| /* |
| * Copyright 2015 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| #include "GrGLSLBlend.h" |
| #include "glsl/GrGLSLFragmentShaderBuilder.h" |
| |
| ////////////////////////////////////////////////////////////////////////////// |
| // Advanced (non-coeff) blend helpers |
| ////////////////////////////////////////////////////////////////////////////// |
| |
| static void hard_light(GrGLSLFragmentBuilder* fsBuilder, |
| const char* final, |
| const char* src, |
| const char* dst) { |
| static const char kComponents[] = { 'r', 'g', 'b' }; |
| for (size_t i = 0; i < SK_ARRAY_COUNT(kComponents); ++i) { |
| char component = kComponents[i]; |
| fsBuilder->codeAppendf("if (2.0 * %s.%c <= %s.a) {", src, component, src); |
| fsBuilder->codeAppendf("%s.%c = 2.0 * %s.%c * %s.%c;", |
| final, component, src, component, dst, component); |
| fsBuilder->codeAppend("} else {"); |
| fsBuilder->codeAppendf("%s.%c = %s.a * %s.a - 2.0 * (%s.a - %s.%c) * (%s.a - %s.%c);", |
| final, component, src, dst, dst, dst, component, src, src, |
| component); |
| fsBuilder->codeAppend("}"); |
| } |
| fsBuilder->codeAppendf("%s.rgb += %s.rgb * (1.0 - %s.a) + %s.rgb * (1.0 - %s.a);", |
| final, src, dst, dst, src); |
| } |
| |
| // Does one component of color-dodge |
| static void color_dodge_component(GrGLSLFragmentBuilder* fsBuilder, |
| const char* final, |
| const char* src, |
| const char* dst, |
| const char component) { |
| fsBuilder->codeAppendf("if (0.0 == %s.%c) {", dst, component); |
| fsBuilder->codeAppendf("%s.%c = %s.%c * (1.0 - %s.a);", |
| final, component, src, component, dst); |
| fsBuilder->codeAppend("} else {"); |
| fsBuilder->codeAppendf("float d = %s.a - %s.%c;", src, src, component); |
| fsBuilder->codeAppend("if (0.0 == d) {"); |
| fsBuilder->codeAppendf("%s.%c = %s.a * %s.a + %s.%c * (1.0 - %s.a) + %s.%c * (1.0 - %s.a);", |
| final, component, src, dst, src, component, dst, dst, component, |
| src); |
| fsBuilder->codeAppend("} else {"); |
| fsBuilder->codeAppendf("d = min(%s.a, %s.%c * %s.a / d);", |
| dst, dst, component, src); |
| fsBuilder->codeAppendf("%s.%c = d * %s.a + %s.%c * (1.0 - %s.a) + %s.%c * (1.0 - %s.a);", |
| final, component, src, src, component, dst, dst, component, src); |
| fsBuilder->codeAppend("}"); |
| fsBuilder->codeAppend("}"); |
| } |
| |
| // Does one component of color-burn |
| static void color_burn_component(GrGLSLFragmentBuilder* fsBuilder, |
| const char* final, |
| const char* src, |
| const char* dst, |
| const char component) { |
| fsBuilder->codeAppendf("if (%s.a == %s.%c) {", dst, dst, component); |
| fsBuilder->codeAppendf("%s.%c = %s.a * %s.a + %s.%c * (1.0 - %s.a) + %s.%c * (1.0 - %s.a);", |
| final, component, src, dst, src, component, dst, dst, component, |
| src); |
| fsBuilder->codeAppendf("} else if (0.0 == %s.%c) {", src, component); |
| fsBuilder->codeAppendf("%s.%c = %s.%c * (1.0 - %s.a);", |
| final, component, dst, component, src); |
| fsBuilder->codeAppend("} else {"); |
| fsBuilder->codeAppendf("float d = max(0.0, %s.a - (%s.a - %s.%c) * %s.a / %s.%c);", |
