Implement transform/clip support for Android WebView.

cc/output/direct_renderer.cc

 // Copyright 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 "cc/output/direct_renderer.h"
 
 #include <utility>
 #include <vector>
 
 #include "base/debug/trace_event.h"
@@ skipping 61 matching lines @@
 // static
 void DirectRenderer::QuadRectTransform(gfx::Transform* quad_rect_transform,
                                        const gfx::Transform& quad_transform,
                                        const gfx::RectF& quad_rect) {
   *quad_rect_transform = quad_transform;
   quad_rect_transform->Translate(0.5 * quad_rect.width() + quad_rect.x(),
                                  0.5 * quad_rect.height() + quad_rect.y());
   quad_rect_transform->Scale(quad_rect.width(), quad_rect.height());
 }
 
-// static
-void DirectRenderer::InitializeMatrices(DrawingFrame* frame,
+void DirectRenderer::InitializeViewport(DrawingFrame* frame,
                                         gfx::Rect draw_rect,
+                                        gfx::Rect viewport_rect,
+                                        gfx::Size surface_size,
                                         bool flip_y) {
+  DCHECK_GE(viewport_rect.x(), 0);
+  DCHECK_GE(viewport_rect.y(), 0);
+  DCHECK_LE(viewport_rect.right(), surface_size.width());
+  DCHECK_LE(viewport_rect.bottom(), surface_size.height());
   if (flip_y) {
     frame->projection_matrix = OrthoProjectionMatrix(draw_rect.x(),
                                                      draw_rect.right(),
                                                      draw_rect.bottom(),
                                                      draw_rect.y());
   } else {
     frame->projection_matrix = OrthoProjectionMatrix(draw_rect.x(),
                                                      draw_rect.right(),
                                                      draw_rect.y(),
                                                      draw_rect.bottom());
   }
-  frame->window_matrix =
-      window_matrix(0, 0, draw_rect.width(), draw_rect.height());
+
+  gfx::Rect window_rect = viewport_rect;
+  if (flip_y)
+    window_rect.set_y(surface_size.height() - viewport_rect.bottom());
+  frame->window_matrix = window_matrix(window_rect.x(),
+                                       window_rect.y(),
+                                       window_rect.width(),
+                                       window_rect.height());
+  SetDrawViewport(window_rect);
+
   frame->flipped_y = flip_y;
+
+  current_draw_rect_ = draw_rect;
+  current_viewport_rect_ = viewport_rect;
+  current_surface_size_ = surface_size;
 }
 
-// static
-gfx::Rect DirectRenderer::MoveScissorToWindowSpace(
-    const DrawingFrame* frame, const gfx::RectF& scissor_rect) {
-  gfx::Rect scissor_rect_in_canvas_space = gfx::ToEnclosingRect(scissor_rect);
-  // The scissor coordinates must be supplied in viewport space so we need to
-  // offset by the relative position of the top left corner of the current
-  // render pass.
-  gfx::Rect framebuffer_output_rect = frame->current_render_pass->output_rect;
-  scissor_rect_in_canvas_space.set_x(
-      scissor_rect_in_canvas_space.x() - framebuffer_output_rect.x());
-  if (frame->flipped_y && !frame->current_texture) {
-    scissor_rect_in_canvas_space.set_y(
-        framebuffer_output_rect.height() -
-        (scissor_rect_in_canvas_space.bottom() - framebuffer_output_rect.y()));
-  } else {
-    scissor_rect_in_canvas_space.set_y(
-        scissor_rect_in_canvas_space.y() - framebuffer_output_rect.y());
-  }
-  return scissor_rect_in_canvas_space;
+gfx::Rect DirectRenderer::MoveFromDrawToWindowSpace(
+    const gfx::RectF& draw_rect, bool flip_y) const {
+  gfx::Rect window_rect = gfx::ToEnclosingRect(draw_rect);
+  window_rect -= current_draw_rect_.OffsetFromOrigin();
+  window_rect += current_viewport_rect_.OffsetFromOrigin();
+  if (flip_y)
+    window_rect.set_y(current_surface_size_.height() - window_rect.bottom());
+  return window_rect;
 }
 
 DirectRenderer::DirectRenderer(RendererClient* client,
+                               OutputSurface* output_surface,
                                ResourceProvider* resource_provider)
     : Renderer(client),
+      output_surface_(output_surface),
       resource_provider_(resource_provider) {}
 
 DirectRenderer::~DirectRenderer() {}
 
 bool DirectRenderer::CanReadPixels() const { return true; }
 
 void DirectRenderer::SetEnlargePassTextureAmountForTesting(
     gfx::Vector2d amount) {
   enlarge_pass_texture_amount_ = amount;
 }
@@ skipping 54 matching lines @@
                        render_passes_in_draw_order->size());
 
   const RenderPass* root_render_pass = render_passes_in_draw_order->back();
   DCHECK(root_render_pass);
 
   DrawingFrame frame;
   frame.root_render_pass = root_render_pass;
   frame.root_damage_rect =
       Capabilities().using_partial_swap && client_->AllowPartialSwap() ?
       root_render_pass->damage_rect : root_render_pass->output_rect;
-  frame.root_damage_rect.Intersect(gfx::Rect(ViewportSize()));
+  frame.root_damage_rect.Intersect(gfx::Rect(client_->DeviceViewport().size()));
+
+  // 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.
+  output_surface_->Reshape(client_->DeviceViewport().size(),
+                           client_->DeviceScaleFactor());

[piman, 2013/06/10 22:41:43]

Note: this change triggered crbug.com/248213 because we now resize the back
buffer before we recreate it (e.g. after a tab was hidden).
https://codereview.chromium.org/16431008/ fixes the bug on
TextureImageTransportSurface (we don't want to rely on client-side behavior for
correctness), but I'm not sure if there could be subtle issues on other
platforms.

