'result': ['SizedResult<GLint>']},
+  'GetBufferParameteriv': {
+    'type': 'GETn',
+    'result': ['SizedResult<GLint>'],
+    'decoder_func': 'DoGetBufferParameteriv',
+    'expectation': False,
+    'shadowed': True,
+  },
   'GetError': {
     'type': 'Is',
     'decoder_func': 'GetGLError',
@@ -4345,11 +4352,19 @@ class GETnHandler(TypeHandler):
   if (result->size != 0) {
     return error::kInvalidArguments;
   }
-  CopyRealGLErrorsToWrapper();
 """
+    shadowed = func.GetInfo('shadowed')
+    if not shadowed:
+      file.Write("  CopyRealGLErrorsToWrapper();\n");
     file.Write(code)
     func.WriteHandlerImplementation(file)
-    code = """  GLenum error = glGetError();
+    if shadowed:
+      code = """  result->SetNumResults(num_values);
+  return error::kNoError;
+}
+"""
+    else:
+     code = """  GLenum error = glGetError();
   if (error == GL_NO_ERROR) {
     result->SetNumResults(num_values);
   } else {