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++); } }