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1 /*
2  * Copyright 2012 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 "GrGLPath.h"
9 #include "GrGLPathRendering.h"
10 #include "GrGLGpu.h"
11 #include "GrStyle.h"
12 
13 namespace {
verb_to_gl_path_cmd(SkPath::Verb verb)14 inline GrGLubyte verb_to_gl_path_cmd(SkPath::Verb verb) {
15     static const GrGLubyte gTable[] = {
16         GR_GL_MOVE_TO,
17         GR_GL_LINE_TO,
18         GR_GL_QUADRATIC_CURVE_TO,
19         GR_GL_CONIC_CURVE_TO,
20         GR_GL_CUBIC_CURVE_TO,
21         GR_GL_CLOSE_PATH,
22     };
23     GR_STATIC_ASSERT(0 == SkPath::kMove_Verb);
24     GR_STATIC_ASSERT(1 == SkPath::kLine_Verb);
25     GR_STATIC_ASSERT(2 == SkPath::kQuad_Verb);
26     GR_STATIC_ASSERT(3 == SkPath::kConic_Verb);
27     GR_STATIC_ASSERT(4 == SkPath::kCubic_Verb);
28     GR_STATIC_ASSERT(5 == SkPath::kClose_Verb);
29 
30     SkASSERT(verb >= 0 && (size_t)verb < SK_ARRAY_COUNT(gTable));
31     return gTable[verb];
32 }
33 
34 #ifdef SK_DEBUG
num_coords(SkPath::Verb verb)35 inline int num_coords(SkPath::Verb verb) {
36     static const int gTable[] = {
37         2, // move
38         2, // line
39         4, // quad
40         5, // conic
41         6, // cubic
42         0, // close
43     };
44     GR_STATIC_ASSERT(0 == SkPath::kMove_Verb);
45     GR_STATIC_ASSERT(1 == SkPath::kLine_Verb);
46     GR_STATIC_ASSERT(2 == SkPath::kQuad_Verb);
47     GR_STATIC_ASSERT(3 == SkPath::kConic_Verb);
48     GR_STATIC_ASSERT(4 == SkPath::kCubic_Verb);
49     GR_STATIC_ASSERT(5 == SkPath::kClose_Verb);
50 
51     SkASSERT(verb >= 0 && (size_t)verb < SK_ARRAY_COUNT(gTable));
52     return gTable[verb];
53 }
54 #endif
55 
join_to_gl_join(SkPaint::Join join)56 inline GrGLenum join_to_gl_join(SkPaint::Join join) {
57     static GrGLenum gSkJoinsToGrGLJoins[] = {
58         GR_GL_MITER_REVERT,
59         GR_GL_ROUND,
60         GR_GL_BEVEL
61     };
62     return gSkJoinsToGrGLJoins[join];
63     GR_STATIC_ASSERT(0 == SkPaint::kMiter_Join);
64     GR_STATIC_ASSERT(1 == SkPaint::kRound_Join);
65     GR_STATIC_ASSERT(2 == SkPaint::kBevel_Join);
66     GR_STATIC_ASSERT(SK_ARRAY_COUNT(gSkJoinsToGrGLJoins) == SkPaint::kJoinCount);
67 }
68 
cap_to_gl_cap(SkPaint::Cap cap)69 inline GrGLenum cap_to_gl_cap(SkPaint::Cap cap) {
70     static GrGLenum gSkCapsToGrGLCaps[] = {
71         GR_GL_FLAT,
72         GR_GL_ROUND,
73         GR_GL_SQUARE
74     };
75     return gSkCapsToGrGLCaps[cap];
76     GR_STATIC_ASSERT(0 == SkPaint::kButt_Cap);
77     GR_STATIC_ASSERT(1 == SkPaint::kRound_Cap);
78     GR_STATIC_ASSERT(2 == SkPaint::kSquare_Cap);
79     GR_STATIC_ASSERT(SK_ARRAY_COUNT(gSkCapsToGrGLCaps) == SkPaint::kCapCount);
80 }
81 
82 #ifdef SK_DEBUG
verify_floats(const float * floats,int count)83 inline void verify_floats(const float* floats, int count) {
84     for (int i = 0; i < count; ++i) {
85         SkASSERT(!SkScalarIsNaN(SkFloatToScalar(floats[i])));
86     }
87 }
88 #endif
89 
points_to_coords(const SkPoint points[],size_t first_point,size_t amount,GrGLfloat coords[])90 inline void points_to_coords(const SkPoint points[], size_t first_point, size_t amount,
91                              GrGLfloat coords[]) {
92     for (size_t i = 0;  i < amount; ++i) {
93         coords[i * 2] =  SkScalarToFloat(points[first_point + i].fX);
94         coords[i * 2 + 1] = SkScalarToFloat(points[first_point + i].fY);
95     }
96 }
97 
98 template<bool checkForDegenerates>
