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comparison: gfx/skia/trunk/src/gpu/GrBlend.cpp
gfx/skia/trunk/src/gpu/GrBlend.cpp
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| -1:000000000000 | 0:9177110546f1 |
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| 1 | |
| 2 /* | |
| 3 * Copyright 2013 Google Inc. | |
| 4 * | |
| 5 * Use of this source code is governed by a BSD-style license that can be | |
| 6 * found in the LICENSE file. | |
| 7 */ | |
| 8 | |
| 9 #include "GrBlend.h" | |
| 10 | |
| 11 static inline GrBlendCoeff swap_coeff_src_dst(GrBlendCoeff coeff) { | |
| 12 switch (coeff) { | |
| 13 case kDC_GrBlendCoeff: | |
| 14 return kSC_GrBlendCoeff; | |
| 15 case kIDC_GrBlendCoeff: | |
| 16 return kISC_GrBlendCoeff; | |
| 17 case kDA_GrBlendCoeff: | |
| 18 return kSA_GrBlendCoeff; | |
| 19 case kIDA_GrBlendCoeff: | |
| 20 return kISA_GrBlendCoeff; | |
| 21 case kSC_GrBlendCoeff: | |
| 22 return kDC_GrBlendCoeff; | |
| 23 case kISC_GrBlendCoeff: | |
| 24 return kIDC_GrBlendCoeff; | |
| 25 case kSA_GrBlendCoeff: | |
| 26 return kDA_GrBlendCoeff; | |
| 27 case kISA_GrBlendCoeff: | |
| 28 return kIDA_GrBlendCoeff; | |
| 29 default: | |
| 30 return coeff; | |
| 31 } | |
| 32 } | |
| 33 | |
| 34 static inline unsigned saturated_add(unsigned a, unsigned b) { | |
| 35 SkASSERT(a <= 255); | |
| 36 SkASSERT(b <= 255); | |
| 37 unsigned sum = a + b; | |
| 38 if (sum > 255) { | |
| 39 sum = 255; | |
| 40 } | |
| 41 return sum; | |
| 42 } | |
| 43 | |
| 44 static GrColor add_colors(GrColor src, GrColor dst) { | |
| 45 unsigned r = saturated_add(GrColorUnpackR(src), GrColorUnpackR(dst)); | |
| 46 unsigned g = saturated_add(GrColorUnpackG(src), GrColorUnpackG(dst)); | |
| 47 unsigned b = saturated_add(GrColorUnpackB(src), GrColorUnpackB(dst)); | |
| 48 unsigned a = saturated_add(GrColorUnpackA(src), GrColorUnpackA(dst)); | |
| 49 return GrColorPackRGBA(r, g, b, a); | |
| 50 } | |
| 51 | |
| 52 static inline bool valid_color(uint32_t compFlags) { | |
| 53 return (kRGBA_GrColorComponentFlags & compFlags) == kRGBA_GrColorComponentFlags; | |
| 54 } | |
| 55 | |
| 56 static GrColor simplify_blend_term(GrBlendCoeff* srcCoeff, | |
| 57 GrColor srcColor, uint32_t srcCompFlags, | |
| 58 GrColor dstColor, uint32_t dstCompFlags, | |
| 59 GrColor constantColor) { | |
| 60 | |
| 61 SkASSERT(!GrBlendCoeffRefsSrc(*srcCoeff)); | |
| 62 SkASSERT(NULL != srcCoeff); | |
| 63 | |
| 64 // Check whether srcCoeff can be reduced to kOne or kZero based on known color inputs. | |
| 65 // We could pick out the coeff r,g,b,a values here and use them to compute the blend term color, | |
| 66 // if possible, below but that is not implemented now. | |
| 67 switch (*srcCoeff) { | |
| 68 case kIDC_GrBlendCoeff: | |
| 69 dstColor = ~dstColor; // fallthrough | |
| 70 case kDC_GrBlendCoeff: | |
| 71 if (valid_color(dstCompFlags)) { | |
| 72 if (0xffffffff == dstColor) { | |
