Implement external stencil for Android WebView

android_webview/browser/parent_output_surface.cc

 // Copyright 2014 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 "android_webview/browser/parent_output_surface.h"
 
 #include "cc/output/output_surface_client.h"
 #include "gpu/command_buffer/client/gles2_interface.h"
 
 namespace android_webview {
 
 ParentOutputSurface::ParentOutputSurface(
     scoped_refptr<cc::ContextProvider> context_provider)
     : cc::OutputSurface(context_provider) {
+  stencil_state_.stencil_test_enabled = false;
 }
 
 ParentOutputSurface::~ParentOutputSurface() {
 }
 
 void ParentOutputSurface::DidLoseOutputSurface() {
   // Android WebView does not handle context loss.
   LOG(FATAL) << "Render thread context loss";
 }
 
 void ParentOutputSurface::Reshape(const gfx::Size& size,
                                   float scale_factor,
                                   bool has_alpha) {
   DCHECK_EQ(1.f, scale_factor);
   surface_size_ = size;
 }
 
 void ParentOutputSurface::SwapBuffers(cc::CompositorFrame* frame) {
   context_provider_->ContextGL()->ShallowFlushCHROMIUM();
   client_->DidSwapBuffers();
 }
 
+void ParentOutputSurface::ApplyExternalStencil() {
+  DCHECK(stencil_state_.stencil_test_enabled);
+  gpu::gles2::GLES2Interface* gl = context_provider()->ContextGL();
+  gl->StencilFuncSeparate(GL_FRONT, stencil_state_.stencil_front_func,
+                          stencil_state_.stencil_front_mask,
+                          stencil_state_.stencil_front_ref);
+  gl->StencilFuncSeparate(GL_BACK, stencil_state_.stencil_back_func,
+                          stencil_state_.stencil_back_mask,
+                          stencil_state_.stencil_back_ref);
+  gl->StencilMaskSeparate(GL_FRONT, stencil_state_.stencil_front_writemask);
+  gl->StencilMaskSeparate(GL_BACK, stencil_state_.stencil_back_writemask);
+  gl->StencilOpSeparate(GL_FRONT, stencil_state_.stencil_front_fail_op,
+                        stencil_state_.stencil_front_z_fail_op,
+                        stencil_state_.stencil_front_z_pass_op);
+  gl->StencilOpSeparate(GL_BACK, stencil_state_.stencil_back_fail_op,
+                        stencil_state_.stencil_back_z_fail_op,
+                        stencil_state_.stencil_back_z_pass_op);
+}
+
+void ParentOutputSurface::SetGLState(const ScopedAppGLStateRestore& gl_state) {
+  stencil_state_ = gl_state.stencil_state();
+  SetExternalStencilTest(stencil_state_.stencil_test_enabled);
+}
+
 }  // namespace android_webview