1/*
2 * Copyright 2017 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 "SkTypes.h"
9
10#include "SkCanvas.h"
11#include "SkSurface.h"
12
13#if SK_SUPPORT_GPU
14
15#include "GrContext.h"
16#include "GrTest.h"
17#include "Test.h"
18
19static SkBitmap read_pixels(sk_sp<SkSurface> surface) {
20    SkBitmap bmp;
21    bmp.allocN32Pixels(surface->width(), surface->height());
22    if (!surface->readPixels(bmp, 0, 0)) {
23        SkDebugf("readPixels failed\n");
24    }
25    return bmp;
26}
27
28static sk_sp<SkSurface> make_surface(GrContext* context) {
29    SkImageInfo info = SkImageInfo::Make(50, 50, kRGBA_8888_SkColorType, kPremul_SkAlphaType);
30    return SkSurface::MakeRenderTarget(context, SkBudgeted::kNo, info, 4,
31                                       kBottomLeft_GrSurfaceOrigin, nullptr);
32}
33
34// Tests that readPixels returns up-to-date results. Demonstrates a bug on Galaxy S6
35// (Mali T760), in MSAA mode.
36DEF_GPUTEST_FOR_RENDERING_CONTEXTS(skbug6653, reporter, ctxInfo) {
37    GrContext* ctx = ctxInfo.grContext();
38    SkRect rect = SkRect::MakeWH(50, 50);
39
40    SkPaint paint;
41    paint.setColor(SK_ColorWHITE);
42    paint.setStrokeWidth(5);
43    paint.setStyle(SkPaint::kStroke_Style);
44
45    // The one device that fails this test (Galaxy S6) does so in a flaky fashion. Trying many
46    // times makes it more likely to fail. Also, interacting with the phone (eg swiping between
47    // different home screens) while the test is running makes it fail close to 100%.
48    static const int kNumIterations = 50;
49
50    for (int i = 0; i < kNumIterations; ++i) {
51        auto s0 = make_surface(ctx);
52        if (!s0) {
53            // MSAA may not be supported
54            return;
55        }
56
57        auto s1 = make_surface(ctx);
58        s1->getCanvas()->clear(SK_ColorBLACK);
59        s1->getCanvas()->drawOval(rect, paint);
60        SkBitmap b1 = read_pixels(s1);
61        s1 = nullptr;
62
63        // The bug requires that all three of the following surfaces are cleared to the same color
64        auto s2 = make_surface(ctx);
65        s2->getCanvas()->clear(SK_ColorBLUE);
66        SkBitmap b2 = read_pixels(s2);
67        s2 = nullptr;
68
69        auto s3 = make_surface(ctx);
70        s3->getCanvas()->clear(SK_ColorBLUE);
71        SkBitmap b3 = read_pixels(s3);
72        s0->getCanvas()->drawBitmap(b3, 0, 0);
73        s3 = nullptr;
74
75        auto s4 = make_surface(ctx);
76        s4->getCanvas()->clear(SK_ColorBLUE);
77        s4->getCanvas()->drawOval(rect, paint);
78
79        // When this fails, b4 will "succeed", but return an empty bitmap (containing just the
80        // clear color). Regardless, b5 will contain the oval that was just drawn, so diffing the
81        // two bitmaps tests for the failure case.
82        SkBitmap b4 = read_pixels(s4);
83        SkBitmap b5 = read_pixels(s4);
84
85        bool match = true;
86        for (int y = 0; y < b4.height() && match; ++y) {
87            for (int x = 0; x < b4.width() && match; ++x) {
88                uint32_t pixelA = *b4.getAddr32(x, y);
89                uint32_t pixelB = *b5.getAddr32(x, y);
90                if (pixelA != pixelB) {
91                    match = false;
92                }
93            }
94        }
95
96        REPORTER_ASSERT(reporter, match);
97    }
98}
99
100#endif
101