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CLK/Outputs/OpenGL/Primitives/TextureTarget.hpp

96 lines
2.6 KiB
C++

//
// TextureTarget.hpp
// Clock Signal
//
// Created by Thomas Harte on 07/02/2016.
// Copyright 2016 Thomas Harte. All rights reserved.
//
#ifndef TextureTarget_hpp
#define TextureTarget_hpp
#include "../OpenGL.hpp"
#include "Shader.hpp"
#include <memory>
namespace Outputs {
namespace Display {
namespace OpenGL {
/*!
A @c TextureTarget is a framebuffer that can be bound as a texture. So this class
handles render-to-texture framebuffer objects.
*/
class TextureTarget {
public:
/*!
Creates a new texture target. Contents are initially undefined.
Leaves both the generated texture and framebuffer bound.
@throws std::runtime_error if creation fails.
@param width The width of target to create.
@param height The height of target to create.
@param texture_unit A texture unit on which to bind the texture.
@param has_stencil_buffer An 8-bit stencil buffer is attached if this is @c true; no stencil buffer is attached otherwise.
*/
TextureTarget(GLsizei width, GLsizei height, GLenum texture_unit, GLint mag_filter, bool has_stencil_buffer);
~TextureTarget();
/*!
Binds this target as a framebuffer and sets the @c glViewport accordingly.
*/
void bind_framebuffer();
/*!
Binds this target as a texture.
*/
void bind_texture() const;
/*!
@returns the width of the texture target.
*/
GLsizei get_width() const {
return width_;
}
/*!
@returns the height of the texture target.
*/
GLsizei get_height() const {
return height_;
}
/*!
Draws this texture to the currently-bound framebuffer, which has the aspect ratio
@c aspect_ratio. This texture will fill the height of the frame buffer, and pick
an appropriate width based on the aspect ratio.
@c colour_threshold sets a threshold test that each colour must satisfy to be
output. A threshold of 0.0f means that all colours will pass through. A threshold
of 0.5f means that only colour components above 0.5f will pass through, with
0.5f being substituted elsewhere. This provides a way to ensure that the sort of
persistent low-value errors that can result from an IIR are hidden.
*/
void draw(float aspect_ratio, float colour_threshold = 0.0f) const;
private:
GLuint framebuffer_ = 0, texture_ = 0, renderbuffer_ = 0;
const GLsizei width_ = 0, height_ = 0;
GLsizei expanded_width_ = 0, expanded_height_ = 0;
const GLenum texture_unit_ = 0;
mutable std::unique_ptr<Shader> pixel_shader_;
mutable GLuint drawing_vertex_array_ = 0, drawing_array_buffer_ = 0;
mutable float set_aspect_ratio_ = 0.0f;
mutable GLint threshold_uniform_;
};
}
}
}
#endif /* TextureTarget_hpp */