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CLK/Outputs/CRT/Internals/ArrayBuilder.hpp

102 lines
3.6 KiB
C++

//
// ArrayBuilder.hpp
// Clock Signal
//
// Created by Thomas Harte on 17/11/2016.
// Copyright © 2016 Thomas Harte. All rights reserved.
//
#ifndef ArrayBuilder_hpp
#define ArrayBuilder_hpp
#include <functional>
#include <memory>
#include <vector>
#include "OpenGL.hpp"
namespace Outputs {
namespace CRT {
/*!
Owns two array buffers, an 'input' and an 'output' and vends pointers to allow an owner to write provisional data into those
plus a flush function to lock provisional data into place. Also supplies a submit method to transfer all currently locked
data to the GPU and bind_input/output methods to bind the internal buffers.
It is safe for one thread to communicate via the get_*_storage and flush inputs asynchronously from another that is making
use of the bind and submit outputs.
*/
class ArrayBuilder {
public:
/// Creates an instance of ArrayBuilder with @c output_size bytes of storage for the output buffer and
/// @c input_size bytes of storage for the input buffer.
ArrayBuilder(std::size_t input_size, std::size_t output_size);
/// Creates an instance of ArrayBuilder with @c output_size bytes of storage for the output buffer and
/// @c input_size bytes of storage for the input buffer that, rather than using OpenGL, will submit data
/// to the @c submission_function. [Teleological: this is provided as a testing hook.]
ArrayBuilder(std::size_t input_size, std::size_t output_size, std::function<void(bool is_input, uint8_t *, std::size_t)> submission_function);
/// Attempts to add @c size bytes to the input set.
/// @returns a pointer to the allocated area if allocation was possible; @c nullptr otherwise.
uint8_t *get_input_storage(std::size_t size);
/// Attempts to add @c size bytes to the output set.
/// @returns a pointer to the allocated area if allocation was possible; @c nullptr otherwise.
uint8_t *get_output_storage(std::size_t size);
/// @returns @c true if either of the input or output storage areas is currently exhausted; @c false otherwise.
bool is_full();
/// If neither input nor output was exhausted since the last flush, atomically commits both input and output
/// up to the currently allocated size for use upon the next @c submit, giving the supplied function a
/// chance to perform last-minute processing. Otherwise acts as a no-op.
void flush(const std::function<void(uint8_t *input, std::size_t input_size, uint8_t *output, std::size_t output_size)> &);
/// Binds the input array to GL_ARRAY_BUFFER.
void bind_input();
/// Binds the output array to GL_ARRAY_BUFFER.
void bind_output();
struct Submission {
std::size_t input_size, output_size;
};
/// Submits all flushed input and output data to the corresponding arrays.
/// @returns A @c Submission record, indicating how much data of each type was submitted.
Submission submit();
private:
class Buffer {
public:
Buffer(std::size_t size, std::function<void(bool is_input, uint8_t *, std::size_t)> submission_function);
~Buffer();
uint8_t *get_storage(std::size_t size);
uint8_t *get_unflushed(std::size_t &size);
void flush();
std::size_t submit(bool is_input);
void bind();
void reset();
private:
bool is_full = false;
GLuint buffer = 0;
std::function<void(bool is_input, uint8_t *, std::size_t)> submission_function_;
std::vector<uint8_t> data;
std::size_t allocated_data = 0;
std::size_t flushed_data = 0;
std::size_t submitted_data = 0;
} output_, input_;
uint8_t *get_storage(std::size_t size, Buffer &buffer);
bool is_full_ = false;
};
}
}
#endif /* ArrayBuilder_hpp */