| dst, dst, dst, component, src, src, component); |
| fsBuilder->codeAppendf("%s.%c = %s.a * d + %s.%c * (1.0 - %s.a) + %s.%c * (1.0 - %s.a);", |
| final, component, src, src, component, dst, dst, component, src); |
| fsBuilder->codeAppend("}"); |
| } |
| |
| // Does one component of soft-light. Caller should have already checked that dst alpha > 0. |
| static void soft_light_component_pos_dst_alpha(GrGLSLFragmentBuilder* fsBuilder, |
| const char* final, |
| const char* src, |
| const char* dst, |
| const char component) { |
| // if (2S < Sa) |
| fsBuilder->codeAppendf("if (2.0 * %s.%c <= %s.a) {", src, component, src); |
| // (D^2 (Sa-2 S))/Da+(1-Da) S+D (-Sa+2 S+1) |
| fsBuilder->codeAppendf("%s.%c = (%s.%c*%s.%c*(%s.a - 2.0*%s.%c)) / %s.a +" |
| "(1.0 - %s.a) * %s.%c + %s.%c*(-%s.a + 2.0*%s.%c + 1.0);", |
| final, component, dst, component, dst, component, src, src, |
| component, dst, dst, src, component, dst, component, src, src, |
| component); |
| // else if (4D < Da) |
| fsBuilder->codeAppendf("} else if (4.0 * %s.%c <= %s.a) {", |
| dst, component, dst); |
| fsBuilder->codeAppendf("float DSqd = %s.%c * %s.%c;", |
| dst, component, dst, component); |
| fsBuilder->codeAppendf("float DCub = DSqd * %s.%c;", dst, component); |
| fsBuilder->codeAppendf("float DaSqd = %s.a * %s.a;", dst, dst); |
| fsBuilder->codeAppendf("float DaCub = DaSqd * %s.a;", dst); |
| // (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 |
| fsBuilder->codeAppendf("%s.%c =" |
| "(DaSqd*(%s.%c - %s.%c * (3.0*%s.a - 6.0*%s.%c - 1.0)) +" |
| " 12.0*%s.a*DSqd*(%s.a - 2.0*%s.%c) - 16.0*DCub * (%s.a - 2.0*%s.%c) -" |
| " DaCub*%s.%c) / DaSqd;", |
| final, component, src, component, dst, component, |
| src, src, component, dst, src, src, component, src, src, |
| component, src, component); |
| fsBuilder->codeAppendf("} else {"); |
| // -sqrt(Da * D) (Sa-2 S)-Da S+D (Sa-2 S+1)+S |
| fsBuilder->codeAppendf("%s.%c = %s.%c*(%s.a - 2.0*%s.%c + 1.0) + %s.%c -" |
| " sqrt(%s.a*%s.%c)*(%s.a - 2.0*%s.%c) - %s.a*%s.%c;", |
| final, component, dst, component, src, src, component, src, component, |
| dst, dst, component, src, src, component, dst, src, component); |
| fsBuilder->codeAppendf("}"); |
| } |
| |
| // Adds a function that takes two colors and an alpha as input. It produces a color with the |
| // hue and saturation of the first color, the luminosity of the second color, and the input |
| // alpha. It has this signature: |
| // vec3 set_luminance(vec3 hueSatColor, float alpha, vec3 lumColor). |
| static void add_lum_function(GrGLSLFragmentBuilder* fsBuilder, SkString* setLumFunction) { |
| // Emit a helper that gets the luminance of a color. |
| SkString getFunction; |
| GrGLSLShaderVar getLumArgs[] = { |
| GrGLSLShaderVar("color", kVec3f_GrSLType), |
| }; |
| SkString getLumBody("return dot(vec3(0.3, 0.59, 0.11), color);"); |
| fsBuilder->emitFunction(kFloat_GrSLType, |
| "luminance", |
| SK_ARRAY_COUNT(getLumArgs), getLumArgs, |
| getLumBody.c_str(), |
| &getFunction); |
| |
