Don't overdraw TileGrids

Given the visible area info, we can just tune the shader and matrix to draw
partial tile at the edge of TileGrids. This could save a lot of GPU time.

Change-Id: I1a45aa9a3a76ab5894096828bfff83057b1c9272

9 files changed, 56 insertions, 28 deletions

diff --git a/Source/WebCore/platform/graphics/android/rendering/DrawQuadData.h b/Source/WebCore/platform/graphics/android/rendering/DrawQuadData.h
index 687808d..bce82f2 100644
--- a/Source/WebCore/platform/graphics/android/rendering/DrawQuadData.h
+++ b/Source/WebCore/platform/graphics/android/rendering/DrawQuadData.h
@@ -29,6 +29,7 @@
 #if USE(ACCELERATED_COMPOSITING)
 
 #include "Color.h"
+#include "FloatPoint.h"
 #include "SkRect.h"
 #include <GLES2/gl2.h>
 
@@ -49,12 +50,14 @@ public:
                  const TransformationMatrix* drawMatrix = 0,
                  const SkRect* geometry = 0,
                  float opacity = 1.0f,
-                 bool forceBlending = true)
+                 bool forceBlending = true,
+                 FloatPoint fillPortion = FloatPoint(1.0f, 1.0f))
         : m_type(type)
         , m_drawMatrix(drawMatrix)
         , m_geometry(geometry)
         , m_opacity(opacity)
         , m_forceBlending(forceBlending)
+        , m_fillPortion(fillPortion.x(), fillPortion.y())
     {
     }
 
@@ -64,6 +67,7 @@ public:
         , m_geometry(data.m_geometry)
         , m_opacity(data.m_opacity)
         , m_forceBlending(data.m_forceBlending)
+        , m_fillPortion(data.m_fillPortion.x(), data.m_fillPortion.y())
     {
     }
 
@@ -86,6 +90,7 @@ public:
     virtual int textureId() const { return 0; }
     virtual GLint textureFilter() const { return 0; }
     virtual GLenum textureTarget() const { return 0; }
+    virtual FloatPoint fillPortion() const { return m_fillPortion; }
 
 private:
     DrawQuadType m_type;
@@ -93,6 +98,7 @@ private:
     const SkRect* m_geometry;
     float m_opacity;
     bool m_forceBlending;
+    FloatPoint m_fillPortion;
 };
 
 class PureColorQuadData : public DrawQuadData {
diff --git a/Source/WebCore/platform/graphics/android/rendering/ShaderProgram.cpp b/Source/WebCore/platform/graphics/android/rendering/ShaderProgram.cpp
index b1fe2f4..817efb8 100644
--- a/Source/WebCore/platform/graphics/android/rendering/ShaderProgram.cpp
+++ b/Source/WebCore/platform/graphics/android/rendering/ShaderProgram.cpp
@@ -47,10 +47,11 @@ namespace WebCore {
 static const char gVertexShader[] =
     "attribute vec4 vPosition;\n"
     "uniform mat4 projectionMatrix;\n"
+    "uniform vec2 fillPortion;\n"
     "varying vec2 v_texCoord;\n"
     "void main() {\n"
     "  gl_Position = projectionMatrix * vPosition;\n"
-    "  v_texCoord = vec2(vPosition);\n"
+    "  v_texCoord = vPosition.xy * fillPortion;\n"
     "}\n";
 
 static const char gFragmentShader[] =
@@ -273,41 +274,45 @@ void ShaderProgram::initGLResources()
     GLint pureColorProjMtx = glGetUniformLocation(pureColorProgram, "projectionMatrix");
     GLint pureColorValue = glGetUniformLocation(pureColorProgram, "inputColor");
     m_handleArray[PureColor].init(-1, -1, pureColorPosition, pureColorProgram,
-                                  pureColorProjMtx, pureColorValue, -1, -1);
+                                  pureColorProjMtx, pureColorValue, -1, -1, -1);
 
     GLint tex2DAlpha = glGetUniformLocation(tex2DProgram, "alpha");
     GLint tex2DPosition = glGetAttribLocation(tex2DProgram, "vPosition");
     GLint tex2DProjMtx = glGetUniformLocation(tex2DProgram, "projectionMatrix");
     GLint tex2DTexSampler = glGetUniformLocation(tex2DProgram, "s_texture");
+    GLint tex2DFillPortion = glGetUniformLocation(tex2DProgram, "fillPortion");
     m_handleArray[Tex2D].init(tex2DAlpha, -1, tex2DPosition, tex2DProgram,
-                              tex2DProjMtx, -1, tex2DTexSampler, -1);
+                              tex2DProjMtx, -1, tex2DTexSampler, -1, tex2DFillPortion);
 
