OpenSpace/modules/globebrowsing/other/pixelbuffercontainer.h

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 * OpenSpace                                                                             *
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 * Copyright (c) 2014-2017                                                               *
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#ifndef __OPENSPACE_MODULE_GLOBEBROWSING___PIXEL_BUFFER_CONTAINER___H__
#define __OPENSPACE_MODULE_GLOBEBROWSING___PIXEL_BUFFER_CONTAINER___H__

#include <modules/globebrowsing/other/pixelbuffer.h>

#include <map>

namespace openspace {
namespace globebrowsing {

/**
 * Templated class which owns one or many <code>PixelBuffer</code>s. The
 * <code>KeyType</code> is used to map a pixel buffer but only if it is not already
 * mapped.
 */
template <class KeyType>
class PixelBufferContainer
{
public:
    /**
     * Creates numPixelBuffers pixel buffer objects, each with numBytesPerBuffer bytes
     * allocated on the GPU.
     * \param numBytesPerBuffer is the number of bytes per pixel buffer. All pixel
     * buffers within a <code>PixelBufferContainer</code> have the same number of bytes
     * \param usage is the <code>Usage</code> as described by <code>PixelBuffer</code>
     * \param numPixelBuffers is the number of pixel buffers to create for this container.
     * If numPixelBuffers is omitted, no pixel buffers are created.
     */
    PixelBufferContainer(size_t numBytesPerBuffer,
        globebrowsing::PixelBuffer::Usage usage, size_t numPixelBuffers = 0);
    ~PixelBufferContainer() = default;

    /**
     * Finds a Pixel buffer and maps it if it is available.
     * \param key is the identifier for the pixel buffer which can be used later when
     * unmapping the mapped pixel buffer.
     * \param access is the access as described by <code>PixelBuffer</code>
     * \returns an address pointer to DMA if the mapping succeeded. Otherwise a nullptr
     * is returned. The mapping can fail if the buffer identified with <code>key</code>
     * is already mapped or if something else failed.
     */
    void* mapBuffer(KeyType key, PixelBuffer::Access access);
    
    /**
     * Finds a Pixel buffer and maps a range of it if it is available.
     * \param key is the identifier for the pixel buffer which can be used later when
     * unmapping the mapped pixel buffer.
     * \param offet is the number of bytes to the first address to get in the buffer
     * \param length is the number of bytes to access in the buffer
     * \param access is the access as described by <code>PixelBuffer</code>
     * \returns an address pointer to DMA if the mapping succeeded. Otherwise a nullptr
     * is returned. The mapping can fail if the buffer identified with <code>key</code>
     * is already mapped or if something else failed.
     */
    void* mapBufferRange(KeyType key, GLintptr offset, GLsizeiptr length,
        GLbitfield access);

    /**
     * Unmaps all buffers in the PixelBufferContainer.
     * \returns true if the unmapping succeeded, otherwise false.
     */
    bool resetMappedBuffers();

    /**
     * Unmaps a buffer that has previously been mapped. This buffer is identified using
     * <code>key</code>.
     * \param key is the identifier of the mapped buffer.
     * \returns true if the unmapping succeeded, otherwise false.
     */
    bool unMapBuffer(KeyType key);

    /**
     * \returns the <code>GLuint</code> id of a pixel buffer identified by <code>key</code>
     * if it currently is mapped.
     */
    GLuint idOfMappedBuffer(KeyType key);
private:
    const globebrowsing::PixelBuffer::Usage _usage;

    std::vector<std::unique_ptr<PixelBuffer>> _pixelBuffers;
    
    // Maps from KeyType to index of mapped buffers
    std::map<KeyType, int> _indexMap;
};

} // namespace globebrowsing
} // namespace openspace

#include "pixelbuffercontainer.inl"

#endif // __OPENSPACE_MODULE_GLOBEBROWSING___PIXEL_BUFFER_CONTAINER___H__