| // Emit the set luminance function. |
| GrGLSLShaderVar setLumArgs[] = { |
| GrGLSLShaderVar("hueSat", kVec3f_GrSLType), |
| GrGLSLShaderVar("alpha", kFloat_GrSLType), |
| GrGLSLShaderVar("lumColor", kVec3f_GrSLType), |
| }; |
| SkString setLumBody; |
| setLumBody.printf("float diff = %s(lumColor - hueSat);", getFunction.c_str()); |
| setLumBody.append("vec3 outColor = hueSat + diff;"); |
| setLumBody.appendf("float outLum = %s(outColor);", getFunction.c_str()); |
| setLumBody.append("float minComp = min(min(outColor.r, outColor.g), outColor.b);" |
| "float maxComp = max(max(outColor.r, outColor.g), outColor.b);" |
| "if (minComp < 0.0 && outLum != minComp) {" |
| "outColor = outLum + ((outColor - vec3(outLum, outLum, outLum)) * outLum) /" |
| "(outLum - minComp);" |
| "}" |
| "if (maxComp > alpha && maxComp != outLum) {" |
| "outColor = outLum +" |
| "((outColor - vec3(outLum, outLum, outLum)) * (alpha - outLum)) /" |
| "(maxComp - outLum);" |
| "}" |
| "return outColor;"); |
| fsBuilder->emitFunction(kVec3f_GrSLType, |
| "set_luminance", |
| SK_ARRAY_COUNT(setLumArgs), setLumArgs, |
| setLumBody.c_str(), |
| setLumFunction); |
| } |
| |
| // Adds a function that creates a color with the hue and luminosity of one input color and |
| // the saturation of another color. It will have this signature: |
| // float set_saturation(vec3 hueLumColor, vec3 satColor) |
| static void add_sat_function(GrGLSLFragmentBuilder* fsBuilder, SkString* setSatFunction) { |
| // Emit a helper that gets the saturation of a color |
| SkString getFunction; |
| GrGLSLShaderVar getSatArgs[] = { GrGLSLShaderVar("color", kVec3f_GrSLType) }; |
| SkString getSatBody; |
| getSatBody.printf("return max(max(color.r, color.g), color.b) - " |
| "min(min(color.r, color.g), color.b);"); |
| fsBuilder->emitFunction(kFloat_GrSLType, |
| "saturation", |
| SK_ARRAY_COUNT(getSatArgs), getSatArgs, |
| getSatBody.c_str(), |
| &getFunction); |
| |
| // Emit a helper that sets the saturation given sorted input channels. This used |
| // to use inout params for min, mid, and max components but that seems to cause |
| // problems on PowerVR drivers. So instead it returns a vec3 where r, g ,b are the |
| // adjusted min, mid, and max inputs, respectively. |
| SkString helperFunction; |
| GrGLSLShaderVar helperArgs[] = { |
| GrGLSLShaderVar("minComp", kFloat_GrSLType), |
| GrGLSLShaderVar("midComp", kFloat_GrSLType), |
| GrGLSLShaderVar("maxComp", kFloat_GrSLType), |
| GrGLSLShaderVar("sat", kFloat_GrSLType), |
| }; |
| static const char kHelperBody[] = "if (minComp < maxComp) {" |
| "vec3 result;" |
| "result.r = 0.0;" |
| "result.g = sat * (midComp - minComp) / (maxComp - minComp);" |
| "result.b = sat;" |
| "return result;" |
| "} else {" |
| "return vec3(0, 0, 0);" |
| "}"; |
| fsBuilder->emitFunction(kVec3f_GrSLType, |
| "set_saturation_helper", |
| SK_ARRAY_COUNT(helperArgs), helperArgs, |
| kHelperBody, |
| &helperFunction); |
| |
| GrGLSLShaderVar setSatArgs[] = { |
| GrGLSLShaderVar("hueLumColor", kVec3f_GrSLType), |
