skia2/include/private/GrColor.h
Brian Osman c6444d2f26 Enable wide color support in CCPR
Unlike other ops, always use half-float colors. The logic around the
Instance struct makes dynamically switching color size tricky.
CCPR stores color in a per-instance attribute though, so the cost of
always using FP16 is much lower.

Bug: skia:
Change-Id: I9c0c64940f74f915a18417a5830030558e065d28
Reviewed-on: https://skia-review.googlesource.com/c/182760
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
2019-01-10 13:53:31 +00:00

115 lines
3.5 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 "SkColor.h"
#include "SkColorData.h"
#include "SkColorPriv.h"
#include "SkHalf.h"
/**
* GrColor is 4 bytes for R, G, B, A, in a specific order defined below. Whether the color is
* premultiplied or not depends on the context in which it is being used.
*/
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.
#ifdef SK_CPU_BENDIAN
#define GrColor_SHIFT_R 24
#define GrColor_SHIFT_G 16
#define GrColor_SHIFT_B 8
#define GrColor_SHIFT_A 0
#else
#define GrColor_SHIFT_R 0
#define GrColor_SHIFT_G 8
#define GrColor_SHIFT_B 16
#define GrColor_SHIFT_A 24
#endif
/**
* Pack 4 components (RGBA) into a GrColor int
*/
static inline GrColor GrColorPackRGBA(unsigned r, unsigned g, unsigned b, unsigned a) {
SkASSERT((uint8_t)r == r);
SkASSERT((uint8_t)g == g);
SkASSERT((uint8_t)b == b);
SkASSERT((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))
/** Normalizes and coverts an uint8_t to a float. [0, 255] -> [0.0, 1.0] */
static inline float GrNormalizeByteToFloat(uint8_t value) {
static const float ONE_OVER_255 = 1.f / 255.f;
return value * ONE_OVER_255;
}
/** Returns true if all channels are in [0, 1]. Used to pick vertex attribute types. */
static inline bool SkPMColor4fFitsInBytes(const SkPMColor4f& color) {
SkASSERT(color.fA >= 0.0f && color.fA <= 1.0f);
return color.fR >= 0.0f && color.fR <= 1.0f &&
color.fG >= 0.0f && color.fG <= 1.0f &&
color.fB >= 0.0f && color.fB <= 1.0f;
}
static inline uint64_t SkPMColor4f_toFP16(const SkPMColor4f& color) {
uint64_t halfColor;
SkFloatToHalf_finite_ftz(Sk4f::Load(color.vec())).store(&halfColor);
return halfColor;
}
/**
* GrVertexColor is a helper for writing colors to a vertex attribute. It stores either GrColor
* or four half-float channels, depending on the wideColor parameter. GrVertexWriter will write
* the correct amount of data. Note that the GP needs to have been constructed with the correct
* attribute type for colors, to match the usage here.
*/
class GrVertexColor {
public:
explicit GrVertexColor(const SkPMColor4f& color, bool wideColor)
: fWideColor(wideColor) {
if (wideColor) {
SkFloatToHalf_finite_ftz(Sk4f::Load(color.vec())).store(&fColor);
} else {
fColor[0] = color.toBytes_RGBA();
}
}
size_t size() const { return fWideColor ? 8 : 4; }
private:
friend struct GrVertexWriter;
uint32_t fColor[2];
bool fWideColor;
};
#endif