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 "SkBlendModePriv.h" 11 12 ////////////////////////////////////////////////////////////////////////////// 13 // Advanced (non-coeff) blend helpers 14 ////////////////////////////////////////////////////////////////////////////// 15 16 static void hard_light(GrGLSLFragmentBuilder* fsBuilder, 17 const char* final, 18 const char* src, 19 const char* dst) { 20 static const char kComponents[] = { 'r', 'g', 'b' }; 21 for (size_t i = 0; i < SK_ARRAY_COUNT(kComponents); ++i) { 22 char component = kComponents[i]; 23 fsBuilder->codeAppendf("if (2.0 * %s.%c <= %s.a) {", src, component, src); 24 fsBuilder->codeAppendf("%s.%c = 2.0 * %s.%c * %s.%c;", 25 final, component, src, component, dst, component); 26 fsBuilder->codeAppend("} else {"); 27 fsBuilder->codeAppendf("%s.%c = %s.a * %s.a - 2.0 * (%s.a - %s.%c) * (%s.a - %s.%c);", 28 final, component, src, dst, dst, dst, component, src, src, 29 component); 30 fsBuilder->codeAppend("}"); 31 } 32 fsBuilder->codeAppendf("%s.rgb += %s.rgb * (1.0 - %s.a) + %s.rgb * (1.0 - %s.a);", 33 final, src, dst, dst, src); 34 } 35 36 // Does one component of color-dodge 37 static void color_dodge_component(GrGLSLFragmentBuilder* fsBuilder, 38 const char* final, 39 const char* src, 40 const char* dst, 41 const char component) { 42 fsBuilder->codeAppendf("if (0.0 == %s.%c) {", dst, component); 43 fsBuilder->codeAppendf("%s.%c = %s.%c * (1.0 - %s.a);", 44 final, component, src, component, dst); 45 fsBuilder->codeAppend("} else {"); 46 fsBuilder->codeAppendf("float d = %s.a - %s.%c;", src, src, component); 47 fsBuilder->codeAppend("if (0.0 == d) {"); 48 fsBuilder->codeAppendf("%s.%c = %s.a * %s.a + %s.%c * (1.0 - %s.a) + %s.%c * (1.0 - %s.a);", 49 final, component, src, dst, src, component, dst, dst, component, 50 src); 51 fsBuilder->codeAppend("} else {"); 52 fsBuilder->codeAppendf("d = min(%s.a, %s.%c * %s.a / d);", 53 dst, dst, component, src); 54 fsBuilder->codeAppendf("%s.%c = d * %s.a + %s.%c * (1.0 - %s.a) + %s.%c * (1.0 - %s.a);", 55 final, component, src, src, component, dst, dst, component, src); 56 fsBuilder->codeAppend("}"); 57 fsBuilder->codeAppend("}"); 58 } 59 60 // Does one component of color-burn 61 static void color_burn_component(GrGLSLFragmentBuilder* fsBuilder, 62 const char* final, 63 const char* src, 64 const char* dst, 65 const char component) { 66 fsBuilder->codeAppendf("if (%s.a == %s.%c) {", dst, dst, component); 67 fsBuilder->codeAppendf("%s.%c = %s.a * %s.a + %s.%c * (1.0 - %s.a) + %s.%c * (1.0 - %s.a);", 68 final, component, src, dst, src, component, dst, dst, component, 69 src); 70 fsBuilder->codeAppendf("} else if (0.0 == %s.%c) {", src, component); 71 fsBuilder->codeAppendf("%s.%c = %s.%c * (1.0 - %s.a);", 72 final, component, dst, component, src); 73 fsBuilder->codeAppend("} else {"); 74 fsBuilder->codeAppendf("float d = max(0.0, %s.a - (%s.a - %s.%c) * %s.a / %s.%c);", 75 dst, dst, dst, component, src, src, component); 76 fsBuilder->codeAppendf("%s.%c = %s.a * d + %s.%c * (1.0 - %s.a) + %s.%c * (1.0 - %s.a);", 77 final, component, src, src, component, dst, dst, component, src); 78 fsBuilder->codeAppend("}"); 79 } 80 81 // Does one component of soft-light. Caller should have already checked that dst alpha > 0. 