94efbf51f5
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=5121 Change-Id: If8d13638f80f42161cbc766a2666c5789e5772c8 Reviewed-on: https://skia-review.googlesource.com/5121 Reviewed-by: Ethan Nicholas <ethannicholas@google.com> Commit-Queue: Brian Salomon <bsalomon@google.com>
116 lines
3.6 KiB
C++
116 lines
3.6 KiB
C++
/*
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* Copyright 2016 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef GrSwizzle_DEFINED
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#define GrSwizzle_DEFINED
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#include "GrColor.h"
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#include "SkRandom.h"
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/** Represents a rgba swizzle. It can be converted either into a string or a eight bit int.
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Currently there is no way to specify an arbitrary swizzle, just some static swizzles and an
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assignment operator. That could be relaxed. */
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class GrSwizzle {
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private:
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char fSwiz[5];
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uint8_t fKey;
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static constexpr int CToI(char c) {
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return ('r' == c) ? (GrColor_SHIFT_R / 8) :
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('g' == c) ? (GrColor_SHIFT_G / 8) :
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('b' == c) ? (GrColor_SHIFT_B / 8) :
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('a' == c) ? (GrColor_SHIFT_A / 8) : -1;
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}
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static constexpr char IToC(int idx) {
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return (8 * idx) == GrColor_SHIFT_R ? 'r' :
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(8 * idx) == GrColor_SHIFT_G ? 'g' :
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(8 * idx) == GrColor_SHIFT_B ? 'b' :
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(8 * idx) == GrColor_SHIFT_A ? 'a' : 'x';
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}
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constexpr GrSwizzle(const char c[4])
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: fSwiz{c[0], c[1], c[2], c[3], 0}
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, fKey((CToI(c[0]) << 0) | (CToI(c[1]) << 2) | (CToI(c[2]) << 4) | (CToI(c[3]) << 6)) {}
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GR_STATIC_ASSERT(sizeof(char[4]) == sizeof(uint32_t));
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uint32_t* asUIntPtr() { return SkTCast<uint32_t*>(fSwiz); }
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uint32_t asUInt() const { return *SkTCast<const uint32_t*>(fSwiz); }
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public:
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GrSwizzle() { *this = RGBA(); }
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GrSwizzle(const GrSwizzle& that) { *this = that; }
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GrSwizzle& operator=(const GrSwizzle& that) {
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memcpy(this, &that, sizeof(GrSwizzle));
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return *this;
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}
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/** Recreates a GrSwizzle from the output of asKey() */
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void setFromKey(uint8_t key) {
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fKey = key;
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for (int i = 0; i < 4; ++i) {
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fSwiz[i] = IToC(key & 3);
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key >>= 2;
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}
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SkASSERT(fSwiz[4] == 0);
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}
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bool operator==(const GrSwizzle& that) const { return this->asUInt() == that.asUInt(); }
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bool operator!=(const GrSwizzle& that) const { return !(*this == that); }
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/** Compact representation of the swizzle suitable for a key. */
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uint8_t asKey() const { return fKey; }
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/** 4 char null terminated string consisting only of chars 'r', 'g', 'b', 'a'. */
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const char* c_str() const { return fSwiz; }
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/** Applies this swizzle to the input color and returns the swizzled color. */
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GrColor applyTo(GrColor color) const {
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int idx;
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uint32_t key = fKey;
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// Index of the input color that should be mapped to output r.
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idx = (key & 3);
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uint32_t outR = (color >> idx * 8) & 0xFF;
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key >>= 2;
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idx = (key & 3);
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uint32_t outG = (color >> idx * 8) & 0xFF;
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key >>= 2;
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idx = (key & 3);
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uint32_t outB = (color >> idx * 8) & 0xFF;
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key >>= 2;
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idx = (key & 3);
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uint32_t outA = (color >> idx * 8) & 0xFF;
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return GrColorPackRGBA(outR, outG, outB, outA);
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}
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static GrSwizzle RGBA() { return GrSwizzle("rgba"); }
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static GrSwizzle AAAA() { return GrSwizzle("aaaa"); }
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static GrSwizzle RRRR() { return GrSwizzle("rrrr"); }
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static GrSwizzle BGRA() { return GrSwizzle("bgra"); }
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static GrSwizzle CreateRandom(SkRandom* random) {
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switch (random->nextU() % 4) {
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case 0:
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return RGBA();
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case 1:
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return BGRA();
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case 2:
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return RRRR();
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case 3:
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return AAAA();
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default:
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SkFAIL("Mod is broken?!?");
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return RGBA();
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}
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}
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};
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#endif
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