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1 // Copyright 2016 The Chromium Authors. All rights reserved. | 1 // Copyright 2016 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #include "cc/tiles/mipmap_util.h" | 5 #include "cc/tiles/mipmap_util.h" |
6 | 6 |
7 namespace cc { | 7 namespace cc { |
8 namespace { | 8 namespace { |
9 // Calculates the size of |axis_base_size| at the given |mip_level| using | 9 // Calculates the size of |axis_base_size| at the given |mip_level| using |
10 // OpenGL rounding rules. | 10 // OpenGL rounding rules. |
11 int ScaleAxisToMipLevel(int axis_base_size, int mip_level) { | 11 int ScaleAxisToMipLevel(int axis_base_size, int mip_level) { |
12 DCHECK_GE(mip_level, 0); | 12 DCHECK_GE(mip_level, 0); |
13 DCHECK_LT(mip_level, 32); | 13 DCHECK_LT(mip_level, 32); |
14 return std::max(1, axis_base_size >> mip_level); | 14 return std::max(1, axis_base_size >> mip_level); |
15 } | 15 } |
16 | 16 |
17 } // namespace | 17 } // namespace |
18 | 18 |
19 int MipMapUtil::GetLevelForSize(const gfx::Size& src_size, | 19 int MipMapUtil::GetLevelForSize(const gfx::Size& src_size, |
20 const gfx::Size& target_size) { | 20 const gfx::Size& target_size) { |
21 int src_height = src_size.height(); | 21 int src_height = src_size.height(); |
22 int src_width = src_size.width(); | 22 int src_width = src_size.width(); |
23 int target_height = target_size.height(); | 23 int target_height = target_size.height(); |
24 int target_width = target_size.width(); | 24 int target_width = target_size.width(); |
25 bool target_invalid = target_height == 0 || target_width == 0; | 25 DCHECK_GT(target_height, 0); |
26 bool src_invalid = src_height == 0 || src_width == 0; | 26 DCHECK_GT(target_width, 0); |
27 if (target_invalid || src_invalid) | 27 DCHECK_GT(src_width, 0); |
28 return -1; | 28 DCHECK_GT(src_height, 0); |
29 | 29 |
30 int next_mip_height = src_height; | 30 int next_mip_height = src_height; |
31 int next_mip_width = src_width; | 31 int next_mip_width = src_width; |
32 for (int current_mip_level = 0;; current_mip_level++) { | 32 for (int current_mip_level = 0;; current_mip_level++) { |
33 int mip_height = next_mip_height; | 33 int mip_height = next_mip_height; |
34 int mip_width = next_mip_width; | 34 int mip_width = next_mip_width; |
35 | 35 |
36 next_mip_height = ScaleAxisToMipLevel(src_height, current_mip_level + 1); | 36 next_mip_height = ScaleAxisToMipLevel(src_height, current_mip_level + 1); |
37 next_mip_width = ScaleAxisToMipLevel(src_width, current_mip_level + 1); | 37 next_mip_width = ScaleAxisToMipLevel(src_width, current_mip_level + 1); |
38 | 38 |
39 // Check if an axis on the next mip level would be smaller than the target. | 39 // Check if an axis on the next mip level would be smaller than the target. |
40 // If so, use the current mip level. | 40 // If so, use the current mip level. |
41 // This effectively always uses the larger image and always scales down. | 41 // This effectively always uses the larger image and always scales down. |
42 if (next_mip_height < target_height || next_mip_width < target_width) { | 42 if (next_mip_height < target_height || next_mip_width < target_width) { |
43 return current_mip_level; | 43 return current_mip_level; |
44 } | 44 } |
45 | 45 |
46 if (mip_height == 1 && mip_width == 1) { | 46 if (mip_height == 1 && mip_width == 1) { |
47 // We have reached the final mip level | 47 // We have reached the final mip level |
48 return current_mip_level; | 48 return current_mip_level; |
49 } | 49 } |
50 } | 50 } |
51 } | 51 } |
52 | 52 |
53 SkSize MipMapUtil::GetScaleAdjustmentForLevel(const gfx::Size& src_size, | 53 SkSize MipMapUtil::GetScaleAdjustmentForLevel(const gfx::Size& src_size, |
54 int mip_level) { | 54 int mip_level) { |
55 if (src_size.width() == 0 || src_size.height() == 0 || mip_level == -1) | 55 DCHECK_GT(src_size.width(), 0); |
56 return SkSize::Make(-1, -1); | 56 DCHECK_GT(src_size.height(), 0); |
| 57 DCHECK_GE(mip_level, 0); |
57 | 58 |
58 gfx::Size target_size = GetSizeForLevel(src_size, mip_level); | 59 gfx::Size target_size = GetSizeForLevel(src_size, mip_level); |
59 | 60 |
60 return SkSize::Make( | 61 return SkSize::Make( |
61 static_cast<float>(target_size.width()) / src_size.width(), | 62 static_cast<float>(target_size.width()) / src_size.width(), |
62 static_cast<float>(target_size.height()) / src_size.height()); | 63 static_cast<float>(target_size.height()) / src_size.height()); |
63 } | 64 } |
64 | 65 |
65 gfx::Size MipMapUtil::GetSizeForLevel(const gfx::Size& src_size, | 66 gfx::Size MipMapUtil::GetSizeForLevel(const gfx::Size& src_size, |
66 int mip_level) { | 67 int mip_level) { |
67 if (src_size.width() == 0 || src_size.height() == 0 || mip_level == -1) | 68 DCHECK_GT(src_size.width(), 0); |
68 return gfx::Size(-1, -1); | 69 DCHECK_GT(src_size.height(), 0); |
| 70 DCHECK_GE(mip_level, 0); |
69 | 71 |
70 return gfx::Size(ScaleAxisToMipLevel(src_size.width(), mip_level), | 72 return gfx::Size(ScaleAxisToMipLevel(src_size.width(), mip_level), |
71 ScaleAxisToMipLevel(src_size.height(), mip_level)); | 73 ScaleAxisToMipLevel(src_size.height(), mip_level)); |
72 } | 74 } |
73 | 75 |
74 SkSize MipMapUtil::GetScaleAdjustmentForSize(const gfx::Size& src_size, | 76 SkSize MipMapUtil::GetScaleAdjustmentForSize(const gfx::Size& src_size, |
75 const gfx::Size& target_size) { | 77 const gfx::Size& target_size) { |
76 int target_mip_level = GetLevelForSize(src_size, target_size); | 78 int target_mip_level = GetLevelForSize(src_size, target_size); |
77 return GetScaleAdjustmentForLevel(src_size, target_mip_level); | 79 return GetScaleAdjustmentForLevel(src_size, target_mip_level); |
78 } | 80 } |
79 | 81 |
80 } // namespace cc | 82 } // namespace cc |
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