1/*
2 * Copyright 2011 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 "SkRandom.h"
9#include "Test.h"
10#include "gradients/SkClampRange.h"
11
12static skiatest::Reporter* gReporter;
13#define R_ASSERT(cond) if (!(cond)) {      \
14    SkDebugf("%d: %s\n", __LINE__, #cond); \
15    REPORTER_ASSERT(gReporter, cond);      \
16}
17
18// Arbitrary sentinel values outside [0, 0xFFFF].
19static const int kV0 = -42, kV1 = -53, kRamp = -64;
20
21static void check_value(int64_t bigfx, int expected) {
22    if (bigfx < 0) {
23        R_ASSERT(expected == kV0);
24    } else if (bigfx > 0xFFFF) {
25        R_ASSERT(expected == kV1);
26    } else if (bigfx == 0xFFFF) {
27        // Either one is fine (and we do see both).
28        R_ASSERT(expected == kV1 || expected == kRamp);
29    } else {
30        R_ASSERT(expected == kRamp);
31    }
32}
33
34static void slow_check(const SkClampRange& range,
35                       const SkFixed fx, SkFixed dx, int count) {
36    SkASSERT(range.fCount0 + range.fCount1 + range.fCount2 == count);
37
38    // If dx is large, fx will overflow if updated naively.  So we use more bits.
39    int64_t bigfx = fx;
40
41    for (int i = 0; i < range.fCount0; i++) {
42        check_value(bigfx, range.fV0);
43        bigfx += dx;
44    }
45
46    for (int i = 0; i < range.fCount1; i++) {
47        check_value(bigfx, kRamp);
48        bigfx += dx;
49    }
50
51    for (int i = 0; i < range.fCount2; i++) {
52        check_value(bigfx, range.fV1);
53        bigfx += dx;
54    }
55}
56
57
58static void test_range(SkFixed fx, SkFixed dx, int count) {
59    SkClampRange range;
60    range.init(fx, dx, count, kV0, kV1);
61    slow_check(range, fx, dx, count);
62}
63
64#define ff(x)   SkIntToFixed(x)
65
66DEF_TEST(ClampRange, reporter) {
67    gReporter = reporter;
68
69    test_range(0, 0, 20);
70    test_range(0xFFFF, 0, 20);
71    test_range(-ff(2), 0, 20);
72    test_range( ff(2), 0, 20);
73
74    test_range(-10, 1, 20);
75    test_range(10, -1, 20);
76    test_range(-10, 3, 20);
77    test_range(10, -3, 20);
78
79    test_range(ff(1),  ff(16384),  100);
80    test_range(ff(-1), ff(-16384), 100);
81    test_range(ff(1)/2, ff(16384), 100);
82    // TODO(reed): skia:2481, fix whatever bug this is, then uncomment
83    //test_range(ff(1)/2, ff(-16384), 100);
84
85    SkRandom rand;
86
87    // test non-overflow cases
88    for (int i = 0; i < 1000000; i++) {
89        SkFixed fx = rand.nextS() >> 1;
90        SkFixed sx = rand.nextS() >> 1;
91        int count = rand.nextU() % 1000 + 1;
92        SkFixed dx = (sx - fx) / count;
93        test_range(fx, dx, count);
94    }
95
96    // TODO(reed): skia:2481, fix whatever bug this is, then uncomment
97    /*
98    // test overflow cases
99    for (int i = 0; i < 100000; i++) {
100        SkFixed fx = rand.nextS();
101        SkFixed dx = rand.nextS();
102        int count = rand.nextU() % 1000 + 1;
103        test_range(fx, dx, count);
104    }
105    */
106}
107