Bug 1444432 - Create Compositor::BlitRenderTarget and implement it for CompositorOGL. r=jrmuizel

MozReview-Commit-ID: Jz3bawvz1pv

--HG--
extra : rebase_source : 1b3e332aa2a312f6acc77b057bc466afc813990e

gfx/gl/GLBlitHelper.cpp

@@ -1158,7 +1158,8 @@ GLBlitHelper::DrawBlitTextureToFramebuffer(const GLuint srcTex,
 
 void
 GLBlitHelper::BlitFramebuffer(const gfx::IntSize& srcSize,
-                              const gfx::IntSize& destSize) const
+                              const gfx::IntSize& destSize,
+                              GLuint filter) const
 {
     MOZ_ASSERT(mGL->IsSupported(GLFeature::framebuffer_blit));
 
@@ -1166,7 +1167,7 @@ GLBlitHelper::BlitFramebuffer(const gfx::IntSize& srcSize,
     mGL->fBlitFramebuffer(0, 0,  srcSize.width,  srcSize.height,
                           0, 0, destSize.width, destSize.height,
                           LOCAL_GL_COLOR_BUFFER_BIT,
-                          LOCAL_GL_NEAREST);
+                          filter);
 }
 
 // --
@@ -1174,7 +1175,8 @@ GLBlitHelper::BlitFramebuffer(const gfx::IntSize& srcSize,
 void
 GLBlitHelper::BlitFramebufferToFramebuffer(const GLuint srcFB, const GLuint destFB,
                                            const gfx::IntSize& srcSize,
-                                           const gfx::IntSize& destSize) const
+                                           const gfx::IntSize& destSize,
+                                           GLuint filter) const
 {
     MOZ_ASSERT(mGL->IsSupported(GLFeature::framebuffer_blit));
     MOZ_ASSERT(!srcFB || mGL->fIsFramebuffer(srcFB));
@@ -1184,7 +1186,7 @@ GLBlitHelper::BlitFramebufferToFramebuffer(const GLuint srcFB, const GLuint dest
     mGL->fBindFramebuffer(LOCAL_GL_READ_FRAMEBUFFER, srcFB);
     mGL->fBindFramebuffer(LOCAL_GL_DRAW_FRAMEBUFFER, destFB);
 
-    BlitFramebuffer(srcSize, destSize);
+    BlitFramebuffer(srcSize, destSize, filter);
 }
 
 void

gfx/gl/GLBlitHelper.h

@@ -163,10 +163,12 @@ public:
     ~GLBlitHelper();
 
     void BlitFramebuffer(const gfx::IntSize& srcSize,
-                         const gfx::IntSize& destSize) const;
+                         const gfx::IntSize& destSize,
+                         GLuint filter = LOCAL_GL_NEAREST) const;
     void BlitFramebufferToFramebuffer(GLuint srcFB, GLuint destFB,
                                       const gfx::IntSize& srcSize,
-                                      const gfx::IntSize& destSize) const;
+                                      const gfx::IntSize& destSize,
+                                      GLuint filter = LOCAL_GL_NEAREST) const;
     void BlitFramebufferToTexture(GLuint destTex, const gfx::IntSize& srcSize,
                                   const gfx::IntSize& destSize,
                                   GLenum destTarget = LOCAL_GL_TEXTURE_2D) const;

gfx/layers/Compositor.h

@@ -280,6 +280,16 @@ public:
   virtual already_AddRefed<AsyncReadbackBuffer>
   CreateAsyncReadbackBuffer(const gfx::IntSize& aSize) { return nullptr; }
 
+  /**
+   * Draw a part of aSource into the current render target.
+   * Scaling is done with linear filtering.
+   * Returns whether the operation was successful.
+   */
+  virtual bool
+  BlitRenderTarget(CompositingRenderTarget* aSource,
+                   const gfx::IntSize& aSourceSize,
+                   const gfx::IntSize& aDestSize) { return false; }
+
   /**
    * Sets the given surface as the target for subsequent calls to DrawQuad.
    * Passing null as aSurface sets the screen as the target.

gfx/layers/opengl/CompositorOGL.cpp

@@ -44,6 +44,7 @@
 #include "GLReadTexImageHelper.h"
 #include "GLBlitTextureImageHelper.h"
 #include "HeapCopyOfStackArray.h"
+#include "GLBlitHelper.h"
 #include "mozilla/gfx/Swizzle.h"
 
 #if MOZ_WIDGET_ANDROID
@@ -711,6 +712,24 @@ CompositorOGL::ReadbackRenderTarget(CompositingRenderTarget* aSource,
   return true;
 }
 
+bool
+CompositorOGL::BlitRenderTarget(CompositingRenderTarget* aSource,
+                                const gfx::IntSize& aSourceSize,
+                                const gfx::IntSize& aDestSize)
+{
+  if (!mGLContext->IsSupported(GLFeature::framebuffer_blit)) {
+    return false;
+  }
+  CompositingRenderTargetOGL* source =
+    static_cast<CompositingRenderTargetOGL*>(aSource);
+  GLuint srcFBO = source->GetFBO();
+  GLuint destFBO = mCurrentRenderTarget->GetFBO();
+  mGLContext->BlitHelper()->
+    BlitFramebufferToFramebuffer(srcFBO, destFBO, aSourceSize, aDestSize,
+                                 LOCAL_GL_LINEAR);
+  return true;
+}
+
 static GLenum
 GetFrameBufferInternalFormat(GLContext* gl,
                              GLuint aFrameBuffer,

gfx/layers/opengl/CompositorOGL.h

@@ -165,6 +165,11 @@ public:
   virtual already_AddRefed<AsyncReadbackBuffer>
   CreateAsyncReadbackBuffer(const gfx::IntSize& aSize) override;
 
+  virtual bool
+  BlitRenderTarget(CompositingRenderTarget* aSource,
+                   const gfx::IntSize& aSourceSize,
+                   const gfx::IntSize& aDestSize) override;
+
   virtual void DrawQuad(const gfx::Rect& aRect,
                         const gfx::IntRect& aClipRect,
                         const EffectChain &aEffectChain,