| 73 *srcCoeff = kOne_GrBlendCoeff; | |
| 74 } else if (0 == dstColor) { | |
| 75 *srcCoeff = kZero_GrBlendCoeff; | |
| 76 } | |
| 77 } | |
| 78 break; | |
| 79 | |
| 80 case kIDA_GrBlendCoeff: | |
| 81 dstColor = ~dstColor; // fallthrough | |
| 82 case kDA_GrBlendCoeff: | |
| 83 if (kA_GrColorComponentFlag & dstCompFlags) { | |
| 84 if (0xff == GrColorUnpackA(dstColor)) { | |
| 85 *srcCoeff = kOne_GrBlendCoeff; | |
| 86 } else if (0 == GrColorUnpackA(dstColor)) { | |
| 87 *srcCoeff = kZero_GrBlendCoeff; | |
| 88 } | |
| 89 } | |
| 90 break; | |
| 91 | |
| 92 case kIConstC_GrBlendCoeff: | |
| 93 constantColor = ~constantColor; // fallthrough | |
| 94 case kConstC_GrBlendCoeff: | |
| 95 if (0xffffffff == constantColor) { | |
| 96 *srcCoeff = kOne_GrBlendCoeff; | |
| 97 } else if (0 == constantColor) { | |
| 98 *srcCoeff = kZero_GrBlendCoeff; | |
| 99 } | |
| 100 break; | |
| 101 | |
| 102 case kIConstA_GrBlendCoeff: | |
| 103 constantColor = ~constantColor; // fallthrough | |
| 104 case kConstA_GrBlendCoeff: | |
| 105 if (0xff == GrColorUnpackA(constantColor)) { | |
| 106 *srcCoeff = kOne_GrBlendCoeff; | |
| 107 } else if (0 == GrColorUnpackA(constantColor)) { | |
| 108 *srcCoeff = kZero_GrBlendCoeff; | |
| 109 } | |
| 110 break; | |
| 111 | |
| 112 default: | |
| 113 break; | |
| 114 } | |
| 115 // We may have invalidated these above and shouldn't read them again. | |
| 116 SkDEBUGCODE(dstColor = constantColor = GrColor_ILLEGAL;) | |
| 117 | |
| 118 if (kZero_GrBlendCoeff == *srcCoeff || (valid_color(srcCompFlags) && 0 == srcColor)) { | |
| 119 *srcCoeff = kZero_GrBlendCoeff; | |
| 120 return 0; | |
| 121 } | |
| 122 | |
| 123 if (kOne_GrBlendCoeff == *srcCoeff && valid_color(srcCompFlags)) { | |
| 124 return srcColor; | |
| 125 } else { | |
| 126 return GrColor_ILLEGAL; | |
| 127 } | |
| 128 } | |
| 129 | |
| 130 GrColor GrSimplifyBlend(GrBlendCoeff* srcCoeff, | |
| 131 GrBlendCoeff* dstCoeff, | |
| 132 GrColor srcColor, uint32_t srcCompFlags, | |
| 133 GrColor dstColor, uint32_t dstCompFlags, | |
| 134 GrColor constantColor) { | |
| 135 GrColor srcTermColor = simplify_blend_term(srcCoeff, | |
| 136 srcColor, srcCompFlags, | |
| 137 dstColor, dstCompFlags, | |
| 138 constantColor); | |
| 139 | |
| 140 // We call the same function to simplify the dst blend coeff. We trick it out by swapping the | |
| 141 // src and dst. | |
| 142 GrBlendCoeff spoofedCoeff = swap_coeff_src_dst(*dstCoeff); | |
| 143 GrColor dstTermColor = simplify_blend_term(&spoofedCoeff, | |
| 144 dstColor, dstCompFlags, | |
| 145 srcColor, srcCompFlags, | |
| 146 constantColor); | |
| 147 *dstCoeff = swap_coeff_src_dst(spoofedCoeff); | |
| 148 | |
| 149 if (GrColor_ILLEGAL != srcTermColor && GrColor_ILLEGAL != dstTermColor) { | |
| 150 return add_colors(srcTermColor, dstTermColor); | |
| 151 } else { | |
| 152 return GrColor_ILLEGAL; | |
| 153 } | |
| 154 } |
