Update layers based on the dirty region.

Bug #3413433

This helps Launcher when a widget updates during a scroll, or when interacting
with widgets on the workspace if layers are still turned on.

Change-Id: Ic7a42eb34f74f4ae988039754f815e2efd1d1e4f

3 files changed, 49 insertions, 20 deletions

diff --git a/libs/hwui/LayerRenderer.cpp b/libs/hwui/LayerRenderer.cpp
index 691f649..aebd2b7 100644
--- a/libs/hwui/LayerRenderer.cpp
+++ b/libs/hwui/LayerRenderer.cpp
@@ -16,8 +16,11 @@
 
 #define LOG_TAG "OpenGLRenderer"
 
+#include <ui/Rect.h>
+
 #include "LayerRenderer.h"
 #include "Properties.h"
+#include "Rect.h"
 
 namespace android {
 namespace uirenderer {
@@ -30,12 +33,24 @@ void LayerRenderer::prepareDirty(float left, float top, float right, float botto
     LAYER_RENDERER_LOGD("Rendering into layer, fbo = %d", mLayer->fbo);
 
 #if RENDER_LAYERS_AS_REGIONS
-    mLayer->region.clear();
+    Rect dirty(left, top, right, bottom);
+    if (dirty.isEmpty() || (dirty.left <= 0 && dirty.top <= 0 &&
+            dirty.right >= mLayer->width && dirty.bottom >= mLayer->height)) {
+        mLayer->region.clear();
+        dirty.set(0.0f, 0.0f, mLayer->width, mLayer->height);
+    } else {
+        android::Rect r(dirty.left, dirty.top, dirty.right, dirty.bottom);
+        mLayer->region.subtractSelf(r);
+    }
 #endif
 
     glBindFramebuffer(GL_FRAMEBUFFER, mLayer->fbo);
 
+#if RENDER_LAYERS_AS_REGIONS
+    OpenGLRenderer::prepareDirty(dirty.left, dirty.top, dirty.right, dirty.bottom, opaque);
+#else
     OpenGLRenderer::prepareDirty(0.0f, 0.0f, mLayer->width, mLayer->height, opaque);
+#endif
 }
 
 void LayerRenderer::finish() {
diff --git a/libs/hwui/OpenGLRenderer.cpp b/libs/hwui/OpenGLRenderer.cpp
index 2960395..90d6ea1 100644
--- a/libs/hwui/OpenGLRenderer.cpp
+++ b/libs/hwui/OpenGLRenderer.cpp
@@ -671,25 +671,7 @@ void OpenGLRenderer::composeLayerRegion(Layer* layer, const Rect& rect) {
         finishDrawTexture();
 
 #if DEBUG_LAYERS_AS_REGIONS
-        uint32_t colors[] = {
-                0x7fff0000, 0x7f00ff00,
-                0x7f0000ff, 0x7fff00ff,
-        };
-
-        int offset = 0;
-        int32_t top = rects[0].top;
-        int i = 0;
-
-        for (size_t i = 0; i < count; i++) {
-            if (top != rects[i].top) {
-                offset ^= 0x2;
-                top = rects[i].top;
-            }
-
-            Rect r(rects[i].left, rects[i].top, rects[i].right, rects[i].bottom);
-            drawColorRect(r.left, r.top, r.right, r.bottom, colors[offset + (i & 0x1)],
-                    SkXfermode::kSrcOver_Mode);
-        }
+        drawRegionRects(layer->region);
 #endif
 
         layer->region.clear();
@@ -699,6 +681,32 @@ void OpenGLRenderer::composeLayerRegion(Layer* layer, const Rect& rect) {
 #endif
 }
 
+void OpenGLRenderer::drawRegionRects(const Region& region) {
+#if DEBUG_LAYERS_AS_REGIONS
+    size_t count;
+    const android::Rect* rects = region.getArray(&count);
+
+    uint32_t colors[] = {
+            0x7fff0000, 0x7f00ff00,
+            0x7f0000ff, 0x7fff00ff,
+    };
+
+    int offset = 0;
+    int32_t top = rects[0].top;
+
+    for (size_t i = 0; i < count; i++) {
+        if (top != rects[i].top) {
+            offset ^= 0x2;
+            top = rects[i].top;
+        }
+
+        Rect r(rects[i].left, rects[i].top, rects[i].right, rects[i].bottom);
+        drawColorRect(r.left, r.top, r.right, r.bottom, colors[offset + (i & 0x1)],
+                SkXfermode::kSrcOver_Mode);
+    }
+#endif
+}
+
 void OpenGLRenderer::dirtyLayer(const float left, const float top,
         const float right, const float bottom, const mat4 transform) {
 #if RENDER_LAYERS_AS_REGIONS
@@ -1626,6 +1634,10 @@ void OpenGLRenderer::drawLayer(Layer* layer, float x, float y, SkPaint* paint) {
                     GL_UNSIGNED_SHORT, layer->meshIndices);
 
             finishDrawTexture();
+
+#if DEBUG_LAYERS_AS_REGIONS
+            drawRegionRects(layer->region);
+#endif
         }
     }
 #else
diff --git a/libs/hwui/OpenGLRenderer.h b/libs/hwui/OpenGLRenderer.h
index 64def03..7bbf034 100644
--- a/libs/hwui/OpenGLRenderer.h
+++ b/libs/hwui/OpenGLRenderer.h
@@ -455,6 +455,8 @@ private:
     void setupDrawMesh(GLvoid* vertices, GLvoid* texCoords = NULL, GLuint vbo = 0);
     void finishDrawTexture();
 
+    void drawRegionRects(const Region& region);
+
     /**
      * Should be invoked every time the glScissor is modified.
      */