skia2/tests/Float16Test.cpp

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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"
#include "SkColor.h"
#include "SkHalf.h"
#include "SkOpts.h"
#include "SkPixmap.h"
#include "SkPM4f.h"
#include "SkRandom.h"
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.getSafeSize() == SkToSizeT(w * h * sizeof(uint64_t)));
SkColor4f c4 { 0.5f, 1, 0.5f, 0.25f };
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));
}
}
}
DEF_TEST(float_to_half, reporter) {
const float fs[] = { 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0 };
const uint16_t hs[] = { 0x3c00, 0x4000, 0x4200, 0x4400, 0x4500, 0x4600, 0x4700 };
uint16_t hscratch[7];
SkOpts::float_to_half(hscratch, fs, 7);
REPORTER_ASSERT(reporter, 0 == memcmp(hscratch, hs, sizeof(hs)));
float fscratch[7];
SkOpts::half_to_float(fscratch, hs, 7);
REPORTER_ASSERT(reporter, 0 == memcmp(fscratch, fs, sizeof(fs)));
}
static uint32_t u(float f) {
uint32_t x;
memcpy(&x, &f, 4);
return x;
}
DEF_TEST(HalfToFloat_01, r) {
for (uint16_t h = 0; h < 0x8000; h++) {
float f = SkHalfToFloat(h);
if (f >= 0 && f <= 1) {
float got = SkHalfToFloat_01(h)[0];
if (got != f) {
SkDebugf("0x%04x -> 0x%08x (%g), want 0x%08x (%g)\n",
h,
u(got), got,
u(f), f);
}
REPORTER_ASSERT(r, SkHalfToFloat_01(h)[0] == f);
REPORTER_ASSERT(r, SkFloatToHalf_01(SkHalfToFloat_01(h)) == h);
}
}
}
DEF_TEST(FloatToHalf_01, r) {
#if 0
for (uint32_t bits = 0; bits < 0x80000000; bits++) {
#else
SkRandom rand;
for (int i = 0; i < 1000000; i++) {
uint32_t bits = rand.nextU();
#endif
float f;
memcpy(&f, &bits, 4);
if (f >= 0 && f <= 1) {
uint16_t h1 = (uint16_t)SkFloatToHalf_01(Sk4f(f,0,0,0)),
h2 = SkFloatToHalf(f);
bool ok = (h1 == h2 || h1 == h2-1);
REPORTER_ASSERT(r, ok);
if (!ok) {
SkDebugf("%08x (%d) -> %04x (%d), want %04x (%d)\n",
bits, bits>>23, h1, h1>>10, h2, h2>>10);
break;
}
}
}
}