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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 "SkAutoPixmapStorage.h"
#include "SkColor.h"
#include "SkHalf.h"
#include "SkOpts.h"
#include "SkPM4f.h"
#include "SkPixmap.h"
#include "SkRandom.h"
#include "SkTo.h"
#include "Test.h"
#include <cmath>
static bool eq_within_half_float(float a, float b) {
const float kTolerance = 1.0f / (1 << (8 + 10));
SkHalf ha = SkFloatToHalf(a);
SkHalf hb = SkFloatToHalf(b);
float a2 = SkHalfToFloat(ha);
float b2 = SkHalfToFloat(hb);
return fabsf(a2 - b2) <= kTolerance;
}
static bool eq_within_half_float(const SkPM4f& a, const SkPM4f& b) {
for (int i = 0; i < 4; ++i) {
if (!eq_within_half_float(a.fVec[i], b.fVec[i])) {
return false;
}
}
return true;
}
DEF_TEST(color_half_float, reporter) {
const int w = 100;
const int h = 100;
SkImageInfo info = SkImageInfo::Make(w, h, kRGBA_F16_SkColorType, kPremul_SkAlphaType);
SkAutoPixmapStorage pm;
pm.alloc(info);
REPORTER_ASSERT(reporter, pm.computeByteSize() == SkToSizeT(w * h * sizeof(uint64_t)));
SkColor4f c4 { 1, 0.5f, 0.25f, 0.5f };
pm.erase(c4);
SkPM4f origpm4 = c4.premul();
for (int y = 0; y < pm.height(); ++y) {
for (int x = 0; x < pm.width(); ++x) {
SkPM4f pm4 = SkPM4f::FromF16(pm.addrF16(x, y));
REPORTER_ASSERT(reporter, eq_within_half_float(origpm4, pm4));
}
}
}
static bool is_denorm(uint16_t h) {
return (h & 0x7fff) < 0x0400;
}
static bool is_finite(uint16_t h) {
return (h & 0x7c00) != 0x7c00;
}
DEF_TEST(SkHalfToFloat_finite_ftz, r) {
for (uint32_t h = 0; h <= 0xffff; h++) {
if (!is_finite(h)) {
// _finite_ftz() only works for values that can be represented as a finite half float.
continue;
}
// _finite_ftz() may flush denorms to zero. 0.0f will compare == with both +0.0f and -0.0f.
float expected = SkHalfToFloat(h),
alternate = is_denorm(h) ? 0.0f : expected;
float actual = SkHalfToFloat_finite_ftz(h)[0];
REPORTER_ASSERT(r, actual == expected || actual == alternate);
}
}
DEF_TEST(SkFloatToHalf_finite_ftz, r) {
#if 0
for (uint64_t bits = 0; bits <= 0xffffffff; bits++) {
#else
SkRandom rand;
for (int i = 0; i < 1000000; i++) {
uint32_t bits = rand.nextU();
#endif
float f;
memcpy(&f, &bits, 4);
uint16_t expected = SkFloatToHalf(f);
if (!is_finite(expected)) {
// _finite_ftz() only works for values that can be represented as a finite half float.
continue;
}
uint16_t alternate = expected;
if (is_denorm(expected)) {
// _finite_ftz() may flush denorms to zero, and happens to keep the sign bit.
alternate = std::signbit(f) ? 0x8000 : 0x0000;
}
uint16_t actual = SkFloatToHalf_finite_ftz(Sk4f{f})[0];
// _finite_ftz() may truncate instead of rounding, so it may be one too small.
REPORTER_ASSERT(r, actual == expected || actual == expected - 1 ||
actual == alternate || actual == alternate - 1);
}
}
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