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 "SkColor.h"
10#include "SkHalf.h"
11#include "SkOpts.h"
12#include "SkPixmap.h"
13#include "SkPM4f.h"
14#include "SkRandom.h"
15
16static bool eq_within_half_float(float a, float b) {
17    const float kTolerance = 1.0f / (1 << (8 + 10));
18
19    SkHalf ha = SkFloatToHalf(a);
20    SkHalf hb = SkFloatToHalf(b);
21    float a2 = SkHalfToFloat(ha);
22    float b2 = SkHalfToFloat(hb);
23    return fabsf(a2 - b2) <= kTolerance;
24}
25
26static bool eq_within_half_float(const SkPM4f& a, const SkPM4f& b) {
27    for (int i = 0; i < 4; ++i) {
28        if (!eq_within_half_float(a.fVec[i], b.fVec[i])) {
29            return false;
30        }
31    }
32    return true;
33}
34
35DEF_TEST(color_half_float, reporter) {
36    const int w = 100;
37    const int h = 100;
38
39    SkImageInfo info = SkImageInfo::Make(w, h, kRGBA_F16_SkColorType, kPremul_SkAlphaType);
40
41    SkAutoPixmapStorage pm;
42    pm.alloc(info);
43    REPORTER_ASSERT(reporter, pm.getSafeSize() == SkToSizeT(w * h * sizeof(uint64_t)));
44
45    SkColor4f c4 { 0.5f, 1, 0.5f, 0.25f };
46    pm.erase(c4);
47
48    SkPM4f origpm4 = c4.premul();
49    for (int y = 0; y < pm.height(); ++y) {
50        for (int x = 0; x < pm.width(); ++x) {
51            SkPM4f pm4 = SkPM4f::FromF16(pm.addrF16(x, y));
52            REPORTER_ASSERT(reporter, eq_within_half_float(origpm4, pm4));
53        }
54    }
55}
56
57DEF_TEST(float_to_half, reporter) {
58    const float    fs[] = {    1.0,    2.0,    3.0,    4.0,    5.0,    6.0,    7.0 };
59    const uint16_t hs[] = { 0x3c00, 0x4000, 0x4200, 0x4400, 0x4500, 0x4600, 0x4700 };
60
61    uint16_t hscratch[7];
62    SkOpts::float_to_half(hscratch, fs, 7);
63    REPORTER_ASSERT(reporter, 0 == memcmp(hscratch, hs, sizeof(hs)));
64
65    float fscratch[7];
66    SkOpts::half_to_float(fscratch, hs, 7);
67    REPORTER_ASSERT(reporter, 0 == memcmp(fscratch, fs, sizeof(fs)));
68}
69
70static uint32_t u(float f) {
71    uint32_t x;
72    memcpy(&x, &f, 4);
73    return x;
74}
75
76DEF_TEST(HalfToFloat_01, r) {
77    for (uint16_t h = 0; h < 0x8000; h++) {
78        float f = SkHalfToFloat(h);
79        if (f >= 0 && f <= 1) {
80            float got = SkHalfToFloat_01(h)[0];
81            if (got != f) {
82                SkDebugf("0x%04x -> 0x%08x (%g), want 0x%08x (%g)\n",
83                        h,
84                        u(got), got,
85                        u(f), f);
86            }
87            REPORTER_ASSERT(r, SkHalfToFloat_01(h)[0] == f);
88            REPORTER_ASSERT(r, SkFloatToHalf_01(SkHalfToFloat_01(h)) == h);
89        }
90    }
91}
92
93DEF_TEST(FloatToHalf_01, r) {
94#if 0
95    for (uint32_t bits = 0; bits < 0x80000000; bits++) {
96#else
97    SkRandom rand;
98    for (int i = 0; i < 1000000; i++) {
99        uint32_t bits = rand.nextU();
100#endif
101        float f;
102        memcpy(&f, &bits, 4);
103        if (f >= 0 && f <= 1) {
104            uint16_t h1 = (uint16_t)SkFloatToHalf_01(Sk4f(f,0,0,0)),
105                     h2 = SkFloatToHalf(f);
106            bool ok = (h1 == h2 || h1 == h2-1);
107            REPORTER_ASSERT(r, ok);
108            if (!ok) {
109                SkDebugf("%08x (%d) -> %04x (%d), want %04x (%d)\n",
110                         bits, bits>>23, h1, h1>>10, h2, h2>>10);
111                break;
112            }
113        }
114    }
115}
116