1/*
2 * Copyright (c) 2010, Google Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are
6 * met:
7 *
8 *     * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *     * Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following disclaimer
12 * in the documentation and/or other materials provided with the
13 * distribution.
14 *     * Neither the name of Google Inc. nor the names of its
15 * contributors may be used to endorse or promote products derived from
16 * this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#ifndef DrawingBuffer_h
32#define DrawingBuffer_h
33
34#include "core/platform/graphics/GraphicsContext3D.h"
35#include "core/platform/graphics/GraphicsTypes3D.h"
36#include "core/platform/graphics/IntSize.h"
37
38#include "public/platform/WebExternalTextureLayerClient.h"
39#include "public/platform/WebExternalTextureMailbox.h"
40#include "wtf/Noncopyable.h"
41#include "wtf/OwnPtr.h"
42#include "wtf/PassOwnPtr.h"
43
44namespace WebKit {
45class WebExternalBitmap;
46class WebExternalTextureLayer;
47class WebGraphicsContext3D;
48class WebLayer;
49}
50
51namespace WebCore {
52class GraphicsContext3D;
53class ImageData;
54
55// Abstract interface to allow basic context eviction management
56class ContextEvictionManager : public RefCounted<ContextEvictionManager> {
57public:
58    virtual ~ContextEvictionManager() {};
59
60    virtual void forciblyLoseOldestContext(const String& reason) = 0;
61    virtual IntSize oldestContextSize() = 0;
62};
63
64// Manages a rendering target (framebuffer + attachment) for a canvas.  Can publish its rendering
65// results to a WebKit::WebLayer for compositing.
66class DrawingBuffer : public RefCounted<DrawingBuffer>, public WebKit::WebExternalTextureLayerClient  {
67    struct MailboxInfo : public RefCounted<MailboxInfo> {
68        WebKit::WebExternalTextureMailbox mailbox;
69        unsigned textureId;
70        IntSize size;
71    };
72public:
73    enum PreserveDrawingBuffer {
74        Preserve,
75        Discard
76    };
77
78    static PassRefPtr<DrawingBuffer> create(GraphicsContext3D*, const IntSize&, PreserveDrawingBuffer, PassRefPtr<ContextEvictionManager>);
79
80    ~DrawingBuffer();
81
82    // Clear all resources from this object, as well as context. Called when context is destroyed
83    // to prevent invalid accesses to the resources.
84    void releaseResources();
85
86    // Issues a glClear() on all framebuffers associated with this DrawingBuffer. The caller is responsible for
87    // making the context current and setting the clear values and masks. Modifies the framebuffer binding.
88    void clearFramebuffers(GC3Dbitfield clearMask);
89
90    // Given the desired buffer size, provides the largest dimensions that will fit in the pixel budget.
91    IntSize adjustSize(const IntSize&);
92    void reset(const IntSize&);
93    void bind();
94    IntSize size() const { return m_size; }
95    bool isZeroSized() const { return m_size.isEmpty(); }
96
97    // Copies the multisample color buffer to the normal color buffer and leaves m_fbo bound.
98    void commit(long x = 0, long y = 0, long width = -1, long height = -1);
99
100    // commit should copy the full multisample buffer, and not respect the
101    // current scissor bounds. Track the state of the scissor test so that it
102    // can be disabled during calls to commit.
103    void setScissorEnabled(bool scissorEnabled) { m_scissorEnabled = scissorEnabled; }
104
105    // The DrawingBuffer needs to track the texture bound to texture unit 0.
106    // The bound texture is tracked to avoid costly queries during rendering.
107    void setTexture2DBinding(Platform3DObject texture) { m_texture2DBinding = texture; }
108
109    // The DrawingBuffer needs to track the currently bound framebuffer so it
110    // restore the binding when needed.
111    void setFramebufferBinding(Platform3DObject fbo) { m_framebufferBinding = fbo; }
112
113    // Track the currently active texture unit. Texture unit 0 is used as host for a scratch
114    // texture.
115    void setActiveTextureUnit(GC3Dint textureUnit) { m_activeTextureUnit = textureUnit; }
116
117    bool multisample() const;
118
119    Platform3DObject framebuffer() const;
120
121    void markContentsChanged() { m_contentsChanged = true; }
122
123    WebKit::WebLayer* platformLayer();
124    void paintCompositedResultsToCanvas(ImageBuffer*);
125
126    // WebExternalTextureLayerClient implementation.
