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/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include <initializer_list>
#include "Test.h"
#if SK_SUPPORT_GPU
#include "GrContext.h"
#include "SkCanvas.h"
#include "SkColorFilter.h"
#include "SkSurface.h"
#include "SkUtils.h"
/** convert 0..1 linear value to 0..1 srgb */
static float linear_to_srgb(float linear) {
if (linear <= 0.0031308) {
return linear * 12.92f;
} else {
return 1.055f * powf(linear, 1.f / 2.4f) - 0.055f;
}
}
/** convert 0..1 srgb value to 0..1 linear */
static float srgb_to_linear(float srgb) {
if (srgb <= 0.04045f) {
return srgb / 12.92f;
} else {
return powf((srgb + 0.055f) / 1.055f, 2.4f);
}
}
bool check_gamma(uint32_t src, uint32_t dst, bool toSRGB, float error,
uint32_t* expected) {
bool result = true;
uint32_t expectedColor = src & 0xff000000;
// Alpha should always be exactly preserved.
if ((src & 0xff000000) != (dst & 0xff000000)) {
result = false;
}
// need to unpremul before we can perform srgb magic
float invScale = 0;
float alpha = SkGetPackedA32(src);
if (alpha) {
invScale = 255.0f / alpha;
}
for (int c = 0; c < 3; ++c) {
float srcComponent = ((src & (0xff << (c * 8))) >> (c * 8)) * invScale;
float lower = SkTMax(0.f, srcComponent - error);
float upper = SkTMin(255.f, srcComponent + error);
if (toSRGB) {
lower = linear_to_srgb(lower / 255.f);
upper = linear_to_srgb(upper / 255.f);
} else {
lower = srgb_to_linear(lower / 255.f);
upper = srgb_to_linear(upper / 255.f);
}
lower *= alpha;
upper *= alpha;
SkASSERT(lower >= 0.f && lower <= 255.f);
SkASSERT(upper >= 0.f && upper <= 255.f);
uint8_t dstComponent = (dst & (0xff << (c * 8))) >> (c * 8);
if (dstComponent < SkScalarFloorToInt(lower) ||
dstComponent > SkScalarCeilToInt(upper)) {
result = false;
}
uint8_t expectedComponent = SkScalarRoundToInt((lower + upper) * 0.5f);
expectedColor |= expectedComponent << (c * 8);
}
*expected = expectedColor;
return result;
}
DEF_GPUTEST_FOR_RENDERING_CONTEXTS(ApplyGamma, reporter, ctxInfo) {
GrContext* context = ctxInfo.grContext();
static const int kW = 256;
static const int kH = 256;
static const size_t kRowBytes = sizeof(uint32_t) * kW;
GrSurfaceDesc baseDesc;
baseDesc.fConfig = kRGBA_8888_GrPixelConfig;
baseDesc.fWidth = kW;
baseDesc.fHeight = kH;
const SkImageInfo ii = SkImageInfo::MakeN32Premul(kW, kH);
SkAutoTMalloc<uint32_t> srcPixels(kW * kH);
for (int y = 0; y < kH; ++y) {
for (int x = 0; x < kW; ++x) {
srcPixels.get()[y*kW+x] = SkPreMultiplyARGB(x, y, x, 0xFF);
}
}
SkBitmap bm;
bm.installPixels(ii, srcPixels.get(), kRowBytes);
SkAutoTMalloc<uint32_t> read(kW * kH);
// We allow more error on GPUs with lower precision shader variables.
float error = context->caps()->shaderCaps()->floatPrecisionVaries() ? 1.2f : 0.5f;
for (auto toSRGB : { false, true }) {
sk_sp<SkSurface> dst(SkSurface::MakeRenderTarget(context, SkBudgeted::kNo, ii));
if (!dst) {
ERRORF(reporter, "Could not create surfaces for copy surface test.");
continue;
}
SkCanvas* dstCanvas = dst->getCanvas();
dstCanvas->clear(SK_ColorRED);
dstCanvas->flush();
SkPaint gammaPaint;
gammaPaint.setBlendMode(SkBlendMode::kSrc);
gammaPaint.setColorFilter(toSRGB ? SkColorFilter::MakeLinearToSRGBGamma()
: SkColorFilter::MakeSRGBToLinearGamma());
dstCanvas->drawBitmap(bm, 0, 0, &gammaPaint);
dstCanvas->flush();
sk_memset32(read.get(), 0, kW * kH);
if (!dstCanvas->readPixels(ii, read.get(), kRowBytes, 0, 0)) {
ERRORF(reporter, "Error calling readPixels");
continue;
}
bool abort = false;
// Validate that pixels were copied/transformed correctly.
for (int y = 0; y < kH && !abort; ++y) {
for (int x = 0; x < kW && !abort; ++x) {
uint32_t r = read.get()[y * kW + x];
uint32_t s = srcPixels.get()[y * kW + x];
uint32_t expected;
if (!check_gamma(s, r, toSRGB, error, &expected)) {
ERRORF(reporter, "Expected dst %d,%d to contain 0x%08x "
"from src 0x%08x and mode %s. Got %08x", x, y, expected, s,
toSRGB ? "ToSRGB" : "ToLinear", r);
abort = true;
break;
}
}
}
}
}
#endif
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