Composite layers as regions.

This change detects what area of a layer was drawn into and generates a mesh
to match this area exactly. This can be used to avoid blending empty pixels
when the layer is composited.
This change also adds proper layers support to lines rendering and implements
layers composition in a more readable way.

Change-Id: I4a5588b98b19bd66891ebdc39631b193c5e31999

4 files changed, 62 insertions, 53 deletions

diff --git a/libs/hwui/Caches.cpp b/libs/hwui/Caches.cpp
index 40dd117..406d09f 100644
--- a/libs/hwui/Caches.cpp
+++ b/libs/hwui/Caches.cpp
@@ -53,6 +53,10 @@ Caches::Caches(): Singleton<Caches>(), blend(false), lastSrcMode(GL_ZERO),
 
     mDebugLevel = readDebugLevel();
     LOGD("Enabling debug mode %d", mDebugLevel);
+
+#if RENDER_LAYERS_AS_REGIONS
+    LOGD("Layers will be composited as regions");
+#endif
 }
 
 Caches::~Caches() {
diff --git a/libs/hwui/OpenGLRenderer.cpp b/libs/hwui/OpenGLRenderer.cpp
index 61241e0..99bb6f0 100644
--- a/libs/hwui/OpenGLRenderer.cpp
+++ b/libs/hwui/OpenGLRenderer.cpp
@@ -604,43 +604,23 @@ void OpenGLRenderer::composeLayerRegion(Layer* layer, const Rect& rect) {
         size_t count;
         const android::Rect* rects = layer->region.getArray(&count);
 
-        setupDraw();
-
-        ProgramDescription description;
-        description.hasTexture = true;
-
         const float alpha = layer->alpha / 255.0f;
-        const bool setColor = description.setColor(alpha, alpha, alpha, alpha);
-        chooseBlending(layer->blend || layer->alpha < 255, layer->mode, description, false);
-
-        useProgram(mCaches.programCache.get(description));
-
-        // Texture
-        bindTexture(layer->texture);
-        glUniform1i(mCaches.currentProgram->getUniform("sampler"), 0);
-
-        // Always premultiplied
-        if (setColor) {
-            mCaches.currentProgram->setColor(alpha, alpha, alpha, alpha);
-        }
-
-        // Mesh
-        int texCoordsSlot = mCaches.currentProgram->getAttrib("texCoords");
-        glEnableVertexAttribArray(texCoordsSlot);
-
-        mModelView.loadIdentity();
-        mCaches.currentProgram->set(mOrthoMatrix, mModelView, *mSnapshot->transform);
-
         const float texX = 1.0f / float(layer->width);
         const float texY = 1.0f / float(layer->height);
 
         TextureVertex* mesh = mCaches.getRegionMesh();
         GLsizei numQuads = 0;
 
-        glVertexAttribPointer(mCaches.currentProgram->position, 2, GL_FLOAT, GL_FALSE,
-                gMeshStride, &mesh[0].position[0]);
-        glVertexAttribPointer(texCoordsSlot, 2, GL_FLOAT, GL_FALSE,
-                gMeshStride, &mesh[0].texture[0]);
+        setupDraw();
+        setupDrawWithTexture();
+        setupDrawColor(alpha, alpha, alpha, alpha);
+        setupDrawBlending(layer->blend || layer->alpha < 255, layer->mode, false);
+        setupDrawProgram();
+        setupDrawDirtyRegionsDisabled();
+        setupDrawPureColorUniforms();
+        setupDrawTexture(layer->texture);
+        setupDrawModelViewIdentity();
+        setupDrawMesh(&mesh[0].position[0], &mesh[0].texture[0]);
 
         for (size_t i = 0; i < count; i++) {
             const android::Rect* r = &rects[i];
@@ -670,7 +650,7 @@ void OpenGLRenderer::composeLayerRegion(Layer* layer, const Rect& rect) {
         }
 
         glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
-        glDisableVertexAttribArray(texCoordsSlot);
+        finishDrawTexture();
 
 #if DEBUG_LAYERS_AS_REGIONS
         uint32_t colors[] = {
@@ -1186,7 +1166,6 @@ void OpenGLRenderer::drawPatch(SkBitmap* bitmap, const int32_t* xDivs, const int
 }
 
 void OpenGLRenderer::drawLines(float* points, int count, SkPaint* paint) {
-    // TODO: Should do quickReject for each line
     if (mSnapshot->isIgnored()) return;
 
     const bool isAA = paint->isAntiAlias();
@@ -1200,6 +1179,7 @@ void OpenGLRenderer::drawLines(float* points, int count, SkPaint* paint) {
     getAlphaAndMode(paint, &alpha, &mode);
 
     int verticesCount = count >> 2;
+    int generatedVerticesCount = 0;
     if (!isHairLine) {
         // TODO: AA needs more vertices
         verticesCount *= 6;
@@ -1246,31 +1226,55 @@ void OpenGLRenderer::drawLines(float* points, int count, SkPaint* paint) {
             vec2 p3 = b + n;
             vec2 p4 = b - n;
 
