gecko-dev/dom/canvas/WebGLElementArrayCache.h

104 строки
3.5 KiB
C++

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef WEBGL_ELEMENT_ARRAY_CACHE_H
#define WEBGL_ELEMENT_ARRAY_CACHE_H
#include "GLDefs.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/UniquePtr.h"
#include "nscore.h"
#include "nsTArray.h"
#include <stdint.h>
namespace mozilla {
template<typename T>
struct WebGLElementArrayCacheTree;
/* WebGLElementArrayCache implements WebGL element array buffer validation for
* drawElements.
*
* Its exposes methods meant to be called by WebGL method implementations:
*
* - Validate, to be called by WebGLContext::DrawElements, is where we use the
* cache.
*
* - BufferData and BufferSubData, to be called by eponymous WebGL methods, are
* how data is fed into the cache.
*
* Most of the implementation is hidden in the auxilary class template,
* WebGLElementArrayCacheTree. Refer to its code for design comments.
*/
class WebGLElementArrayCache {
public:
bool BufferData(const void* ptr, size_t byteLength);
bool BufferSubData(size_t pos, const void* ptr, size_t updateByteSize);
bool Validate(GLenum type, uint32_t maxAllowed, size_t first, size_t count,
uint32_t* const out_upperBound);
template<typename T>
T Element(size_t i) const { return Elements<T>()[i]; }
WebGLElementArrayCache();
~WebGLElementArrayCache();
size_t SizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const;
bool BeenUsedWithMultipleTypes() const;
private:
/* Returns true if a drawElements call with the given parameters should
* succeed, false otherwise.
*
* In other words, this returns true if all entries in the element array at
* positions:
*
* first .. first+count-1
*
* are less than or equal to maxAllowed.
*
* Input parameters:
* maxAllowed: Maximum value to be allowed in the specificied portion of
* the element array.
* first: Start of the portion of the element array to consume.
* count: Number of entries from the element array to consume.
*
* Output parameter:
* out_upperBound: Upon success, is set to the actual maximum value in the
* specified range, which is then guaranteed to be less
* than or equal to maxAllowed. upon failure, is set to
* the first value in the specified range, that is greater
* than maxAllowed.
*/
template<typename T>
bool Validate(uint32_t maxAllowed, size_t first, size_t count,
uint32_t* const out_upperBound);
template<typename T>
const T* Elements() const {
return reinterpret_cast<const T*>(mBytes.Elements());
}
template<typename T>
T* Elements() { return reinterpret_cast<T*>(mBytes.Elements()); }
bool UpdateTrees(size_t firstByte, size_t lastByte);
template<typename T>
friend struct WebGLElementArrayCacheTree;
template<typename T>
friend struct TreeForType;
FallibleTArray<uint8_t> mBytes;
UniquePtr<WebGLElementArrayCacheTree<uint8_t>> mUint8Tree;
UniquePtr<WebGLElementArrayCacheTree<uint16_t>> mUint16Tree;
UniquePtr<WebGLElementArrayCacheTree<uint32_t>> mUint32Tree;
};
} // end namespace mozilla
#endif // WEBGL_ELEMENT_ARRAY_CACHE_H