82 static void soft_light_component_pos_dst_alpha(GrGLSLFragmentBuilder* fsBuilder, 83 const char* final, 84 const char* src, 85 const char* dst, 86 const char component) { 87 // if (2S < Sa) 88 fsBuilder->codeAppendf("if (2.0 * %s.%c <= %s.a) {", src, component, src); 89 // (D^2 (Sa-2 S))/Da+(1-Da) S+D (-Sa+2 S+1) 90 fsBuilder->codeAppendf("%s.%c = (%s.%c*%s.%c*(%s.a - 2.0*%s.%c)) / %s.a +" 91 "(1.0 - %s.a) * %s.%c + %s.%c*(-%s.a + 2.0*%s.%c + 1.0);", 92 final, component, dst, component, dst, component, src, src, 93 component, dst, dst, src, component, dst, component, src, src, 94 component); 95 // else if (4D < Da) 96 fsBuilder->codeAppendf("} else if (4.0 * %s.%c <= %s.a) {", 97 dst, component, dst); 98 fsBuilder->codeAppendf("float DSqd = %s.%c * %s.%c;", 99 dst, component, dst, component); 100 fsBuilder->codeAppendf("float DCub = DSqd * %s.%c;", dst, component); 101 fsBuilder->codeAppendf("float DaSqd = %s.a * %s.a;", dst, dst); 102 fsBuilder->codeAppendf("float DaCub = DaSqd * %s.a;", dst); 103 // (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^2 104 fsBuilder->codeAppendf("%s.%c =" 105 "(DaSqd*(%s.%c - %s.%c * (3.0*%s.a - 6.0*%s.%c - 1.0)) +" 106 " 12.0*%s.a*DSqd*(%s.a - 2.0*%s.%c) - 16.0*DCub * (%s.a - 2.0*%s.%c) -" 107 " DaCub*%s.%c) / DaSqd;", 108 final, component, src, component, dst, component, 109 src, src, component, dst, src, src, component, src, src, 110 component, src, component); 111 fsBuilder->codeAppendf("} else {"); 112 // -sqrt(Da * D) (Sa-2 S)-Da S+D (Sa-2 S+1)+S 113 fsBuilder->codeAppendf("%s.%c = %s.%c*(%s.a - 2.0*%s.%c + 1.0) + %s.%c -" 114 " sqrt(%s.a*%s.%c)*(%s.a - 2.0*%s.%c) - %s.a*%s.%c;", 115 final, component, dst, component, src, src, component, src, component, 116 dst, dst, component, src, src, component, dst, src, component); 117 fsBuilder->codeAppendf("}"); 118 } 119 120 // Adds a function that takes two colors and an alpha as input. It produces a color with the 121 // hue and saturation of the first color, the luminosity of the second color, and the input 122 // alpha. It has this signature: 123 // vec3 set_luminance(vec3 hueSatColor, float alpha, vec3 lumColor). 124 static void add_lum_function(GrGLSLFragmentBuilder* fsBuilder, SkString* setLumFunction) { 125 // Emit a helper that gets the luminance of a color. 126 SkString getFunction; 127 GrShaderVar getLumArgs[] = { 128 GrShaderVar("color", kVec3f_GrSLType), 129 }; 130 SkString getLumBody("return dot(vec3(0.3, 0.59, 0.11), color);"); 131 fsBuilder->emitFunction(kFloat_GrSLType, 132 "luminance", 133 SK_ARRAY_COUNT(getLumArgs), getLumArgs, 134 getLumBody.c_str(), 135 &getFunction); 136 137 // Emit the set luminance function. 138 GrShaderVar setLumArgs[] = { 139 GrShaderVar("hueSat", kVec3f_GrSLType), 140 GrShaderVar("alpha", kFloat_GrSLType), 141 GrShaderVar("lumColor", kVec3f_GrSLType), 142 }; 143 SkString setLumBody; 144 setLumBody.printf("float diff = %s(lumColor - hueSat);", getFunction.c_str()); 145 setLumBody.append("vec3 outColor = hueSat + diff;"); 146 setLumBody.appendf("float outLum = %s(outColor);", getFunction.c_str()); 147 setLumBody.append("float minComp = min(min(outColor.r, outColor.g), outColor.b);" 148 "float maxComp = max(max(outColor.r, outColor.g), outColor.b);" 149 "if (minComp < 0.0 && outLum != minComp) {" 150 "outColor = outLum + ((outColor - vec3(outLum, outLum, outLum)) * outLum) /" 151 "(outLum - minComp);" 152 "}" 153 "if (maxComp > alpha && maxComp != outLum) {" 154 "outColor = outLum +" 155 "((outColor - vec3(outLum, outLum, outLum)) * (alpha - outLum)) /" 156 "(maxComp - outLum);" 157 "}" 158 "return outColor;"); 159 fsBuilder->emitFunction(kVec3f_GrSLType, 160 "set_luminance", 161 SK_ARRAY_COUNT(setLumArgs), setLumArgs, 162 setLumBody.c_str(), 163 setLumFunction); 164 } 165 166 // Adds a function that creates a color with the hue and luminosity of one input color and 167 // the saturation of another color. It will have this signature: 168 // float set_saturation(vec3 hueLumColor, vec3 satColor) 169 static void add_sat_function(GrGLSLFragmentBuilder* fsBuilder, SkString* setSatFunction) { 170 // Emit a helper that gets the saturation of a color 171 SkString getFunction; 172 GrShaderVar getSatArgs[] = { GrShaderVar("color", kVec3f_GrSLType) }; 173 SkString getSatBody; 174 getSatBody.printf("return max(max(color.r, color.g), color.b) - " 175 "min(min(color.r, color.g), color.b);"); 176 fsBuilder->emitFunction(kFloat_GrSLType, 177 "saturation", 178 SK_ARRAY_COUNT(getSatArgs), getSatArgs, 179 getSatBody.c_str(), 180 &getFunction); 181 182 // Emit a helper that sets the saturation given sorted input channels. This used 183 // to use inout params for min, mid, and max components but that seems to cause 184 // problems on PowerVR drivers. So instead it returns a vec3 where r, g ,b are the 185 // adjusted min, mid, and max inputs, respectively. 186 SkString helperFunction; 187 GrShaderVar helperArgs[] = { 188 GrShaderVar("minComp", kFloat_GrSLType), 189 GrShaderVar("midComp", kFloat_GrSLType), 190 GrShaderVar("maxComp", kFloat_GrSLType), 191 GrShaderVar("sat", kFloat_GrSLType), 192 }; 193 static const char kHelperBody[] = "if (minComp < maxComp) {" 194 "vec3 result;" 195 "result.r = 0.0;" 196 "result.g = sat * (midComp - minComp) / (maxComp - minComp);" 197 "result.b = sat;" 198 "return result;" 199 "} else {" 200 "return vec3(0, 0, 0);" 201 "}"; 202 fsBuilder->emitFunction(kVec3f_GrSLType, 203 "set_saturation_helper", 204 SK_ARRAY_COUNT(helperArgs), helperArgs, 205 kHelperBody, 206 &helperFunction); 207 208 GrShaderVar setSatArgs[] = { 209 GrShaderVar("hueLumColor", kVec3f_GrSLType), 210 GrShaderVar("satColor", kVec3f_GrSLType), 211 }; 212 const char* helpFunc = helperFunction.c_str(); 213 SkString setSatBody; 214 setSatBody.appendf("float sat = %s(satColor);" 215 "if (hueLumColor.r <= hueLumColor.g) {" 216 "if (hueLumColor.g <= hueLumColor.b) {" 217 "hueLumColor.rgb = %s(hueLumColor.r, hueLumColor.g, hueLumColor.b, sat);" 218 "} else if (hueLumColor.r <= hueLumColor.b) {" 219 "hueLumColor.rbg = %s(hueLumColor.r, hueLumColor.b, hueLumColor.g, sat);" 220 "} else {" 221 "hueLumColor.brg = %s(hueLumColor.b, hueLumColor.r, hueLumColor.g, sat);" 222 "}" 223 "} else if (hueLumColor.r <= hueLumColor.b) {" 224 "hueLumColor.grb = %s(hueLumColor.g, hueLumColor.r, hueLumColor.b, sat);" 225 "} else if (hueLumColor.g <= hueLumColor.b) {" 226 "hueLumColor.gbr = %s(hueLumColor.g, hueLumColor.b, hueLumColor.r, sat);" 227 "} else {" 228 "hueLumColor.bgr = %s(hueLumColor.b, hueLumColor.g, hueLumColor.r, sat);" 229 "}" 230 "return hueLumColor;", 231 