src/third_party/skia/src/gpu/effects/GrConvexPolyEffect.cpp

   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 "gl/builders/GrGLProgramBuilder.h"
   9 #include "GrConvexPolyEffect.h"
  10
  11 #include "gl/GrGLProcessor.h"
  12 #include "gl/GrGLSL.h"
  13 #include "GrTBackendProcessorFactory.h"
  14
  15 #include "SkPath.h"
  16
  17 //////////////////////////////////////////////////////////////////////////////
  18 class GLAARectEffect;
  19
  20 class AARectEffect : public GrFragmentProcessor {
  21 public:
  22     typedef GLAARectEffect GLProcessor;
  23
  24     const SkRect& getRect() const { return fRect; }
  25
  26     static const char* Name() { return "AARect"; }
  27
  28     static GrFragmentProcessor* Create(GrPrimitiveEdgeType edgeType, const SkRect& rect) {
  29         return SkNEW_ARGS(AARectEffect, (edgeType, rect));
  30     }
  31
  32     virtual void getConstantColorComponents(GrColor* color,
  33                                             uint32_t* validFlags) const SK_OVERRIDE {
  34         if (fRect.isEmpty()) {
  35             // An empty rect will have no coverage anywhere.
  36             *color = 0x00000000;
  37             *validFlags = kRGBA_GrColorComponentFlags;
  38         } else {
  39             *validFlags = 0;
  40         }
  41     }
  42
  43     GrPrimitiveEdgeType getEdgeType() const { return fEdgeType; }
  44
  45     virtual const GrBackendFragmentProcessorFactory& getFactory() const SK_OVERRIDE;
  46
  47 private:
  48     AARectEffect(GrPrimitiveEdgeType edgeType, const SkRect& rect) : fRect(rect), fEdgeType(edgeType) {
  49         this->setWillReadFragmentPosition();
  50     }
  51
  52     virtual bool onIsEqual(const GrProcessor& other) const SK_OVERRIDE {
  53         const AARectEffect& aare = other.cast<AARectEffect>();
  54         return fRect == aare.fRect;
  55     }
  56
  57     SkRect              fRect;
  58     GrPrimitiveEdgeType fEdgeType;
  59
  60     typedef GrFragmentProcessor INHERITED;
  61
  62     GR_DECLARE_FRAGMENT_PROCESSOR_TEST;
  63
  64 };
  65
  66 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(AARectEffect);
  67
  68 GrFragmentProcessor* AARectEffect::TestCreate(SkRandom* random,
  69                                               GrContext*,
  70                                               const GrDrawTargetCaps& caps,
  71                                               GrTexture*[]) {
  72     SkRect rect = SkRect::MakeLTRB(random->nextSScalar1(),
  73                                    random->nextSScalar1(),
  74                                    random->nextSScalar1(),
  75                                    random->nextSScalar1());
  76     GrFragmentProcessor* fp;
  77     do {
  78         GrPrimitiveEdgeType edgeType = static_cast<GrPrimitiveEdgeType>(random->nextULessThan(
  79                                                                     kGrProcessorEdgeTypeCnt));
  80
  81         fp = AARectEffect::Create(edgeType, rect);
  82     } while (NULL == fp);
  83     return fp;
  84 }
  85
  86 //////////////////////////////////////////////////////////////////////////////
  87
  88 class GLAARectEffect : public GrGLFragmentProcessor {
  89 public:
  90     GLAARectEffect(const GrBackendProcessorFactory&, const GrProcessor&);
  91
  92     virtual void emitCode(GrGLProgramBuilder* builder,
  93                           const GrFragmentProcessor& fp,
  94                           const GrProcessorKey& key,
  95                           const char* outputColor,
  96                           const char* inputColor,
  97                           const TransformedCoordsArray&,
  98                           const TextureSamplerArray&) SK_OVERRIDE;
  99
 100     static inline void GenKey(const GrProcessor&, const GrGLCaps&, GrProcessorKeyBuilder*);
 101
 102     virtual void setData(const GrGLProgramDataManager&, const GrProcessor&) SK_OVERRIDE;
 103
 104 private:
 105     GrGLProgramDataManager::UniformHandle fRectUniform;
 106     SkRect                                fPrevRect;
 107     typedef GrGLFragmentProcessor INHERITED;
 108 };
 109
 110 GLAARectEffect::GLAARectEffect(const GrBackendProcessorFactory& factory,
 111                                const GrProcessor& effect)
 112     : INHERITED (factory) {
 113     fPrevRect.fLeft = SK_ScalarNaN;
 114 }
 115
 116 void GLAARectEffect::emitCode(GrGLProgramBuilder* builder,
 117                               const GrFragmentProcessor& fp,
 118                               const GrProcessorKey& key,
 119                               const char* outputColor,
 120                               const char* inputColor,
 121                               const TransformedCoordsArray&,
 122                               const TextureSamplerArray& samplers) {
 123     const AARectEffect& aare = fp.cast<AARectEffect>();
 124     const char *rectName;
 125     // The rect uniform's xyzw refer to (left + 0.5, top + 0.5, right - 0.5, bottom - 0.5),
 126     // respectively.
