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 "GrConvexPolyEffect.h"
9 #include "SkPathPriv.h"
10 #include "effects/GrConstColorProcessor.h"
11 #include "glsl/GrGLSLFragmentProcessor.h"
12 #include "glsl/GrGLSLFragmentShaderBuilder.h"
13 #include "glsl/GrGLSLProgramDataManager.h"
14 #include "glsl/GrGLSLUniformHandler.h"
15 #include "../private/GrGLSL.h"
16 
17 //////////////////////////////////////////////////////////////////////////////
18 class AARectEffect : public GrFragmentProcessor {
19 public:
getRect() const20     const SkRect& getRect() const { return fRect; }
21 
Make(GrPrimitiveEdgeType edgeType,const SkRect & rect)22     static sk_sp<GrFragmentProcessor> Make(GrPrimitiveEdgeType edgeType, const SkRect& rect) {
23         return sk_sp<GrFragmentProcessor>(new AARectEffect(edgeType, rect));
24     }
25 
getEdgeType() const26     GrPrimitiveEdgeType getEdgeType() const { return fEdgeType; }
27 
name() const28     const char* name() const override { return "AARect"; }
29 
30     void onGetGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder*) const override;
31 
32 private:
AARectEffect(GrPrimitiveEdgeType edgeType,const SkRect & rect)33     AARectEffect(GrPrimitiveEdgeType edgeType, const SkRect& rect)
34             : INHERITED(kCompatibleWithCoverageAsAlpha_OptimizationFlag)
35             , fRect(rect)
36             , fEdgeType(edgeType) {
37         this->initClassID<AARectEffect>();
38     }
39 
40     GrGLSLFragmentProcessor* onCreateGLSLInstance() const override;
41 
onIsEqual(const GrFragmentProcessor & other) const42     bool onIsEqual(const GrFragmentProcessor& other) const override {
43         const AARectEffect& aare = other.cast<AARectEffect>();
44         return fRect == aare.fRect;
45     }
46 
47     SkRect              fRect;
48     GrPrimitiveEdgeType fEdgeType;
49 
50     typedef GrFragmentProcessor INHERITED;
51 
52     GR_DECLARE_FRAGMENT_PROCESSOR_TEST;
53 
54 };
55 
56 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(AARectEffect);
57 
58 #if GR_TEST_UTILS
TestCreate(GrProcessorTestData * d)59 sk_sp<GrFragmentProcessor> AARectEffect::TestCreate(GrProcessorTestData* d) {
60     SkRect rect = SkRect::MakeLTRB(d->fRandom->nextSScalar1(),
61                                    d->fRandom->nextSScalar1(),
62                                    d->fRandom->nextSScalar1(),
63                                    d->fRandom->nextSScalar1());
64     sk_sp<GrFragmentProcessor> fp;
65     do {
66         GrPrimitiveEdgeType edgeType = static_cast<GrPrimitiveEdgeType>(
67                 d->fRandom->nextULessThan(kGrProcessorEdgeTypeCnt));
68 
69         fp = AARectEffect::Make(edgeType, rect);
70     } while (nullptr == fp);
71     return fp;
72 }
73 #endif
74 
75 //////////////////////////////////////////////////////////////////////////////
76 
77 class GLAARectEffect : public GrGLSLFragmentProcessor {
78 public:
GLAARectEffect()79     GLAARectEffect() {
80         fPrevRect.fLeft = SK_ScalarNaN;
81     }
82 
83     void emitCode(EmitArgs&) override;
84 
85     static inline void GenKey(const GrProcessor&, const GrShaderCaps&, GrProcessorKeyBuilder*);
86 
87 protected:
88     void onSetData(const GrGLSLProgramDataManager&, const GrProcessor&) override;
89 
90 private:
91     GrGLSLProgramDataManager::UniformHandle fRectUniform;
92     SkRect                                  fPrevRect;
93 
94     typedef GrGLSLFragmentProcessor INHERITED;
95 };
96 
emitCode(EmitArgs & args)97 void GLAARectEffect::emitCode(EmitArgs& args) {
98     const AARectEffect& aare = args.fFp.cast<AARectEffect>();
99     const char *rectName;
100     // The rect uniform's xyzw refer to (left + 0.5, top + 0.5, right - 0.5, bottom - 0.5),
101     // respectively.