getFunction.c_str(), helpFunc, helpFunc, helpFunc, helpFunc, 232 helpFunc, helpFunc); 233 fsBuilder->emitFunction(kVec3f_GrSLType, 234 "set_saturation", 235 SK_ARRAY_COUNT(setSatArgs), setSatArgs, 236 setSatBody.c_str(), 237 setSatFunction); 238 } 239 240 static void emit_advanced_xfermode_code(GrGLSLFragmentBuilder* fsBuilder, const char* srcColor, 241 const char* dstColor, const char* outputColor, 242 SkBlendMode mode) { 243 SkASSERT(srcColor); 244 SkASSERT(dstColor); 245 SkASSERT(outputColor); 246 // These all perform src-over on the alpha channel. 247 fsBuilder->codeAppendf("%s.a = %s.a + (1.0 - %s.a) * %s.a;", 248 outputColor, srcColor, srcColor, dstColor); 249 250 switch (mode) { 251 case SkBlendMode::kOverlay: 252 // Overlay is Hard-Light with the src and dst reversed 253 hard_light(fsBuilder, outputColor, dstColor, srcColor); 254 break; 255 case SkBlendMode::kDarken: 256 fsBuilder->codeAppendf("%s.rgb = min((1.0 - %s.a) * %s.rgb + %s.rgb, " 257 "(1.0 - %s.a) * %s.rgb + %s.rgb);", 258 outputColor, 259 srcColor, dstColor, srcColor, 260 dstColor, srcColor, dstColor); 261 break; 262 case SkBlendMode::kLighten: 263 fsBuilder->codeAppendf("%s.rgb = max((1.0 - %s.a) * %s.rgb + %s.rgb, " 264 "(1.0 - %s.a) * %s.rgb + %s.rgb);", 265 outputColor, 266 srcColor, dstColor, srcColor, 267 dstColor, srcColor, dstColor); 268 break; 269 case SkBlendMode::kColorDodge: 270 color_dodge_component(fsBuilder, outputColor, srcColor, dstColor, 'r'); 271 color_dodge_component(fsBuilder, outputColor, srcColor, dstColor, 'g'); 272 color_dodge_component(fsBuilder, outputColor, srcColor, dstColor, 'b'); 273 break; 274 case SkBlendMode::kColorBurn: 275 color_burn_component(fsBuilder, outputColor, srcColor, dstColor, 'r'); 276 color_burn_component(fsBuilder, outputColor, srcColor, dstColor, 'g'); 277 color_burn_component(fsBuilder, outputColor, srcColor, dstColor, 'b'); 278 break; 279 case SkBlendMode::kHardLight: 280 hard_light(fsBuilder, outputColor, srcColor, dstColor); 281 break; 282 case SkBlendMode::kSoftLight: 283 fsBuilder->codeAppendf("if (0.0 == %s.a) {", dstColor); 284 fsBuilder->codeAppendf("%s.rgba = %s;", outputColor, srcColor); 285 fsBuilder->codeAppendf("} else {"); 286 soft_light_component_pos_dst_alpha(fsBuilder, outputColor, srcColor, dstColor, 'r'); 287 soft_light_component_pos_dst_alpha(fsBuilder, outputColor, srcColor, dstColor, 'g'); 288 soft_light_component_pos_dst_alpha(fsBuilder, outputColor, srcColor, dstColor, 'b'); 289 fsBuilder->codeAppendf("}"); 290 break; 291 case SkBlendMode::kDifference: 292 fsBuilder->codeAppendf("%s.rgb = %s.rgb + %s.rgb -" 293 "2.0 * min(%s.rgb * %s.a, %s.rgb * %s.a);", 294 outputColor, srcColor, dstColor, srcColor, dstColor, 295 dstColor, srcColor); 296 break; 297 case SkBlendMode::kExclusion: 298 fsBuilder->codeAppendf("%s.rgb = %s.rgb + %s.rgb - " 299 "2.0 * %s.rgb * %s.rgb;", 300 outputColor, dstColor, srcColor, dstColor, srcColor); 301 break; 302 case SkBlendMode::kMultiply: 303 fsBuilder->codeAppendf("%s.rgb = (1.0 - %s.a) * %s.rgb + " 304 "(1.0 - %s.a) * %s.rgb + " 305 "%s.rgb * %s.rgb;", 306 outputColor, srcColor, dstColor, dstColor, srcColor, 307 srcColor, dstColor); 308 break; 309 case SkBlendMode::kHue: { 310 // SetLum(SetSat(S * Da, Sat(D * Sa)), Sa*Da, D*Sa) + (1 - Sa) * D + (1 - Da) * S 311 SkString setSat, setLum; 