1 /* 2 * Copyright 2015 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #include "GrGLSLBlend.h" 9 #include "glsl/GrGLSLFragmentShaderBuilder.h" 10 #include "glsl/GrGLSLProgramBuilder.h" 11 #include "SkBlendModePriv.h" 12 13 ////////////////////////////////////////////////////////////////////////////// 14 // Advanced (non-coeff) blend helpers 15 ////////////////////////////////////////////////////////////////////////////// 16 17 static void hard_light(GrGLSLFragmentBuilder* fsBuilder, 18 const char* final, 19 const char* src, 20 const char* dst) { 21 static const char kComponents[] = { 'r', 'g', 'b' }; 22 for (size_t i = 0; i < SK_ARRAY_COUNT(kComponents); ++i) { 23 char component = kComponents[i]; 24 fsBuilder->codeAppendf("if (2.0 * %s.%c <= %s.a) {", src, component, src); 25 fsBuilder->codeAppendf("%s.%c = 2.0 * %s.%c * %s.%c;", 26 final, component, src, component, dst, component); 27 fsBuilder->codeAppend("} else {"); 28 fsBuilder->codeAppendf("%s.%c = %s.a * %s.a - 2.0 * (%s.a - %s.%c) * (%s.a - %s.%c);", 29 final, component, src, dst, dst, dst, component, src, src, 30 component); 31 fsBuilder->codeAppend("}"); 32 } 33 fsBuilder->codeAppendf("%s.rgb += %s.rgb * (1.0 - %s.a) + %s.rgb * (1.0 - %s.a);", 34 final, src, dst, dst, src); 35 } 36 37 // Does one component of color-dodge 38 static void color_dodge_component(GrGLSLFragmentBuilder* fsBuilder, 39 const char* final, 40 const char* src, 41 const char* dst, 42 const char component) { 43 const char* divisorGuard = ""; 44 const GrShaderCaps* shaderCaps = fsBuilder->getProgramBuilder()->shaderCaps(); 45 if (shaderCaps->mustGuardDivisionEvenAfterExplicitZeroCheck()) { 46 divisorGuard = "+ 0.00000001"; 47 } 48 49 fsBuilder->codeAppendf("if (0.0 == %s.%c) {", dst, component); 50 fsBuilder->codeAppendf("%s.%c = %s.%c * (1.0 - %s.a);", 51 final, component, src, component, dst); 52 fsBuilder->codeAppend("} else {"); 53 fsBuilder->codeAppendf("half d = %s.a - %s.%c;", src, src, component); 54 fsBuilder->codeAppend("if (0.0 == d) {"); 55 fsBuilder->codeAppendf("%s.%c = %s.a * %s.a + %s.%c * (1.0 - %s.a) + %s.%c * (1.0 - %s.a);", 56 final, component, src, dst, src, component, dst, dst, component, 57 src); 58 fsBuilder->codeAppend("} else {"); 59 fsBuilder->codeAppendf("d = min(%s.a, %s.%c * %s.a / (d %s));", 60 dst, dst, component, src, divisorGuard); 61 fsBuilder->codeAppendf("%s.%c = d * %s.a + %s.%c * (1.0 - %s.a) + %s.%c * (1.0 - %s.a);", 62 final, component, src, src, component, dst, dst, component, src); 63 fsBuilder->codeAppend("}"); 64 fsBuilder->codeAppend("}"); 65 } 66 67 // Does one component of color-burn 68 static void color_burn_component(GrGLSLFragmentBuilder* fsBuilder, 69 const char* final, 70 const char* src, 71 const char* dst, 72 const char component) { 73 const char* divisorGuard = ""; 74 const GrShaderCaps* shaderCaps = fsBuilder->getProgramBuilder()->shaderCaps(); 75 if (shaderCaps->mustGuardDivisionEvenAfterExplicitZeroCheck()) { 76 divisorGuard = "+ 0.00000001"; 77 } 78 79 fsBuilder->codeAppendf("if (%s.a == %s.