 127     fRectUniform = builder->addUniform(GrGLProgramBuilder::kFragment_Visibility,
 128                                        kVec4f_GrSLType,
 129                                        "rect",
 130                                        &rectName);
 131
 132     GrGLFragmentShaderBuilder* fsBuilder = builder->getFragmentShaderBuilder();
 133     const char* fragmentPos = fsBuilder->fragmentPosition();
 134     if (GrProcessorEdgeTypeIsAA(aare.getEdgeType())) {
 135         // The amount of coverage removed in x and y by the edges is computed as a pair of negative
 136         // numbers, xSub and ySub.
 137         fsBuilder->codeAppend("\t\tfloat xSub, ySub;\n");
 138         fsBuilder->codeAppendf("\t\txSub = min(%s.x - %s.x, 0.0);\n", fragmentPos, rectName);
 139         fsBuilder->codeAppendf("\t\txSub += min(%s.z - %s.x, 0.0);\n", rectName, fragmentPos);
 140         fsBuilder->codeAppendf("\t\tySub = min(%s.y - %s.y, 0.0);\n", fragmentPos, rectName);
 141         fsBuilder->codeAppendf("\t\tySub += min(%s.w - %s.y, 0.0);\n", rectName, fragmentPos);
 142         // Now compute coverage in x and y and multiply them to get the fraction of the pixel
 143         // covered.
 144         fsBuilder->codeAppendf("\t\tfloat alpha = (1.0 + max(xSub, -1.0)) * (1.0 + max(ySub, -1.0));\n");
 145     } else {
 146         fsBuilder->codeAppendf("\t\tfloat alpha = 1.0;\n");
 147         fsBuilder->codeAppendf("\t\talpha *= (%s.x - %s.x) > -0.5 ? 1.0 : 0.0;\n", fragmentPos, rectName);
 148         fsBuilder->codeAppendf("\t\talpha *= (%s.z - %s.x) > -0.5 ? 1.0 : 0.0;\n", rectName, fragmentPos);
 149         fsBuilder->codeAppendf("\t\talpha *= (%s.y - %s.y) > -0.5 ? 1.0 : 0.0;\n", fragmentPos, rectName);
 150         fsBuilder->codeAppendf("\t\talpha *= (%s.w - %s.y) > -0.5 ? 1.0 : 0.0;\n", rectName, fragmentPos);
 151     }
 152
 153     if (GrProcessorEdgeTypeIsInverseFill(aare.getEdgeType())) {
 154         fsBuilder->codeAppend("\t\talpha = 1.0 - alpha;\n");
 155     }
 156     fsBuilder->codeAppendf("\t\t%s = %s;\n", outputColor,
 157                            (GrGLSLExpr4(inputColor) * GrGLSLExpr1("alpha")).c_str());
 158 }
 159
 160 void GLAARectEffect::setData(const GrGLProgramDataManager& pdman, const GrProcessor& processor) {
 161     const AARectEffect& aare = processor.cast<AARectEffect>();
 162     const SkRect& rect = aare.getRect();
 163     if (rect != fPrevRect) {
 164         pdman.set4f(fRectUniform, rect.fLeft + 0.5f, rect.fTop + 0.5f,
 165                    rect.fRight - 0.5f, rect.fBottom - 0.5f);
 166         fPrevRect = rect;
 167     }
 168 }
 169
 170 void GLAARectEffect::GenKey(const GrProcessor& processor, const GrGLCaps&,
 171                             GrProcessorKeyBuilder* b) {
 172     const AARectEffect& aare = processor.cast<AARectEffect>();
 173     b->add32(aare.getEdgeType());
 174 }
 175
 176 const GrBackendFragmentProcessorFactory& AARectEffect::getFactory() const {
 177     return GrTBackendFragmentProcessorFactory<AARectEffect>::getInstance();
 178 }
 179
 180 //////////////////////////////////////////////////////////////////////////////
 181
 182 class GrGLConvexPolyEffect : public GrGLFragmentProcessor {
 183 public:
 184     GrGLConvexPolyEffect(const GrBackendProcessorFactory&, const GrProcessor&);
 185
 186     virtual void emitCode(GrGLProgramBuilder* builder,
 187                           const GrFragmentProcessor& fp,
 188                           const GrProcessorKey& key,
 189                           const char* outputColor,
 190                           const char* inputColor,
 191                           const TransformedCoordsArray&,
 192                           const TextureSamplerArray&) SK_OVERRIDE;
 193
 194     static inline void GenKey(const GrProcessor&, const GrGLCaps&, GrProcessorKeyBuilder*);
 195
 196     virtual void setData(const GrGLProgramDataManager&, const GrProcessor&) SK_OVERRIDE;
 197
 198 private:
 199     GrGLProgramDataManager::UniformHandle fEdgeUniform;