312 add_sat_function(fsBuilder, &setSat); 313 add_lum_function(fsBuilder, &setLum); 314 fsBuilder->codeAppendf("vec4 dstSrcAlpha = %s * %s.a;", 315 dstColor, srcColor); 316 fsBuilder->codeAppendf("%s.rgb = %s(%s(%s.rgb * %s.a, dstSrcAlpha.rgb)," 317 "dstSrcAlpha.a, dstSrcAlpha.rgb);", 318 outputColor, setLum.c_str(), setSat.c_str(), srcColor, 319 dstColor); 320 fsBuilder->codeAppendf("%s.rgb += (1.0 - %s.a) * %s.rgb + (1.0 - %s.a) * %s.rgb;", 321 outputColor, srcColor, dstColor, dstColor, srcColor); 322 break; 323 } 324 case SkBlendMode::kSaturation: { 325 // SetLum(SetSat(D * Sa, Sat(S * Da)), Sa*Da, D*Sa)) + (1 - Sa) * D + (1 - Da) * S 326 SkString setSat, setLum; 327 add_sat_function(fsBuilder, &setSat); 328 add_lum_function(fsBuilder, &setLum); 329 fsBuilder->codeAppendf("vec4 dstSrcAlpha = %s * %s.a;", 330 dstColor, srcColor); 331 fsBuilder->codeAppendf("%s.rgb = %s(%s(dstSrcAlpha.rgb, %s.rgb * %s.a)," 332 "dstSrcAlpha.a, dstSrcAlpha.rgb);", 333 outputColor, setLum.c_str(), setSat.c_str(), srcColor, 334 dstColor); 335 fsBuilder->codeAppendf("%s.rgb += (1.0 - %s.a) * %s.rgb + (1.0 - %s.a) * %s.rgb;", 336 outputColor, srcColor, dstColor, dstColor, srcColor); 337 break; 338 } 339 case SkBlendMode::kColor: { 340 // SetLum(S * Da, Sa* Da, D * Sa) + (1 - Sa) * D + (1 - Da) * S 341 SkString setLum; 342 add_lum_function(fsBuilder, &setLum); 343 fsBuilder->codeAppendf("vec4 srcDstAlpha = %s * %s.a;", 344 srcColor, dstColor); 345 fsBuilder->codeAppendf("%s.rgb = %s(srcDstAlpha.rgb, srcDstAlpha.a, %s.rgb * %s.a);", 346 outputColor, setLum.c_str(), dstColor, srcColor); 347 fsBuilder->codeAppendf("%s.rgb += (1.0 - %s.a) * %s.rgb + (1.0 - %s.a) * %s.rgb;", 348 outputColor, srcColor, dstColor, dstColor, srcColor); 349 break; 350 } 351 case SkBlendMode::kLuminosity: { 352 // SetLum(D * Sa, Sa* Da, S * Da) + (1 - Sa) * D + (1 - Da) * S 353 SkString setLum; 354 add_lum_function(fsBuilder, &setLum); 355 fsBuilder->codeAppendf("vec4 srcDstAlpha = %s * %s.a;", 356 srcColor, dstColor); 357 fsBuilder->codeAppendf("%s.rgb = %s(%s.rgb * %s.a, srcDstAlpha.a, srcDstAlpha.rgb);", 358 outputColor, setLum.c_str(), dstColor, srcColor); 359 fsBuilder->codeAppendf("%s.rgb += (1.0 - %s.a) * %s.rgb + (1.0 - %s.a) * %s.rgb;", 360 outputColor, srcColor, dstColor, dstColor, srcColor); 361 break; 362 } 363 default: 364 SkFAIL("Unknown Custom Xfer mode."); 365 break; 366 } 367 } 368 369 ////////////////////////////////////////////////////////////////////////////// 370 // Porter-Duff blend helper 371 ////////////////////////////////////////////////////////////////////////////// 372 373 static bool append_porterduff_term(GrGLSLFragmentBuilder* fsBuilder, SkBlendModeCoeff coeff, 374 const char* colorName, const char* srcColorName, 375 const char* dstColorName, bool hasPrevious) { 376 if (SkBlendModeCoeff::kZero == coeff) { 377 return hasPrevious; 378 } else { 379 if (hasPrevious) { 380 fsBuilder->codeAppend(" + "); 381 } 382 fsBuilder->codeAppendf("%s", colorName); 383 switch (coeff) { 384 case SkBlendModeCoeff::kOne: 385 break; 386 case SkBlendModeCoeff::kSC: 387 fsBuilder->codeAppendf(" * %s", srcColorName); 388 break; 389 case SkBlendModeCoeff::kISC: 390 fsBuilder->codeAppendf(" * (vec4(1.0) - %s)", srcColorName); 391 break; 392 case SkBlendModeCoeff::kDC: 393 