aboutsummaryrefslogtreecommitdiffhomepage
path: root/src/gpu/GrStencil.cpp
blob: 767726084cffac43c3fb3ceca1e4a1f66d0e7ea4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395

/*
 * Copyright 2011 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */


#include "GrStencil.h"

////////////////////////////////////////////////////////////////////////////////
// Stencil Rules for Merging user stencil space into clip

// We can't include the clip bit in the ref or mask values because the division
// between user and clip bits in the stencil depends on the number of stencil
// bits in the runtime. Comments below indicate what the code should do to
// incorporate the clip bit into these settings.

///////
// Replace

// set the ref to be the clip bit, but mask it out for the test
GR_STATIC_CONST_SAME_STENCIL(gUserToClipReplace,
    kReplace_StencilOp,
    kZero_StencilOp,
    kLess_StencilFunc,
    0xffff,           // unset clip bit
    0x0000,           // set clip bit
    0xffff);

GR_STATIC_CONST_SAME_STENCIL(gInvUserToClipReplace,
    kReplace_StencilOp,
    kZero_StencilOp,
    kEqual_StencilFunc,
    0xffff,           // unset clip bit
    0x0000,           // set clip bit
    0xffff);

///////
// Intersect
GR_STATIC_CONST_SAME_STENCIL(gUserToClipIsect,
    kReplace_StencilOp,
    kZero_StencilOp,
    kLess_StencilFunc,
    0xffff,
    0x0000,           // set clip bit
    0xffff);

GR_STATIC_CONST_SAME_STENCIL(gInvUserToClipIsect,
    kReplace_StencilOp,
    kZero_StencilOp,
    kEqual_StencilFunc,
    0xffff,
    0x0000,           // set clip bit
    0xffff);

///////
// Difference
GR_STATIC_CONST_SAME_STENCIL(gUserToClipDiff,
    kReplace_StencilOp,
    kZero_StencilOp,
    kEqual_StencilFunc,
    0xffff,
    0x0000,           // set clip bit
    0xffff);

GR_STATIC_CONST_SAME_STENCIL(gInvUserToClipDiff,
    kReplace_StencilOp,
    kZero_StencilOp,
    kLess_StencilFunc,
    0xffff,
    0x0000,           // set clip bit
    0xffff);

///////
// Union

// first pass makes all the passing cases >= just clip bit set.
GR_STATIC_CONST_SAME_STENCIL(gUserToClipUnionPass0,
    kReplace_StencilOp,
    kKeep_StencilOp,
    kLEqual_StencilFunc,
    0xffff,
    0x0001,           // set clip bit
    0xffff);

// second pass allows anything greater than just clip bit set to pass
GR_STATIC_CONST_SAME_STENCIL(gUserToClipUnionPass1,
    kReplace_StencilOp,
    kZero_StencilOp,
    kLEqual_StencilFunc,
    0xffff,
    0x0000,           // set clip bit
    0xffff);

// first pass finds zeros in the user bits and if found sets
// the clip bit to 1
GR_STATIC_CONST_SAME_STENCIL(gInvUserToClipUnionPass0,
    kReplace_StencilOp,
    kKeep_StencilOp,
    kEqual_StencilFunc,
    0xffff,
    0x0000,           // set clip bit
    0x0000            // set clip bit
);

// second pass zeros the user bits
GR_STATIC_CONST_SAME_STENCIL(gInvUserToClipUnionPass1,
    kZero_StencilOp,
    kZero_StencilOp,
    kLess_StencilFunc,
    0xffff,
    0x0000,
    0xffff            // unset clip bit
);

///////
// Xor
GR_STATIC_CONST_SAME_STENCIL(gUserToClipXorPass0,
    kInvert_StencilOp,
    kKeep_StencilOp,
    kEqual_StencilFunc,
    0xffff,           // unset clip bit
    0x0000,
    0xffff);

GR_STATIC_CONST_SAME_STENCIL(gUserToClipXorPass1,
    kReplace_StencilOp,
    kZero_StencilOp,
    kGreater_StencilFunc,
    0xffff,
    0x0000,          // set clip bit
    0xffff);

GR_STATIC_CONST_SAME_STENCIL(gInvUserToClipXorPass0,
    kInvert_StencilOp,
    kKeep_StencilOp,
    kEqual_StencilFunc,
    0xffff,           // unset clip bit
    0x0000,
    0xffff);

GR_STATIC_CONST_SAME_STENCIL(gInvUserToClipXorPass1,
    kReplace_StencilOp,
    kZero_StencilOp,
    kLess_StencilFunc,
    0xffff,
    0x0000,          // set clip bit
    0xffff);

///////
// Reverse Diff
GR_STATIC_CONST_SAME_STENCIL(gUserToClipRDiffPass0,
    kInvert_StencilOp,
    kZero_StencilOp,
    kLess_StencilFunc,
    0xffff,         // unset clip bit
    0x0000,         // set clip bit
    0xffff);