 200     SkScalar                              fPrevEdges[3 * GrConvexPolyEffect::kMaxEdges];
 201     typedef GrGLFragmentProcessor INHERITED;
 202 };
 203
 204 GrGLConvexPolyEffect::GrGLConvexPolyEffect(const GrBackendProcessorFactory& factory,
 205                                            const GrProcessor&)
 206     : INHERITED (factory) {
 207     fPrevEdges[0] = SK_ScalarNaN;
 208 }
 209
 210 void GrGLConvexPolyEffect::emitCode(GrGLProgramBuilder* builder,
 211                                     const GrFragmentProcessor& fp,
 212                                     const GrProcessorKey& key,
 213                                     const char* outputColor,
 214                                     const char* inputColor,
 215                                     const TransformedCoordsArray&,
 216                                     const TextureSamplerArray& samplers) {
 217     const GrConvexPolyEffect& cpe = fp.cast<GrConvexPolyEffect>();
 218
 219     const char *edgeArrayName;
 220     fEdgeUniform = builder->addUniformArray(GrGLProgramBuilder::kFragment_Visibility,
 221                                             kVec3f_GrSLType,
 222                                             "edges",
 223                                             cpe.getEdgeCount(),
 224                                             &edgeArrayName);
 225     GrGLFragmentShaderBuilder* fsBuilder = builder->getFragmentShaderBuilder();
 226     fsBuilder->codeAppend("\t\tfloat alpha = 1.0;\n");
 227     fsBuilder->codeAppend("\t\tfloat edge;\n");
 228     const char* fragmentPos = fsBuilder->fragmentPosition();
 229     for (int i = 0; i < cpe.getEdgeCount(); ++i) {
 230         fsBuilder->codeAppendf("\t\tedge = dot(%s[%d], vec3(%s.x, %s.y, 1));\n",
 231                                edgeArrayName, i, fragmentPos, fragmentPos);
 232         if (GrProcessorEdgeTypeIsAA(cpe.getEdgeType())) {
 233             fsBuilder->codeAppend("\t\tedge = clamp(edge, 0.0, 1.0);\n");
 234         } else {
 235             fsBuilder->codeAppend("\t\tedge = edge >= 0.5 ? 1.0 : 0.0;\n");
 236         }
 237         fsBuilder->codeAppend("\t\talpha *= edge;\n");
 238     }
 239
 240     // Woe is me. See skbug.com/2149.
 241     if (kTegra2_GrGLRenderer == builder->ctxInfo().renderer()) {
 242         fsBuilder->codeAppend("\t\tif (-1.0 == alpha) {\n\t\t\tdiscard;\n\t\t}\n");
 243     }
 244
 245     if (GrProcessorEdgeTypeIsInverseFill(cpe.getEdgeType())) {
 246         fsBuilder->codeAppend("\talpha = 1.0 - alpha;\n");
 247     }
 248     fsBuilder->codeAppendf("\t%s = %s;\n", outputColor,
 249                            (GrGLSLExpr4(inputColor) * GrGLSLExpr1("alpha")).c_str());
 250 }
 251
 252 void GrGLConvexPolyEffect::setData(const GrGLProgramDataManager& pdman, const GrProcessor& effect) {
 253     const GrConvexPolyEffect& cpe = effect.cast<GrConvexPolyEffect>();
 254     size_t byteSize = 3 * cpe.getEdgeCount() * sizeof(SkScalar);
 255     if (0 != memcmp(fPrevEdges, cpe.getEdges(), byteSize)) {
 256         pdman.set3fv(fEdgeUniform, cpe.getEdgeCount(), cpe.getEdges());
 257         memcpy(fPrevEdges, cpe.getEdges(), byteSize);
 258     }
 259 }
 260
 261 void GrGLConvexPolyEffect::GenKey(const GrProcessor& processor, const GrGLCaps&,
 262                                   GrProcessorKeyBuilder* b) {
 263     const GrConvexPolyEffect& cpe = processor.cast<GrConvexPolyEffect>();
 264     GR_STATIC_ASSERT(kGrProcessorEdgeTypeCnt <= 8);
 265     uint32_t key = (cpe.getEdgeCount() << 3) | cpe.getEdgeType();
 266     b->add32(key);
 267 }
 268
 269 //////////////////////////////////////////////////////////////////////////////
 270
 271 GrFragmentProcessor* GrConvexPolyEffect::Create(GrPrimitiveEdgeType type, const SkPath& path,
 272                                                 const SkVector* offset) {
 273     if (kHairlineAA_GrProcessorEdgeType == type) {
 274         return NULL;
 275     }
 276     if (path.getSegmentMasks() != SkPath::kLine_SegmentMask ||
 277         !path.isConvex()) {
