/*
* Copyright 2015 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 "GrContextPriv.h"
#include "GrSurfaceContext.h"
#include "SkCanvas.h"
#include "SkGr.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;
}
}
}
/** tests a conversion with an error tolerance */
template <float (*CONVERT)(float)> static bool check_conversion(uint32_t input, uint32_t output,
float error) {
// alpha should always be exactly preserved.
if ((input & 0xff000000) != (output & 0xff000000)) {
return false;
}
for (int c = 0; c < 3; ++c) {
uint8_t inputComponent = (uint8_t) ((input & (0xff << (c*8))) >> (c*8));
float lower = SkTMax(0.f, (float) inputComponent - error);
float upper = SkTMin(255.f, (float) inputComponent + error);
lower = CONVERT(lower / 255.f);
upper = CONVERT(upper / 255.f);
SkASSERT(lower >= 0.f && lower <= 255.f);
SkASSERT(upper >= 0.f && upper <= 255.f);
uint8_t outputComponent = (output & (0xff << (c*8))) >> (c*8);
if (outputComponent < SkScalarFloorToInt(lower * 255.f) ||
outputComponent > SkScalarCeilToInt(upper * 255.f)) {
return false;
}
}
return true;
}
/** tests a forward and backward conversion with an error tolerance */
template <float (*FORWARD)(float), float (*BACKWARD)(float)>
static bool check_double_conversion(uint32_t input, uint32_t output, float error) {
// alpha should always be exactly preserved.
if ((input & 0xff000000) != (output & 0xff000000)) {
return false;
}
for (int c = 0; c < 3; ++c) {
uint8_t inputComponent = (uint8_t) ((input & (0xff << (c*8))) >> (c*8));
float lower = SkTMax(0.f, (float) inputComponent - error);
float upper = SkTMin(255.f, (float) inputComponent + error);
lower = FORWARD(lower / 255.f);
upper = FORWARD(upper / 255.f);
SkASSERT(lower >= 0.f && lower <= 255.f);
SkASSERT(upper >= 0.f && upper <= 255.f);
uint8_t upperComponent = SkScalarCeilToInt(upper * 255.f);
uint8_t lowerComponent = SkScalarFloorToInt(lower * 255.f);
lower = SkTMax(0.f, (float) lowerComponent - error);
upper = SkTMin(255.f, (float) upperComponent + error);
lower = BACKWARD(lowerComponent / 255.f);
upper = BACKWARD(upperComponent / 255.f);
SkASSERT(lower >= 0.f && lower <= 255.f);
SkASSERT(upper >= 0.f && upper <= 255.f);
upperComponent = SkScalarCeilToInt(upper * 255.f);
lowerComponent = SkScalarFloorToInt(lower * 255.f);
uint8_t outputComponent = (output & (0xff << (c*8))) >> (c*8);
if (outputComponent < lowerComponent || outputComponent > upperComponent) {
return false;
}
}
return true;
}
static bool check_srgb_to_linear_conversion(uint32_t srgb, uint32_t linear, float error) {
return check_conversion<srgb_to_linear>(srgb, linear, error);
}
static bool check_linear_to_srgb_conversion(uint32_t linear, uint32_t srgb, float error) {
return check_conversion<linear_to_srgb>(linear, srgb, error);
}
static bool check_linear_to_srgb_to_linear_conversion(uint32_t input, uint32_t output, float error) {
return check_double_conversion<linear_to_srgb, srgb_to_linear>(input, output, error);
}
static bool check_srgb_to_linear_to_srgb_conversion(uint32_t input, uint32_t output, float error) {
return check_double_conversion<srgb_to_linear, linear_to_srgb>(input, output, error);
}
static bool check_no_conversion(uint32_t input, uint32_t output, float error) {
// This is a bit of a hack to check identity transformations that may lose precision.