     GLint tex2DInvAlpha = glGetUniformLocation(tex2DInvProgram, "alpha");
     GLint tex2DInvContrast = glGetUniformLocation(tex2DInvProgram, "contrast");
     GLint tex2DInvPosition = glGetAttribLocation(tex2DInvProgram, "vPosition");
     GLint tex2DInvProjMtx = glGetUniformLocation(tex2DInvProgram, "projectionMatrix");
     GLint tex2DInvTexSampler = glGetUniformLocation(tex2DInvProgram, "s_texture");
+    GLint tex2DInvFillPortion = glGetUniformLocation(tex2DInvProgram, "fillPortion");
     m_handleArray[Tex2DInv].init(tex2DInvAlpha, tex2DInvContrast,
                                  tex2DInvPosition, tex2DInvProgram,
                                  tex2DInvProjMtx, -1,
-                                 tex2DInvTexSampler, -1);
+                                 tex2DInvTexSampler, -1, tex2DInvFillPortion);
 
     GLint texOESAlpha = glGetUniformLocation(texOESProgram, "alpha");
     GLint texOESPosition = glGetAttribLocation(texOESProgram, "vPosition");
     GLint texOESProjMtx = glGetUniformLocation(texOESProgram, "projectionMatrix");
     GLint texOESTexSampler = glGetUniformLocation(texOESProgram, "s_texture");
+    GLint texOESFillPortion = glGetUniformLocation(texOESProgram, "fillPortion");
     m_handleArray[TexOES].init(texOESAlpha, -1, texOESPosition, texOESProgram,
-                               texOESProjMtx, -1, texOESTexSampler, -1);
+                               texOESProjMtx, -1, texOESTexSampler, -1, texOESFillPortion);
 
     GLint texOESInvAlpha = glGetUniformLocation(texOESInvProgram, "alpha");
     GLint texOESInvContrast = glGetUniformLocation(texOESInvProgram, "contrast");
     GLint texOESInvPosition = glGetAttribLocation(texOESInvProgram, "vPosition");
     GLint texOESInvProjMtx = glGetUniformLocation(texOESInvProgram, "projectionMatrix");
     GLint texOESInvTexSampler = glGetUniformLocation(texOESInvProgram, "s_texture");
+    GLint texOESInvFillPortion = glGetUniformLocation(texOESInvProgram, "fillPortion");
     m_handleArray[TexOESInv].init(texOESInvAlpha, texOESInvContrast,
                                   texOESInvPosition, texOESInvProgram,
                                   texOESInvProjMtx, -1,
-                                  texOESInvTexSampler, -1);
+                                  texOESInvTexSampler, -1, texOESInvFillPortion);
 
     GLint videoPosition = glGetAttribLocation(videoProgram, "vPosition");
     GLint videoProjMtx = glGetUniformLocation(videoProgram, "projectionMatrix");
@@ -315,7 +320,7 @@ void ShaderProgram::initGLResources()
     GLint videoTexMtx = glGetUniformLocation(videoProgram, "textureMatrix");
     m_handleArray[Video].init(-1, -1, videoPosition, videoProgram,
                               videoProjMtx, -1, videoTexSampler,
-                              videoTexMtx);
+                              videoTexMtx, -1);
 
     const GLfloat coord[] = {
         0.0f, 0.0f, // C
@@ -589,7 +594,7 @@ float ShaderProgram::zValue(const TransformationMatrix& drawMatrix, float w, flo
 void ShaderProgram::drawQuadInternal(ShaderType type, const GLfloat* matrix,
                                     int textureId, float opacity,
                                     GLenum textureTarget, GLenum filter,
-                                    const Color& pureColor)
+                                    const Color& pureColor, const FloatPoint& fillPortion)
 {
     glUseProgram(m_handleArray[type].programHandle);
     glUniformMatrix4fv(m_handleArray[type].projMtxHandle, 1, GL_FALSE, matrix);
@@ -605,6 +610,8 @@ void ShaderProgram::drawQuadInternal(ShaderType type, const GLfloat* matrix,
         GLint contrastHandle = m_handleArray[type].contrastHandle;
         if (contrastHandle != -1)
             glUniform1f(contrastHandle, m_contrast);
+
+        glUniform2f(m_handleArray[type].fillPortionHandle, fillPortion.x(), fillPortion.y());
     } else {
         glUniform4f(m_handleArray[type].pureColorHandle,
                     pureColor.red() / 255.0, pureColor.green() / 255.0,
@@ -636,7 +643,7 @@ GLfloat* ShaderProgram::getTileProjectionMatrix(const DrawQuadData* data)
 
