Cache GL's viewport on the GPU command buffer client side.

gpu/command_buffer/client/gles2_implementation.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.
 
 // A class to emulate GLES2 over command buffers.
 
 #include "gpu/command_buffer/client/gles2_implementation.h"
 
 #include <GLES2/gl2.h>
 #include <GLES2/gl2ext.h>
@@ skipping 786 matching lines @@
       return true;
     case GL_MAX_VERTEX_ATTRIBS:
       *params = capabilities_.max_vertex_attribs;
       return true;
     case GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS:
       *params = capabilities_.max_vertex_texture_image_units;
       return true;
     case GL_MAX_VERTEX_UNIFORM_VECTORS:
       *params = capabilities_.max_vertex_uniform_vectors;
       return true;
+    case GL_MAX_VIEWPORT_DIMS:
+      params[0] = capabilities_.max_viewport_width;
+      params[1] = capabilities_.max_viewport_height;
+      return true;
     case GL_NUM_COMPRESSED_TEXTURE_FORMATS:
       *params = capabilities_.num_compressed_texture_formats;
       return true;
     case GL_NUM_SHADER_BINARY_FORMATS:
       *params = capabilities_.num_shader_binary_formats;
       return true;
     case GL_RENDERBUFFER_BINDING:
       *params = bound_renderbuffer_;
       return true;
     case GL_TEXTURE_BINDING_2D:
@@ skipping 23 matching lines @@
     case GL_TIMESTAMP_EXT:
       // We convert all GPU timestamps to CPU time.
       *params = base::saturated_cast<GLint>(
           (base::TimeTicks::Now() - base::TimeTicks()).InMicroseconds()
           * base::Time::kNanosecondsPerMicrosecond);
       return true;
     case GL_GPU_DISJOINT_EXT:
       *params = static_cast<GLint>(query_tracker_->CheckAndResetDisjoint());
       return true;
 
+    case GL_VIEWPORT:
+      if (state_.viewport_width > 0 || state_.viewport_height > 0) {
+        params[0] = state_.viewport_x;
+        params[1] = state_.viewport_y;
+        params[2] = std::min(state_.viewport_width,
+                             capabilities_.max_viewport_width);
+        params[3] = std::min(state_.viewport_height,
+                             capabilities_.max_viewport_height);
+        return true;
+      }
+      // If they haven't been cached on the client side, go to service side
+      // to query the underlying driver.
+      return false;
+
     // Non-cached parameters.
     case GL_ALIASED_LINE_WIDTH_RANGE:
     case GL_ALIASED_POINT_SIZE_RANGE:
     case GL_ALPHA_BITS:
     case GL_BLEND:
     case GL_BLEND_COLOR:
     case GL_BLEND_DST_ALPHA:
     case GL_BLEND_DST_RGB:
     case GL_BLEND_EQUATION_ALPHA:
     case GL_BLEND_EQUATION_RGB:
@@ skipping 12 matching lines @@
     case GL_DEPTH_RANGE:
     case GL_DEPTH_TEST:
     case GL_DEPTH_WRITEMASK:
     case GL_DITHER:
     case GL_FRONT_FACE:
     case GL_GENERATE_MIPMAP_HINT:
     case GL_GREEN_BITS:
     case GL_IMPLEMENTATION_COLOR_READ_FORMAT:
     case GL_IMPLEMENTATION_COLOR_READ_TYPE:
     case GL_LINE_WIDTH:
-    case GL_MAX_VIEWPORT_DIMS:
     case GL_PACK_ALIGNMENT:
     case GL_POLYGON_OFFSET_FACTOR:
     case GL_POLYGON_OFFSET_FILL:
     case GL_POLYGON_OFFSET_UNITS:
     case GL_RED_BITS:
     case GL_SAMPLE_ALPHA_TO_COVERAGE:
     case GL_SAMPLE_BUFFERS:
     case GL_SAMPLE_COVERAGE:
     case GL_SAMPLE_COVERAGE_INVERT:
     case GL_SAMPLE_COVERAGE_VALUE:
@@ skipping 14 matching lines @@
     case GL_STENCIL_FAIL:
     case GL_STENCIL_FUNC:
     case GL_STENCIL_PASS_DEPTH_FAIL:
     case GL_STENCIL_PASS_DEPTH_PASS:
     case GL_STENCIL_REF:
     case GL_STENCIL_TEST:
     case GL_STENCIL_VALUE_MASK:
     case GL_STENCIL_WRITEMASK:
     case GL_SUBPIXEL_BITS:
     case GL_UNPACK_ALIGNMENT:
-    case GL_VIEWPORT:
       return false;
     default:
       break;
   }
 
   if (capabilities_.major_version < 3) {
     return false;
   }
 
   // ES3 parameters.
@@ skipping 6095 matching lines @@
     return;
   }
   GetStringHelper(GL_EXTENSIONS);
 }
 
 void GLES2Implementation::InvalidateCachedExtensions() {
   cached_extension_string_ = nullptr;
   cached_extensions_.clear();
 }
 
+void GLES2Implementation::Viewport(GLint x,
+                                   GLint y,
+                                   GLsizei width,
+                                   GLsizei height) {
+  GPU_CLIENT_SINGLE_THREAD_CHECK();
+  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glViewport(" << x << ", " << y
+                     << ", " << width << ", " << height << ")");
+  if (width < 0 || height < 0) {
+    SetGLError(GL_INVALID_VALUE, "glViewport", "negative width/height");
+    return;
+  }
+  state_.SetViewport(x, y, width, height);
+  helper_->Viewport(x, y, width, height);
+  CheckGLError();
+}
+
 // 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/client/gles2_implementation_impl_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu