Implement transform/clip support for Android WebView.

cc/output/gl_renderer.cc

 // Copyright 2010 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 "cc/output/gl_renderer.h"
 
 #include <algorithm>
 #include <limits>
 #include <set>
 #include <string>
@@ skipping 107 matching lines @@
         << "Requested Skia GPU backend, but can't use it.";
   }
 
   return renderer.Pass();
 }
 
 GLRenderer::GLRenderer(RendererClient* client,
                        OutputSurface* output_surface,
                        ResourceProvider* resource_provider,
                        int highp_threshold_min)
-    : DirectRenderer(client, resource_provider),
+    : DirectRenderer(client, output_surface, resource_provider),
       offscreen_framebuffer_id_(0),
       shared_geometry_quad_(gfx::RectF(-0.5f, -0.5f, 1.0f, 1.0f)),
-      output_surface_(output_surface),
       context_(output_surface->context3d()),
-      is_viewport_changed_(false),
       is_backbuffer_discarded_(false),
       discard_backbuffer_when_not_visible_(false),
       is_using_bind_uniform_(false),
       visible_(true),
       is_scissor_enabled_(false),
       highp_threshold_min_(highp_threshold_min),
       highp_threshold_cache_(0),
       on_demand_tile_raster_resource_id_(0) {
   DCHECK(context_);
 }
@@ skipping 124 matching lines @@
   stats.bytesVisible = bytes_visible;
   stats.bytesVisibleAndNearby = bytes_visible_and_nearby;
   stats.bytesAllocated = bytes_allocated;
   stats.backbufferRequested = !is_backbuffer_discarded_;
   context_->sendManagedMemoryStatsCHROMIUM(&stats);
 }
 
 void GLRenderer::ReleaseRenderPassTextures() { render_pass_textures_.clear(); }
 
 void GLRenderer::ViewportChanged() {
-  is_viewport_changed_ = true;
   ReinitializeGrCanvas();
 }
 
 void GLRenderer::ClearFramebuffer(DrawingFrame* frame) {
   // On DEBUG builds, opaque render passes are cleared to blue to easily see
   // regions that were not drawn on the screen.
   if (frame->current_render_pass->has_transparent_background)
     GLC(context_, context_->clearColor(0, 0, 0, 0));
   else
     GLC(context_, context_->clearColor(0, 0, 1, 1));
 
   bool always_clear = false;
 #ifndef NDEBUG
   always_clear = true;
 #endif
   if (always_clear || frame->current_render_pass->has_transparent_background) {
     GLbitfield clear_bits = GL_COLOR_BUFFER_BIT;
     // Only the Skia GPU backend uses the stencil buffer.  No need to clear it
     // otherwise.
     if (CanUseSkiaGPUBackend())
       clear_bits |= GL_STENCIL_BUFFER_BIT;
     context_->clear(clear_bits);
   }
 }
 
 void GLRenderer::BeginDrawingFrame(DrawingFrame* frame) {
   // FIXME: Remove this once backbuffer is automatically recreated on first use
   EnsureBackbuffer();
 
-  if (ViewportSize().IsEmpty())
+  if (client_->DeviceViewport().IsEmpty())
     return;
 
   TRACE_EVENT0("cc", "GLRenderer::DrawLayers");
-  if (is_viewport_changed_) {
-    // Only reshape when we know we are going to draw. Otherwise, the reshape
-    // can leave the window at the wrong size if we never draw and the proper
-    // viewport size is never set.
-    is_viewport_changed_ = false;
-    output_surface_->Reshape(gfx::Size(ViewportWidth(), ViewportHeight()),
-                             DeviceScaleFactor());
-  }
 
   MakeContextCurrent();
 
   ReinitializeGLState();
 }
 
 void GLRenderer::DoNoOp() {
   GLC(context_, context_->bindFramebuffer(GL_FRAMEBUFFER, 0));
   GLC(context_, context_->flush());
 }
@@ skipping 1166 matching lines @@
   // Reset the canvas matrix to identity because the clip rect is in target
   // space.
   SkMatrix sk_identity;
   sk_identity.setIdentity();
   sk_canvas_->setMatrix(sk_identity);
 
   if (is_scissor_enabled_) {
     sk_canvas_->clipRect(gfx::RectToSkRect(scissor_rect_),
                          SkRegion::kReplace_Op);
   } else {
-    sk_canvas_->clipRect(gfx::RectToSkRect(gfx::Rect(ViewportSize())),
+    sk_canvas_->clipRect(gfx::RectToSkRect(client_->DeviceViewport()),
                          SkRegion::kReplace_Op);
   }
 
   gfx::Transform contents_device_transform = frame->window_matrix *
     frame->projection_matrix * quad->quadTransform();
   contents_device_transform.Translate(quad->rect.x(),
                                       quad->rect.y());
   contents_device_transform.FlattenTo2d();
   SkMatrix sk_device_matrix;
   gfx::TransformToFlattenedSkMatrix(contents_device_transform,
@@ skipping 446 matching lines @@
 void GLRenderer::SwapBuffers(const ui::LatencyInfo& latency_info) {
   DCHECK(visible_);
   DCHECK(!is_backbuffer_discarded_);
 
   TRACE_EVENT0("cc", "GLRenderer::SwapBuffers");
   // We're done! Time to swapbuffers!
 
   if (capabilities_.using_partial_swap && client_->AllowPartialSwap()) {
     // If supported, we can save significant bandwidth by only swapping the
     // damaged/scissored region (clamped to the viewport)
-    swap_buffer_rect_.Intersect(gfx::Rect(ViewportSize()));
+    swap_buffer_rect_.Intersect(client_->DeviceViewport());
     int flipped_y_pos_of_rect_bottom =
-        ViewportHeight() - swap_buffer_rect_.y() - swap_buffer_rect_.height();
+        client_->DeviceViewport().height() - swap_buffer_rect_.y() -
+        swap_buffer_rect_.height();
     output_surface_->PostSubBuffer(gfx::Rect(swap_buffer_rect_.x(),
                                              flipped_y_pos_of_rect_bottom,
                                              swap_buffer_rect_.width(),
                                              swap_buffer_rect_.height()),
                                    latency_info);
   } else {
     output_surface_->SwapBuffers(latency_info);
   }
 
   swap_buffer_rect_ = gfx::Rect();
@@ skipping 133 matching lines @@
 
   // This is an asyncronous call since the callback is not null.
   DoGetFramebufferPixels(pixels, rect, flipped_y, cleanup_callback);
 }
 
 void GLRenderer::DoGetFramebufferPixels(
     uint8* dest_pixels,
     gfx::Rect rect,
     bool flipped_y,
     const AsyncGetFramebufferPixelsCleanupCallback& cleanup_callback) {
-  DCHECK(rect.right() <= ViewportWidth());
-  DCHECK(rect.bottom() <= ViewportHeight());
+  DCHECK(rect.right() <= client_->DeviceViewport().width());
+  DCHECK(rect.bottom() <= client_->DeviceViewport().height());
 
   bool is_async = !cleanup_callback.is_null();
 
   MakeContextCurrent();
 
   bool do_workaround = NeedsIOSurfaceReadbackWorkaround();
 
   unsigned temporary_texture = 0;
   unsigned temporary_fbo = 0;
 
@@ skipping 17 matching lines @@
             GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE));
     GLC(context_,
         context_->texParameteri(
             GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE));
     // Copy the contents of the current (IOSurface-backed) framebuffer into a
     // temporary texture.
     GLC(context_,
         context_->copyTexImage2D(GL_TEXTURE_2D,
                                  0,
                                  GL_RGBA,
                                  0,

[danakj, 2013/06/05 17:40:53]

Should this be using the ViewportRect's x/y values? Should we be storing the
current framebuffer as a rect instead of just the size?

Can you add a test with a readback that would have a non-0 ViewportRect?

                                  0,
                                  current_framebuffer_size_.width(),
                                  current_framebuffer_size_.height(),
                                  0));
     temporary_fbo = context_->createFramebuffer();
     // Attach this texture to an FBO, and perform the readback from that FBO.
     GLC(context_, context_->bindFramebuffer(GL_FRAMEBUFFER, temporary_fbo));
     GLC(context_,
         context_->framebufferTexture2D(GL_FRAMEBUFFER,
                                        GL_COLOR_ATTACHMENT0,
                                        GL_TEXTURE_2D,
                                        temporary_texture,
                                        0));
 
     DCHECK(context_->checkFramebufferStatus(GL_FRAMEBUFFER) ==
            GL_FRAMEBUFFER_COMPLETE);
   }
 
   unsigned buffer = context_->createBuffer();
   GLC(context_, context_->bindBuffer(GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM,
                                      buffer));
   GLC(context_, context_->bufferData(GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM,
                                      4 * rect.size().GetArea(),
                                      NULL,
                                      GL_STREAM_READ));
 
   GLC(context_,
       context_->readPixels(rect.x(),

[danakj, 2013/06/05 17:40:53]

Should this be offset by the current_framebuffer rect's origin?