GR_STATIC_CONST_SAME_STENCIL(gUserToClipRDiffPass1,
    kReplace_StencilOp,
    kZero_StencilOp,
    kEqual_StencilFunc,
    0x0000,          // set clip bit
    0x0000,          // set clip bit
    0xffff);

// We are looking for stencil values that are all zero. The first pass sets the
// clip bit if the stencil is all zeros. The second pass clears the user bits.
GR_STATIC_CONST_SAME_STENCIL(gInvUserToClipRDiffPass0,
    kInvert_StencilOp,
    kZero_StencilOp,
    kEqual_StencilFunc,
    0xffff,
    0x0000,
    0x0000           // set clip bit
);

GR_STATIC_CONST_SAME_STENCIL(gInvUserToClipRDiffPass1,
    kZero_StencilOp,
    kZero_StencilOp,
    kAlways_StencilFunc,
    0xffff,
    0x0000,
    0xffff           // unset clip bit
);

///////
// Direct to Stencil

// We can render a clip element directly without first writing to the client
// portion of the clip when the fill is not inverse and the set operation will
// only modify the in/out status of samples covered by the clip element.

// this one only works if used right after stencil clip was cleared.
// Our clip mask creation code doesn't allow midstream replace ops.
GR_STATIC_CONST_SAME_STENCIL(gReplaceClip,
    kReplace_StencilOp,
    kReplace_StencilOp,
    kAlways_StencilFunc,
    0xffff,
    0x0000,           // set clip bit
    0x0000            // set clipBit
);

GR_STATIC_CONST_SAME_STENCIL(gUnionClip,
    kReplace_StencilOp,
    kReplace_StencilOp,
    kAlways_StencilFunc,
    0xffff,
    0x0000,           // set clip bit
    0x0000            // set clip bit
);

GR_STATIC_CONST_SAME_STENCIL(gXorClip,
    kInvert_StencilOp,
    kInvert_StencilOp,
    kAlways_StencilFunc,
    0xffff,
    0x0000,
    0x0000            // set clip bit
);

GR_STATIC_CONST_SAME_STENCIL(gDiffClip,
    kZero_StencilOp,
    kZero_StencilOp,
    kAlways_StencilFunc,
    0xffff,
    0x0000,
    0x0000            // set clip bit
);

bool GrStencilSettings::GetClipPasses(
                            SkRegion::Op op,
                            bool canBeDirect,
                            unsigned int stencilClipMask,
                            bool invertedFill,
                            int* numPasses,
                            GrStencilSettings settings[kMaxStencilClipPasses]) {
    if (canBeDirect && !invertedFill) {
        *numPasses = 0;
        switch (op) {
            case SkRegion::kReplace_Op:
                *numPasses = 1;
                settings[0] = gReplaceClip;
                break;
            case SkRegion::kUnion_Op:
                *numPasses = 1;
                settings[0] = gUnionClip;
                break;
            case SkRegion::kXOR_Op:
                *numPasses = 1;
                settings[0] = gXorClip;
                break;
            case SkRegion::kDifference_Op:
                *numPasses = 1;
                settings[0] = gDiffClip;
                break;
            default: // suppress warning
                break;
        }
        if (1 == *numPasses) {
            settings[0].fFuncRefs[kFront_Face]   |= stencilClipMask;
            settings[0].fWriteMasks[kFront_Face] |= stencilClipMask;
            settings[0].fFuncRefs[kBack_Face] =
                settings[0].fFuncRefs[kFront_Face];
            settings[0].fWriteMasks[kBack_Face] =
                settings[0].fWriteMasks[kFront_Face];
            return true;
        }
    }
    switch (op) {
        // if we make the path renderer go to stencil we always give it a
        // non-inverted fill and we use the stencil rules on the client->clipbit
        // pass to select either the zeros or nonzeros.
        case SkRegion::kReplace_Op:
            *numPasses= 1;
            settings[0] = invertedFill ? gInvUserToClipReplace :
                                         gUserToClipReplace;
            settings[0].fFuncMasks[kFront_Face] &= ~stencilClipMask;
            settings[0].fFuncRefs[kFront_Face] |= stencilClipMask;
            settings[0].fFuncMasks[kBack_Face] =
                settings[0].fFuncMasks[kFront_Face];
            settings[0].fFuncRefs[kBack_Face] =
                settings[0].fFuncRefs[kFront_Face];
            break;
        case SkRegion::kIntersect_Op:
            *numPasses = 1;
            settings[0] = invertedFill ? gInvUserToClipIsect : gUserToClipIsect;
            settings[0].fFuncRefs[kFront_Face] = stencilClipMask;
            settings[0].fFuncRefs[kBack_Face] =
                settings[0].fFuncRefs[kFront_Face];
            break;
        case SkRegion::kUnion_Op:
            *numPasses = 2;
            if (invertedFill) {
                settings[0] = gInvUserToClipUnionPass0;
                settings[0].fFuncMasks[kFront_Face] &= ~stencilClipMask;
                settings[0].fFuncMasks[kBack_Face] =
                    settings[0].fFuncMasks[kFront_Face];
                settings[0].fFuncRefs[kFront_Face] |= stencilClipMask;
                settings[0].fFuncRefs[kBack_Face] =
                    settings[0].fFuncRefs[kFront_Face];
                settings[0].fWriteMasks[kFront_Face] |= stencilClipMask;
                settings[0].fWriteMasks[kBack_Face] =
                    settings[0].fWriteMasks[kFront_Face];