     const TransformationMatrix* matrix = data->drawMatrix();
     const SkRect* geometry = data->geometry();
-
+    FloatPoint fillPortion = data->fillPortion();
     // This modifiedDrawMatrix tranform (0,0)(1x1) to the final rect in screen
     // coordinate, before applying the m_webViewMatrix.
     // It first scale and translate the vertex array from (0,0)(1x1) to real
@@ -648,7 +655,8 @@ GLfloat* ShaderProgram::getTileProjectionMatrix(const DrawQuadData* data)
     if (type == LayerQuad)
         modifiedDrawMatrix = *matrix;
     modifiedDrawMatrix.translate(geometry->fLeft, geometry->fTop);
-    modifiedDrawMatrix.scale3d(geometry->width(), geometry->height(), 1);
+    modifiedDrawMatrix.scale3d(geometry->width() * fillPortion.x(),
+                               geometry->height() * fillPortion.y(), 1);
 
     // Even when we are on a alpha layer or not, we need to respect the
     // m_webViewMatrix, it may contain the layout offset. Normally it is
@@ -693,7 +701,7 @@ void ShaderProgram::drawQuad(const DrawQuadData* data)
     }
     setBlendingState(enableBlending);
     drawQuadInternal(shaderType, matrix, textureId, opacity,
-                     textureTarget, textureFilter, quadColor);
+                     textureTarget, textureFilter, quadColor, data->fillPortion());
 }
 
 void ShaderProgram::drawVideoLayerQuad(const TransformationMatrix& drawMatrix,
@@ -717,7 +725,6 @@ void ShaderProgram::drawVideoLayerQuad(const TransformationMatrix& drawMatrix,
                        projectionMatrix);
     glUniformMatrix4fv(m_handleArray[Video].videoMtxHandle, 1, GL_FALSE,
                        textureMatrix);
-
     glActiveTexture(GL_TEXTURE0);
     glUniform1i(m_handleArray[Video].texSamplerHandle, 0);
     glBindTexture(GL_TEXTURE_EXTERNAL_OES, textureId);
diff --git a/Source/WebCore/platform/graphics/android/rendering/ShaderProgram.h b/Source/WebCore/platform/graphics/android/rendering/ShaderProgram.h
index d93fd89..e290242 100644
--- a/Source/WebCore/platform/graphics/android/rendering/ShaderProgram.h
+++ b/Source/WebCore/platform/graphics/android/rendering/ShaderProgram.h
@@ -59,12 +59,13 @@ struct ShaderHandles {
         , pureColorHandle(-1)
         , texSamplerHandle(-1)
         , videoMtxHandle(-1)
+        , fillPortionHandle(-1)
     {
     }
 
     void init(GLint alphaHdl, GLint contrastHdl, GLint posHdl, GLint pgmHdl,
               GLint projMtxHdl, GLint colorHdl, GLint texSamplerHdl,
-              GLint videoMtxHdl)
+              GLint videoMtxHdl, GLint fillPortionHdl)
     {
         alphaHandle = alphaHdl;
         contrastHandle = contrastHdl;
@@ -74,6 +75,7 @@ struct ShaderHandles {
         pureColorHandle = colorHdl;
         texSamplerHandle = texSamplerHdl;
         videoMtxHandle = videoMtxHdl;
+        fillPortionHandle = fillPortionHdl;
     }
 