| GrGLSLShaderVar("satColor", kVec3f_GrSLType), |
| }; |
| const char* helpFunc = helperFunction.c_str(); |
| SkString setSatBody; |
| setSatBody.appendf("float sat = %s(satColor);" |
| "if (hueLumColor.r <= hueLumColor.g) {" |
| "if (hueLumColor.g <= hueLumColor.b) {" |
| "hueLumColor.rgb = %s(hueLumColor.r, hueLumColor.g, hueLumColor.b, sat);" |
| "} else if (hueLumColor.r <= hueLumColor.b) {" |
| "hueLumColor.rbg = %s(hueLumColor.r, hueLumColor.b, hueLumColor.g, sat);" |
| "} else {" |
| "hueLumColor.brg = %s(hueLumColor.b, hueLumColor.r, hueLumColor.g, sat);" |
| "}" |
| "} else if (hueLumColor.r <= hueLumColor.b) {" |
| "hueLumColor.grb = %s(hueLumColor.g, hueLumColor.r, hueLumColor.b, sat);" |
| "} else if (hueLumColor.g <= hueLumColor.b) {" |
| "hueLumColor.gbr = %s(hueLumColor.g, hueLumColor.b, hueLumColor.r, sat);" |
| "} else {" |
| "hueLumColor.bgr = %s(hueLumColor.b, hueLumColor.g, hueLumColor.r, sat);" |
| "}" |
| "return hueLumColor;", |
| getFunction.c_str(), helpFunc, helpFunc, helpFunc, helpFunc, |
| helpFunc, helpFunc); |
| fsBuilder->emitFunction(kVec3f_GrSLType, |
| "set_saturation", |
| SK_ARRAY_COUNT(setSatArgs), setSatArgs, |
| setSatBody.c_str(), |
| setSatFunction); |
| } |
| |
| static void emit_advanced_xfermode_code(GrGLSLFragmentBuilder* fsBuilder, const char* srcColor, |
| const char* dstColor, const char* outputColor, |
| SkXfermode::Mode mode) { |
| SkASSERT(srcColor); |
| SkASSERT(dstColor); |
| SkASSERT(outputColor); |
| // These all perform src-over on the alpha channel. |
| fsBuilder->codeAppendf("%s.a = %s.a + (1.0 - %s.a) * %s.a;", |
| outputColor, srcColor, srcColor, dstColor); |
| |
| switch (mode) { |
| case SkXfermode::kOverlay_Mode: |
| // Overlay is Hard-Light with the src and dst reversed |
| hard_light(fsBuilder, outputColor, dstColor, srcColor); |
| break; |
| case SkXfermode::kDarken_Mode: |
| fsBuilder->codeAppendf("%s.rgb = min((1.0 - %s.a) * %s.rgb + %s.rgb, " |
| "(1.0 - %s.a) * %s.rgb + %s.rgb);", |
| outputColor, |
| srcColor, dstColor, srcColor, |
| dstColor, srcColor, dstColor); |
| break; |
| case SkXfermode::kLighten_Mode: |
| fsBuilder->codeAppendf("%s.rgb = max((1.0 - %s.a) * %s.rgb + %s.rgb, " |
| "(1.0 - %s.a) * %s.rgb + %s.rgb);", |
| outputColor, |
| srcColor, dstColor, srcColor, |
| dstColor, srcColor, dstColor); |
| break; |
| case SkXfermode::kColorDodge_Mode: |
| color_dodge_component(fsBuilder, outputColor, srcColor, dstColor, 'r'); |
| color_dodge_component(fsBuilder, outputColor, srcColor, dstColor, 'g'); |
| color_dodge_component(fsBuilder, outputColor, srcColor, dstColor, 'b'); |
| break; |
| case SkXfermode::kColorBurn_Mode: |
| color_burn_component(fsBuilder, outputColor, srcColor, dstColor, 'r'); |
| color_burn_component(fsBuilder, outputColor, srcColor, dstColor, 'g'); |
| color_burn_component(fsBuilder, outputColor, srcColor, dstColor, 'b'); |
| break; |
| case SkXfermode::kHardLight_Mode: |
| hard_light(fsBuilder, outputColor, srcColor, dstColor); |
| break; |
| case SkXfermode::kSoftLight_Mode: |