%c) {", dst, dst, component); 80 fsBuilder->codeAppendf("%s.%c = %s.a * %s.a + %s.%c * (1.0 - %s.a) + %s.%c * (1.0 - %s.a);", 81 final, component, src, dst, src, component, dst, dst, component, 82 src); 83 fsBuilder->codeAppendf("} else if (0.0 == %s.%c) {", src, component); 84 fsBuilder->codeAppendf("%s.%c = %s.%c * (1.0 - %s.a);", 85 final, component, dst, component, src); 86 fsBuilder->codeAppend("} else {"); 87 fsBuilder->codeAppendf("half d = max(0.0, %s.a - (%s.a - %s.%c) * %s.a / (%s.%c %s));", 88 dst, dst, dst, component, src, src, component, divisorGuard); 89 fsBuilder->codeAppendf("%s.%c = %s.a * d + %s.%c * (1.0 - %s.a) + %s.%c * (1.0 - %s.a);", 90 final, component, src, src, component, dst, dst, component, src); 91 fsBuilder->codeAppend("}"); 92 } 93 94 // Does one component of soft-light. Caller should have already checked that dst alpha > 0. 95 static void soft_light_component_pos_dst_alpha(GrGLSLFragmentBuilder* fsBuilder, 96 const char* final, 97 const char* src, 98 const char* dst, 99 const char component) { 100 const char* divisorGuard = ""; 101 const GrShaderCaps* shaderCaps = fsBuilder->getProgramBuilder()->shaderCaps(); 102 if (shaderCaps->mustGuardDivisionEvenAfterExplicitZeroCheck()) { 103 divisorGuard = "+ 0.00000001"; 104 } 105 106 // if (2S < Sa) 107 fsBuilder->codeAppendf("if (2.0 * %s.%c <= %s.a) {", src, component, src); 108 // (D^2 (Sa-2 S))/Da+(1-Da) S+D (-Sa+2 S+1) 109 fsBuilder->codeAppendf("%s.%c = (%s.%c*%s.%c*(%s.a - 2.0*%s.%c)) / (%s.a %s) +" 110 "(1.0 - %s.a) * %s.%c + %s.%c*(-%s.a + 2.0*%s.%c + 1.0);", 111 final, component, dst, component, dst, component, src, src, 112 component, dst, divisorGuard, dst, src, component, dst, component, src, 113 src, component); 114 // else if (4D < Da) 115 fsBuilder->codeAppendf("} else if (4.0 * %s.%c <= %s.a) {", 116 dst, component, dst); 117 fsBuilder->codeAppendf("half DSqd = %s.%c * %s.%c;", 118 dst, component, dst, component); 119 fsBuilder->codeAppendf("half DCub = DSqd * %s.%c;", dst, component); 120 fsBuilder->codeAppendf("half DaSqd = %s.a * %s.a;", dst, dst); 121 fsBuilder->codeAppendf("half DaCub = DaSqd * %s.a;", dst); 122 // (Da^3 (-S)+Da^2 (S-D (3 Sa-6 S-1))+12 Da D^2 (Sa-2 S)-16 D^3 (Sa-2 S))/Da^2 123 fsBuilder->codeAppendf("%s.%c =" 124 "(DaSqd*(%s.%c - %s.%c * (3.0*%s.a - 6.0*%s.%c - 1.0)) +" 125 " 12.0*%s.a*DSqd*(%s.a - 2.0*%s.%c) - 16.0*DCub * (%s.a - 2.0*%s.%c) -" 126 " DaCub*%s.%c) / (DaSqd %s);", 127 final, component, src, component, dst, component, 128 src, src, component, dst, src, src, component, src, src, 129 component, src, component, divisorGuard); 130 fsBuilder->codeAppendf("} else {"); 131 // -sqrt(Da * D) (Sa-2 S)-Da S+D (Sa-2 S+1)+S 132 fsBuilder->codeAppendf("%s.%c = %s.%c*(%s.a - 2.0*%s.%c + 1.0) + %s.%c -" 133 " sqrt(%s.a*%s.%c)*(%s.a - 2.0*%s.%c) - %s.a*%s.