1/* 2 * Copyright 2016 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8#include "Test.h" 9#include "SkAutoPixmapStorage.h" 10#include "SkColor.h" 11#include "SkHalf.h" 12#include "SkOpts.h" 13#include "SkPixmap.h" 14#include "SkPM4f.h" 15#include "SkRandom.h" 16 17#include <cmath> 18 19static bool eq_within_half_float(float a, float b) { 20 const float kTolerance = 1.0f / (1 << (8 + 10)); 21 22 SkHalf ha = SkFloatToHalf(a); 23 SkHalf hb = SkFloatToHalf(b); 24 float a2 = SkHalfToFloat(ha); 25 float b2 = SkHalfToFloat(hb); 26 return fabsf(a2 - b2) <= kTolerance; 27} 28 29static bool eq_within_half_float(const SkPM4f& a, const SkPM4f& b) { 30 for (int i = 0; i < 4; ++i) { 31 if (!eq_within_half_float(a.fVec[i], b.fVec[i])) { 32 return false; 33 } 34 } 35 return true; 36} 37 38DEF_TEST(color_half_float, reporter) { 39 const int w = 100; 40 const int h = 100; 41 42 SkImageInfo info = SkImageInfo::Make(w, h, kRGBA_F16_SkColorType, kPremul_SkAlphaType); 43 44 SkAutoPixmapStorage pm; 45 pm.alloc(info); 46 REPORTER_ASSERT(reporter, pm.computeByteSize() == SkToSizeT(w * h * sizeof(uint64_t))); 47 48 SkColor4f c4 { 1, 0.5f, 0.25f, 0.5f }; 49 pm.erase(c4); 50 51 SkPM4f origpm4 = c4.premul(); 52 for (int y = 0; y < pm.height(); ++y) { 53 for (int x = 0; x < pm.width(); ++x) { 54 SkPM4f pm4 = SkPM4f::FromF16(pm.addrF16(x, y)); 55 REPORTER_ASSERT(reporter, eq_within_half_float(origpm4, pm4)); 56 } 57 } 58} 59 60static bool is_denorm(uint16_t h) { 61 return (h & 0x7fff) < 0x0400; 62} 63 64static bool is_finite(uint16_t h) { 65 return (h & 0x7c00) != 0x7c00; 66} 67 68DEF_TEST(SkHalfToFloat_finite_ftz, r) { 69 for (uint32_t h = 0; h <= 0xffff; h++) { 70 if (!is_finite(h)) { 71 // _finite_ftz() only works for values that can be represented as a finite half float. 72 continue; 73 } 74 75 // _finite_ftz() may flush denorms to zero. 0.0f will compare == with both +0.0f and -0.0f. 76 float expected = SkHalfToFloat(h), 77 alternate = is_denorm(h) ? 0.0f : expected; 78 79 float actual = SkHalfToFloat_finite_ftz(h)[0]; 80 81 REPORTER_ASSERT(r, actual == expected || actual == alternate); 82 } 83} 84 85DEF_TEST(SkFloatToHalf_finite_ftz, r) { 86#if 0 87 for (uint64_t bits = 0; bits <= 0xffffffff; bits++) { 88#else 89 SkRandom rand; 90 for (int i = 0; i < 1000000; i++) { 91 uint32_t bits = rand.nextU(); 92#endif 93 float f; 94 memcpy(&f, &bits, 4); 95 96 uint16_t expected = SkFloatToHalf(f); 97 if (!is_finite(expected)) { 98 // _finite_ftz() only works for values that can be represented as a finite half float. 99 continue; 100 } 101 102 uint16_t alternate = expected; 103 if (is_denorm(expected)) { 104 // _finite_ftz() may flush denorms to zero, and happens to keep the sign bit. 105 alternate = std::signbit(f) ? 0x8000 : 0x0000; 106 } 107 108 uint16_t actual = SkFloatToHalf_finite_ftz(Sk4f{f})[0]; 109 // _finite_ftz() may truncate instead of rounding, so it may be one too small. 110 REPORTER_ASSERT(r, actual == expected || actual == expected - 1 || 111 actual == alternate || actual == alternate - 1); 112 } 113} 114