return check_srgb_to_linear_to_srgb_conversion(input, output, error);
}
typedef bool (*CheckFn) (uint32_t orig, uint32_t actual, float error);
void read_and_check_pixels(skiatest::Reporter* reporter, GrSurfaceContext* context,
uint32_t* origData,
const SkImageInfo& dstInfo, CheckFn checker, float error,
const char* subtestName) {
int w = dstInfo.width();
int h = dstInfo.height();
SkAutoTMalloc<uint32_t> readData(w * h);
memset(readData.get(), 0, sizeof(uint32_t) * w * h);
if (!context->readPixels(dstInfo, readData.get(), 0, 0, 0)) {
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 orig = origData[j * w + i];
uint32_t read = readData[j * w + i];
if (!checker(orig, read, error)) {
ERRORF(reporter, "Expected 0x%08x, read back as 0x%08x in %s at %d, %d).",
orig, read, subtestName, i, j);
return;
}
}
}
}
namespace {
enum class Encoding {
kUntagged,
kLinear,
kSRGB,
};
}
static sk_sp<SkColorSpace> encoding_as_color_space(Encoding encoding) {
switch (encoding) {
case Encoding::kUntagged: return nullptr;
case Encoding::kLinear: return SkColorSpace::MakeSRGBLinear();
case Encoding::kSRGB: return SkColorSpace::MakeSRGB();
}
return nullptr;
}
static GrPixelConfig encoding_as_pixel_config(Encoding encoding) {
switch (encoding) {
case Encoding::kUntagged: return kRGBA_8888_GrPixelConfig;
case Encoding::kLinear: return kRGBA_8888_GrPixelConfig;
case Encoding::kSRGB: return kSRGBA_8888_GrPixelConfig;
}
return kUnknown_GrPixelConfig;
}
static const char* encoding_as_str(Encoding encoding) {
switch (encoding) {
case Encoding::kUntagged: return "untagged";
case Encoding::kLinear: return "linear";
case Encoding::kSRGB: return "sRGB";
}
return nullptr;
}
static constexpr int kW = 255;
static constexpr int kH = 255;
static std::unique_ptr<uint32_t[]> make_data() {
std::unique_ptr<uint32_t[]> data(new uint32_t[kW * kH]);
for (int j = 0; j < kH; ++j) {
for (int i = 0; i < kW; ++i) {
data[j * kW + i] = (j << 24) | (i << 16) | (i << 8) | i;
}
}
return data;
}
static sk_sp<GrSurfaceContext> make_surface_context(Encoding contextEncoding, GrContext* context,
skiatest::Reporter* reporter) {
GrSurfaceDesc desc;
desc.fFlags = kRenderTarget_GrSurfaceFlag;
desc.fOrigin = kBottomLeft_GrSurfaceOrigin;
desc.fWidth = kW;
desc.fHeight = kH;
desc.fConfig = encoding_as_pixel_config(contextEncoding);
auto surfaceContext = context->contextPriv().makeDeferredSurfaceContext(
desc, GrMipMapped::kNo, SkBackingFit::kExact, SkBudgeted::kNo,
encoding_as_color_space(contextEncoding));
if (!surfaceContext) {
ERRORF(reporter, "Could not create %s surface context.", encoding_as_str(contextEncoding));
}
return surfaceContext;
}
#ifndef SK_LEGACY_GPU_PIXEL_OPS
static void text_write_fails(Encoding contextEncoding, Encoding writeEncoding, GrContext* context,
skiatest::Reporter* reporter) {
auto surfaceContext = make_surface_context(contextEncoding, context, reporter);
if (!surfaceContext) {
return;
}
auto writeII = SkImageInfo::Make(kW, kH, kRGBA_8888_SkColorType, kPremul_SkAlphaType,
encoding_as_color_space(writeEncoding));
auto data = make_data();
if (surfaceContext->writePixels(writeII, data.get(), 0, 0, 0)) {
ERRORF(reporter, "Expected %s write to %s surface context to fail.",
encoding_as_str(writeEncoding), encoding_as_str(contextEncoding));
}
}
#endif
static void test_write_read(Encoding contextEncoding, Encoding writeEncoding, Encoding readEncoding,
float error, CheckFn check, GrContext* context,