%c;", 134 final, component, dst, component, src, src, component, src, component, 135 dst, dst, component, src, src, component, dst, src, component); 136 fsBuilder->codeAppendf("}"); 137 } 138 139 // Adds a function that takes two colors and an alpha as input. It produces a color with the 140 // hue and saturation of the first color, the luminosity of the second color, and the input 141 // alpha. It has this signature: 142 // float3 set_luminance(float3 hueSatColor, float alpha, float3 lumColor). 143 static void add_lum_function(GrGLSLFragmentBuilder* fsBuilder, SkString* setLumFunction) { 144 // Emit a helper that gets the luminance of a color. 145 SkString getFunction; 146 GrShaderVar getLumArgs[] = { 147 GrShaderVar("color", kHalf3_GrSLType), 148 }; 149 SkString getLumBody("return dot(float3(0.3, 0.59, 0.11), color);"); 150 fsBuilder->emitFunction(kHalf_GrSLType, 151 "luminance", 152 SK_ARRAY_COUNT(getLumArgs), getLumArgs, 153 getLumBody.c_str(), 154 &getFunction); 155 156 // Emit the set luminance function. 157 GrShaderVar setLumArgs[] = { 158 GrShaderVar("hueSat", kHalf3_GrSLType), 159 GrShaderVar("alpha", kHalf_GrSLType), 160 GrShaderVar("lumColor", kHalf3_GrSLType), 161 }; 162 SkString setLumBody; 163 setLumBody.printf("half diff = %s(lumColor - hueSat);", getFunction.c_str()); 164 setLumBody.append("half3 outColor = hueSat + diff;"); 165 setLumBody.appendf("half outLum = %s(outColor);", getFunction.c_str()); 166 setLumBody.append("half minComp = min(min(outColor.r, outColor.g), outColor.b);" 167 "half maxComp = max(max(outColor.r, outColor.g), outColor.b);" 168 "if (minComp < 0.0 && outLum != minComp) {" 169 "outColor = outLum + ((outColor - half3(outLum, outLum, outLum)) * outLum) /" 170 "(outLum - minComp);" 171 "}" 172 "if (maxComp > alpha && maxComp != outLum) {" 173 "outColor = outLum +" 174 "((outColor - half3(outLum, outLum, outLum)) * (alpha - outLum)) /" 175 "(maxComp - outLum);" 176 "}" 177 "return outColor;"); 178 fsBuilder->emitFunction(kHalf3_GrSLType, 179 "set_luminance", 180 SK_ARRAY_COUNT(setLumArgs), setLumArgs, 181 setLumBody.c_str(), 182 setLumFunction); 183 } 184 185 // Adds a function that creates a color with the hue and luminosity of one input color and 186 // the saturation of another color. It will have this signature: 187 // float set_saturation(float3 hueLumColor, float3 satColor) 188 static void add_sat_function(GrGLSLFragmentBuilder* fsBuilder, SkString* setSatFunction) { 189 // Emit a helper that gets the saturation of a color 190 SkString getFunction; 191 GrShaderVar getSatArgs[] = { GrShaderVar("color", kHalf3_GrSLType) }; 192 SkString getSatBody; 193 getSatBody.printf("return max(max(color.r, color.g), color.b) - " 194 "min(min(color.r, color.g), color.b);"); 195 fsBuilder->emitFunction(kHalf_GrSLType, 196 "saturation", 197 SK_ARRAY_COUNT(getSatArgs), getSatArgs, 198 getSatBody.c_str(), 199 &getFunction); 200 201 // Emit a helper that sets the saturation given sorted input channels. This used 202 // to use inout params for min, mid, and max components but that seems to cause 203 // problems on PowerVR drivers. So instead it returns a float3 where r, g ,b are the 204 // adjusted min, mid, and max inputs, respectively. 