GrTexture.h revision b8670998a59d305cd22a3c0cbdc6e075b0a37a6e 
1
2/*
3 * Copyright 2011 Google Inc.
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9#ifndef GrTexture_DEFINED
10#define GrTexture_DEFINED
11
12#include "GrSurface.h"
13
14class GrRenderTarget;
15class GrResourceKey;
16class GrTextureParams;
17
18/*
19 * All uncached textures should have this value as their fClientCacheID
20 */
21static const uint64_t kUncached_CacheID = 0xAAAAAAAA;
22
23/*
24 * Scratch textures should all have this value as their fClientCacheID
25 */
26static const uint64_t kScratch_CacheID = 0xBBBBBBBB;
27
28
29class GrTexture : public GrSurface {
30
31public:
32    SK_DECLARE_INST_COUNT(GrTexture)
33
34    // from GrResource
35    /**
36     * Informational texture flags
37     */
38    enum FlagBits {
39        kFirstBit = (kLastPublic_GrTextureFlagBit << 1),
40
41        /**
42         * This texture should be returned to the texture cache when
43         * it is no longer reffed
44         */
45        kReturnToCache_FlagBit        = kFirstBit,
46    };
47
48    void setFlag(GrTextureFlags flags) {
49        fDesc.fFlags = fDesc.fFlags | flags;
50    }
51    void resetFlag(GrTextureFlags flags) {
52        fDesc.fFlags = fDesc.fFlags & ~flags;
53    }
54    bool isSetFlag(GrTextureFlags flags) const {
55        return 0 != (fDesc.fFlags & flags);
56    }
57
58    /**
59     *  Approximate number of bytes used by the texture
60     */
61    virtual size_t sizeInBytes() const SK_OVERRIDE {
62        return (size_t) fDesc.fWidth *
63                        fDesc.fHeight *
64                        GrBytesPerPixel(fDesc.fConfig);
65    }
66
67    // from GrSurface
68    /**
69     * Read a rectangle of pixels from the texture.
70     * @param left          left edge of the rectangle to read (inclusive)
71     * @param top           top edge of the rectangle to read (inclusive)
72     * @param width         width of rectangle to read in pixels.
73     * @param height        height of rectangle to read in pixels.
74     * @param config        the pixel config of the destination buffer
75     * @param buffer        memory to read the rectangle into.
76     * @param rowBytes      number of bytes bewtween consecutive rows. Zero
77     *                      means rows are tightly packed.
78     *
79     * @return true if the read succeeded, false if not. The read can fail
80     *              because of a unsupported pixel config.
81     */
82    virtual bool readPixels(int left, int top, int width, int height,
83                            GrPixelConfig config, void* buffer,
84                            size_t rowBytes) SK_OVERRIDE;
85
86    /**
87     * Writes a rectangle of pixels to the texture.
88     * @param left          left edge of the rectangle to write (inclusive)
89     * @param top           top edge of the rectangle to write (inclusive)
90     * @param width         width of rectangle to write in pixels.
91     * @param height        height of rectangle to write in pixels.
92     * @param config        the pixel config of the source buffer
93     * @param buffer        memory to read pixels from
94     * @param rowBytes      number of bytes between consecutive rows. Zero
95     *                      means rows are tightly packed.
96     */
97    virtual void writePixels(int left, int top, int width, int height,
98                             GrPixelConfig config, const void* buffer,
99                             size_t rowBytes) SK_OVERRIDE;
100
101    /**
102     * @return this texture
103     */
104    virtual GrTexture* asTexture() SK_OVERRIDE { return this; }
105    virtual const GrTexture* asTexture() const SK_OVERRIDE { return this; }
106
107    /**
108     * Retrieves the render target underlying this texture that can be passed to
109     * GrGpu::setRenderTarget().
110     *
111     * @return    handle to render target or NULL if the texture is not a
112     *            render target
113     */
114    virtual GrRenderTarget* asRenderTarget() SK_OVERRIDE {
115        return fRenderTarget;
116    }
117    virtual const GrRenderTarget* asRenderTarget() const SK_OVERRIDE {
118        return fRenderTarget;
119    }
120
121    // GrTexture
122    /**
123     * Convert from texels to normalized texture coords for POT textures
124     * only.
125     */
126    GrFixed normalizeFixedX(GrFixed x) const {
127        GrAssert(GrIsPow2(fDesc.fWidth));
128        return x >> fShiftFixedX;
129    }
130    GrFixed normalizeFixedY(GrFixed y) const {
131        GrAssert(GrIsPow2(fDesc.fHeight));
132        return y >> fShiftFixedY;
133    }
134
135    /**
136     * Removes the reference on the associated GrRenderTarget held by this
137     * texture. Afterwards asRenderTarget() will return NULL. The
138     * GrRenderTarget survives the release if another ref is held on it.
139     */
140    void releaseRenderTarget();
141
142    /**
143     *  Return the native ID or handle to the texture, depending on the
144     *  platform. e.g. on opengl, return the texture ID.
145     */
146    virtual intptr_t getTextureHandle() const = 0;
147
148    /**
149     *  Call this when the state of the native API texture object is
150     *  altered directly, without being tracked by skia.
151     */
152    virtual void invalidateCachedState() = 0;
153
154#if GR_DEBUG
155    void validate() const {
156        this->INHERITED::validate();
157
158        this->validateDesc();
159    }
160#else
161    void validate() const {}
162#endif
163
164    static GrResourceKey ComputeKey(const GrGpu* gpu,
165                                    const GrTextureParams* sampler,
166                                    const GrTextureDesc& desc,
167                                    bool scratch);
168
169    static bool NeedsResizing(const GrResourceKey& key);
170    static bool IsScratchTexture(const GrResourceKey& key);
171    static bool NeedsFiltering(const GrResourceKey& key);
172
173protected:
174    GrRenderTarget* fRenderTarget; // texture refs its rt representation
175                                   // base class cons sets to NULL
176                                   // subclass cons can create and set
177
178    GrTexture(GrGpu* gpu, const GrTextureDesc& desc)
179    : INHERITED(gpu, desc)
180    , fRenderTarget(NULL) {
181
182        // only make sense if alloc size is pow2
183        fShiftFixedX = 31 - Gr_clz(fDesc.fWidth);
184        fShiftFixedY = 31 - Gr_clz(fDesc.fHeight);
185    }
186
187    // GrResource overrides
188    virtual void onRelease() SK_OVERRIDE;
189    virtual void onAbandon() SK_OVERRIDE;
190
191    void validateDesc() const;
192
193private:
194    // these two shift a fixed-point value into normalized coordinates
195    // for this texture if the texture is power of two sized.
196    int                 fShiftFixedX;
197    int                 fShiftFixedY;
198
199    virtual void internal_dispose() const SK_OVERRIDE;
200
201    typedef GrSurface INHERITED;
202};
203
204#endif
205
206