| fsBuilder->codeAppendf("if (0.0 == %s.a) {", dstColor); |
| fsBuilder->codeAppendf("%s.rgba = %s;", outputColor, srcColor); |
| fsBuilder->codeAppendf("} else {"); |
| soft_light_component_pos_dst_alpha(fsBuilder, outputColor, srcColor, dstColor, 'r'); |
| soft_light_component_pos_dst_alpha(fsBuilder, outputColor, srcColor, dstColor, 'g'); |
| soft_light_component_pos_dst_alpha(fsBuilder, outputColor, srcColor, dstColor, 'b'); |
| fsBuilder->codeAppendf("}"); |
| break; |
| case SkXfermode::kDifference_Mode: |
| fsBuilder->codeAppendf("%s.rgb = %s.rgb + %s.rgb -" |
| "2.0 * min(%s.rgb * %s.a, %s.rgb * %s.a);", |
| outputColor, srcColor, dstColor, srcColor, dstColor, |
| dstColor, srcColor); |
| break; |
| case SkXfermode::kExclusion_Mode: |
| fsBuilder->codeAppendf("%s.rgb = %s.rgb + %s.rgb - " |
| "2.0 * %s.rgb * %s.rgb;", |
| outputColor, dstColor, srcColor, dstColor, srcColor); |
| break; |
| case SkXfermode::kMultiply_Mode: |
| fsBuilder->codeAppendf("%s.rgb = (1.0 - %s.a) * %s.rgb + " |
| "(1.0 - %s.a) * %s.rgb + " |
| "%s.rgb * %s.rgb;", |
| outputColor, srcColor, dstColor, dstColor, srcColor, |
| srcColor, dstColor); |
| break; |
| case SkXfermode::kHue_Mode: { |
| // SetLum(SetSat(S * Da, Sat(D * Sa)), Sa*Da, D*Sa) + (1 - Sa) * D + (1 - Da) * S |
| SkString setSat, setLum; |
| add_sat_function(fsBuilder, &setSat); |
| add_lum_function(fsBuilder, &setLum); |
| fsBuilder->codeAppendf("vec4 dstSrcAlpha = %s * %s.a;", |
| dstColor, srcColor); |
| fsBuilder->codeAppendf("%s.rgb = %s(%s(%s.rgb * %s.a, dstSrcAlpha.rgb)," |
| "dstSrcAlpha.a, dstSrcAlpha.rgb);", |
| outputColor, setLum.c_str(), setSat.c_str(), srcColor, |
| dstColor); |
| fsBuilder->codeAppendf("%s.rgb += (1.0 - %s.a) * %s.rgb + (1.0 - %s.a) * %s.rgb;", |
| outputColor, srcColor, dstColor, dstColor, srcColor); |
| break; |
| } |
| case SkXfermode::kSaturation_Mode: { |
| // SetLum(SetSat(D * Sa, Sat(S * Da)), Sa*Da, D*Sa)) + (1 - Sa) * D + (1 - Da) * S |
| SkString setSat, setLum; |
| add_sat_function(fsBuilder, &setSat); |
| add_lum_function(fsBuilder, &setLum); |
| fsBuilder->codeAppendf("vec4 dstSrcAlpha = %s * %s.a;", |
| dstColor, srcColor); |
| fsBuilder->codeAppendf("%s.rgb = %s(%s(dstSrcAlpha.rgb, %s.rgb * %s.a)," |
| "dstSrcAlpha.a, dstSrcAlpha.rgb);", |
| outputColor, setLum.c_str(), setSat.c_str(), srcColor, |
| dstColor); |
| fsBuilder->codeAppendf("%s.rgb += (1.0 - %s.a) * %s.rgb + (1.0 - %s.a) * %s.rgb;", |
| outputColor, srcColor, dstColor, dstColor, srcColor); |
| break; |
| } |
| case SkXfermode::kColor_Mode: { |
| // SetLum(S * Da, Sa* Da, D * Sa) + (1 - Sa) * D + (1 - Da) * S |
| SkString setLum; |
| add_lum_function(fsBuilder, &setLum); |
| fsBuilder->codeAppendf("vec4 srcDstAlpha = %s * %s.a;", |
| srcColor, dstColor); |
| fsBuilder->codeAppendf("%s.rgb = %s(srcDstAlpha.rgb, srcDstAlpha.a, %s.rgb * %s.a);", |
| outputColor, setLum.c_str(), dstColor, srcColor); |
| fsBuilder->codeAppendf("%s.rgb += (1.0 - %s.a) * %s.rgb + (1.0 - %s.a) * %s.rgb;", |
| outputColor, srcColor, dstColor, dstColor, srcColor); |
| break; |
| } |
