SkPM4f SkPM4f::FromF16(const uint16_t half[4]) {
return {{
SkHalfToFloat(half[0]),
SkHalfToFloat(half[1]),
SkHalfToFloat(half[2]),
SkHalfToFloat(half[3])
}};
}
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;
}
DEF_TEST(FloatToHalf_finite, 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);
if (isfinite(f) && isfinite(SkHalfToFloat(SkFloatToHalf(f)))) {
uint16_t h1 = SkFloatToHalf_finite(Sk4f(f,0,0,0))[0],
h2 = SkFloatToHalf(f);
bool ok = (h1 == h2 || h1 == h2-1);
REPORTER_ASSERT(r, ok);
if (!ok) {
SkDebugf("%08x (%g) -> %04x, want %04x (%g)\n",
bits, f, h1, h2, SkHalfToFloat(h2));
break;
}
}
}
}
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(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(HalfToFloat_finite, r) {
for (uint32_t h = 0; h <= 0xffff; h++) {
float f = SkHalfToFloat(h);
if (isfinite(f)) {
float got = SkHalfToFloat_finite(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_finite(h)[0] == f);
uint64_t result;
SkFloatToHalf_finite(SkHalfToFloat_finite(h)).store(&result);
REPORTER_ASSERT(r, result == h);
}
}
}
static void half_to_float(float dst[], const uint16_t src[], int n) {
while (n-->0) {
*dst++ = SkHalfToFloat(*src++);
}
}
