commit b79a3e301a8d89b9e1b1f6f3d7fd6aa56610a6f0
author Chris Craik <ccraik@google.com> Tue Mar 11 12:20:17 2014 -0700
committer Chris Craik <ccraik@google.com> Wed Mar 12 09:44:41 2014 -0700
tree 6b92898b802b665b62127766baa87e8261569062
parent e361ad7ab15fcf4919a56a6293689d968ee8dcff

Fix orthographic shadows projection, simplify shadow reordering

Separate matrix passed to shadow system into two parts, one for
transforming the polygon XY points (using the actual draw matrix) and
a separate one which respects correct 4x4 3d rotations and
translations for determining Z values.

Change-Id: I7e30a84774a8709df6b2241e8f51fc5583648fe8

libs/hwui/OpenGLRenderer.cpp

diff --git a/libs/hwui/OpenGLRenderer.cpp b/libs/hwui/OpenGLRenderer.cpp
index 7002e26..83de772 100644
--- a/libs/hwui/OpenGLRenderer.cpp
+++ b/libs/hwui/OpenGLRenderer.cpp
@@ -3190,8 +3190,16 @@
     return drawColorRects(rects, count, paint, false, true, true);
 }
 
-status_t OpenGLRenderer::drawShadow(const mat4& casterTransform, float casterAlpha,
-        const SkPath* casterOutline) {
+static void mapPointFakeZ(Vector3& point, const mat4& transformXY, const mat4& transformZ) {
+    // map z coordinate with true 3d matrix
+    point.z = transformZ.mapZ(point);
+
+    // map x,y coordinates with draw/Skia matrix
+    transformXY.mapPoint(point.x, point.y);
+}
+
+status_t OpenGLRenderer::drawShadow(const mat4& casterTransformXY, const mat4& casterTransformZ,
+        float casterAlpha, const SkPath* casterOutline) {
     if (currentSnapshot()->isIgnored()) return DrawGlInfo::kStatusDone;
 
     // TODO: use quickRejectWithScissor. For now, always force enable scissor.
@@ -3217,7 +3225,7 @@
     for (int i = 0; i < casterVertexCount; i++) {
         const Vertex& point2d = casterVertices2d[i];
         casterPolygon[i] = Vector3(point2d.x, point2d.y, 0);
-        casterTransform.mapPoint3d(casterPolygon[i]);
+        mapPointFakeZ(casterPolygon[i], casterTransformXY, casterTransformZ);
     }
 
     // map the centroid of the caster into 3d
@@ -3225,7 +3233,7 @@
             reinterpret_cast<const Vector2*>(casterVertices2d.array()),
             casterVertexCount);
     Vector3 centroid3d(centroid.x, centroid.y, 0);
-    casterTransform.mapPoint3d(centroid3d);
+    mapPointFakeZ(centroid3d, casterTransformXY, casterTransformZ);
 
     // draw caster's shadows
     if (mCaches.propertyAmbientShadowStrength > 0) {
@@ -3244,7 +3252,6 @@
         ShadowTessellator::tessellateSpotShadow(casterPolygon, casterVertexCount,
                 lightPosScale, *currentTransform(), getWidth(), getHeight(),
                 spotShadowVertexBuffer);
-
         drawVertexBuffer(kVertexBufferMode_Shadow, spotShadowVertexBuffer, &paint);
     }