 278         return NULL;
 279     }
 280
 281     if (path.countPoints() > kMaxEdges) {
 282         return NULL;
 283     }
 284
 285     SkPoint pts[kMaxEdges];
 286     SkScalar edges[3 * kMaxEdges];
 287
 288     SkPath::Direction dir;
 289     SkAssertResult(path.cheapComputeDirection(&dir));
 290
 291     SkVector t;
 292     if (NULL == offset) {
 293         t.set(0, 0);
 294     } else {
 295         t = *offset;
 296     }
 297
 298     int count = path.getPoints(pts, kMaxEdges);
 299     int n = 0;
 300     for (int lastPt = count - 1, i = 0; i < count; lastPt = i++) {
 301         if (pts[lastPt] != pts[i]) {
 302             SkVector v = pts[i] - pts[lastPt];
 303             v.normalize();
 304             if (SkPath::kCCW_Direction == dir) {
 305                 edges[3 * n] = v.fY;
 306                 edges[3 * n + 1] = -v.fX;
 307             } else {
 308                 edges[3 * n] = -v.fY;
 309                 edges[3 * n + 1] = v.fX;
 310             }
 311             SkPoint p = pts[i] + t;
 312             edges[3 * n + 2] = -(edges[3 * n] * p.fX + edges[3 * n + 1] * p.fY);
 313             ++n;
 314         }
 315     }
 316     if (path.isInverseFillType()) {
 317         type = GrInvertProcessorEdgeType(type);
 318     }
 319     return Create(type, n, edges);
 320 }
 321
 322 GrFragmentProcessor* GrConvexPolyEffect::Create(GrPrimitiveEdgeType edgeType, const SkRect& rect) {
 323     if (kHairlineAA_GrProcessorEdgeType == edgeType){
 324         return NULL;
 325     }
 326     return AARectEffect::Create(edgeType, rect);
 327 }
 328
 329 GrConvexPolyEffect::~GrConvexPolyEffect() {}
 330
 331 void GrConvexPolyEffect::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const {
 332     *validFlags = 0;
 333 }
 334
 335 const GrBackendFragmentProcessorFactory& GrConvexPolyEffect::getFactory() const {
 336     return GrTBackendFragmentProcessorFactory<GrConvexPolyEffect>::getInstance();
 337 }
 338
 339 GrConvexPolyEffect::GrConvexPolyEffect(GrPrimitiveEdgeType edgeType, int n, const SkScalar edges[])
 340     : fEdgeType(edgeType)
 341     , fEdgeCount(n) {
 342     // Factory function should have already ensured this.
 343     SkASSERT(n <= kMaxEdges);
 344     memcpy(fEdges, edges, 3 * n * sizeof(SkScalar));
 345     // Outset the edges by 0.5 so that a pixel with center on an edge is 50% covered in the AA case
 346     // and 100% covered in the non-AA case.
 347     for (int i = 0; i < n; ++i) {
 348         fEdges[3 * i + 2] += SK_ScalarHalf;
 349     }
 350     this->setWillReadFragmentPosition();
 351 }
 352
 353 bool GrConvexPolyEffect::onIsEqual(const GrProcessor& other) const {
 354     const GrConvexPolyEffect& cpe = other.cast<GrConvexPolyEffect>();
 355     // ignore the fact that 0 == -0 and just use memcmp.
 356     return (cpe.fEdgeType == fEdgeType && cpe.fEdgeCount == fEdgeCount &&
 357             0 == memcmp(cpe.fEdges, fEdges, 3 * fEdgeCount * sizeof(SkScalar)));
 358 }
 359
 360 //////////////////////////////////////////////////////////////////////////////
 361
 362 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrConvexPolyEffect);
 363
 364 GrFragmentProcessor* GrConvexPolyEffect::TestCreate(SkRandom* random,
 365                                                     GrContext*,
 366                                                     const GrDrawTargetCaps& caps,
 367                                                     GrTexture*[]) {
 368     int count = random->nextULessThan(kMaxEdges) + 1;
 369     SkScalar edges[kMaxEdges * 3];
 370     for (int i = 0; i < 3 * count; ++i) {
 371         edges[i] = random->nextSScalar1();
 372     }
 373
 374     GrFragmentProcessor* fp;
 375     do {
 376         GrPrimitiveEdgeType edgeType = static_cast<GrPrimitiveEdgeType>(
 377                                         random->nextULessThan(kGrProcessorEdgeTypeCnt));
 378         fp = GrConvexPolyEffect::Create(edgeType, count, edges);
 379     } while (NULL == fp);
 380     return fp;
 381 }