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132 lines
4.6 KiB
C++
132 lines
4.6 KiB
C++
//
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// OutputShader.cpp
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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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#include "OutputShader.hpp"
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#include <cassert>
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#include <cmath>
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#include <sstream>
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using namespace OpenGL;
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std::string OutputShader::get_input_name(Input input) {
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switch(input) {
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case Input::Horizontal: return "horizontal";
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case Input::Vertical: return "vertical";
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// Intended to be unreachable.
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default: assert(false);
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}
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}
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std::unique_ptr<OutputShader> OutputShader::make_shader(const char *fragment_methods, const char *colour_expression, bool use_usampler) {
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const std::string sampler_type = use_usampler ? "usampler2D" : "sampler2D";
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std::ostringstream vertex_shader;
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vertex_shader <<
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"#version 150\n"
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"in vec2 " << get_input_name(Input::Horizontal) << ";"
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"in vec2 " << get_input_name(Input::Vertical) << ";"
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"uniform vec2 boundsOrigin;"
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"uniform vec2 boundsSize;"
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"uniform vec2 positionConversion;"
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"uniform vec2 scanNormal;"
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"uniform " << sampler_type << " texID;"
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"uniform float inputScaler;"
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"uniform int textureHeightDivisor;"
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"out float lateralVarying;"
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"out vec2 srcCoordinatesVarying;"
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"out vec2 iSrcCoordinatesVarying;"
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"void main(void)"
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"{"
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"float lateral = float(gl_VertexID & 1);"
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"float longitudinal = float((gl_VertexID & 2) >> 1);"
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"float x = mix(horizontal.x, horizontal.y, longitudinal);"
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"lateralVarying = lateral - 0.5;"
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"vec2 vSrcCoordinates = vec2(x, vertical.y);"
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"ivec2 textureSize = textureSize(texID, 0) * ivec2(1, textureHeightDivisor);"
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"iSrcCoordinatesVarying = vSrcCoordinates;"
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"srcCoordinatesVarying = vec2(inputScaler * vSrcCoordinates.x / textureSize.x, (vSrcCoordinates.y + 0.5) / textureSize.y);"
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"srcCoordinatesVarying.x = srcCoordinatesVarying.x - mod(srcCoordinatesVarying.x, 1.0 / textureSize.x);"
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"vec2 vPosition = vec2(x, vertical.x);"
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"vec2 floatingPosition = (vPosition / positionConversion) + lateral * scanNormal;"
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"vec2 mappedPosition = (floatingPosition - boundsOrigin) / boundsSize;"
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"gl_Position = vec4(mappedPosition.x * 2.0 - 1.0, 1.0 - mappedPosition.y * 2.0, 0.0, 1.0);"
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"}";
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std::ostringstream fragment_shader;
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fragment_shader <<
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"#version 150\n"
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"in float lateralVarying;"
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"in vec2 srcCoordinatesVarying;"
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"in vec2 iSrcCoordinatesVarying;"
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"out vec4 fragColour;"
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"uniform " << sampler_type << " texID;"
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"uniform float gamma;"
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<< fragment_methods <<
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"void main(void)"
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"{"
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"fragColour = vec4(pow(" << colour_expression << ", vec3(gamma)), 0.5);"//*cos(lateralVarying)
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"}";
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return std::unique_ptr<OutputShader>(new OutputShader(vertex_shader.str(), fragment_shader.str(), {
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{get_input_name(Input::Horizontal), 0},
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{get_input_name(Input::Vertical), 1}
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}));
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}
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void OutputShader::set_output_size(unsigned int output_width, unsigned int output_height, Outputs::CRT::Rect visible_area) {
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GLfloat outputAspectRatioMultiplier = (static_cast<float>(output_width) / static_cast<float>(output_height)) / (4.0f / 3.0f);
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GLfloat bonusWidth = (outputAspectRatioMultiplier - 1.0f) * visible_area.size.width;
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visible_area.origin.x -= bonusWidth * 0.5f * visible_area.size.width;
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visible_area.size.width *= outputAspectRatioMultiplier;
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set_uniform("boundsOrigin", (GLfloat)visible_area.origin.x, (GLfloat)visible_area.origin.y);
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set_uniform("boundsSize", (GLfloat)visible_area.size.width, (GLfloat)visible_area.size.height);
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}
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void OutputShader::set_source_texture_unit(GLenum unit) {
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set_uniform("texID", (GLint)(unit - GL_TEXTURE0));
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}
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void OutputShader::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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GLfloat scan_angle = atan2f(1.0f / static_cast<float>(height_of_display), 1.0f);
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GLfloat scan_normal[] = { -sinf(scan_angle), cosf(scan_angle)};
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GLfloat multiplier = static_cast<float>(cycles_per_line) / (static_cast<float>(height_of_display) * static_cast<float>(horizontal_scan_period));
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scan_normal[0] *= multiplier;
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scan_normal[1] *= multiplier;
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set_uniform("scanNormal", scan_normal[0], scan_normal[1]);
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set_uniform("positionConversion", (GLfloat)horizontal_scan_period, (GLfloat)vertical_scan_period / (GLfloat)vertical_period_divider);
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}
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void OutputShader::set_gamma_ratio(float ratio) {
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set_uniform("gamma", ratio);
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}
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void OutputShader::set_input_width_scaler(float input_scaler) {
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set_uniform("inputScaler", input_scaler);
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}
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void OutputShader::set_origin_is_double_height(bool is_double_height) {
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set_uniform("textureHeightDivisor", is_double_height ? 2 : 1);
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}
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