     GLint alphaHandle;
@@ -84,6 +86,7 @@ struct ShaderHandles {
     GLint pureColorHandle;
     GLint texSamplerHandle;
     GLint videoMtxHandle;
+    GLint fillPortionHandle;
 };
 
 struct ShaderResource {
@@ -164,7 +167,7 @@ private:
     void setBlendingState(bool enableBlending);
     void drawQuadInternal(ShaderType type, const GLfloat* matrix, int textureId,
                          float opacity, GLenum textureTarget, GLenum filter,
-                         const Color& pureColor);
+                         const Color& pureColor,  const FloatPoint& fillPortion);
     Color shaderColor(Color pureColor, float opacity);
     ShaderType getTextureShaderType(GLenum textureTarget);
     void resetBlending();
diff --git a/Source/WebCore/platform/graphics/android/rendering/Surface.cpp b/Source/WebCore/platform/graphics/android/rendering/Surface.cpp
index a9ebd1e..210f434 100644
--- a/Source/WebCore/platform/graphics/android/rendering/Surface.cpp
+++ b/Source/WebCore/platform/graphics/android/rendering/Surface.cpp
@@ -225,7 +225,6 @@ bool Surface::drawGL(bool layerTilesDisabled)
     if (m_surfaceBacking && !tilesDisabled) {
         ALOGV("drawGL on Surf %p with SurfBack %p", this, m_surfaceBacking);
 
-        // TODO: why this visibleArea is different from visibleRect at zooming for base?
         IntRect drawArea = visibleArea();
         m_surfaceBacking->drawGL(drawArea, opacity(), drawTransform(),
                                  useAggressiveRendering(), background());
diff --git a/Source/WebCore/platform/graphics/android/rendering/Tile.cpp b/Source/WebCore/platform/graphics/android/rendering/Tile.cpp
index f2aa9a0..0501777 100644
--- a/Source/WebCore/platform/graphics/android/rendering/Tile.cpp
+++ b/Source/WebCore/platform/graphics/android/rendering/Tile.cpp
@@ -209,7 +209,8 @@ void Tile::setRepaintPending(bool pending)
 
 bool Tile::drawGL(float opacity, const SkRect& rect, float scale,
                   const TransformationMatrix* transform,
-                  bool forceBlending, bool usePointSampling)
+                  bool forceBlending, bool usePointSampling,
+                  const FloatPoint& fillPortion)
 {
     if (m_x < 0 || m_y < 0 || m_scale != scale)
         return false;
@@ -219,8 +220,12 @@ bool Tile::drawGL(float opacity, const SkRect& rect, float scale,
     if (!m_frontTexture)
         return false;
 
+    if (fillPortion.x() < 1.0f || fillPortion.y() < 1.0f)
+        ALOGV("drawing tile %p (%d, %d with fill portions %f %f",
+              this, m_x, m_y, fillPortion.x(), fillPortion.y());
+
     m_frontTexture->drawGL(isLayerTile(), rect, opacity, transform,
-                           forceBlending, usePointSampling);
+                           forceBlending, usePointSampling, fillPortion);
     return true;
 }
 
diff --git a/Source/WebCore/platform/graphics/android/rendering/Tile.h b/Source/WebCore/platform/graphics/android/rendering/Tile.h
index fa06892..58ba15b 100644
--- a/Source/WebCore/platform/graphics/android/rendering/Tile.h
+++ b/Source/WebCore/platform/graphics/android/rendering/Tile.h
@@ -29,6 +29,7 @@
 #if USE(ACCELERATED_COMPOSITING)
 
 #include "BaseRenderer.h"
+#include "FloatPoint.h"
 #include "SkRect.h"
 #include "SkRegion.h"
 #include "TextureOwner.h"
@@ -102,7 +103,8 @@ public:
     // Return false when real draw didn't happen for any reason.
     bool drawGL(float opacity, const SkRect& rect, float scale,
                 const TransformationMatrix* transform,
-                bool forceBlending = false, bool usePointSampling = false);
+                bool forceBlending, bool usePointSampling,
+                const FloatPoint& fillPortion);
 
     // the only thread-safe function called by the background thread
     void paintBitmap(TilePainter* painter);
diff --git a/Source/WebCore/platform/graphics/android/rendering/TileGrid.cpp b/Source/WebCore/platform/graphics/android/rendering/TileGrid.cpp
index e3aa2a9..7c6175f 100644
--- a/Source/WebCore/platform/graphics/android/rendering/TileGrid.cpp
+++ b/Source/WebCore/platform/graphics/android/rendering/TileGrid.cpp
@@ -232,9 +232,6 @@ void TileGrid::prepareTile(int x, int y, TilePainter* painter,
 
     tile->setContents(x, y, m_scale, isExpandPrefetch);
 