fsBuilder->codeAppendf(" * %s", dstColorName); 394 break; 395 case SkBlendModeCoeff::kIDC: 396 fsBuilder->codeAppendf(" * (vec4(1.0) - %s)", dstColorName); 397 break; 398 case SkBlendModeCoeff::kSA: 399 fsBuilder->codeAppendf(" * %s.a", srcColorName); 400 break; 401 case SkBlendModeCoeff::kISA: 402 fsBuilder->codeAppendf(" * (1.0 - %s.a)", srcColorName); 403 break; 404 case SkBlendModeCoeff::kDA: 405 fsBuilder->codeAppendf(" * %s.a", dstColorName); 406 break; 407 case SkBlendModeCoeff::kIDA: 408 fsBuilder->codeAppendf(" * (1.0 - %s.a)", dstColorName); 409 break; 410 default: 411 SkFAIL("Unsupported Blend Coeff"); 412 } 413 return true; 414 } 415 } 416 417 ////////////////////////////////////////////////////////////////////////////// 418 419 void GrGLSLBlend::AppendMode(GrGLSLFragmentBuilder* fsBuilder, const char* srcColor, 420 const char* dstColor, const char* outColor, 421 SkBlendMode mode) { 422 423 SkBlendModeCoeff srcCoeff, dstCoeff; 424 if (SkBlendMode_AsCoeff(mode, &srcCoeff, &dstCoeff)) { 425 // The only coeff mode that can go out of range is plus. 426 bool clamp = mode == SkBlendMode::kPlus; 427 428 fsBuilder->codeAppendf("%s = ", outColor); 429 if (clamp) { 430 fsBuilder->codeAppend("clamp("); 431 } 432 // append src blend 433 bool didAppend = append_porterduff_term(fsBuilder, srcCoeff, srcColor, srcColor, dstColor, 434 false); 435 // append dst blend 436 if(!append_porterduff_term(fsBuilder, dstCoeff, dstColor, srcColor, dstColor, didAppend)) { 437 fsBuilder->codeAppend("vec4(0, 0, 0, 0)"); 438 } 439 if (clamp) { 440 fsBuilder->codeAppend(", 0, 1);"); 441 } 442 fsBuilder->codeAppend(";"); 443 } else { 444 emit_advanced_xfermode_code(fsBuilder, srcColor, dstColor, outColor, mode); 445 } 446 } 447 448 void GrGLSLBlend::AppendRegionOp(GrGLSLFragmentBuilder* fsBuilder, const char* srcColor, 449 const char* dstColor, const char* outColor, 450 SkRegion::Op regionOp) { 451 SkBlendModeCoeff srcCoeff, dstCoeff; 452 switch (regionOp) { 453 case SkRegion::kReplace_Op: 454 srcCoeff = SkBlendModeCoeff::kOne; 455 dstCoeff = SkBlendModeCoeff::kZero; 456 break; 457 case SkRegion::kIntersect_Op: 458 srcCoeff = SkBlendModeCoeff::kDC; 459 dstCoeff = SkBlendModeCoeff::kZero; 460 break; 461 case SkRegion::kUnion_Op: 462 srcCoeff = SkBlendModeCoeff::kOne; 463 dstCoeff = SkBlendModeCoeff::kISC; 464 break; 465 case SkRegion::kXOR_Op: 466 srcCoeff = SkBlendModeCoeff::kIDC; 467 dstCoeff = SkBlendModeCoeff::kISC; 468 break; 469 case SkRegion::kDifference_Op: 470 srcCoeff = SkBlendModeCoeff::kZero; 471 dstCoeff = SkBlendModeCoeff::kISC; 472 break; 473 case SkRegion::kReverseDifference_Op: 474 srcCoeff = SkBlendModeCoeff::kIDC; 475 dstCoeff = SkBlendModeCoeff::kZero; 476 break; 477 default: 478 SkFAIL("Unsupported Op"); 479 // We should never get here but to make compiler happy 480 srcCoeff = SkBlendModeCoeff::kZero; 481 dstCoeff = SkBlendModeCoeff::kZero; 482 } 483 fsBuilder->codeAppendf("%s = ", outColor); 484 // append src blend 485 bool didAppend = append_porterduff_term(fsBuilder, srcCoeff, srcColor, srcColor, dstColor, 486 false); 487 // append dst blend 488 if(!append_porterduff_term(fsBuilder, dstCoeff, dstColor, srcColor, dstColor, didAppend)) { 489 fsBuilder->codeAppend("vec4(0, 0, 0, 0)"); 490 } 491 fsBuilder->codeAppend(";"); 492 } 493