                            current_framebuffer_size_.height() - rect.bottom(),
                            rect.width(),
                            rect.height(),
                            GL_RGBA,
                            GL_UNSIGNED_BYTE,
                            NULL));
 
   GLC(context_, context_->bindBuffer(GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM,
                                      0));
 
@@ skipping 134 matching lines @@
   return BindFramebufferToTexture(frame, texture, viewport_rect);
 }
 
 void GLRenderer::BindFramebufferToOutputSurface(DrawingFrame* frame) {
   current_framebuffer_lock_.reset();
   output_surface_->BindFramebuffer();
 }
 
 bool GLRenderer::BindFramebufferToTexture(DrawingFrame* frame,
                                           const ScopedResource* texture,
-                                          gfx::Rect framebuffer_rect) {
+                                          gfx::Rect target_rect) {
   DCHECK(texture->id());
 
   current_framebuffer_lock_.reset();
 
   GLC(context_,
       context_->bindFramebuffer(GL_FRAMEBUFFER, offscreen_framebuffer_id_));
   current_framebuffer_lock_ =
       make_scoped_ptr(new ResourceProvider::ScopedWriteLockGL(
           resource_provider_, texture->id()));
   unsigned texture_id = current_framebuffer_lock_->texture_id();
   GLC(context_,
       context_->framebufferTexture2D(
           GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture_id, 0));
 
   DCHECK(context_->checkFramebufferStatus(GL_FRAMEBUFFER) ==
          GL_FRAMEBUFFER_COMPLETE || IsContextLost());
 
-  InitializeMatrices(frame, framebuffer_rect, false);
-  SetDrawViewportSize(framebuffer_rect.size());
+  InitializeMatrices(
+      frame, target_rect, gfx::Rect(target_rect.size()), false);
+  SetDrawViewport(gfx::Rect(target_rect.size()));
 
   return true;
 }
 
 void GLRenderer::SetScissorTestRect(gfx::Rect scissor_rect) {
   EnsureScissorTestEnabled();
 
   // Don't unnecessarily ask the context to change the scissor, because it
   // may cause undesired GPU pipeline flushes.
   if (scissor_rect == scissor_rect_)
     return;
 
   scissor_rect_ = scissor_rect;
   FlushTextureQuadCache();
   GLC(context_,
       context_->scissor(scissor_rect.x(),
                         scissor_rect.y(),
                         scissor_rect.width(),
                         scissor_rect.height()));
 }
 
-void GLRenderer::SetDrawViewportSize(gfx::Size viewport_size) {
-  current_framebuffer_size_ = viewport_size;
-  GLC(context_,
-      context_->viewport(0, 0, viewport_size.width(), viewport_size.height()));
+void GLRenderer::SetDrawViewport(gfx::Rect viewport) {
+  current_framebuffer_size_ = viewport.size();
+  GLC(context_, context_->viewport(viewport.x(),
+                                   viewport.y(),
+                                   viewport.width(),
+                                   viewport.height()));
 }
 
 bool GLRenderer::MakeContextCurrent() { return context_->makeContextCurrent(); }
 
 bool GLRenderer::InitializeSharedObjects() {
   TRACE_EVENT0("cc", "GLRenderer::InitializeSharedObjects");
   MakeContextCurrent();
 
   // Create an FBO for doing offscreen rendering.
   GLC(context_, offscreen_framebuffer_id_ = context_->createFramebuffer());
@@ skipping 453 matching lines @@
     resource_provider_->DeleteResource(on_demand_tile_raster_resource_id_);
 
   ReleaseRenderPassTextures();
 }
 
 void GLRenderer::ReinitializeGrCanvas() {
   if (!CanUseSkiaGPUBackend())
     return;
 
   GrBackendRenderTargetDesc desc;
-  desc.fWidth = ViewportWidth();
-  desc.fHeight = ViewportHeight();
+  desc.fWidth = client_->DeviceViewport().width();
+  desc.fHeight = client_->DeviceViewport().height();
   desc.fConfig = kRGBA_8888_GrPixelConfig;
   desc.fOrigin = kTopLeft_GrSurfaceOrigin;
   desc.fSampleCnt = 1;
   desc.fStencilBits = 8;
   desc.fRenderTargetHandle = 0;
 
   skia::RefPtr<GrSurface> surface(
       skia::AdoptRef(gr_context_->wrapBackendRenderTarget(desc)));
   skia::RefPtr<SkDevice> device(
       skia::AdoptRef(SkGpuDevice::Create(surface.get())));
@@ skipping 23 matching lines @@
   // The Skia GPU backend requires a stencil buffer.  See ReinitializeGrCanvas
   // implementation.
   return gr_context_ && context_->getContextAttributes().stencil;
 }
 
 bool GLRenderer::IsContextLost() {
   return (context_->getGraphicsResetStatusARB() != GL_NO_ERROR);
 }
 
 }  // namespace cc