102     fRectUniform = args.fUniformHandler->addUniform(kFragment_GrShaderFlag,
103                                                     kVec4f_GrSLType,
104                                                     kDefault_GrSLPrecision,
105                                                     "rect",
106                                                     &rectName);
107 
108     GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
109     if (GrProcessorEdgeTypeIsAA(aare.getEdgeType())) {
110         // The amount of coverage removed in x and y by the edges is computed as a pair of negative
111         // numbers, xSub and ySub.
112         fragBuilder->codeAppend("\t\tfloat xSub, ySub;\n");
113         fragBuilder->codeAppendf("\t\txSub = min(sk_FragCoord.x - %s.x, 0.0);\n", rectName);
114         fragBuilder->codeAppendf("\t\txSub += min(%s.z - sk_FragCoord.x, 0.0);\n", rectName);
115         fragBuilder->codeAppendf("\t\tySub = min(sk_FragCoord.y - %s.y, 0.0);\n", rectName);
116         fragBuilder->codeAppendf("\t\tySub += min(%s.w - sk_FragCoord.y, 0.0);\n", rectName);
117         // Now compute coverage in x and y and multiply them to get the fraction of the pixel
118         // covered.
119         fragBuilder->codeAppendf("\t\tfloat alpha = (1.0 + max(xSub, -1.0)) * (1.0 + max(ySub, -1.0));\n");
120     } else {
121         fragBuilder->codeAppendf("\t\tfloat alpha = 1.0;\n");
122         fragBuilder->codeAppendf("\t\talpha *= (sk_FragCoord.x - %s.x) > -0.5 ? 1.0 : 0.0;\n",
123                                  rectName);
124         fragBuilder->codeAppendf("\t\talpha *= (%s.z - sk_FragCoord.x) > -0.5 ? 1.0 : 0.0;\n",
125                                  rectName);
126         fragBuilder->codeAppendf("\t\talpha *= (sk_FragCoord.y - %s.y) > -0.5 ? 1.0 : 0.0;\n",
127                                  rectName);
128         fragBuilder->codeAppendf("\t\talpha *= (%s.w - sk_FragCoord.y) > -0.5 ? 1.0 : 0.0;\n",
129                                  rectName);
130     }
131 
132     if (GrProcessorEdgeTypeIsInverseFill(aare.getEdgeType())) {
133         fragBuilder->codeAppend("\t\talpha = 1.0 - alpha;\n");
134     }
135     fragBuilder->codeAppendf("\t\t%s = %s;\n", args.fOutputColor,
136                              (GrGLSLExpr4(args.fInputColor) * GrGLSLExpr1("alpha")).c_str());
137 }
138 
onSetData(const GrGLSLProgramDataManager & pdman,const GrProcessor & processor)139 void GLAARectEffect::onSetData(const GrGLSLProgramDataManager& pdman,
140                                const GrProcessor& processor) {
141     const AARectEffect& aare = processor.cast<AARectEffect>();
142     const SkRect& rect = aare.getRect();
143     if (rect != fPrevRect) {
144         pdman.set4f(fRectUniform, rect.fLeft + 0.5f, rect.fTop + 0.5f,
145                    rect.fRight - 0.5f, rect.fBottom - 0.5f);
146         fPrevRect = rect;
147     }
148 }
149 
GenKey(const GrProcessor & processor,const GrShaderCaps &,GrProcessorKeyBuilder * b)150 void GLAARectEffect::GenKey(const GrProcessor& processor, const GrShaderCaps&,
151                             GrProcessorKeyBuilder* b) {
