1/*
2 * Copyright 2014 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 "src/gpu/glsl/GrGLSLShaderBuilder.h"
9
10#include "src/gpu/GrShaderCaps.h"
11#include "src/gpu/GrShaderVar.h"
12#include "src/gpu/GrSwizzle.h"
13#include "src/gpu/glsl/GrGLSLBlend.h"
14#include "src/gpu/glsl/GrGLSLColorSpaceXformHelper.h"
15#include "src/gpu/glsl/GrGLSLProgramBuilder.h"
16
17GrGLSLShaderBuilder::GrGLSLShaderBuilder(GrGLSLProgramBuilder* program)
18 : fProgramBuilder(program)
19 , fInputs(GrGLSLProgramBuilder::kVarsPerBlock)
20 , fOutputs(GrGLSLProgramBuilder::kVarsPerBlock)
21 , fFeaturesAddedMask(0)
22 , fCodeIndex(kCode)
23 , fFinalized(false)
24 , fTmpVariableCounter(0) {
25 // We push back some dummy pointers which will later become our header
26 for (int i = 0; i <= kCode; i++) {
27 fShaderStrings.push_back();
28 }
29
30 this->main() = "void main() {";
31}
32
33void GrGLSLShaderBuilder::declAppend(const GrShaderVar& var) {
34 SkString tempDecl;
35 var.appendDecl(fProgramBuilder->shaderCaps(), &tempDecl);
36 this->codeAppendf("%s;", tempDecl.c_str());
37}
38
39void GrGLSLShaderBuilder::declareGlobal(const GrShaderVar& v) {
40 v.appendDecl(this->getProgramBuilder()->shaderCaps(), &this->definitions());
41 this->definitions().append(";");
42}
43
44void GrGLSLShaderBuilder::emitFunction(GrSLType returnType,
45 const char* name,
46 int argCnt,
47 const GrShaderVar* args,
48 const char* body,
49 SkString* outName) {
50 this->functions().append(GrGLSLTypeString(returnType));
51 fProgramBuilder->nameVariable(outName, '\0', name);
52 this->functions().appendf(" %s", outName->c_str());
53 this->functions().append("(");
54 for (int i = 0; i < argCnt; ++i) {
55 args[i].appendDecl(fProgramBuilder->shaderCaps(), &this->functions());
56 if (i < argCnt - 1) {
57 this->functions().append(", ");
58 }
59 }
60 this->functions().append(") {\n");
61 this->functions().append(body);
62 this->functions().append("}\n\n");
63}
64
65static inline void append_texture_swizzle(SkString* out, GrSwizzle swizzle) {
66 if (swizzle != GrSwizzle::RGBA()) {
67 out->appendf(".%s", swizzle.asString().c_str());
68 }
69}
70
71void GrGLSLShaderBuilder::appendTextureLookup(SkString* out,
72 SamplerHandle samplerHandle,
73 const char* coordName) const {
74 const char* sampler = fProgramBuilder->samplerVariable(samplerHandle);
75 out->appendf("sample(%s, %s)", sampler, coordName);
76 append_texture_swizzle(out, fProgramBuilder->samplerSwizzle(samplerHandle));
77}
78
79void GrGLSLShaderBuilder::appendTextureLookup(SamplerHandle samplerHandle,
80 const char* coordName,
81 GrGLSLColorSpaceXformHelper* colorXformHelper) {
82 SkString lookup;
83 this->appendTextureLookup(&lookup, samplerHandle, coordName);
84 this->appendColorGamutXform(lookup.c_str(), colorXformHelper);
85}
86
87void GrGLSLShaderBuilder::appendTextureLookupAndBlend(
88 const char* dst,
89 SkBlendMode mode,
90 SamplerHandle samplerHandle,
91 const char* coordName,
92 GrGLSLColorSpaceXformHelper* colorXformHelper) {
93 if (!dst) {
94 dst = "half4(1)";
95 }
96 SkString lookup;
97 // This works around an issue in SwiftShader where the texture lookup is messed up
98 // if we use blend_modulate instead of simply operator * on dst and the sampled result.
99 // At this time it's unknown if the same problem exists for other modes.
