Create one hole inside the umbra area to avoid overdraw.

bug:13439450

Change-Id: I859575196bd5a3029f447883025a6ec3a1f1face

1 files changed, 17 insertions, 10 deletions

diff --git a/libs/hwui/ShadowTessellator.h b/libs/hwui/ShadowTessellator.h
index c558460..ab039fa 100644
--- a/libs/hwui/ShadowTessellator.h
+++ b/libs/hwui/ShadowTessellator.h
@@ -20,6 +20,7 @@
 
 #include "Debug.h"
 #include "Matrix.h"
+#include "OpenGLRenderer.h"
 #include "VertexBuffer.h"
 
 namespace android {
@@ -30,15 +31,14 @@ namespace uirenderer {
 // Assuming we use 6 rays and only 1 layer, Then we will have 2 hexagons, which
 // are 0 to 5 and 6 to 11. The area between them will be the penumbra area, and
 // the area inside the 2nd hexagon is the umbra.
-// Also, we need to add the centroid "12" to draw the umbra area as triangle fans.
-//
+// Ambient shadow is using only 1 layer for opaque caster, otherwise, spot
+// shadow and ambient shadow are using 2 layers.
 // Triange strip indices for penumbra area: (0, 6, 1, 7, 2, 8, 3, 9, 4, 10, 5, 11, 0, 6)
-// Triange strip indices for numbra area: (6, 12, 7, 12, 8, 12, 9, 12, 10, 12, 11, 12, 6)
 //                 0
 //
 //      5          6         1
 //           11         7
-//                12
+//
 //           10         8
 //      4          9         2
 //
@@ -49,20 +49,27 @@ namespace uirenderer {
 #define SHADOW_RAY_COUNT 128
 
 // The total number of all the vertices representing the shadow.
-#define SHADOW_VERTEX_COUNT (2 * SHADOW_RAY_COUNT + 1)
+// For the case we only have 1 layer, then we will just fill only 2/3 of it.
+#define SHADOW_VERTEX_COUNT (3 * SHADOW_RAY_COUNT)
 
 // The total number of indices used for drawing the shadow geometry as triangle strips.
-#define SHADOW_INDEX_COUNT (2 * SHADOW_RAY_COUNT + 1 + 2 * (SHADOW_RAY_COUNT + 1))
+// Depending on the mode we are drawing, we can have 1 layer or 2 layers.
+// Therefore, we only build the longer index buffer.
+#define TWO_POLY_RING_SHADOW_INDEX_COUNT (4 * (SHADOW_RAY_COUNT + 1))
+#define ONE_POLY_RING_SHADOW_INDEX_COUNT (2 * (SHADOW_RAY_COUNT + 1))
+
+#define MAX_SHADOW_INDEX_COUNT TWO_POLY_RING_SHADOW_INDEX_COUNT
 
 #define SHADOW_MIN_CASTER_Z 0.001f
 
 class ShadowTessellator {
 public:
-    static void tessellateAmbientShadow(const Vector3* casterPolygon,
-            int casterVertexCount, const Vector3& centroid3d,
-            VertexBuffer& shadowVertexBuffer);
+    static VertexBufferMode tessellateAmbientShadow(bool isCasterOpaque,
+            const Vector3* casterPolygon, int casterVertexCount,
+            const Vector3& centroid3d, VertexBuffer& shadowVertexBuffer);
 
-    static void tessellateSpotShadow(const Vector3* casterPolygon, int casterVertexCount,
+    static VertexBufferMode tessellateSpotShadow(bool isCasterOpaque,
+            const Vector3* casterPolygon, int casterVertexCount,
             const Vector3& lightPosScale, const mat4& receiverTransform,
             int screenWidth, int screenHeight, VertexBuffer& shadowVertexBuffer);