[aelias_OOO_until_Jul13, 2013/06/10 22:49:10]

Sorry about that.  This is probably due to the ordering change relative to
EnsureBackbuffer.  We could make EnsureBackbuffer virtual and call it from
DirectRenderer.

 
   BeginDrawingFrame(&frame);
   for (size_t i = 0; i < render_passes_in_draw_order->size(); ++i) {
     RenderPass* pass = render_passes_in_draw_order->at(i);
     DrawRenderPass(&frame, pass);
 
     for (ScopedPtrVector<CopyOutputRequest>::iterator it =
              pass->copy_requests.begin();
          it != pass->copy_requests.end();
          ++it) {
@@ skipping 27 matching lines @@
     render_pass_scissor.Intersect(damage_rect_in_render_pass_space);
   }
 
   return render_pass_scissor;
 }
 
 void DirectRenderer::SetScissorStateForQuad(const DrawingFrame* frame,
                                             const DrawQuad& quad) {
   if (quad.isClipped()) {
     gfx::RectF quad_scissor_rect = quad.clipRect();
-    SetScissorTestRect(MoveScissorToWindowSpace(frame, quad_scissor_rect));
+    SetScissorTestRect(
+        MoveFromDrawToWindowSpace(quad_scissor_rect, frame->flipped_y));
   } else {
     EnsureScissorTestDisabled();
   }
 }
 
 void DirectRenderer::SetScissorStateForQuadWithRenderPassScissor(
     const DrawingFrame* frame,
     const DrawQuad& quad,
     const gfx::RectF& render_pass_scissor,
     bool* should_skip_quad) {
   gfx::RectF quad_scissor_rect = render_pass_scissor;
 
   if (quad.isClipped())
     quad_scissor_rect.Intersect(quad.clipRect());
 
   if (quad_scissor_rect.IsEmpty()) {
     *should_skip_quad = true;
     return;
   }
 
   *should_skip_quad = false;
-  SetScissorTestRect(MoveScissorToWindowSpace(frame, quad_scissor_rect));
+  SetScissorTestRect(
+      MoveFromDrawToWindowSpace(quad_scissor_rect, frame->flipped_y));
 }
 
 void DirectRenderer::FinishDrawingQuadList() {}
 
 void DirectRenderer::DrawRenderPass(DrawingFrame* frame,
                                     const RenderPass* render_pass) {
   TRACE_EVENT0("cc", "DirectRenderer::DrawRenderPass");
   if (!UseRenderPass(frame, render_pass))
     return;
 
   bool using_scissor_as_optimization =
       Capabilities().using_partial_swap && client_->AllowPartialSwap();
   gfx::RectF render_pass_scissor;
 
   if (using_scissor_as_optimization) {
     render_pass_scissor = ComputeScissorRectForRenderPass(frame);
-    SetScissorTestRect(MoveScissorToWindowSpace(frame, render_pass_scissor));
+    SetScissorTestRect(
+        MoveFromDrawToWindowSpace(render_pass_scissor, frame->flipped_y));
   }
 
   if (frame->current_render_pass != frame->root_render_pass ||
       client_->ShouldClearRootRenderPass()) {
     if (!using_scissor_as_optimization)
       EnsureScissorTestDisabled();
     ClearFramebuffer(frame);
   }
 
   const QuadList& quad_list = render_pass->quad_list;
@@ skipping 22 matching lines @@
   }
 }
 
 bool DirectRenderer::UseRenderPass(DrawingFrame* frame,
                                    const RenderPass* render_pass) {
   frame->current_render_pass = render_pass;
   frame->current_texture = NULL;
 
   if (render_pass == frame->root_render_pass) {
     BindFramebufferToOutputSurface(frame);
-    InitializeMatrices(frame, render_pass->output_rect, FlippedFramebuffer());
-    SetDrawViewportSize(render_pass->output_rect.size());
+    InitializeViewport(frame,
+                       render_pass->output_rect,
+                       client_->DeviceViewport(),
+                       output_surface_->SurfaceSize(),
+                       FlippedFramebuffer());
     return true;
   }
 
   if (!resource_provider_)
     return false;
 
   CachedResource* texture = render_pass_textures_.get(render_pass->id);
   DCHECK(texture);
 
   gfx::Size size = RenderPassTextureSize(render_pass);
@@ skipping 21 matching lines @@
 gfx::Size DirectRenderer::RenderPassTextureSize(const RenderPass* render_pass) {
   return render_pass->output_rect.size();
 }
 
 // static
 GLenum DirectRenderer::RenderPassTextureFormat(const RenderPass* render_pass) {
   return GL_RGBA;
 }
 
 }  // namespace cc