127    virtual WebKit::WebGraphicsContext3D* context() OVERRIDE;
128    virtual bool prepareMailbox(WebKit::WebExternalTextureMailbox*, WebKit::WebExternalBitmap*) OVERRIDE;
129    virtual void mailboxReleased(const WebKit::WebExternalTextureMailbox&) OVERRIDE;
130
131private:
132    DrawingBuffer(GraphicsContext3D*, const IntSize&, bool multisampleExtensionSupported,
133                  bool packedDepthStencilExtensionSupported, PreserveDrawingBuffer, PassRefPtr<ContextEvictionManager>);
134
135    void initialize(const IntSize&);
136
137    Platform3DObject frontColorBuffer() const;
138    Platform3DObject colorBuffer() const { return m_colorBuffer; }
139
140    unsigned createColorTexture(const IntSize& size = IntSize());
141    // Create the depth/stencil and multisample buffers, if needed.
142    void createSecondaryBuffers();
143    bool resizeFramebuffer(const IntSize&);
144    bool resizeMultisampleFramebuffer(const IntSize&);
145    void resizeDepthStencil(const IntSize&, int sampleCount);
146    bool checkBufferIntegrity();
147
148    // Bind to the m_framebufferBinding if it's not 0.
149    void restoreFramebufferBinding();
150
151    void clearPlatformLayer();
152
153    PassRefPtr<MailboxInfo> getRecycledMailbox();
154    PassRefPtr<MailboxInfo> createNewMailbox(unsigned);
155
156    // Updates the current size of the buffer, ensuring that s_currentResourceUsePixels is updated.
157    void setSize(const IntSize& size);
158
159    // Calculates the difference in pixels between the current buffer size and the proposed size.
160    int pixelDelta(const IntSize& size);
161
162    // Given the desired buffer size, provides the largest dimensions that will fit in the pixel budget
163    // Returns true if the buffer will only fit if the oldest WebGL context is forcibly lost
164    IntSize adjustSizeWithContextEviction(const IntSize&, bool& evictContext);
165
166    PreserveDrawingBuffer m_preserveDrawingBuffer;
167    bool m_scissorEnabled;
168    Platform3DObject m_texture2DBinding;
169    Platform3DObject m_framebufferBinding;
170    GC3Denum m_activeTextureUnit;
171
172    RefPtr<GraphicsContext3D> m_context;
173    IntSize m_size;
174    bool m_multisampleExtensionSupported;
175    bool m_packedDepthStencilExtensionSupported;
176    Platform3DObject m_fbo;
177    Platform3DObject m_colorBuffer;
178    Platform3DObject m_frontColorBuffer;
179    bool m_separateFrontTexture;
180
181    // This is used when we have OES_packed_depth_stencil.
182    Platform3DObject m_depthStencilBuffer;
183
184    // These are used when we don't.
185    Platform3DObject m_depthBuffer;
186    Platform3DObject m_stencilBuffer;
187
188    // For multisampling.
189    Platform3DObject m_multisampleFBO;
190    Platform3DObject m_multisampleColorBuffer;
191
192    // True if our contents have been modified since the last presentation of this buffer.
193    bool m_contentsChanged;
194
195    GraphicsContext3D::Attributes m_attributes;
196    unsigned m_internalColorFormat;
197    unsigned m_colorFormat;
198    unsigned m_internalRenderbufferFormat;
199    int m_maxTextureSize;
200
201    OwnPtr<WebKit::WebExternalTextureLayer> m_layer;
202
203    // All of the mailboxes that this DrawingBuffer has ever created.
204    Vector<RefPtr<MailboxInfo> > m_textureMailboxes;
205    // Mailboxes that were released by the compositor and can be used again by this DrawingBuffer.
206    Vector<RefPtr<MailboxInfo> > m_recycledMailboxes;
207    RefPtr<MailboxInfo> m_lastColorBuffer;
208
209    RefPtr<ContextEvictionManager> m_contextEvictionManager;
210};
211
212} // namespace WebCore
213
214#endif // DrawingBuffer_h
215