skiatest::Reporter* reporter) {
auto surfaceContext = make_surface_context(contextEncoding, context, reporter);
if (!surfaceContext) {
return;
}
auto writeII = SkImageInfo::Make(kW, kH, kRGBA_8888_SkColorType, kPremul_SkAlphaType,
encoding_as_color_space(writeEncoding));
auto data = make_data();
if (!surfaceContext->writePixels(writeII, data.get(), 0, 0, 0)) {
ERRORF(reporter, "Could not write %s to %s surface context.",
encoding_as_str(writeEncoding), encoding_as_str(contextEncoding));
return;
}
auto readII = SkImageInfo::Make(kW, kH, kRGBA_8888_SkColorType, kPremul_SkAlphaType,
encoding_as_color_space(readEncoding));
SkString testName;
testName.printf("write %s data to a %s context and read as %s.", encoding_as_str(writeEncoding),
encoding_as_str(contextEncoding), encoding_as_str(readEncoding));
read_and_check_pixels(reporter, surfaceContext.get(), data.get(), readII, check, error,
testName.c_str());
}
// Test all combinations of writePixels/readPixels where the surface context/write source/read dst
// are sRGB, linear, or untagged RGBA_8888.
DEF_GPUTEST_FOR_RENDERING_CONTEXTS(SRGBReadWritePixels, reporter, ctxInfo) {
GrContext* context = ctxInfo.grContext();
if (!context->caps()->isConfigRenderable(kSRGBA_8888_GrPixelConfig) &&
!context->caps()->isConfigTexturable(kSRGBA_8888_GrPixelConfig)) {
return;
}
// We allow more error on GPUs with lower precision shader variables.
float error = context->caps()->shaderCaps()->halfIs32Bits() ? 0.5f : 1.2f;
// For the all-sRGB case, we allow a small error only for devices that have
// precision variation because the sRGB data gets converted to linear and back in
// the shader.
float smallError = context->caps()->shaderCaps()->halfIs32Bits() ? 0.0f : 1.f;
///////////////////////////////////////////////////////////////////////////////////////////////
// Write sRGB data to a sRGB context - no conversion on the write.
// back to sRGB no conversion
test_write_read(Encoding::kSRGB, Encoding::kSRGB, Encoding::kSRGB, smallError,
check_no_conversion, context, reporter);
// Untagged read from sRGB is treated as a conversion back to linear. TODO: Fail or don't
// convert?
test_write_read(Encoding::kSRGB, Encoding::kSRGB, Encoding::kUntagged, error,
check_srgb_to_linear_conversion, context, reporter);
// Converts back to linear
test_write_read(Encoding::kSRGB, Encoding::kSRGB, Encoding::kLinear, error,
check_srgb_to_linear_conversion, context, reporter);
#ifdef SK_LEGACY_GPU_PIXEL_OPS
///////////////////////////////////////////////////////////////////////////////////////////////
// Write untagged data to a sRGB context - Currently this treats the untagged data as
// linear and converts to sRGB during the write. TODO: Fail or passthrough?
// read back to srgb, no additional conversion
test_write_read(Encoding::kSRGB, Encoding::kUntagged, Encoding::kSRGB, error,
check_linear_to_srgb_conversion, context, reporter);
// read back to untagged. Currently converts back to linear. TODO: Fail or don't convert?
test_write_read(Encoding::kSRGB, Encoding::kUntagged, Encoding::kUntagged, error,
check_linear_to_srgb_to_linear_conversion, context, reporter);
// Converts back to linear.
test_write_read(Encoding::kSRGB, Encoding::kUntagged, Encoding::kLinear, error,
check_linear_to_srgb_to_linear_conversion, context, reporter);
#else
// Currently writing untagged data to kSRGB fails because SkImageInfoValidConversion fails.
