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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 "Test.h"
#if SK_SUPPORT_GPU
#include "GrCaps.h"
#include "GrContext.h"
#include "GrDrawContext.h"
#include "SkCanvas.h"
#include "SkSurface.h"
// using anonymous namespace because these functions are used as template params.
namespace {
/** convert 0..1 srgb value to 0..1 linear */
float srgb_to_linear(float srgb) {
if (srgb <= 0.04045f) {
return srgb / 12.92f;
} else {
return powf((srgb + 0.055f) / 1.055f, 2.4f);
}
}
/** convert 0..1 linear value to 0..1 srgb */
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;
}
}
}
static bool check_value(U8CPU value, U8CPU expected, U8CPU error) {
if (value >= expected) {
return (value - expected) <= error;
} else {
return (expected - value) <= error;
}
}
void read_and_check_pixels(skiatest::Reporter* reporter, GrTexture* texture, U8CPU expected,
U8CPU error, const char* subtestName) {
int w = texture->width();
int h = texture->height();
SkAutoTMalloc<uint32_t> readData(w * h);
memset(readData.get(), 0, sizeof(uint32_t) * w * h);
if (!texture->readPixels(0, 0, w, h, texture->config(), readData.get())) {
ERRORF(reporter, "Could not read pixels for %s.", subtestName);
return;
}
for (int j = 0; j < h; ++j) {
for (int i = 0; i < w; ++i) {
uint32_t read = readData[j * w + i];
bool success =
check_value(read & 0xff, expected, error) &&
check_value((read >> 8) & 0xff, expected, error) &&
check_value((read >> 16) & 0xff, expected, error);
if (!success) {
ERRORF(reporter, "Expected 0xff%02x%02x%02x, read back as 0x%08x in %s at %d, %d.",
expected, expected, expected, read, subtestName, i, j);
return;
}
}
}
}
DEF_GPUTEST_FOR_GL_RENDERING_CONTEXTS(SRGBMipMaps, reporter, ctxInfo) {
GrContext* context = ctxInfo.grContext();
if (!context->caps()->srgbSupport()) {
return;
}
const int rtS = 16;
const int texS = rtS * 2;
// Fill texture with a dither of black and 60% sRGB (~ 32.5% linear) gray. Although there is
// only one likely failure mode (doing a direct downsample of the sRGB values), this pattern
// maximizes the minimum error across all three conceivable failure modes:
// 1) Likely incorrect:
// (A + B) / 2
// 2) No input decode, decode output:
// linear_to_srgb((A + B) / 2)
// 3) Decode input, no output encode:
// (srgb_to_linear(A) + srgb_to_linear(B)) / 2
const U8CPU srgb60 = sk_float_round2int(0.6f * 255.0f);
static const SkPMColor colors[2] = {
SkPackARGB32(0xFF, srgb60, srgb60, srgb60),
SkPackARGB32(0xFF, 0x00, 0x00, 0x00)
};
uint32_t texData[texS * texS];
for (int y = 0; y < texS; ++y) {
for (int x = 0; x < texS; ++x) {
texData[y * texS + x] = colors[(x + y) % 2];
}
}
// We can be pretty generous with the error detection, thanks to the choice of input.
// The closest likely failure mode is off by > 0.1, so anything that encodes within
// 10/255 of optimal is more than good enough for this test.
const U8CPU expectedSRGB = sk_float_round2int(
linear_to_srgb(srgb_to_linear(srgb60 / 255.0f) / 2.0f) * 255.0f);
const U8CPU expectedLinear = srgb60 / 2;
const U8CPU error = 10;
// Create our test texture
GrSurfaceDesc desc;
desc.fFlags = kNone_GrSurfaceFlags;
desc.fConfig = kSRGBA_8888_GrPixelConfig;
desc.fWidth = texS;
desc.fHeight = texS;
GrTextureProvider* texProvider = context->textureProvider();
SkAutoTUnref<GrTexture> texture(texProvider->createTexture(desc, SkBudgeted::kNo, texData, 0));
// Create two draw contexts (L32 and S32)
sk_sp<SkColorSpace> srgbColorSpace = SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named);
sk_sp<GrDrawContext> l32DrawContext = context->makeDrawContext(SkBackingFit::kExact, rtS, rtS,
kRGBA_8888_GrPixelConfig,
nullptr);
sk_sp<GrDrawContext> s32DrawContext = context->makeDrawContext(SkBackingFit::kExact, rtS, rtS,
kSRGBA_8888_GrPixelConfig,
std::move(srgbColorSpace));
SkRect rect = SkRect::MakeWH(SkIntToScalar(rtS), SkIntToScalar(rtS));
GrNoClip noClip;
GrPaint paint;
paint.setPorterDuffXPFactory(SkXfermode::kSrc_Mode);
GrTextureParams mipMapParams(SkShader::kRepeat_TileMode, GrTextureParams::kMipMap_FilterMode);
paint.addColorTextureProcessor(texture, nullptr, SkMatrix::MakeScale(0.5f), mipMapParams);
// 1) Draw texture to S32 surface (should generate/use sRGB mips)
paint.setGammaCorrect(true);
s32DrawContext->drawRect(noClip, paint, SkMatrix::I(), rect);
read_and_check_pixels(reporter, s32DrawContext->asTexture().get(), expectedSRGB, error,
"first render of sRGB");
// 2) Draw texture to L32 surface (should generate/use linear mips)
paint.setGammaCorrect(false);
l32DrawContext->drawRect(noClip, paint, SkMatrix::I(), rect);
read_and_check_pixels(reporter, l32DrawContext->asTexture().get(), expectedLinear, error,
"re-render as linear");
// 3) Go back to sRGB
paint.setGammaCorrect(true);
s32DrawContext->drawRect(noClip, paint, SkMatrix::I(), rect);
read_and_check_pixels(reporter, s32DrawContext->asTexture().get(), expectedSRGB, error,
"re-render as sRGB");
}
#endif
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