init_path_object_for_general_path(GrGLGpu * gpu,GrGLuint pathID,const SkPath & skPath)99 inline bool init_path_object_for_general_path(GrGLGpu* gpu, GrGLuint pathID,
100                                               const SkPath& skPath) {
101     SkDEBUGCODE(int numCoords = 0);
102     int verbCnt = skPath.countVerbs();
103     int pointCnt = skPath.countPoints();
104     int minCoordCnt = pointCnt * 2;
105 
106     SkSTArray<16, GrGLubyte, true> pathCommands(verbCnt);
107     SkSTArray<16, GrGLfloat, true> pathCoords(minCoordCnt);
108     bool lastVerbWasMove = true; // A path with just "close;" means "moveto(0,0); close;"
109     SkPoint points[4];
110     SkPath::RawIter iter(skPath);
111     SkPath::Verb verb;
112     while ((verb = iter.next(points)) != SkPath::kDone_Verb) {
113         pathCommands.push_back(verb_to_gl_path_cmd(verb));
114         GrGLfloat coords[6];
115         int coordsForVerb;
116         switch (verb) {
117             case SkPath::kMove_Verb:
118                 if (checkForDegenerates) {
119                     lastVerbWasMove = true;
120                 }
121                 points_to_coords(points, 0, 1, coords);
122                 coordsForVerb = 2;
123                 break;
124             case SkPath::kLine_Verb:
125                 if (checkForDegenerates) {
126                     if (SkPath::IsLineDegenerate(points[0], points[1], true)) {
127                         return false;
128                     }
129                     lastVerbWasMove = false;
130                 }
131 
132                 points_to_coords(points, 1, 1, coords);
133                 coordsForVerb = 2;
134                 break;
135             case SkPath::kConic_Verb:
136                 if (checkForDegenerates) {
137                     if (SkPath::IsQuadDegenerate(points[0], points[1], points[2], true)) {
138                         return false;
139                     }
140                     lastVerbWasMove = false;
141                 }
142                 points_to_coords(points, 1, 2, coords);
143                 coords[4] = SkScalarToFloat(iter.conicWeight());
144                 coordsForVerb = 5;
145                 break;
146             case SkPath::kQuad_Verb:
147                 if (checkForDegenerates) {
148                     if (SkPath::IsQuadDegenerate(points[0], points[1], points[2], true)) {
149                         return false;
150                     }
151                     lastVerbWasMove = false;
152                 }
153                 points_to_coords(points, 1, 2, coords);
154                 coordsForVerb = 4;
155                 break;
156             case SkPath::kCubic_Verb:
157                 if (checkForDegenerates) {
158                     if (SkPath::IsCubicDegenerate(points[0], points[1], points[2], points[3],
159                                                   true)) {
160                         return false;
161                     }
162                     lastVerbWasMove = false;
163                 }
164                 points_to_coords(points, 1, 3, coords);
165                 coordsForVerb = 6;
166                 break;
167             case SkPath::kClose_Verb:
168                 if (checkForDegenerates) {
169                     if (lastVerbWasMove) {
170                         // Interpret "move(x,y);close;" as "move(x,y);lineto(x,y);close;".
171                         // which produces a degenerate segment.
