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CLK/Outputs/CRT/Internals/Shaders/OutputShader.cpp

126 lines
3.8 KiB
C++

//
// OutputShader.cpp
// Clock Signal
//
// Created by Thomas Harte on 27/04/2016.
// Copyright © 2016 Thomas Harte. All rights reserved.
//
#include "OutputShader.hpp"
#include <stdlib.h>
#include <math.h>
using namespace OpenGL;
namespace {
const OpenGL::Shader::AttributeBinding bindings[] =
{
{"position", 0},
{"srcCoordinates", 1},
{nullptr}
};
}
std::unique_ptr<OutputShader> OutputShader::make_shader(const char *fragment_methods, const char *colour_expression, bool use_usampler)
{
const char *sampler_type = use_usampler ? "usampler2D" : "sampler2D";
char *vertex_shader;
asprintf(&vertex_shader,
"#version 150\n"
"in vec2 horizontal;"
"in vec2 vertical;"
"uniform vec2 boundsOrigin;"
"uniform vec2 boundsSize;"
"uniform vec2 positionConversion;"
"uniform vec2 scanNormal;"
"uniform %s texID;"
"uniform float inputScaler;"
"out float lateralVarying;"
"out vec2 srcCoordinatesVarying;"
"out vec2 iSrcCoordinatesVarying;"
"void main(void)"
"{"
"float lateral = float(gl_VertexID & 1);"
"float longitudinal = float((gl_VertexID & 2) >> 1);"
"float x = mix(horizontal.x, horizontal.y, longitudinal);"
"lateralVarying = lateral - 0.5;"
"vec2 vSrcCoordinates = vec2(x, vertical.y);"
"ivec2 textureSize = textureSize(texID, 0);"
"iSrcCoordinatesVarying = vSrcCoordinates;"
"srcCoordinatesVarying = vec2(inputScaler * vSrcCoordinates.x / textureSize.x, (vSrcCoordinates.y + 0.5) / textureSize.y);"
"vec2 vPosition = vec2(x, vertical.x);"
"vec2 floatingPosition = (vPosition / positionConversion) + lateral * scanNormal;"
"vec2 mappedPosition = (floatingPosition - boundsOrigin) / boundsSize;"
"gl_Position = vec4(mappedPosition.x * 2.0 - 1.0, 1.0 - mappedPosition.y * 2.0, 0.0, 1.0);"
"}", sampler_type);
char *fragment_shader;
asprintf(&fragment_shader,
"#version 150\n"
"in float lateralVarying;"
"in vec2 srcCoordinatesVarying;"
"in vec2 iSrcCoordinatesVarying;"
"out vec4 fragColour;"
"uniform %s texID;"
"\n%s\n"
"void main(void)"
"{"
"fragColour = vec4(%s, 0.5);"//*cos(lateralVarying)
"}",
sampler_type, fragment_methods, colour_expression);
std::unique_ptr<OutputShader> result(new OutputShader(vertex_shader, fragment_shader, bindings));
free(vertex_shader);
free(fragment_shader);
return result;
}
void OutputShader::set_output_size(unsigned int output_width, unsigned int output_height, Outputs::CRT::Rect visible_area)
{
GLfloat outputAspectRatioMultiplier = ((float)output_width / (float)output_height) / (4.0f / 3.0f);
GLfloat bonusWidth = (outputAspectRatioMultiplier - 1.0f) * visible_area.size.width;
visible_area.origin.x -= bonusWidth * 0.5f * visible_area.size.width;
visible_area.size.width *= outputAspectRatioMultiplier;
set_uniform("boundsOrigin", (GLfloat)visible_area.origin.x, (GLfloat)visible_area.origin.y);
set_uniform("boundsSize", (GLfloat)visible_area.size.width, (GLfloat)visible_area.size.height);
}
void OutputShader::set_source_texture_unit(GLenum unit)
{
set_uniform("texID", (GLint)(unit - GL_TEXTURE0));
}
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)
{
GLfloat scan_angle = atan2f(1.0f / (float)height_of_display, 1.0f);
GLfloat scan_normal[] = { -sinf(scan_angle), cosf(scan_angle)};
GLfloat multiplier = (float)cycles_per_line / ((float)height_of_display * (float)horizontal_scan_period);
scan_normal[0] *= multiplier;
scan_normal[1] *= multiplier;
set_uniform("scanNormal", scan_normal[0], scan_normal[1]);
set_uniform("positionConversion", (GLfloat)horizontal_scan_period, (GLfloat)vertical_scan_period / (GLfloat)vertical_period_divider);
}
void OutputShader::set_input_width_scaler(float input_scaler)
{
set_uniform("inputScaler", input_scaler);
}