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109 lines
3.8 KiB
C++
109 lines
3.8 KiB
C++
//
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// OutputShader.hpp
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// Clock Signal
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//
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// Created by Thomas Harte on 27/04/2016.
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// Copyright 2016 Thomas Harte. All rights reserved.
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//
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#ifndef OutputShader_hpp
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#define OutputShader_hpp
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#include "Shader.hpp"
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#include "../../ScanTarget.hpp"
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#include <memory>
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namespace OpenGL {
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class OutputShader: public Shader {
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public:
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enum class Input {
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/// A 2d vector; the first element is the horizontal start of this scan, the second element is the end.
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Horizontal,
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/// A 2d vector; the first element is the vertical start of this scan, the second element is the end.
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Vertical
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};
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/*!
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Obtains the name of a designated input. Designated inputs are guaranteed to have the same attribute location
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across multiple instances of OutputShader. So binding a vertex array to these inputs for any instance of
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OutputShader allows that array to work with all instances of OutputShader.
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@param input The input to query.
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@returns The name used in this shader's source for the nominated input.
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*/
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static std::string get_input_name(Input input);
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/*!
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Constructs and returns an instance of OutputShader. OutputShaders are intended to read source data
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from a texture and draw a single raster scan containing that data as output.
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Does not catch any of the exceptions potentially thrown by `Shader::Shader`.
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All instances of OutputShader are guaranteed to use the same attribute locations for their inputs.
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@param fragment_methods A block of code that will appear within the global area of the fragment shader.
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@param colour_expression An expression that should evaluate to a `vec3` indicating the colour at the current location. The
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decision should be a function of the uniform `texID`, which will be either a `usampler2D` or a `sampler2D` as per the
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`use_usampler` parameter, and the inputs `srcCoordinatesVarying` which is a location within the texture from which to
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take the source value, and `iSrcCoordinatesVarying` which is a value proportional to `srcCoordinatesVarying` but scaled
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so that one unit equals one source sample.
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@param use_usampler Dictates the type of the `texID` uniform; will be a `usampler2D` if this parameter is `true`, a
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`sampler2D` otherwise.
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@returns an instance of OutputShader.
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*/
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static std::unique_ptr<OutputShader> make_shader(const char *fragment_methods, const char *colour_expression, bool use_usampler);
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using Shader::Shader;
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/*!
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Queues configuration for output to an area of `output_width` and `output_height` pixels, ensuring
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the largest possible drawing size that allows everything within `visible_area` to be visible, to
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occur upon the next `bind`.
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*/
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void set_output_size(unsigned int output_width, unsigned int output_height, Outputs::Display::Rect visible_area);
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/*!
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Queues setting of the texture unit (as an enum, e.g. `GL_TEXTURE0`) for source data upon the next `bind`.
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*/
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void set_source_texture_unit(GLenum unit);
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/*!
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Queues configuring this shader's understanding of how to map from the source vertex stream to screen coordinates,
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to occur upon the next `bind`.
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*/
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void set_timing(unsigned int height_of_display, unsigned int cycles_per_line, unsigned int horizontal_scan_period, unsigned int vertical_scan_period, unsigned int vertical_period_divider);
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/*!
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*/
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void set_origin_is_double_height(bool is_double_height);
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void set_gamma_ratio(float ratio);
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/*!
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Sets the proportion of the input area that should be considered the whole width: 1.0 means use all available
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space, 0.5 means use half, etc.
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*/
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void set_input_width_scaler(float input_scaler);
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/*!
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@returns The location, in eye coordinates, of the left edge of the output area.
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*/
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float get_left_extent();
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/*!
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@returns The location, in eye coordinates, of the right edge of the output area.
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*/
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float get_right_extent();
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private:
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float left_extent_ = 0.0f;
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float right_extent_ = 0.0f;
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};
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}
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#endif /* OutputShader_hpp */
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