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 "GrPath.h"
9
get_top_n_float_bits(float f)10 template<int NumBits> static uint64_t get_top_n_float_bits(float f) {
11 char* floatData = reinterpret_cast<char*>(&f);
12 uint32_t floatBits = *reinterpret_cast<uint32_t*>(floatData);
13 return floatBits >> (32 - NumBits);
14 }
15
ComputeKey(const SkPath & path,const SkStrokeRec & stroke,GrUniqueKey * key)16 void GrPath::ComputeKey(const SkPath& path, const SkStrokeRec& stroke, GrUniqueKey* key) {
17 static const GrUniqueKey::Domain kDomain = GrUniqueKey::GenerateDomain();
18 GrUniqueKey::Builder builder(key, kDomain, 3);
19 *reinterpret_cast<uint64_t*>(&builder[0]) = ComputeStrokeKey(stroke);
20 builder[2] = path.getGenerationID();
21 }
22
ComputeStrokeKey(const SkStrokeRec & stroke)23 uint64_t GrPath::ComputeStrokeKey(const SkStrokeRec& stroke) {
24 enum {
25 kStyleBits = 2,
26 kJoinBits = 2,
27 kCapBits = 2,
28 kWidthBits = 29,
29 kMiterBits = 29,
30
31 kJoinShift = kStyleBits,
32 kCapShift = kJoinShift + kJoinBits,
33 kWidthShift = kCapShift + kCapBits,
34 kMiterShift = kWidthShift + kWidthBits,
35
36 kBitCount = kMiterShift + kMiterBits
37 };
38
39 SK_COMPILE_ASSERT(SkStrokeRec::kStyleCount <= (1 << kStyleBits), style_shift_will_be_wrong);
40 SK_COMPILE_ASSERT(SkPaint::kJoinCount <= (1 << kJoinBits), cap_shift_will_be_wrong);
41 SK_COMPILE_ASSERT(SkPaint::kCapCount <= (1 << kCapBits), miter_shift_will_be_wrong);
42 SK_COMPILE_ASSERT(kBitCount == 64, wrong_stroke_key_size);
43
44 if (!stroke.needToApply()) {
45 return SkStrokeRec::kFill_Style;
46 }
47
48 uint64_t key = stroke.getStyle();
49 key |= stroke.getJoin() << kJoinShift;
50 key |= stroke.getCap() << kCapShift;
51 key |= get_top_n_float_bits<kWidthBits>(stroke.getWidth()) << kWidthShift;
52 key |= get_top_n_float_bits<kMiterBits>(stroke.getMiter()) << kMiterShift;
53
54 return key;
55 }
56