172                         return false;
173                     }
174                 }
175                 continue;
176             default:
177                 SkASSERT(false);  // Not reached.
178                 continue;
179         }
180         SkDEBUGCODE(numCoords += num_coords(verb));
181         SkDEBUGCODE(verify_floats(coords, coordsForVerb));
182         pathCoords.push_back_n(coordsForVerb, coords);
183     }
184     SkASSERT(verbCnt == pathCommands.count());
185     SkASSERT(numCoords == pathCoords.count());
186 
187     GR_GL_CALL(gpu->glInterface(),
188                PathCommands(pathID, pathCommands.count(), pathCommands.begin(),
189                             pathCoords.count(), GR_GL_FLOAT, pathCoords.begin()));
190     return true;
191 }
192 
193 /*
194  * For now paths only natively support winding and even odd fill types
195  */
convert_skpath_filltype(SkPath::FillType fill)196 static GrPathRendering::FillType convert_skpath_filltype(SkPath::FillType fill) {
197     switch (fill) {
198         default:
199             SK_ABORT("Incomplete Switch\n");
200         case SkPath::kWinding_FillType:
201         case SkPath::kInverseWinding_FillType:
202             return GrPathRendering::kWinding_FillType;
203         case SkPath::kEvenOdd_FillType:
204         case SkPath::kInverseEvenOdd_FillType:
205             return GrPathRendering::kEvenOdd_FillType;
206     }
207 }
208 
209 } // namespace
210 
InitPathObjectPathDataCheckingDegenerates(GrGLGpu * gpu,GrGLuint pathID,const SkPath & skPath)211 bool GrGLPath::InitPathObjectPathDataCheckingDegenerates(GrGLGpu* gpu, GrGLuint pathID,
212                                                          const SkPath& skPath) {
213     return init_path_object_for_general_path<true>(gpu, pathID, skPath);
214 }
215 
InitPathObjectPathData(GrGLGpu * gpu,GrGLuint pathID,const SkPath & skPath)216 void GrGLPath::InitPathObjectPathData(GrGLGpu* gpu,
217                                       GrGLuint pathID,
218                                       const SkPath& skPath) {
219     SkASSERT(!skPath.isEmpty());
220 
221 #if 1  //  SK_SCALAR_IS_FLOAT
222     // This branch does type punning, converting SkPoint* to GrGLfloat*.
223     if ((skPath.getSegmentMasks() & SkPath::kConic_SegmentMask) == 0) {
224         int verbCnt = skPath.countVerbs();
225         int pointCnt = skPath.countPoints();
226         int coordCnt = pointCnt * 2;
227         SkSTArray<16, GrGLubyte, true> pathCommands(verbCnt);
228         SkSTArray<16, GrGLfloat, true> pathCoords(coordCnt);
229 
230         static_assert(sizeof(SkPoint) == sizeof(GrGLfloat) * 2, "sk_point_not_two_floats");
231 
232         pathCommands.resize_back(verbCnt);
233         pathCoords.resize_back(coordCnt);
234         skPath.getPoints(reinterpret_cast<SkPoint*>(&pathCoords[0]), pointCnt);
235         skPath.getVerbs(&pathCommands[0], verbCnt);
236 
237         SkDEBUGCODE(int verbCoordCnt = 0);
238         for (int i = 0; i < verbCnt; ++i) {
239             SkPath::Verb v = static_cast<SkPath::Verb>(pathCommands[i]);
240             pathCommands[i] = verb_to_gl_path_cmd(v);
241             SkDEBUGCODE(verbCoordCnt += num_coords(v));
242         }
243         SkASSERT(verbCnt == pathCommands.count());
244         SkASSERT(verbCoordCnt == pathCoords.count());
245         SkDEBUGCODE(verify_floats(&pathCoords[0], pathCoords.count()));
246         GR_GL_CALL(gpu->glInterface(), PathCommands(pathID, pathCommands.count(), &pathCommands[0],
247                                                     pathCoords.count(), GR_GL_FLOAT,
248                                                     &pathCoords[0]));
249         return;
250     }
251 #endif
252     SkAssertResult(init_path_object_for_general_path<false>(gpu, pathID, skPath));
253 }
254 
InitPathObjectStroke(GrGLGpu * gpu,GrGLuint pathID,const SkStrokeRec & stroke)255 void GrGLPath::InitPathObjectStroke(GrGLGpu* gpu, GrGLuint pathID, const SkStrokeRec& stroke) {