text_write_fails(Encoding::kSRGB, Encoding::kUntagged, context, reporter);
#endif
///////////////////////////////////////////////////////////////////////////////////////////////
// Write linear data to a sRGB context. It gets converted to sRGB on write. The reads
// are all the same as the above cases where the original data was untagged.
test_write_read(Encoding::kSRGB, Encoding::kLinear, Encoding::kSRGB, error,
check_linear_to_srgb_conversion, context, reporter);
// TODO: Fail or don't convert?
test_write_read(Encoding::kSRGB, Encoding::kLinear, Encoding::kUntagged, error,
check_linear_to_srgb_to_linear_conversion, context, reporter);
test_write_read(Encoding::kSRGB, Encoding::kLinear, Encoding::kLinear, error,
check_linear_to_srgb_to_linear_conversion, context, reporter);
///////////////////////////////////////////////////////////////////////////////////////////////
// Write data to an untagged context. The write does no conversion no matter what encoding the
// src data has.
for (auto writeEncoding : {Encoding::kSRGB, Encoding::kUntagged, Encoding::kLinear}) {
// The read from untagged to sRGB also does no conversion. TODO: Should it just fail?
test_write_read(Encoding::kUntagged, writeEncoding, Encoding::kSRGB, error,
check_no_conversion, context, reporter);
// Reading untagged back as untagged should do no conversion.
test_write_read(Encoding::kUntagged, writeEncoding, Encoding::kUntagged, error,
check_no_conversion, context, reporter);
// Reading untagged back as linear does no conversion. TODO: Should it just fail?
test_write_read(Encoding::kUntagged, writeEncoding, Encoding::kLinear, error,
check_no_conversion, context, reporter);
}
///////////////////////////////////////////////////////////////////////////////////////////////
// Write sRGB data to a linear context - converts to sRGB on the write.
// converts back to sRGB on read.
test_write_read(Encoding::kLinear, Encoding::kSRGB, Encoding::kSRGB, error,
check_srgb_to_linear_to_srgb_conversion, context, reporter);
// Reading untagged data from linear currently does no conversion. TODO: Should it fail?
test_write_read(Encoding::kLinear, Encoding::kSRGB, Encoding::kUntagged, error,
check_srgb_to_linear_conversion, context, reporter);
// Stays linear when read.
test_write_read(Encoding::kLinear, Encoding::kSRGB, Encoding::kLinear, error,
check_srgb_to_linear_conversion, context, reporter);
///////////////////////////////////////////////////////////////////////////////////////////////
// Write untagged data to a linear context. Currently does no conversion. TODO: Should this
// fail?
#ifdef SK_LEGACY_GPU_PIXEL_OPS
// Reading to sRGB does a conversion.
test_write_read(Encoding::kLinear, Encoding::kUntagged, Encoding::kSRGB, error,
check_linear_to_srgb_conversion, context, reporter);
// Reading to untagged does no conversion. TODO: Should it fail?
test_write_read(Encoding::kLinear, Encoding::kUntagged, Encoding::kUntagged, error,
check_no_conversion, context, reporter);
// Stays linear when read.
test_write_read(Encoding::kLinear, Encoding::kUntagged, Encoding::kLinear, error,
check_no_conversion, context, reporter);
#else
// Currently writing untagged data to kLinear fails because SkImageInfoValidConversion fails.
text_write_fails(Encoding::kSRGB, Encoding::kUntagged, context, reporter);
#endif
///////////////////////////////////////////////////////////////////////////////////////////////
// Write linear data to a linear context. Does no conversion.
// Reading to sRGB does a conversion.
test_write_read(Encoding::kLinear, Encoding::kLinear, Encoding::kSRGB, error,
check_linear_to_srgb_conversion, context, reporter);
// Reading to untagged does no conversion. TODO: Should it fail?
test_write_read(Encoding::kLinear, Encoding::kLinear, Encoding::kUntagged, error,
check_no_conversion, context, reporter);
// Stays linear when read.
test_write_read(Encoding::kLinear, Encoding::kLinear, Encoding::kLinear, error,
check_no_conversion, context, reporter);
}
#endif