-    // TODO: move below (which is largely the same for layers / tiled page) into
-    // prepareGL() function
-
     if (tile->isDirty() || !tile->frontTexture())
         tile->reserveTexture();
 
@@ -299,6 +296,10 @@ void TileGrid::drawGL(const IntRect& visibleArea, float opacity,
     bool usePointSampling =
         TilesManager::instance()->shader()->usePointSampling(m_scale, transform);
 
+
+    float maxTileWidth = visibleArea.maxX() / tileWidth;
+    float maxTileHeight = visibleArea.maxY() / tileWidth;
+
     for (unsigned int i = 0; i < m_tiles.size(); i++) {
         Tile* tile = m_tiles[i];
 
@@ -314,8 +315,11 @@ void TileGrid::drawGL(const IntRect& visibleArea, float opacity,
                   tile->scale(), m_scale, tile->isTileReady(), tile->isDirty());
 
             bool forceBaseBlending = background ? background->hasAlpha() : false;
+
+            FloatPoint fillPortion(std::min(maxTileWidth - tile->x(), 1.0f),
+                                   std::min(maxTileHeight - tile->y(), 1.0f));
             bool success = tile->drawGL(opacity, rect, m_scale, transform,
-                                        forceBaseBlending, usePointSampling);
+                                        forceBaseBlending, usePointSampling, fillPortion);
             if (semiOpaqueBaseSurface && success) {
                 // Cut the successful drawn tile area from the missing region.
                 missingRegion.op(SkIRect::MakeXYWH(tile->x(), tile->y(), 1, 1),
diff --git a/Source/WebCore/platform/graphics/android/rendering/TileTexture.cpp b/Source/WebCore/platform/graphics/android/rendering/TileTexture.cpp
index 3dceda9..54c67cc 100644
--- a/Source/WebCore/platform/graphics/android/rendering/TileTexture.cpp
+++ b/Source/WebCore/platform/graphics/android/rendering/TileTexture.cpp
@@ -120,7 +120,8 @@ void TileTexture::transferComplete()
 
 void TileTexture::drawGL(bool isLayer, const SkRect& rect, float opacity,
                          const TransformationMatrix* transform,
-                         bool forceBlending, bool usePointSampling)
+                         bool forceBlending, bool usePointSampling,
+                         const FloatPoint& fillPortion)
 {
     ShaderProgram* shader = TilesManager::instance()->shader();
 
@@ -134,7 +135,7 @@ void TileTexture::drawGL(bool isLayer, const SkRect& rect, float opacity,
     // TODO: Don't blend tiles if they are fully opaque.
     bool useBlending = forceBlending || isLayer;
     DrawQuadData commonData(isLayer ? LayerQuad : BaseQuad, transform, &rect,
-                            opacity, useBlending);
+                            opacity, useBlending, fillPortion);
     if (isPureColor()) {
         PureColorQuadData data(commonData, pureColor());
         shader->drawQuad(&data);
diff --git a/Source/WebCore/platform/graphics/android/rendering/TileTexture.h b/Source/WebCore/platform/graphics/android/rendering/TileTexture.h
index a624c1d..b694241 100644
--- a/Source/WebCore/platform/graphics/android/rendering/TileTexture.h
+++ b/Source/WebCore/platform/graphics/android/rendering/TileTexture.h
@@ -26,11 +26,12 @@
 #ifndef TileTexture_h
 #define TileTexture_h
 
-#include "TextureInfo.h"
 #include "Color.h"
+#include "FloatPoint.h"
 #include "SkBitmap.h"
 #include "SkRect.h"
 #include "SkSize.h"
+#include "TextureInfo.h"
 
 #include <GLES2/gl2.h>
 
@@ -80,8 +81,8 @@ public:
     Color pureColor() { return m_pureColor; }
 
     void drawGL(bool isLayer, const SkRect& rect, float opacity,
-                const TransformationMatrix* transform, bool forceBlending = false,
-                bool usePointSampling = false);
+                const TransformationMatrix* transform, bool forceBlending, bool usePointSampling,
+                const FloatPoint& fillPortion);
 private:
     TextureInfo m_ownTextureInfo;
     SkSize m_size;