100 if (mode == SkBlendMode::kModulate) {
101 this->codeAppend("(");
102 this->appendTextureLookup(&lookup, samplerHandle, coordName);
103 this->appendColorGamutXform(lookup.c_str(), colorXformHelper);
104 this->codeAppendf(" * %s)", dst);
105 } else {
106 this->codeAppendf("%s(", GrGLSLBlend::BlendFuncName(mode));
107 this->appendTextureLookup(&lookup, samplerHandle, coordName);
108 this->appendColorGamutXform(lookup.c_str(), colorXformHelper);
109 this->codeAppendf(", %s)", dst);
110 }
111}
112
113void GrGLSLShaderBuilder::appendColorGamutXform(SkString* out,
114 const char* srcColor,
115 GrGLSLColorSpaceXformHelper* colorXformHelper) {
116 if (!colorXformHelper || colorXformHelper->isNoop()) {
117 *out = srcColor;
118 return;
119 }
120
121 GrGLSLUniformHandler* uniformHandler = fProgramBuilder->uniformHandler();
122
123 // We define up to three helper functions, to keep things clearer. One for the source transfer
124 // function, one for the (inverse) destination transfer function, and one for the gamut xform.
125 // Any combination of these may be present, although some configurations are much more likely.
126
127 auto emitTFFunc = [=](const char* name, GrGLSLProgramDataManager::UniformHandle uniform,
128 TFKind kind) {
129 const GrShaderVar gTFArgs[] = { GrShaderVar("x", kHalf_GrSLType) };
130 const char* coeffs = uniformHandler->getUniformCStr(uniform);
131 SkString body;
132 // Temporaries to make evaluation line readable. We always use the sRGBish names, so the
133 // PQ and HLG math is confusing.
134 body.appendf("half G = %s[0];", coeffs);
135 body.appendf("half A = %s[1];", coeffs);
136 body.appendf("half B = %s[2];", coeffs);
137 body.appendf("half C = %s[3];", coeffs);
138 body.appendf("half D = %s[4];", coeffs);
139 body.appendf("half E = %s[5];", coeffs);
140 body.appendf("half F = %s[6];", coeffs);
141 body.append("half s = sign(x);");
142 body.append("x = abs(x);");
143 switch (kind) {
144 case TFKind::sRGBish_TF:
145 body.append("x = (x < D) ? (C * x) + F : pow(A * x + B, G) + E;");
146 break;
147 case TFKind::PQish_TF:
148 body.append("x = pow(max(A + B * pow(x, C), 0) / (D + E * pow(x, C)), F);");
149 break;
150 case TFKind::HLGish_TF:
151 body.append("x = (x*A <= 1) ? pow(x*A, B) : exp((x-E)*C) + D;");
152 break;
153 case TFKind::HLGinvish_TF:
154 body.append("x = (x <= 1) ? A * pow(x, B) : C * log(x - D) + E;");
155 break;
156 default:
157 SkASSERT(false);
158 break;
159 }
160 body.append("return s * x;");
161 SkString funcName;
162 this->emitFunction(kHalf_GrSLType, name, SK_ARRAY_COUNT(gTFArgs), gTFArgs, body.c_str(),
163 &funcName);
164 return funcName;
165 };
166
167 SkString srcTFFuncName;
168 if (colorXformHelper->applySrcTF()) {
169 srcTFFuncName = emitTFFunc("src_tf", colorXformHelper->srcTFUniform(),
170 colorXformHelper->srcTFKind());
171 }
172
173 SkString dstTFFuncName;
174 if (colorXformHelper->applyDstTF()) {
175 dstTFFuncName = emitTFFunc("dst_tf", colorXformHelper->dstTFUniform(),
176 colorXformHelper->dstTFKind());
177 }
178
179 SkString gamutXformFuncName;
180 if (colorXformHelper->applyGamutXform()) {
181 const GrShaderVar gGamutXformArgs[] = { GrShaderVar("color", kHalf4_GrSLType) };
182 const char* xform = uniformHandler->getUniformCStr(colorXformHelper->gamutXformUniform());
183 SkString body;
184 body.appendf("color.rgb = (%s * color.rgb);", xform);
185 body.append("return color;");
186 this->emitFunction(kHalf4_GrSLType, "gamut_xform", SK_ARRAY_COUNT(gGamutXformArgs),
187 gGamutXformArgs, body.c_str(), &gamutXformFuncName);
188 }
189
190 // Now define a wrapper function that applies all the intermediate steps
191 {
192 // Some GPUs require full float to get results that are as accurate as expected/required.
193 // Most GPUs work just fine with half float. Strangely, the GPUs that have this bug
194 // (Mali G series) only require us to promote the type of a few temporaries here --
195 // the helper functions above can always be written to use half.
