Rework shadow interpolation

bug:16852257

Use pow(alpha, 1.5) to avoid harsh edges on shadow alpha ramps.

Also adjusts shadow constants to compensate.

Change-Id: I5869956d7d292db2a8e496bc320084b6d64c3fb7

1 files changed, 12 insertions, 8 deletions

diff --git a/libs/hwui/Program.h b/libs/hwui/Program.h
index 3e191d0a0186..1d95c40b6233 100644
--- a/libs/hwui/Program.h
+++ b/libs/hwui/Program.h
@@ -72,19 +72,20 @@ namespace uirenderer {
 #define PROGRAM_MODULATE_SHIFT 35
 
 #define PROGRAM_HAS_AA_SHIFT 36
+#define PROGRAM_HAS_SHADOW_AA_SHIFT 37
 
-#define PROGRAM_HAS_EXTERNAL_TEXTURE_SHIFT 37
-#define PROGRAM_HAS_TEXTURE_TRANSFORM_SHIFT 38
+#define PROGRAM_HAS_EXTERNAL_TEXTURE_SHIFT 38
+#define PROGRAM_HAS_TEXTURE_TRANSFORM_SHIFT 39
 
-#define PROGRAM_HAS_GAMMA_CORRECTION 39
+#define PROGRAM_HAS_GAMMA_CORRECTION 40
 
-#define PROGRAM_IS_SIMPLE_GRADIENT 40
+#define PROGRAM_IS_SIMPLE_GRADIENT 41
 
-#define PROGRAM_HAS_COLORS 41
+#define PROGRAM_HAS_COLORS 42
 
-#define PROGRAM_HAS_DEBUG_HIGHLIGHT 42
-#define PROGRAM_EMULATE_STENCIL 43
-#define PROGRAM_HAS_ROUND_RECT_CLIP 44
+#define PROGRAM_HAS_DEBUG_HIGHLIGHT 43
+#define PROGRAM_EMULATE_STENCIL 44
+#define PROGRAM_HAS_ROUND_RECT_CLIP 45
 
 ///////////////////////////////////////////////////////////////////////////////
 // Types
@@ -135,6 +136,7 @@ struct ProgramDescription {
     bool isBitmapNpot;
 
     bool isAA; // drawing with a per-vertex alpha
+    bool isShadowAA; // drawing per vertex alpha with shadow interpolation
 
     bool hasGradient;
     Gradient gradientType;
@@ -175,6 +177,7 @@ struct ProgramDescription {
         hasColors = false;
 
         isAA = false;
+        isShadowAA = false;
 
         modulate = false;
 
@@ -262,6 +265,7 @@ struct ProgramDescription {
         if (swapSrcDst) key |= PROGRAM_KEY_SWAP_SRC_DST;
         if (modulate) key |= programid(0x1) << PROGRAM_MODULATE_SHIFT;
         if (isAA) key |= programid(0x1) << PROGRAM_HAS_AA_SHIFT;
+        if (isShadowAA) key |= programid(0x1) << PROGRAM_HAS_SHADOW_AA_SHIFT;
         if (hasExternalTexture) key |= programid(0x1) << PROGRAM_HAS_EXTERNAL_TEXTURE_SHIFT;
         if (hasTextureTransform) key |= programid(0x1) << PROGRAM_HAS_TEXTURE_TRANSFORM_SHIFT;
         if (hasGammaCorrection) key |= programid(0x1) << PROGRAM_HAS_GAMMA_CORRECTION;