152     const AARectEffect& aare = processor.cast<AARectEffect>();
153     b->add32(aare.getEdgeType());
154 }
155 
onGetGLSLProcessorKey(const GrShaderCaps & caps,GrProcessorKeyBuilder * b) const156 void AARectEffect::onGetGLSLProcessorKey(const GrShaderCaps& caps, GrProcessorKeyBuilder* b) const {
157     GLAARectEffect::GenKey(*this, caps, b);
158 }
159 
onCreateGLSLInstance() const160 GrGLSLFragmentProcessor* AARectEffect::onCreateGLSLInstance() const  {
161     return new GLAARectEffect;
162 }
163 
164 //////////////////////////////////////////////////////////////////////////////
165 
166 class GrGLConvexPolyEffect : public GrGLSLFragmentProcessor {
167 public:
GrGLConvexPolyEffect()168     GrGLConvexPolyEffect() {
169         for (size_t i = 0; i < SK_ARRAY_COUNT(fPrevEdges); ++i) {
170             fPrevEdges[i] = SK_ScalarNaN;
171         }
172     }
173 
174     void emitCode(EmitArgs&) override;
175 
176     static inline void GenKey(const GrProcessor&, const GrShaderCaps&, GrProcessorKeyBuilder*);
177 
178 protected:
179     void onSetData(const GrGLSLProgramDataManager&, const GrProcessor&) override;
180 
181 private:
182     GrGLSLProgramDataManager::UniformHandle fEdgeUniform;
183     SkScalar                                fPrevEdges[3 * GrConvexPolyEffect::kMaxEdges];
184     typedef GrGLSLFragmentProcessor INHERITED;
185 };
186 
emitCode(EmitArgs & args)187 void GrGLConvexPolyEffect::emitCode(EmitArgs& args) {
188     const GrConvexPolyEffect& cpe = args.fFp.cast<GrConvexPolyEffect>();
189 
190     const char *edgeArrayName;
191     fEdgeUniform = args.fUniformHandler->addUniformArray(kFragment_GrShaderFlag,
192                                                          kVec3f_GrSLType,
193                                                          kDefault_GrSLPrecision,
194                                                          "edges",
195                                                          cpe.getEdgeCount(),
196                                                          &edgeArrayName);
197     GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
198     fragBuilder->codeAppend("\t\tfloat alpha = 1.0;\n");
199     fragBuilder->codeAppend("\t\tfloat edge;\n");
200     for (int i = 0; i < cpe.getEdgeCount(); ++i) {
201         fragBuilder->codeAppendf("\t\tedge = dot(%s[%d], vec3(sk_FragCoord.x, sk_FragCoord.y, "
202                                                              "1));\n",
203                                  edgeArrayName, i);
204         if (GrProcessorEdgeTypeIsAA(cpe.getEdgeType())) {
205             fragBuilder->codeAppend("\t\tedge = clamp(edge, 0.0, 1.0);\n");
206         } else {
207             fragBuilder->codeAppend("\t\tedge = edge >= 0.5 ? 1.0 : 0.0;\n");
208         }
209         fragBuilder->codeAppend("\t\talpha *= edge;\n");
210     }
211 
212     if (GrProcessorEdgeTypeIsInverseFill(cpe.getEdgeType())) {
213         fragBuilder->codeAppend("\talpha = 1.0 - alpha;\n");
214     }
215     fragBuilder->codeAppendf("\t%s = %s;\n", args.fOutputColor,
216                              (GrGLSLExpr4(args.fInputColor) * GrGLSLExpr1("alpha")).c_str());
217 }
