commit f74e8e0602100e048c13ea262f0c19c3b8738b6f
author Mathias Agopian <mathias@google.com> Mon Apr 16 03:14:05 2012 -0700
committer Mathias Agopian <mathias@google.com> Mon Apr 16 03:19:15 2012 -0700
tree f638df8f71e2f311de8831ca62b851d242476b8c
parent a2f4e56fec0fb36c4a370eb23d6e9dc57f250b59

don't attempt to clip layers anymore using glScissor

this seems to hurt performance on some GPU. this change
might negatively affect performance on other GPUs though, but
probably in less time-sensitive cases. If this becomes a
problem it might become necessary to pre-clip the geometry
(so that we don't have to use glScissor).

This improves the rotation animation quite a bit.

Change-Id: I5dbe1286f7ad858ef2c1e1ad9a07ee3f26c0b1f3

services/surfaceflinger/LayerBase.cpp

diff --git a/services/surfaceflinger/LayerBase.cpp b/services/surfaceflinger/LayerBase.cpp
index 416fc93..694ecde 100644
--- a/services/surfaceflinger/LayerBase.cpp
+++ b/services/surfaceflinger/LayerBase.cpp
@@ -231,7 +231,9 @@
     const uint32_t hw_h = hw.getHeight();
 
     uint32_t w = s.w;
-    uint32_t h = s.h;    
+    uint32_t h = s.h;
+
+    mNumVertices = 4;
     tr.transform(mVertices[0], 0, 0);
     tr.transform(mVertices[1], 0, h);
     tr.transform(mVertices[2], w, h);
@@ -268,27 +270,6 @@
         const Transform& planeTransform, Region& outDirtyRegion) {
 }
 
-void LayerBase::drawRegion(const Region& reg) const
-{
-    Region::const_iterator it = reg.begin();
-    Region::const_iterator const end = reg.end();
-    if (it != end) {
-        Rect r;
-        const DisplayHardware& hw(graphicPlane(0).displayHardware());
-        const int32_t fbWidth  = hw.getWidth();
-        const int32_t fbHeight = hw.getHeight();
-        const GLshort vertices[][2] = { { 0, 0 }, { fbWidth, 0 }, 
-                { fbWidth, fbHeight }, { 0, fbHeight }  };
-        glVertexPointer(2, GL_SHORT, 0, vertices);
-        while (it != end) {
-            const Rect& r = *it++;
-            const GLint sy = fbHeight - (r.top + r.height());
-            glScissor(r.left, sy, r.width(), r.height());
-            glDrawArrays(GL_TRIANGLE_FAN, 0, 4); 
-        }
-    }
-}
-
 void LayerBase::setGeometry(hwc_layer_t* hwcl)
 {
     hwcl->compositionType = HWC_FRAMEBUFFER;
@@ -345,9 +326,6 @@
 
 void LayerBase::draw(const Region& clip) const
 {
-    // reset GL state
-    glEnable(GL_SCISSOR_TEST);
-
     onDraw(clip);
 }
 
@@ -371,16 +349,8 @@
     glDisable(GL_TEXTURE_2D);
     glDisable(GL_BLEND);
 
-    Region::const_iterator it = clip.begin();
-    Region::const_iterator const end = clip.end();
-    glEnable(GL_SCISSOR_TEST);
     glVertexPointer(2, GL_FLOAT, 0, mVertices);
-    while (it != end) {
-        const Rect& r = *it++;
-        const GLint sy = fbHeight - (r.top + r.height());
-        glScissor(r.left, sy, r.width(), r.height());
-        glDrawArrays(GL_TRIANGLE_FAN, 0, 4); 
-    }
+    glDrawArrays(GL_TRIANGLE_FAN, 0, mNumVertices);
 }
 
 void LayerBase::clearWithOpenGL(const Region& clip) const
@@ -434,15 +404,8 @@
     glEnableClientState(GL_TEXTURE_COORD_ARRAY);
     glVertexPointer(2, GL_FLOAT, 0, mVertices);
     glTexCoordPointer(2, GL_FLOAT, 0, texCoords);
+    glDrawArrays(GL_TRIANGLE_FAN, 0, mNumVertices);
 
-    Region::const_iterator it = clip.begin();
-    Region::const_iterator const end = clip.end();
-    while (it != end) {
-        const Rect& r = *it++;
-        const GLint sy = fbHeight - (r.top + r.height());
-        glScissor(r.left, sy, r.width(), r.height());
-        glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
-    }
     glDisableClientState(GL_TEXTURE_COORD_ARRAY);
     glDisable(GL_BLEND);
 }