skia2/tests/ReadWriteAlphaTest.cpp

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/*
* Copyright 2012 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"
// This test is specific to the GPU backend.
#if SK_SUPPORT_GPU
#include "GrContext.h"
#include "SkCanvas.h"
#include "SkSurface.h"
// This was made indivisible by 4 to ensure we test setting GL_PACK_ALIGNMENT properly.
static const int X_SIZE = 13;
static const int Y_SIZE = 13;
static void validate_alpha_data(skiatest::Reporter* reporter, int w, int h, const uint8_t* actual,
size_t actualRowBytes, const uint8_t* expected, SkString extraMsg) {
for (int y = 0; y < h; ++y) {
for (int x = 0; x < w; ++x) {
uint8_t a = actual[y * actualRowBytes + x];
uint8_t e = expected[y * w + x];
if (e != a) {
ERRORF(reporter,
"Failed alpha readback. Expected: 0x%02x, Got: 0x%02x at (%d,%d), %s",
e, a, x, y, extraMsg.c_str());
return;
}
}
}
}
DEF_GPUTEST_FOR_RENDERING_CONTEXTS(ReadWriteAlpha, reporter, ctxInfo) {
unsigned char alphaData[X_SIZE * Y_SIZE];
static const int kClearValue = 0x2;
bool match;
static const size_t kRowBytes[] = {0, X_SIZE, X_SIZE + 1, 2 * X_SIZE - 1};
{
GrSurfaceDesc desc;
desc.fFlags = kNone_GrSurfaceFlags;
desc.fConfig = kAlpha_8_GrPixelConfig; // it is a single channel texture
desc.fWidth = X_SIZE;
desc.fHeight = Y_SIZE;
// We are initializing the texture with zeros here
memset(alphaData, 0, X_SIZE * Y_SIZE);
sk_sp<GrTexture> texture(
ctxInfo.grContext()->textureProvider()->createTexture(desc, SkBudgeted::kNo, alphaData,
0));
if (!texture) {
ERRORF(reporter, "Could not create alpha texture.");
return;
}
const SkImageInfo ii = SkImageInfo::MakeA8(X_SIZE, Y_SIZE);
sk_sp<SkSurface> surf(SkSurface::MakeRenderTarget(ctxInfo.grContext(),
SkBudgeted::kNo, ii));
// create a distinctive texture
for (int y = 0; y < Y_SIZE; ++y) {
for (int x = 0; x < X_SIZE; ++x) {
alphaData[y * X_SIZE + x] = y*X_SIZE+x;
}
}
for (auto rowBytes : kRowBytes) {
// upload the texture (do per-rowbytes iteration because we may overwrite below).
bool result = texture->writePixels(0, 0, desc.fWidth, desc.fHeight, desc.fConfig,
alphaData, 0);
REPORTER_ASSERT_MESSAGE(reporter, result, "Initial A8 writePixels failed");
size_t nonZeroRowBytes = rowBytes ? rowBytes : X_SIZE;
std::unique_ptr<uint8_t[]> readback(new uint8_t[nonZeroRowBytes * Y_SIZE]);
// clear readback to something non-zero so we can detect readback failures
memset(readback.get(), kClearValue, nonZeroRowBytes * Y_SIZE);
// read the texture back
result = texture->readPixels(0, 0, desc.fWidth, desc.fHeight, desc.fConfig,
readback.get(), rowBytes);
REPORTER_ASSERT_MESSAGE(reporter, result, "Initial A8 readPixels failed");
// make sure the original & read back versions match
SkString msg;
msg.printf("rb:%d A8", SkToU32(rowBytes));
validate_alpha_data(reporter, X_SIZE, Y_SIZE, readback.get(), nonZeroRowBytes,
alphaData, msg);
// Now try writing to a single channel surface (if we could create one).
if (surf) {
SkCanvas* canvas = surf->getCanvas();
SkPaint paint;
const SkRect rect = SkRect::MakeLTRB(-10, -10, X_SIZE + 10, Y_SIZE + 10);
paint.setColor(SK_ColorWHITE);
canvas->drawRect(rect, paint);
memset(readback.get(), kClearValue, nonZeroRowBytes * Y_SIZE);
result = surf->readPixels(ii, readback.get(), nonZeroRowBytes, 0, 0);
REPORTER_ASSERT_MESSAGE(reporter, result, "A8 readPixels after clear failed");
match = true;
for (int y = 0; y < Y_SIZE && match; ++y) {
for (int x = 0; x < X_SIZE && match; ++x) {
uint8_t rbValue = readback.get()[y * nonZeroRowBytes + x];
if (0xFF != rbValue) {
ERRORF(reporter,
"Failed alpha readback after clear. Expected: 0xFF, Got: 0x%02x"
" at (%d,%d), rb:%d", rbValue, x, y, SkToU32(rowBytes));
match = false;
}
}
}
}
}
}
static const GrPixelConfig kRGBAConfigs[] {
kRGBA_8888_GrPixelConfig,
kBGRA_8888_GrPixelConfig,
kSRGBA_8888_GrPixelConfig
};
for (int y = 0; y < Y_SIZE; ++y) {
for (int x = 0; x < X_SIZE; ++x) {
alphaData[y * X_SIZE + x] = y*X_SIZE+x;
}
}
// Attempt to read back just alpha from a RGBA/BGRA texture. Once with a texture-only src and
// once with a render target.
for (auto cfg : kRGBAConfigs) {
for (int rt = 0; rt < 2; ++rt) {
GrSurfaceDesc desc;
desc.fFlags = rt ? kRenderTarget_GrSurfaceFlag : kNone_GrSurfaceFlags;
desc.fConfig = cfg;
desc.fWidth = X_SIZE;
desc.fHeight = Y_SIZE;
uint32_t rgbaData[X_SIZE * Y_SIZE];
// Make the alpha channel of the rgba texture come from alphaData.
for (int y = 0; y < Y_SIZE; ++y) {
for (int x = 0; x < X_SIZE; ++x) {
rgbaData[y * X_SIZE + x] = GrColorPackRGBA(6, 7, 8, alphaData[y * X_SIZE + x]);
}
}
sk_sp<GrTexture> texture(
ctxInfo.grContext()->textureProvider()->createTexture(desc, SkBudgeted::kNo,
rgbaData, 0));
if (!texture) {
// We always expect to be able to create a RGBA texture
if (!rt && kRGBA_8888_GrPixelConfig == desc.fConfig) {
ERRORF(reporter, "Failed to create RGBA texture.");
}
continue;
}
for (auto rowBytes : kRowBytes) {
size_t nonZeroRowBytes = rowBytes ? rowBytes : X_SIZE;
std::unique_ptr<uint8_t[]> readback(new uint8_t[nonZeroRowBytes * Y_SIZE]);
// Clear so we don't accidentally see values from previous iteration.
memset(readback.get(), kClearValue, nonZeroRowBytes * Y_SIZE);
// read the texture back
bool result = texture->readPixels(0, 0, desc.fWidth, desc.fHeight,
kAlpha_8_GrPixelConfig,
readback.get(), rowBytes);
REPORTER_ASSERT_MESSAGE(reporter, result, "8888 readPixels failed");
// make sure the original & read back versions match
SkString msg;
msg.printf("rt:%d, rb:%d 8888", rt, SkToU32(rowBytes));
validate_alpha_data(reporter, X_SIZE, Y_SIZE, readback.get(), nonZeroRowBytes,
alphaData, msg);
}
}
}
}
#endif