218 
onSetData(const GrGLSLProgramDataManager & pdman,const GrProcessor & effect)219 void GrGLConvexPolyEffect::onSetData(const GrGLSLProgramDataManager& pdman,
220                                      const GrProcessor& effect) {
221     const GrConvexPolyEffect& cpe = effect.cast<GrConvexPolyEffect>();
222     size_t byteSize = 3 * cpe.getEdgeCount() * sizeof(SkScalar);
223     if (0 != memcmp(fPrevEdges, cpe.getEdges(), byteSize)) {
224         pdman.set3fv(fEdgeUniform, cpe.getEdgeCount(), cpe.getEdges());
225         memcpy(fPrevEdges, cpe.getEdges(), byteSize);
226     }
227 }
228 
GenKey(const GrProcessor & processor,const GrShaderCaps &,GrProcessorKeyBuilder * b)229 void GrGLConvexPolyEffect::GenKey(const GrProcessor& processor, const GrShaderCaps&,
230                                   GrProcessorKeyBuilder* b) {
231     const GrConvexPolyEffect& cpe = processor.cast<GrConvexPolyEffect>();
232     GR_STATIC_ASSERT(kGrProcessorEdgeTypeCnt <= 8);
233     uint32_t key = (cpe.getEdgeCount() << 3) | cpe.getEdgeType();
234     b->add32(key);
235 }
236 
237 //////////////////////////////////////////////////////////////////////////////
238 
Make(GrPrimitiveEdgeType type,const SkPath & path)239 sk_sp<GrFragmentProcessor> GrConvexPolyEffect::Make(GrPrimitiveEdgeType type, const SkPath& path) {
240     if (kHairlineAA_GrProcessorEdgeType == type) {
241         return nullptr;
242     }
243     if (path.getSegmentMasks() != SkPath::kLine_SegmentMask ||
244         !path.isConvex()) {
245         return nullptr;
246     }
247 
248     SkPathPriv::FirstDirection dir;
249     // The only way this should fail is if the clip is effectively a infinitely thin line. In that
250     // case nothing is inside the clip. It'd be nice to detect this at a higher level and either
251     // skip the draw or omit the clip element.
252     if (!SkPathPriv::CheapComputeFirstDirection(path, &dir)) {
253         if (GrProcessorEdgeTypeIsInverseFill(type)) {
254             return GrConstColorProcessor::Make(GrColor4f::OpaqueWhite(),
255                                                GrConstColorProcessor::kModulateRGBA_InputMode);
256         }
257         // This could use kIgnore instead of kModulateRGBA but it would trigger a debug print
258         // about a coverage processor not being compatible with the alpha-as-coverage optimization.
259         // We don't really care about this unlikely case so we just use kModulateRGBA to suppress
260         // the print.
261         return GrConstColorProcessor::Make(GrColor4f::TransparentBlack(),
262                                            GrConstColorProcessor::kModulateRGBA_InputMode);
263     }
264 
265     SkScalar        edges[3 * kMaxEdges];
266     SkPoint         pts[4];
267     SkPath::Verb    verb;
268     SkPath::Iter    iter(path, true);
269 
270     // SkPath considers itself convex so long as there is a convex contour within it,
271     // regardless of any degenerate contours such as a string of moveTos before it.
272     // Iterate here to consume any degenerate contours and only process the points
273     // on the actual convex contour.
