Fix clamp lowbits extraction when combined with non-clamp

R=reed@google.com

Change-Id: I1dc17c827077e968d4dbcd0f9ea8da8e1732b253
Reviewed-on: https://skia-review.googlesource.com/6231
Commit-Queue: Florin Malita <fmalita@google.com>
Reviewed-by: Mike Reed <reed@google.com>

2 files changed, 7 insertions, 33 deletions

diff --git a/src/core/SkBitmapProcState.h b/src/core/SkBitmapProcState.h
index 88e5193b2a..73eaf4fb7c 100644
--- a/src/core/SkBitmapProcState.h
+++ b/src/core/SkBitmapProcState.h
@@ -76,7 +76,6 @@ struct SkBitmapProcState : public SkBitmapProcInfo {
                                  SkPMColor colors[]);
 
     typedef U16CPU (*FixedTileProc)(SkFixed);   // returns 0..0xFFFF
-    typedef U16CPU (*FixedTileLowBitsProc)(SkFixed, int);   // returns 0..0xF
     typedef U16CPU (*IntTileProc)(int value, int count);   // returns 0..count-1
 
     SkMatrix::MapXYProc fInvProc;           // chooseProcs
@@ -85,8 +84,6 @@ struct SkBitmapProcState : public SkBitmapProcInfo {
 
     FixedTileProc       fTileProcX;         // chooseProcs
     FixedTileProc       fTileProcY;         // chooseProcs
-    FixedTileLowBitsProc fTileLowBitsProcX; // chooseProcs
-    FixedTileLowBitsProc fTileLowBitsProcY; // chooseProcs
     IntTileProc         fIntTileProcY;      // chooseProcs
     SkFixed             fFilterOneX;
     SkFixed             fFilterOneY;
diff --git a/src/core/SkBitmapProcState_matrixProcs.cpp b/src/core/SkBitmapProcState_matrixProcs.cpp
index 1b747de280..073e594f1b 100644
--- a/src/core/SkBitmapProcState_matrixProcs.cpp
+++ b/src/core/SkBitmapProcState_matrixProcs.cpp
@@ -124,17 +124,15 @@ static SkBitmapProcState::MatrixProc RepeatX_RepeatY_Procs[] = {
 
 #define MAKENAME(suffix)        GeneralXY ## suffix
 #define PREAMBLE(state)         SkBitmapProcState::FixedTileProc tileProcX = (state).fTileProcX; (void) tileProcX; \
-                                SkBitmapProcState::FixedTileProc tileProcY = (state).fTileProcY; (void) tileProcY; \
-                                SkBitmapProcState::FixedTileLowBitsProc tileLowBitsProcX = (state).fTileLowBitsProcX; (void) tileLowBitsProcX; \
-                                SkBitmapProcState::FixedTileLowBitsProc tileLowBitsProcY = (state).fTileLowBitsProcY; (void) tileLowBitsProcY
-#define PREAMBLE_PARAM_X        , SkBitmapProcState::FixedTileProc tileProcX, SkBitmapProcState::FixedTileLowBitsProc tileLowBitsProcX
-#define PREAMBLE_PARAM_Y        , SkBitmapProcState::FixedTileProc tileProcY, SkBitmapProcState::FixedTileLowBitsProc tileLowBitsProcY
-#define PREAMBLE_ARG_X          , tileProcX, tileLowBitsProcX
-#define PREAMBLE_ARG_Y          , tileProcY, tileLowBitsProcY
+                                SkBitmapProcState::FixedTileProc tileProcY = (state).fTileProcY; (void) tileProcY;
+#define PREAMBLE_PARAM_X        , SkBitmapProcState::FixedTileProc tileProcX
+#define PREAMBLE_PARAM_Y        , SkBitmapProcState::FixedTileProc tileProcY
+#define PREAMBLE_ARG_X          , tileProcX
+#define PREAMBLE_ARG_Y          , tileProcY
 #define TILEX_PROCF(fx, max)    SK_USHIFT16(tileProcX(fx) * ((max) + 1))
 #define TILEY_PROCF(fy, max)    SK_USHIFT16(tileProcY(fy) * ((max) + 1))
-#define TILEX_LOW_BITS(fx, max) tileLowBitsProcX(fx, (max) + 1)
-#define TILEY_LOW_BITS(fy, max) tileLowBitsProcY(fy, (max) + 1)
+#define TILEX_LOW_BITS(fx, max) (((fx * (max + 1)) >> 12) & 0xF)
+#define TILEY_LOW_BITS(fy, max) (((fy * (max + 1)) >> 12) & 0xF)
 #include "SkBitmapProcState_matrix.h"
 
 struct GeneralTileProcs {
@@ -188,25 +186,6 @@ static SkBitmapProcState::FixedTileProc choose_tile_proc(unsigned m) {
     return fixed_mirror;
 }
 
-static inline U16CPU fixed_clamp_lowbits(SkFixed x, int) {
-    return (x >> 12) & 0xF;
-}
-
-static inline U16CPU fixed_repeat_or_mirrow_lowbits(SkFixed x, int scale) {
-    return ((x * scale) >> 12) & 0xF;
-}
-
-static SkBitmapProcState::FixedTileLowBitsProc choose_tile_lowbits_proc(unsigned m) {
-    if (SkShader::kClamp_TileMode == m) {
-        return fixed_clamp_lowbits;
-    } else {
-        SkASSERT(SkShader::kMirror_TileMode == m ||
-                 SkShader::kRepeat_TileMode == m);
-        // mirror and repeat have the same behavior for the low bits.
-        return fixed_repeat_or_mirrow_lowbits;
-    }
-}
-
 static inline U16CPU int_clamp(int x, int n) {
     if (x >= n) {
         x = n - 1;
@@ -514,7 +493,5 @@ SkBitmapProcState::MatrixProc SkBitmapProcState::chooseMatrixProc(bool trivial_m
 
     fTileProcX = choose_tile_proc(fTileModeX);
     fTileProcY = choose_tile_proc(fTileModeY);
-    fTileLowBitsProcX = choose_tile_lowbits_proc(fTileModeX);
-    fTileLowBitsProcY = choose_tile_lowbits_proc(fTileModeY);
     return GeneralXY_Procs[index];
 }