-            // Draw the line as 2 triangles, could be optimized
-            // by using only 4 vertices and the correct indices
-            // Also we should probably used non textured vertices
-            // when line AA is disabled to save on bandwidth
-            TextureVertex::set(vertex++, p1.x, p1.y, 0.0f, 0.0f);
-            TextureVertex::set(vertex++, p2.x, p2.y, 0.0f, 0.0f);
-            TextureVertex::set(vertex++, p3.x, p3.y, 0.0f, 0.0f);
-            TextureVertex::set(vertex++, p1.x, p1.y, 0.0f, 0.0f);
-            TextureVertex::set(vertex++, p3.x, p3.y, 0.0f, 0.0f);
-            TextureVertex::set(vertex++, p4.x, p4.y, 0.0f, 0.0f);
-
-            // TODO: Mark the dirty regions when RENDER_LAYERS_AS_REGIONS is set
+            const float left = fmin(p1.x, fmin(p2.x, fmin(p3.x, p4.x)));
+            const float right = fmax(p1.x, fmax(p2.x, fmax(p3.x, p4.x)));
+            const float top = fmin(p1.y, fmin(p2.y, fmin(p3.y, p4.y)));
+            const float bottom = fmax(p1.y, fmax(p2.y, fmax(p3.y, p4.y)));
+
+            if (!quickReject(left, top, right, bottom)) {
+                // Draw the line as 2 triangles, could be optimized
+                // by using only 4 vertices and the correct indices
+                // Also we should probably used non textured vertices
+                // when line AA is disabled to save on bandwidth
+                TextureVertex::set(vertex++, p1.x, p1.y, 0.0f, 0.0f);
+                TextureVertex::set(vertex++, p2.x, p2.y, 0.0f, 0.0f);
+                TextureVertex::set(vertex++, p3.x, p3.y, 0.0f, 0.0f);
+                TextureVertex::set(vertex++, p1.x, p1.y, 0.0f, 0.0f);
+                TextureVertex::set(vertex++, p3.x, p3.y, 0.0f, 0.0f);
+                TextureVertex::set(vertex++, p4.x, p4.y, 0.0f, 0.0f);
+
+                generatedVerticesCount += 6;
+
+                dirtyLayer(left, top, right, bottom, *mSnapshot->transform);
+            }
         }
 
-        // GL_LINE does not give the result we want to match Skia
-        glDrawArrays(GL_TRIANGLES, 0, verticesCount);
+        if (generatedVerticesCount > 0) {
+            // GL_LINE does not give the result we want to match Skia
+            glDrawArrays(GL_TRIANGLES, 0, generatedVerticesCount);
+        }
     } else {
         // TODO: Handle the AA case
         for (int i = 0; i < count; i += 4) {
-            TextureVertex::set(vertex++, points[i], points[i + 1], 0.0f, 0.0f);
-            TextureVertex::set(vertex++, points[i + 2], points[i + 3], 0.0f, 0.0f);
+            const float left = fmin(points[i], points[i + 1]);
+            const float right = fmax(points[i], points[i + 1]);
+            const float top = fmin(points[i + 2], points[i + 3]);
+            const float bottom = fmax(points[i + 2], points[i + 3]);
+
+            if (!quickReject(left, top, right, bottom)) {
+                TextureVertex::set(vertex++, points[i], points[i + 1], 0.0f, 0.0f);
+                TextureVertex::set(vertex++, points[i + 2], points[i + 3], 0.0f, 0.0f);
+
+                generatedVerticesCount += 2;
+
+                dirtyLayer(left, top, right, bottom, *mSnapshot->transform);
+            }
         }
 
-        glLineWidth(1.0f);
-        glDrawArrays(GL_LINES, 0, verticesCount);
+        if (generatedVerticesCount > 0) {
+            glLineWidth(1.0f);
+            glDrawArrays(GL_LINES, 0, generatedVerticesCount);
+        }
     }
 }
 
diff --git a/libs/hwui/Properties.h b/libs/hwui/Properties.h
index c474936..6a0d7ea 100644
--- a/libs/hwui/Properties.h
+++ b/libs/hwui/Properties.h
@@ -26,7 +26,7 @@
  */
 
 // If turned on, layers drawn inside FBOs are optimized with regions
-#define RENDER_LAYERS_AS_REGIONS 0
+#define RENDER_LAYERS_AS_REGIONS 1
 
 /**
  * Debug level for app developers.
diff --git a/tests/HwAccelerationTest/src/com/android/test/hwui/LinesActivity.java b/tests/HwAccelerationTest/src/com/android/test/hwui/LinesActivity.java
index 91e3b84..8ca842e 100644
--- a/tests/HwAccelerationTest/src/com/android/test/hwui/LinesActivity.java
+++ b/tests/HwAccelerationTest/src/com/android/test/hwui/LinesActivity.java
@@ -23,6 +23,7 @@ import android.graphics.BitmapFactory;
 import android.graphics.BitmapShader;
 import android.graphics.Canvas;
 import android.graphics.Paint;
+import android.graphics.drawable.ColorDrawable;
 import android.os.Bundle;
 import android.view.View;
 
@@ -31,7 +32,9 @@ public class LinesActivity extends Activity {
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
+        getWindow().setBackgroundDrawable(new ColorDrawable(0xffffffff));
         final LinesView view = new LinesView(this);
+        //view.setAlpha(0.80f);
         setContentView(view);
     }
 
@@ -91,8 +94,6 @@ public class LinesActivity extends Activity {
         protected void onDraw(Canvas canvas) {
             super.onDraw(canvas);
 
-            canvas.drawARGB(255, 255, 255, 255);
-
             canvas.save();
             canvas.translate(100.0f, 20.0f);