274     int n = 0;
275     while ((verb = iter.next(pts, true, true)) != SkPath::kDone_Verb) {
276         switch (verb) {
277             case SkPath::kMove_Verb:
278                 SkASSERT(n == 0);
279             case SkPath::kClose_Verb:
280                 break;
281             case SkPath::kLine_Verb: {
282                 if (n >= kMaxEdges) {
283                     return nullptr;
284                 }
285                 SkVector v = pts[1] - pts[0];
286                 v.normalize();
287                 if (SkPathPriv::kCCW_FirstDirection == dir) {
288                     edges[3 * n] = v.fY;
289                     edges[3 * n + 1] = -v.fX;
290                 } else {
291                     edges[3 * n] = -v.fY;
292                     edges[3 * n + 1] = v.fX;
293                 }
294                 edges[3 * n + 2] = -(edges[3 * n] * pts[1].fX + edges[3 * n + 1] * pts[1].fY);
295                 ++n;
296                 break;
297             }
298             default:
299                 return nullptr;
300         }
301     }
302 
303     if (path.isInverseFillType()) {
304         type = GrInvertProcessorEdgeType(type);
305     }
306     return Make(type, n, edges);
307 }
308 
Make(GrPrimitiveEdgeType edgeType,const SkRect & rect)309 sk_sp<GrFragmentProcessor> GrConvexPolyEffect::Make(GrPrimitiveEdgeType edgeType,
310                                                     const SkRect& rect) {
311     if (kHairlineAA_GrProcessorEdgeType == edgeType){
312         return nullptr;
313     }
314     return AARectEffect::Make(edgeType, rect);
315 }
316 
~GrConvexPolyEffect()317 GrConvexPolyEffect::~GrConvexPolyEffect() {}
318 
onGetGLSLProcessorKey(const GrShaderCaps & caps,GrProcessorKeyBuilder * b) const319 void GrConvexPolyEffect::onGetGLSLProcessorKey(const GrShaderCaps& caps,
320                                                GrProcessorKeyBuilder* b) const {
321     GrGLConvexPolyEffect::GenKey(*this, caps, b);
322 }
323 
onCreateGLSLInstance() const324 GrGLSLFragmentProcessor* GrConvexPolyEffect::onCreateGLSLInstance() const  {
325     return new GrGLConvexPolyEffect;
326 }
327 
GrConvexPolyEffect(GrPrimitiveEdgeType edgeType,int n,const SkScalar edges[])328 GrConvexPolyEffect::GrConvexPolyEffect(GrPrimitiveEdgeType edgeType, int n, const SkScalar edges[])
329         : INHERITED(kCompatibleWithCoverageAsAlpha_OptimizationFlag)
330         , fEdgeType(edgeType)
331         , fEdgeCount(n) {
332     this->initClassID<GrConvexPolyEffect>();
333     // Factory function should have already ensured this.
334     SkASSERT(n <= kMaxEdges);
335     memcpy(fEdges, edges, 3 * n * sizeof(SkScalar));
336     // Outset the edges by 0.5 so that a pixel with center on an edge is 50% covered in the AA case
337     // and 100% covered in the non-AA case.
338     for (int i = 0; i < n; ++i) {
339         fEdges[3 * i + 2] += SK_ScalarHalf;
340     }
341 }
342 
onIsEqual(const GrFragmentProcessor & other) const343 bool GrConvexPolyEffect::onIsEqual(const GrFragmentProcessor& other) const {
344     const GrConvexPolyEffect& cpe = other.cast<GrConvexPolyEffect>();
345     // ignore the fact that 0 == -0 and just use memcmp.
346     return (cpe.fEdgeType == fEdgeType && cpe.fEdgeCount == fEdgeCount &&
347             0 == memcmp(cpe.fEdges, fEdges, 3 * fEdgeCount * sizeof(SkScalar)));
348 }
349 
350 //////////////////////////////////////////////////////////////////////////////
351 
352 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrConvexPolyEffect);
353 
354 #if GR_TEST_UTILS
TestCreate(GrProcessorTestData * d)355 sk_sp<GrFragmentProcessor> GrConvexPolyEffect::TestCreate(GrProcessorTestData* d) {
356     int count = d->fRandom->nextULessThan(kMaxEdges) + 1;
357     SkScalar edges[kMaxEdges * 3];
358     for (int i = 0; i < 3 * count; ++i) {
359         edges[i] = d->fRandom->nextSScalar1();
360     }
361 
362     sk_sp<GrFragmentProcessor> fp;
363     do {
364         GrPrimitiveEdgeType edgeType = static_cast<GrPrimitiveEdgeType>(
365                 d->fRandom->nextULessThan(kGrProcessorEdgeTypeCnt));
366         fp = GrConvexPolyEffect::Make(edgeType, count, edges);
367     } while (nullptr == fp);
368     return fp;
369 }
370 #endif
371