1
2/*
3 * Copyright 2010 Google Inc.
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9
10
11#ifndef GrColor_DEFINED
12#define GrColor_DEFINED
13
14#include "include/core/SkColor.h"
15#include "include/core/SkColorPriv.h"
16#include "include/gpu/GrTypes.h"
17#include "include/private/SkColorData.h"
18#include "include/private/SkHalf.h"
19
20/**
21 * GrColor is 4 bytes for R, G, B, A, in a specific order defined below. Whether the color is
22 * premultiplied or not depends on the context in which it is being used.
23 */
24typedef uint32_t GrColor;
25
26// shift amount to assign a component to a GrColor int
27// These shift values are chosen for compatibility with GL attrib arrays
28// ES doesn't allow BGRA vertex attrib order so if they were not in this order
29// we'd have to swizzle in shaders.
30#ifdef SK_CPU_BENDIAN
31 #define GrColor_SHIFT_R 24
32 #define GrColor_SHIFT_G 16
33 #define GrColor_SHIFT_B 8
34 #define GrColor_SHIFT_A 0
35#else
36 #define GrColor_SHIFT_R 0
37 #define GrColor_SHIFT_G 8
38 #define GrColor_SHIFT_B 16
39 #define GrColor_SHIFT_A 24
40#endif
41
42/**
43 * Pack 4 components (RGBA) into a GrColor int
44 */
45static inline GrColor GrColorPackRGBA(unsigned r, unsigned g, unsigned b, unsigned a) {
46 SkASSERT((uint8_t)r == r);
47 SkASSERT((uint8_t)g == g);
48 SkASSERT((uint8_t)b == b);
49 SkASSERT((uint8_t)a == a);
50 return (r << GrColor_SHIFT_R) |
51 (g << GrColor_SHIFT_G) |
52 (b << GrColor_SHIFT_B) |
53 (a << GrColor_SHIFT_A);
54}
55
56// extract a component (byte) from a GrColor int
57
58#define GrColorUnpackR(color) (((color) >> GrColor_SHIFT_R) & 0xFF)
59#define GrColorUnpackG(color) (((color) >> GrColor_SHIFT_G) & 0xFF)
60#define GrColorUnpackB(color) (((color) >> GrColor_SHIFT_B) & 0xFF)
61#define GrColorUnpackA(color) (((color) >> GrColor_SHIFT_A) & 0xFF)
62
63/**
64 * Since premultiplied means that alpha >= color, we construct a color with
65 * each component==255 and alpha == 0 to be "illegal"
66 */
67#define GrColor_ILLEGAL (~(0xFF << GrColor_SHIFT_A))
68
69/** Normalizes and coverts an uint8_t to a float. [0, 255] -> [0.0, 1.0] */
70static inline float GrNormalizeByteToFloat(uint8_t value) {
71 static const float ONE_OVER_255 = 1.f / 255.f;
72 return value * ONE_OVER_255;
73}
74
75/** Used to pick vertex attribute types. */
76static inline bool SkPMColor4fFitsInBytes(const SkPMColor4f& color) {
77 // Might want to instead check that the components are [0...a] instead of [0...1]?
78 return color.fitsInBytes();
79}
80
81static inline uint64_t SkPMColor4f_toFP16(const SkPMColor4f& color) {
82 uint64_t halfColor;
83 SkFloatToHalf_finite_ftz(Sk4f::Load(color.vec())).store(&halfColor);
84 return halfColor;
85}
86
87/**
88 * GrVertexColor is a helper for writing colors to a vertex attribute. It stores either GrColor
89 * or four half-float channels, depending on the wideColor parameter. GrVertexWriter will write
90 * the correct amount of data. Note that the GP needs to have been constructed with the correct
91 * attribute type for colors, to match the usage here.
92 */
93class GrVertexColor {
94public:
95 explicit GrVertexColor(const SkPMColor4f& color, bool wideColor)
96 : fWideColor(wideColor) {
97 if (wideColor) {
98 memcpy(fColor, color.vec(), sizeof(fColor));
99 } else {
100 fColor[0] = color.toBytes_RGBA();
101 }
102 }
103
104 size_t size() const { return fWideColor ? 16 : 4; }
105
106private:
107 friend struct GrVertexWriter;
108
109 uint32_t fColor[4];
110 bool fWideColor;
111};
112
113#endif
114