e16efc1882
git-svn-id: http://skia.googlecode.com/svn/trunk@7406 2bbb7eff-a529-9590-31e7-b0007b416f81
71 lines
2.1 KiB
C
71 lines
2.1 KiB
C
|
|
/*
|
|
* Copyright 2010 Google Inc.
|
|
*
|
|
* Use of this source code is governed by a BSD-style license that can be
|
|
* found in the LICENSE file.
|
|
*/
|
|
|
|
|
|
|
|
#ifndef GrColor_DEFINED
|
|
#define GrColor_DEFINED
|
|
|
|
#include "GrTypes.h"
|
|
|
|
/**
|
|
* GrColor is 4 bytes for R, G, B, A, in a compile-time specific order. The
|
|
* components are stored premultiplied.
|
|
*/
|
|
typedef uint32_t GrColor;
|
|
|
|
|
|
// shift amount to assign a component to a GrColor int
|
|
// These shift values are chosen for compatibility with GL attrib arrays
|
|
// ES doesn't allow BGRA vertex attrib order so if they were not in this order
|
|
// we'd have to swizzle in shaders. Note the assumption that the cpu is little
|
|
// endian.
|
|
#define GrColor_SHIFT_R 0
|
|
#define GrColor_SHIFT_G 8
|
|
#define GrColor_SHIFT_B 16
|
|
#define GrColor_SHIFT_A 24
|
|
|
|
/**
|
|
* Pack 4 components (RGBA) into a GrColor int
|
|
*/
|
|
static inline GrColor GrColorPackRGBA(unsigned r, unsigned g,
|
|
unsigned b, unsigned a) {
|
|
GrAssert((uint8_t)r == r);
|
|
GrAssert((uint8_t)g == g);
|
|
GrAssert((uint8_t)b == b);
|
|
GrAssert((uint8_t)a == a);
|
|
return (r << GrColor_SHIFT_R) |
|
|
(g << GrColor_SHIFT_G) |
|
|
(b << GrColor_SHIFT_B) |
|
|
(a << GrColor_SHIFT_A);
|
|
}
|
|
|
|
// extract a component (byte) from a GrColor int
|
|
|
|
#define GrColorUnpackR(color) (((color) >> GrColor_SHIFT_R) & 0xFF)
|
|
#define GrColorUnpackG(color) (((color) >> GrColor_SHIFT_G) & 0xFF)
|
|
#define GrColorUnpackB(color) (((color) >> GrColor_SHIFT_B) & 0xFF)
|
|
#define GrColorUnpackA(color) (((color) >> GrColor_SHIFT_A) & 0xFF)
|
|
|
|
/**
|
|
* Since premultiplied means that alpha >= color, we construct a color with
|
|
* each component==255 and alpha == 0 to be "illegal"
|
|
*/
|
|
#define GrColor_ILLEGAL (~(0xFF << GrColor_SHIFT_A))
|
|
|
|
/** Converts a GrColor to an rgba array of GrGLfloat */
|
|
static inline void GrColorToRGBAFloat(GrColor color, float rgba[4]) {
|
|
static const float ONE_OVER_255 = 1.f / 255.f;
|
|
rgba[0] = GrColorUnpackR(color) * ONE_OVER_255;
|
|
rgba[1] = GrColorUnpackG(color) * ONE_OVER_255;
|
|
rgba[2] = GrColorUnpackB(color) * ONE_OVER_255;
|
|
rgba[3] = GrColorUnpackA(color) * ONE_OVER_255;
|
|
}
|
|
|
|
#endif
|