256     SkASSERT(!stroke.isHairlineStyle());
257     GR_GL_CALL(gpu->glInterface(),
258                PathParameterf(pathID, GR_GL_PATH_STROKE_WIDTH, SkScalarToFloat(stroke.getWidth())));
259     GR_GL_CALL(gpu->glInterface(),
260                PathParameterf(pathID, GR_GL_PATH_MITER_LIMIT, SkScalarToFloat(stroke.getMiter())));
261     GrGLenum join = join_to_gl_join(stroke.getJoin());
262     GR_GL_CALL(gpu->glInterface(), PathParameteri(pathID, GR_GL_PATH_JOIN_STYLE, join));
263     GrGLenum cap = cap_to_gl_cap(stroke.getCap());
264     GR_GL_CALL(gpu->glInterface(), PathParameteri(pathID, GR_GL_PATH_END_CAPS, cap));
265     GR_GL_CALL(gpu->glInterface(), PathParameterf(pathID, GR_GL_PATH_STROKE_BOUND, 0.02f));
266 }
267 
InitPathObjectEmptyPath(GrGLGpu * gpu,GrGLuint pathID)268 void GrGLPath::InitPathObjectEmptyPath(GrGLGpu* gpu, GrGLuint pathID) {
269     GR_GL_CALL(gpu->glInterface(), PathCommands(pathID, 0, nullptr, 0, GR_GL_FLOAT, nullptr));
270 }
271 
GrGLPath(GrGLGpu * gpu,const SkPath & origSkPath,const GrStyle & style)272 GrGLPath::GrGLPath(GrGLGpu* gpu, const SkPath& origSkPath, const GrStyle& style)
273     : INHERITED(gpu, origSkPath, style),
274       fPathID(gpu->glPathRendering()->genPaths(1)) {
275 
276     if (origSkPath.isEmpty()) {
277         InitPathObjectEmptyPath(gpu, fPathID);
278         fShouldStroke = false;
279         fShouldFill = false;
280     } else {
281         const SkPath* skPath = &origSkPath;
282         SkTLazy<SkPath> tmpPath;
283         SkStrokeRec stroke(SkStrokeRec::kFill_InitStyle);
284 
285         if (style.pathEffect()) {
286             // Skia stroking and NVPR stroking differ with respect to dashing
287             // pattern.
288             // Convert a dashing (or other path effect) to either a stroke or a fill.
289             if (style.applyPathEffectToPath(tmpPath.init(), &stroke, *skPath, SK_Scalar1)) {
290                 skPath = tmpPath.get();
291             }
292         } else {
293             stroke = style.strokeRec();
294         }
295 
296         bool didInit = false;
297         if (stroke.needToApply() && stroke.getCap() != SkPaint::kButt_Cap) {
298             // Skia stroking and NVPR stroking differ with respect to stroking
299             // end caps of empty subpaths.
300             // Convert stroke to fill if path contains empty subpaths.
301             didInit = InitPathObjectPathDataCheckingDegenerates(gpu, fPathID, *skPath);
302             if (!didInit) {
303                 if (!tmpPath.isValid()) {
304                     tmpPath.init();
305                 }
306                 SkAssertResult(stroke.applyToPath(tmpPath.get(), *skPath));
307                 skPath = tmpPath.get();
308                 stroke.setFillStyle();
309             }
310         }
311 
312         if (!didInit) {
313             InitPathObjectPathData(gpu, fPathID, *skPath);
314         }
315 
316         fShouldStroke = stroke.needToApply();
317         fShouldFill = stroke.isFillStyle() ||
318                 stroke.getStyle() == SkStrokeRec::kStrokeAndFill_Style;
319 
320         fFillType = convert_skpath_filltype(skPath->getFillType());
321         fBounds = skPath->getBounds();
322         SkScalar radius = stroke.getInflationRadius();
323         fBounds.outset(radius, radius);
324         if (fShouldStroke) {
325             InitPathObjectStroke(gpu, fPathID, stroke);
326         }
327     }
328 
329     this->registerWithCache(SkBudgeted::kYes);
330 }
331 
onRelease()332 void GrGLPath::onRelease() {
333     if (0 != fPathID) {
334         static_cast<GrGLGpu*>(this->getGpu())->glPathRendering()->deletePaths(fPathID, 1);
335         fPathID = 0;
336     }
337 
338     INHERITED::onRelease();
339 }
340 
onAbandon()341 void GrGLPath::onAbandon() {
342     fPathID = 0;
343 
344     INHERITED::onAbandon();
345 }
346