205 SkString helperFunction; 206 GrShaderVar helperArgs[] = { 207 GrShaderVar("minComp", kHalf_GrSLType), 208 GrShaderVar("midComp", kHalf_GrSLType), 209 GrShaderVar("maxComp", kHalf_GrSLType), 210 GrShaderVar("sat", kHalf_GrSLType), 211 }; 212 static const char kHelperBody[] = "if (minComp < maxComp) {" 213 "half3 result;" 214 "result.r = 0.0;" 215 "result.g = sat * (midComp - minComp) / (maxComp - minComp);" 216 "result.b = sat;" 217 "return result;" 218 "} else {" 219 "return half3(0, 0, 0);" 220 "}"; 221 fsBuilder->emitFunction(kHalf3_GrSLType, 222 "set_saturation_helper", 223 SK_ARRAY_COUNT(helperArgs), helperArgs, 224 kHelperBody, 225 &helperFunction); 226 227 GrShaderVar setSatArgs[] = { 228 GrShaderVar("hueLumColor", kHalf3_GrSLType), 229 GrShaderVar("satColor", kHalf3_GrSLType), 230 }; 231 const char* helpFunc = helperFunction.c_str(); 232 SkString setSatBody; 233 setSatBody.appendf("half sat = %s(satColor);" 234 "if (hueLumColor.r <= hueLumColor.g) {" 235 "if (hueLumColor.g <= hueLumColor.b) {" 236 "hueLumColor.rgb = %s(hueLumColor.r, hueLumColor.g, hueLumColor.b, sat);" 237 "} else if (hueLumColor.r <= hueLumColor.b) {" 238 "hueLumColor.rbg = %s(hueLumColor.r, hueLumColor.b, hueLumColor.g, sat);" 239 "} else {" 240 "hueLumColor.brg = %s(hueLumColor.b, hueLumColor.r, hueLumColor.g, sat);" 241 "}" 242 "} else if (hueLumColor.r <= hueLumColor.b) {" 243 "hueLumColor.grb = %s(hueLumColor.g, hueLumColor.r, hueLumColor.b, sat);" 244 "} else if (hueLumColor.g <= hueLumColor.b) {" 245 "hueLumColor.gbr = %s(hueLumColor.g, hueLumColor.b, hueLumColor.r, sat);" 246 "} else {" 247 "hueLumColor.bgr = %s(hueLumColor.b, hueLumColor.g, hueLumColor.r, sat);" 248 "}" 249 "return hueLumColor;", 250 getFunction.c_str(), helpFunc, helpFunc, helpFunc, helpFunc, 251 helpFunc, helpFunc); 252 fsBuilder->emitFunction(kHalf3_GrSLType, 253 "set_saturation", 254 SK_ARRAY_COUNT(setSatArgs), setSatArgs, 255 setSatBody.c_str(), 256 setSatFunction); 257 } 258 259 static void emit_advanced_xfermode_code(GrGLSLFragmentBuilder* fsBuilder, const char* srcColor, 260 const char* dstColor, const char* outputColor, 261 SkBlendMode mode) { 262 SkASSERT(srcColor); 263 SkASSERT(dstColor); 264 SkASSERT(outputColor); 265 // These all perform src-over on the alpha channel. 266 fsBuilder->codeAppendf("%s.a = %s.a + (1.0 - %s.a) * %s.a;", 267 outputColor, srcColor, srcColor, dstColor); 268 269 switch (mode) { 270 case SkBlendMode::kOverlay: 271 // Overlay is Hard-Light with the src and dst reversed 272 hard_light(fsBuilder, outputColor, dstColor, srcColor); 273 break; 274 case SkBlendMode::kDarken: 275 fsBuilder->codeAppendf("%s.rgb = min((1.0 - %s.a) * %s.rgb + %s.rgb, " 276 "(1.0 - %s.a) * %s.rgb + %s.rgb);", 277 outputColor, 278 