                settings[1] = gInvUserToClipUnionPass1;
                settings[1].fWriteMasks[kFront_Face] &= ~stencilClipMask;
                settings[1].fWriteMasks[kBack_Face] &=
                    settings[1].fWriteMasks[kFront_Face];

            } else {
                settings[0] = gUserToClipUnionPass0;
                settings[0].fFuncMasks[kFront_Face] &= ~stencilClipMask;
                settings[0].fFuncRefs[kFront_Face] |= stencilClipMask;
                settings[0].fFuncMasks[kBack_Face] =
                    settings[0].fFuncMasks[kFront_Face];
                settings[0].fFuncRefs[kBack_Face] =
                    settings[0].fFuncRefs[kFront_Face];

                settings[1] = gUserToClipUnionPass1;
                settings[1].fFuncRefs[kFront_Face] |= stencilClipMask;
                settings[1].fFuncRefs[kBack_Face] =
                    settings[1].fFuncRefs[kFront_Face];
            }
            break;
        case SkRegion::kXOR_Op:
            *numPasses = 2;
            if (invertedFill) {
                settings[0] = gInvUserToClipXorPass0;
                settings[0].fFuncMasks[kFront_Face] &= ~stencilClipMask;
                settings[0].fFuncMasks[kBack_Face] =
                    settings[0].fFuncMasks[kFront_Face];

                settings[1] = gInvUserToClipXorPass1;
                settings[1].fFuncRefs[kFront_Face] |= stencilClipMask;
                settings[1].fFuncRefs[kBack_Face] =
                    settings[1].fFuncRefs[kFront_Face];
            } else {
                settings[0] = gUserToClipXorPass0;
                settings[0].fFuncMasks[kFront_Face] &= ~stencilClipMask;
                settings[0].fFuncMasks[kBack_Face] =
                    settings[0].fFuncMasks[kFront_Face];

                settings[1] = gUserToClipXorPass1;
                settings[1].fFuncRefs[kFront_Face] |= stencilClipMask;
                settings[1].fFuncRefs[kBack_Face] =
                    settings[1].fFuncRefs[kFront_Face];
            }
            break;
        case SkRegion::kDifference_Op:
            *numPasses = 1;
            settings[0] = invertedFill ? gInvUserToClipDiff : gUserToClipDiff;
            settings[0].fFuncRefs[kFront_Face] |= stencilClipMask;
            settings[0].fFuncRefs[kBack_Face] =
                settings[0].fFuncRefs[kFront_Face];
            break;
        case SkRegion::kReverseDifference_Op:
            if (invertedFill) {
                *numPasses = 2;
                settings[0] = gInvUserToClipRDiffPass0;
                settings[0].fWriteMasks[kFront_Face] |= stencilClipMask;
                settings[0].fWriteMasks[kBack_Face] =
                    settings[0].fWriteMasks[kFront_Face];
                settings[1] = gInvUserToClipRDiffPass1;
                settings[1].fWriteMasks[kFront_Face] &= ~stencilClipMask;
                settings[1].fWriteMasks[kBack_Face] =
                    settings[1].fWriteMasks[kFront_Face];
            } else {
                *numPasses = 2;
                settings[0] = gUserToClipRDiffPass0;
                settings[0].fFuncMasks[kFront_Face] &= ~stencilClipMask;
                settings[0].fFuncMasks[kBack_Face] =
                    settings[0].fFuncMasks[kFront_Face];
                settings[0].fFuncRefs[kFront_Face] |= stencilClipMask;
                settings[0].fFuncRefs[kBack_Face] =
                    settings[0].fFuncRefs[kFront_Face];

                settings[1] = gUserToClipRDiffPass1;
                settings[1].fFuncMasks[kFront_Face] |= stencilClipMask;
                settings[1].fFuncRefs[kFront_Face] |= stencilClipMask;
                settings[1].fFuncMasks[kBack_Face] =
                    settings[1].fFuncMasks[kFront_Face];
                settings[1].fFuncRefs[kBack_Face] =
                    settings[1].fFuncRefs[kFront_Face];
            }
            break;
        default:
            GrCrash("Unknown set op");
    }
    return false;
}