1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
|
/*
* Copyright 2012 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef GrClipMaskManager_DEFINED
#define GrClipMaskManager_DEFINED
#include "GrClipMaskCache.h"
#include "GrContext.h"
#include "GrDrawState.h"
#include "GrReducedClip.h"
#include "GrStencil.h"
#include "GrTexture.h"
#include "SkClipStack.h"
#include "SkDeque.h"
#include "SkPath.h"
#include "SkRefCnt.h"
#include "SkTLList.h"
#include "SkTypes.h"
class GrGpu;
class GrPathRenderer;
class GrPathRendererChain;
class GrTexture;
class SkPath;
/**
* The clip mask creator handles the generation of the clip mask. If anti
* aliasing is requested it will (in the future) generate a single channel
* (8bit) mask. If no anti aliasing is requested it will generate a 1-bit
* mask in the stencil buffer. In the non anti-aliasing case, if the clip
* mask can be represented as a rectangle then scissoring is used. In all
* cases scissoring is used to bound the range of the clip mask.
*/
class GrClipMaskManager : public SkNoncopyable {
public:
GrClipMaskManager()
: fGpu(NULL)
, fCurrClipMaskType(kNone_ClipMaskType) {
}
/**
* Creates a clip mask if necessary as a stencil buffer or alpha texture
* and sets the GrGpu's scissor and stencil state. If the return is false
* then the draw can be skipped. The AutoRestoreEffects is initialized by
* the manager when it must install additional effects to implement the
* clip. devBounds is optional but can help optimize clipping.
*/
bool setupClipping(const GrClipData* clipDataIn, GrDrawState::AutoRestoreEffects*,
const SkRect* devBounds);
void releaseResources();
bool isClipInStencil() const {
return kStencil_ClipMaskType == fCurrClipMaskType;
}
bool isClipInAlpha() const {
return kAlpha_ClipMaskType == fCurrClipMaskType;
}
void invalidateStencilMask() {
if (kStencil_ClipMaskType == fCurrClipMaskType) {
fCurrClipMaskType = kNone_ClipMaskType;
}
}
GrContext* getContext() {
return fAACache.getContext();
}
void setGpu(GrGpu* gpu);
void adjustPathStencilParams(GrStencilSettings* settings);
private:
/**
* Informs the helper function adjustStencilParams() about how the stencil
* buffer clip is being used.
*/
enum StencilClipMode {
// Draw to the clip bit of the stencil buffer
kModifyClip_StencilClipMode,
// Clip against the existing representation of the clip in the high bit
// of the stencil buffer.
kRespectClip_StencilClipMode,
// Neither writing to nor clipping against the clip bit.
kIgnoreClip_StencilClipMode,
};
GrGpu* fGpu;
/**
* We may represent the clip as a mask in the stencil buffer or as an alpha
* texture. It may be neither because the scissor rect suffices or we
* haven't yet examined the clip.
*/
enum ClipMaskType {
kNone_ClipMaskType,
kStencil_ClipMaskType,
kAlpha_ClipMaskType,
} fCurrClipMaskType;
GrClipMaskCache fAACache; // cache for the AA path
// Draws the clip into the stencil buffer
bool createStencilClipMask(int32_t elementsGenID,
GrReducedClip::InitialState initialState,
const GrReducedClip::ElementList& elements,
const SkIRect& clipSpaceIBounds,
const SkIPoint& clipSpaceToStencilOffset);
// Creates an alpha mask of the clip. The mask is a rasterization of elements through the
// rect specified by clipSpaceIBounds.
GrTexture* createAlphaClipMask(int32_t elementsGenID,
GrReducedClip::InitialState initialState,
const GrReducedClip::ElementList& elements,
const SkIRect& clipSpaceIBounds);
// Similar to createAlphaClipMask but it rasterizes in SW and uploads to the result texture.
GrTexture* createSoftwareClipMask(int32_t elementsGenID,
GrReducedClip::InitialState initialState,
const GrReducedClip::ElementList& elements,
const SkIRect& clipSpaceIBounds);
// Gets a texture to use for the clip mask. If true is returned then a cached mask was found
// that already contains the rasterization of the clip stack, otherwise an uninitialized texture
// is returned. 'willUpload' is set when the alpha mask needs to be uploaded from the CPU.
bool getMaskTexture(int32_t elementsGenID,
const SkIRect& clipSpaceIBounds,
GrTexture** result,
bool willUpload);
bool useSWOnlyPath(const GrReducedClip::ElementList& elements);
// Draws a clip element into the target alpha mask. The caller should have already setup the
// desired blend operation. Optionally if the caller already selected a path renderer it can
// be passed. Otherwise the function will select one if the element is a path.
bool drawElement(GrTexture* target, const SkClipStack::Element*, GrPathRenderer* = NULL);
// Determines whether it is possible to draw the element to both the stencil buffer and the
// alpha mask simultaneously. If so and the element is a path a compatible path renderer is
// also returned.
bool canStencilAndDrawElement(GrTexture* target, const SkClipStack::Element*, GrPathRenderer**);
void mergeMask(GrTexture* dstMask,
GrTexture* srcMask,
SkRegion::Op op,
const SkIRect& dstBound,
const SkIRect& srcBound);
void getTemp(int width, int height, GrAutoScratchTexture* temp);
void setupCache(const SkClipStack& clip,
const SkIRect& bounds);
/**
* Called prior to return control back the GrGpu in setupClipping. It
* updates the GrGpu with stencil settings that account stencil-based
* clipping.
*/
void setGpuStencil();
/**
* Adjusts the stencil settings to account for interaction with stencil
* clipping.
*/
void adjustStencilParams(GrStencilSettings* settings,
StencilClipMode mode,
int stencilBitCnt);
typedef SkNoncopyable INHERITED;
};
#endif // GrClipMaskManager_DEFINED
|