srcColor, dstColor, srcColor, 279 dstColor, srcColor, dstColor); 280 break; 281 case SkBlendMode::kLighten: 282 fsBuilder->codeAppendf("%s.rgb = max((1.0 - %s.a) * %s.rgb + %s.rgb, " 283 "(1.0 - %s.a) * %s.rgb + %s.rgb);", 284 outputColor, 285 srcColor, dstColor, srcColor, 286 dstColor, srcColor, dstColor); 287 break; 288 case SkBlendMode::kColorDodge: 289 color_dodge_component(fsBuilder, outputColor, srcColor, dstColor, 'r'); 290 color_dodge_component(fsBuilder, outputColor, srcColor, dstColor, 'g'); 291 color_dodge_component(fsBuilder, outputColor, srcColor, dstColor, 'b'); 292 break; 293 case SkBlendMode::kColorBurn: 294 color_burn_component(fsBuilder, outputColor, srcColor, dstColor, 'r'); 295 color_burn_component(fsBuilder, outputColor, srcColor, dstColor, 'g'); 296 color_burn_component(fsBuilder, outputColor, srcColor, dstColor, 'b'); 297 break; 298 case SkBlendMode::kHardLight: 299 hard_light(fsBuilder, outputColor, srcColor, dstColor); 300 break; 301 case SkBlendMode::kSoftLight: 302 fsBuilder->codeAppendf("if (0.0 == %s.a) {", dstColor); 303 fsBuilder->codeAppendf("%s.rgba = %s;", outputColor, srcColor); 304 fsBuilder->codeAppendf("} else {"); 305 soft_light_component_pos_dst_alpha(fsBuilder, outputColor, srcColor, dstColor, 'r'); 306 soft_light_component_pos_dst_alpha(fsBuilder, outputColor, srcColor, dstColor, 'g'); 307 soft_light_component_pos_dst_alpha(fsBuilder, outputColor, srcColor, dstColor, 'b'); 308 fsBuilder->codeAppendf("}"); 309 break; 310 case SkBlendMode::kDifference: 311 fsBuilder->codeAppendf("%s.rgb = %s.rgb + %s.rgb -" 312 "2.0 * min(%s.rgb * %s.a, %s.rgb * %s.a);", 313 outputColor, srcColor, dstColor, srcColor, dstColor, 314 dstColor, srcColor); 315 break; 316 case SkBlendMode::kExclusion: 317 fsBuilder->codeAppendf("%s.rgb = %s.rgb + %s.rgb - " 318 "2.0 * %s.rgb * %s.rgb;", 319 outputColor, dstColor, srcColor, dstColor, srcColor); 320 break; 321 case SkBlendMode::kMultiply: 322 fsBuilder->codeAppendf("%s.rgb = (1.0 - %s.a) * %s.rgb + " 323 "(1.0 - %s.a) * %s.rgb + " 324 "%s.rgb * %s.rgb;", 325 outputColor, srcColor, dstColor, dstColor, srcColor, 326 srcColor, dstColor); 327 break; 328 case SkBlendMode::kHue: { 329 // SetLum(SetSat(S * Da, Sat(D * Sa)), Sa*Da, D*Sa) + (1 - Sa) * D + (1 - Da) * S 330 SkString setSat, setLum; 331 add_sat_function(fsBuilder, &setSat); 332 add_lum_function(fsBuilder, &setLum); 333 fsBuilder->codeAppendf("half4 dstSrcAlpha = %s * %s.a;", 334 dstColor, srcColor); 335 fsBuilder->codeAppendf("%s.rgb = %s(%s(%s.rgb * %s.a, dstSrcAlpha.rgb)," 336 "dstSrcAlpha.a, dstSrcAlpha.rgb);", 337 outputColor, setLum.c_str(), setSat.c_str(), srcColor, 338 dstColor); 339 fsBuilder->codeAppendf("%s.rgb += (1.0 - %s.a) * %s.rgb + (1.0 - %s.a) * %s.rgb;", 340 outputColor, srcColor, dstColor, dstColor, srcColor); 341 break; 342 } 343 case SkBlendMode::kSaturation: { 344 // SetLum(SetSat(D * Sa, Sat(S * Da)), Sa*Da, D*Sa)) + (1 - Sa) * D + (1 - Da) * S 345 SkString setSat, setLum; 