196 bool useFloat = fProgramBuilder->shaderCaps()->colorSpaceMathNeedsFloat();
197
198 const GrShaderVar gColorXformArgs[] = {
199 GrShaderVar("color", useFloat ? kFloat4_GrSLType : kHalf4_GrSLType)};
200 SkString body;
201 if (colorXformHelper->applyUnpremul()) {
202 body.appendf("color = unpremul%s(color);", useFloat ? "_float" : "");
203 }
204 if (colorXformHelper->applySrcTF()) {
205 body.appendf("color.r = %s(half(color.r));", srcTFFuncName.c_str());
206 body.appendf("color.g = %s(half(color.g));", srcTFFuncName.c_str());
207 body.appendf("color.b = %s(half(color.b));", srcTFFuncName.c_str());
208 }
209 if (colorXformHelper->applyGamutXform()) {
210 body.appendf("color = %s(half4(color));", gamutXformFuncName.c_str());
211 }
212 if (colorXformHelper->applyDstTF()) {
213 body.appendf("color.r = %s(half(color.r));", dstTFFuncName.c_str());
214 body.appendf("color.g = %s(half(color.g));", dstTFFuncName.c_str());
215 body.appendf("color.b = %s(half(color.b));", dstTFFuncName.c_str());
216 }
217 if (colorXformHelper->applyPremul()) {
218 body.append("color.rgb *= color.a;");
219 }
220 body.append("return half4(color);");
221 SkString colorXformFuncName;
222 this->emitFunction(kHalf4_GrSLType, "color_xform", SK_ARRAY_COUNT(gColorXformArgs),
223 gColorXformArgs, body.c_str(), &colorXformFuncName);
224 out->appendf("%s(%s)", colorXformFuncName.c_str(), srcColor);
225 }
226}
227
228void GrGLSLShaderBuilder::appendColorGamutXform(const char* srcColor,
229 GrGLSLColorSpaceXformHelper* colorXformHelper) {
230 SkString xform;
231 this->appendColorGamutXform(&xform, srcColor, colorXformHelper);
232 this->codeAppend(xform.c_str());
233}
234
235bool GrGLSLShaderBuilder::addFeature(uint32_t featureBit, const char* extensionName) {
236 if (featureBit & fFeaturesAddedMask) {
237 return false;
238 }
239 this->extensions().appendf("#extension %s: require\n", extensionName);
240 fFeaturesAddedMask |= featureBit;
241 return true;
242}
243
244void GrGLSLShaderBuilder::appendDecls(const VarArray& vars, SkString* out) const {
245 for (const auto& v : vars.items()) {
246 v.appendDecl(fProgramBuilder->shaderCaps(), out);
247 out->append(";\n");
248 }
249}
250
251void GrGLSLShaderBuilder::addLayoutQualifier(const char* param, InterfaceQualifier interface) {
252 SkASSERT(fProgramBuilder->shaderCaps()->generation() >= k330_GrGLSLGeneration ||
253 fProgramBuilder->shaderCaps()->mustEnableAdvBlendEqs());
254 fLayoutParams[interface].push_back() = param;
255}
256
257void GrGLSLShaderBuilder::compileAndAppendLayoutQualifiers() {
258 static const char* interfaceQualifierNames[] = {
259 "in",
260 "out"
261 };
262
263 for (int interface = 0; interface <= kLastInterfaceQualifier; ++interface) {
264 const SkTArray<SkString>& params = fLayoutParams[interface];
265 if (params.empty()) {
266 continue;
267 }
268 this->layoutQualifiers().appendf("layout(%s", params[0].c_str());
269 for (int i = 1; i < params.count(); ++i) {
270 this->layoutQualifiers().appendf(", %s", params[i].c_str());
271 }
272 this->layoutQualifiers().appendf(") %s;\n", interfaceQualifierNames[interface]);
273 }
274
275 static_assert(0 == GrGLSLShaderBuilder::kIn_InterfaceQualifier);
276 static_assert(1 == GrGLSLShaderBuilder::kOut_InterfaceQualifier);
277 static_assert(SK_ARRAY_COUNT(interfaceQualifierNames) == kLastInterfaceQualifier + 1);
278}
279
280void GrGLSLShaderBuilder::finalize(uint32_t visibility) {
281 SkASSERT(!fFinalized);
282 this->compileAndAppendLayoutQualifiers();
283 SkASSERT(visibility);
284 fProgramBuilder->appendUniformDecls((GrShaderFlags) visibility, &this->uniforms());
285 this->appendDecls(fInputs, &this->inputs());
286 this->appendDecls(fOutputs, &this->outputs());
287 this->onFinalize();
288 // append the 'footer' to code
289 this->code().append("}");
290
291 for (int i = 0; i <= fCodeIndex; i++) {
292 fCompilerString.append(fShaderStrings[i].c_str(), fShaderStrings[i].size());
293 }
294
295 fFinalized = true;
296}
297