| case SkXfermode::kLuminosity_Mode: { |
| // SetLum(D * Sa, Sa* Da, S * Da) + (1 - Sa) * D + (1 - Da) * S |
| SkString setLum; |
| add_lum_function(fsBuilder, &setLum); |
| fsBuilder->codeAppendf("vec4 srcDstAlpha = %s * %s.a;", |
| srcColor, dstColor); |
| fsBuilder->codeAppendf("%s.rgb = %s(%s.rgb * %s.a, srcDstAlpha.a, srcDstAlpha.rgb);", |
| outputColor, setLum.c_str(), dstColor, srcColor); |
| fsBuilder->codeAppendf("%s.rgb += (1.0 - %s.a) * %s.rgb + (1.0 - %s.a) * %s.rgb;", |
| outputColor, srcColor, dstColor, dstColor, srcColor); |
| break; |
| } |
| default: |
| SkFAIL("Unknown Custom Xfer mode."); |
| break; |
| } |
| } |
| |
| ////////////////////////////////////////////////////////////////////////////// |
| // Porter-Duff blend helper |
| ////////////////////////////////////////////////////////////////////////////// |
| |
| static bool append_porterduff_term(GrGLSLFragmentBuilder* fsBuilder, SkXfermode::Coeff coeff, |
| const char* colorName, const char* srcColorName, |
| const char* dstColorName, bool hasPrevious) { |
| if (SkXfermode::kZero_Coeff == coeff) { |
| return hasPrevious; |
| } else { |
| if (hasPrevious) { |
| fsBuilder->codeAppend(" + "); |
| } |
| fsBuilder->codeAppendf("%s", colorName); |
| switch (coeff) { |
| case SkXfermode::kOne_Coeff: |
| break; |
| case SkXfermode::kSC_Coeff: |
| fsBuilder->codeAppendf(" * %s", srcColorName); |
| break; |
| case SkXfermode::kISC_Coeff: |
| fsBuilder->codeAppendf(" * (vec4(1.0) - %s)", srcColorName); |
| break; |
| case SkXfermode::kDC_Coeff: |
| fsBuilder->codeAppendf(" * %s", dstColorName); |
| break; |
| case SkXfermode::kIDC_Coeff: |
| fsBuilder->codeAppendf(" * (vec4(1.0) - %s)", dstColorName); |
| break; |
| case SkXfermode::kSA_Coeff: |
| fsBuilder->codeAppendf(" * %s.a", srcColorName); |
| break; |
| case SkXfermode::kISA_Coeff: |
| fsBuilder->codeAppendf(" * (1.0 - %s.a)", srcColorName); |
| break; |
| case SkXfermode::kDA_Coeff: |
| fsBuilder->codeAppendf(" * %s.a", dstColorName); |
| break; |
| case SkXfermode::kIDA_Coeff: |
| fsBuilder->codeAppendf(" * (1.0 - %s.a)", dstColorName); |
| break; |
| default: |
| SkFAIL("Unsupported Blend Coeff"); |
| } |
| return true; |
| } |
| } |
| |
| ////////////////////////////////////////////////////////////////////////////// |
| |
| void GrGLSLBlend::AppendMode(GrGLSLFragmentBuilder* fsBuilder, const char* srcColor, |
| const char* dstColor, const char* outColor, |
| SkXfermode::Mode mode) { |
| |
| SkXfermode::Coeff srcCoeff, dstCoeff; |
| if (SkXfermode::ModeAsCoeff(mode, &srcCoeff, &dstCoeff)) { |
| fsBuilder->codeAppendf("%s = ", outColor); |
| // append src blend |
| bool didAppend = append_porterduff_term(fsBuilder, srcCoeff, srcColor, srcColor, dstColor, |
| false); |
| // append dst blend |
| if(!append_porterduff_term(fsBuilder, dstCoeff, dstColor, srcColor, dstColor, didAppend)) { |
| fsBuilder->codeAppend("vec4(0, 0, 0, 0)"); |
| } |
| fsBuilder->codeAppend(";"); |
| } else { |
| emit_advanced_xfermode_code(fsBuilder, srcColor, dstColor, outColor, mode); |
| } |
| } |