346 add_sat_function(fsBuilder, &setSat); 347 add_lum_function(fsBuilder, &setLum); 348 fsBuilder->codeAppendf("half4 dstSrcAlpha = %s * %s.a;", 349 dstColor, srcColor); 350 fsBuilder->codeAppendf("%s.rgb = %s(%s(dstSrcAlpha.rgb, %s.rgb * %s.a)," 351 "dstSrcAlpha.a, dstSrcAlpha.rgb);", 352 outputColor, setLum.c_str(), setSat.c_str(), srcColor, 353 dstColor); 354 fsBuilder->codeAppendf("%s.rgb += (1.0 - %s.a) * %s.rgb + (1.0 - %s.a) * %s.rgb;", 355 outputColor, srcColor, dstColor, dstColor, srcColor); 356 break; 357 } 358 case SkBlendMode::kColor: { 359 // SetLum(S * Da, Sa* Da, D * Sa) + (1 - Sa) * D + (1 - Da) * S 360 SkString setLum; 361 add_lum_function(fsBuilder, &setLum); 362 fsBuilder->codeAppendf("half4 srcDstAlpha = %s * %s.a;", 363 srcColor, dstColor); 364 fsBuilder->codeAppendf("%s.rgb = %s(srcDstAlpha.rgb, srcDstAlpha.a, %s.rgb * %s.a);", 365 outputColor, setLum.c_str(), dstColor, srcColor); 366 fsBuilder->codeAppendf("%s.rgb += (1.0 - %s.a) * %s.rgb + (1.0 - %s.a) * %s.rgb;", 367 outputColor, srcColor, dstColor, dstColor, srcColor); 368 break; 369 } 370 case SkBlendMode::kLuminosity: { 371 // SetLum(D * Sa, Sa* Da, S * Da) + (1 - Sa) * D + (1 - Da) * S 372 SkString setLum; 373 add_lum_function(fsBuilder, &setLum); 374 fsBuilder->codeAppendf("half4 srcDstAlpha = %s * %s.a;", 375 srcColor, dstColor); 376 fsBuilder->codeAppendf("%s.rgb = %s(%s.rgb * %s.a, srcDstAlpha.a, srcDstAlpha.rgb);", 377 outputColor, setLum.c_str(), dstColor, srcColor); 378 fsBuilder->codeAppendf("%s.rgb += (1.0 - %s.a) * %s.rgb + (1.0 - %s.a) * %s.rgb;", 379 outputColor, srcColor, dstColor, dstColor, srcColor); 380 break; 381 } 382 default: 383 SK_ABORT("Unknown Custom Xfer mode."); 384 break; 385 } 386 } 387 388 ////////////////////////////////////////////////////////////////////////////// 389 // Porter-Duff blend helper 390 ////////////////////////////////////////////////////////////////////////////// 391 392 static bool append_porterduff_term(GrGLSLFragmentBuilder* fsBuilder, SkBlendModeCoeff coeff, 393 const char* colorName, const char* srcColorName, 394 const char* dstColorName, bool hasPrevious) { 395 if (SkBlendModeCoeff::kZero == coeff) { 396 return hasPrevious; 397 } else { 398 if (hasPrevious) { 399 fsBuilder->codeAppend(" + "); 400 } 401 fsBuilder->codeAppendf("%s", colorName); 402 switch (coeff) { 403 case SkBlendModeCoeff::kOne: 404 break; 405 case SkBlendModeCoeff::kSC: 406 fsBuilder->codeAppendf(" * %s", srcColorName); 407 break; 408 case SkBlendModeCoeff::kISC: 409 fsBuilder->codeAppendf(" * (half4(1.0) - %s)", srcColorName); 410 break; 411 case SkBlendModeCoeff::kDC: 412 fsBuilder->codeAppendf(" * %s", dstColorName); 413 break; 414 case SkBlendModeCoeff::kIDC: 415 fsBuilder->codeAppendf(" * (half4(1.0) - %s)", dstColorName); 416 break; 417 case SkBlendModeCoeff::kSA: 418 fsBuilder->codeAppendf(" * %s.a", srcColorName); 419 break; 420 case SkBlendModeCoeff::kISA: 421 fsBuilder->codeAppendf(" * (1.0 - %s.a)", srcColorName); 422 break; 423 case SkBlendModeCoeff::kDA: 424 fsBuilder->codeAppendf(" * %s.a", dstColorName); 425 break; 426 case SkBlendModeCoeff::kIDA: 427 fsBuilder->codeAppendf(" * (1.0 - %s.a)", dstColorName); 428 break; 429 default: 430 SK_ABORT("Unsupported Blend Coeff"); 431 } 432 return true; 433 } 434 } 435 436 ////////////////////////////////////////////////////////////////////////////// 437 438 void GrGLSLBlend::AppendMode(GrGLSLFragmentBuilder* fsBuilder, const char* srcColor, 439 const char* dstColor, const char* outColor, 440 SkBlendMode mode) { 441 442 SkBlendModeCoeff srcCoeff, dstCoeff; 443 if (SkBlendMode_AsCoeff(mode, &srcCoeff, &dstCoeff)) { 444 // The only coeff mode that can go out of range is plus. 445 bool clamp = mode == SkBlendMode::kPlus; 446 447 fsBuilder->codeAppendf("%s = ", outColor); 448 if (clamp) { 449 fsBuilder->codeAppend("clamp("); 450 } 451 // append src blend 452 bool didAppend = append_porterduff_term(fsBuilder, srcCoeff, srcColor, srcColor, dstColor, 453 false); 454 // append dst blend 455 if(!append_porterduff_term(fsBuilder, dstCoeff, dstColor, srcColor, dstColor, didAppend)) { 456 fsBuilder->codeAppend("half4(0, 0, 0, 0)"); 457 } 458 if (clamp) { 459 fsBuilder->codeAppend(", 0, 1);"); 460 } 461 fsBuilder->codeAppend(";"); 462 } else { 463 emit_advanced_xfermode_code(fsBuilder, srcColor, dstColor, outColor, mode); 464 } 465 } 466 467 void GrGLSLBlend::AppendRegionOp(GrGLSLFragmentBuilder* fsBuilder, const char* srcColor, 468 const char* dstColor, const char* outColor, 469 SkRegion::Op regionOp) { 470 SkBlendModeCoeff srcCoeff, dstCoeff; 471 switch (regionOp) { 472 case SkRegion::kReplace_Op: 473 srcCoeff = SkBlendModeCoeff::kOne; 474 dstCoeff = SkBlendModeCoeff::kZero; 475 break; 476 case SkRegion::kIntersect_Op: 477 srcCoeff = SkBlendModeCoeff::kDC; 478 dstCoeff = SkBlendModeCoeff::kZero; 479 break; 480 case SkRegion::kUnion_Op: 481 srcCoeff = SkBlendModeCoeff::kOne; 482 dstCoeff = SkBlendModeCoeff::kISC; 483 break; 484 case SkRegion::kXOR_Op: 485 srcCoeff = SkBlendModeCoeff::kIDC; 486 dstCoeff = SkBlendModeCoeff::kISC; 487 break; 488 case SkRegion::kDifference_Op: 489 srcCoeff = SkBlendModeCoeff::kZero; 490 dstCoeff = SkBlendModeCoeff::kISC; 491 break; 492 case SkRegion::kReverseDifference_Op: 493 srcCoeff = SkBlendModeCoeff::kIDC; 494 dstCoeff = SkBlendModeCoeff::kZero; 495 break; 496 default: 497 SK_ABORT("Unsupported Op"); 498 // We should never get here but to make compiler happy 499 srcCoeff = SkBlendModeCoeff::kZero; 500 dstCoeff = SkBlendModeCoeff::kZero; 501 } 502 fsBuilder->codeAppendf("%s = ", outColor); 503 // append src blend 504 bool didAppend = append_porterduff_term(fsBuilder, srcCoeff, srcColor, srcColor, dstColor, 505 false); 506 // append dst blend 507 if(!append_porterduff_term(fsBuilder, dstCoeff, dstColor, srcColor, dstColor, didAppend)) { 508 fsBuilder->codeAppend("half4(0, 0, 0, 0)"); 509 } 510 fsBuilder->codeAppend(";"); 511 } 512