84 lines
2.5 KiB
GLSL
84 lines
2.5 KiB
GLSL
// #type vertex
|
|
#version 460 core
|
|
|
|
layout (location = 0) in vec2 aPos;
|
|
layout (location = 1) in vec2 aUV;
|
|
|
|
layout (location = 0) out vec2 oUV;
|
|
|
|
void main()
|
|
{
|
|
oUV = aUV;
|
|
gl_Position = vec4(aPos, 0.0, 1.0);
|
|
}
|
|
|
|
// #type fragment
|
|
#version 460 core
|
|
|
|
precision highp float;
|
|
|
|
// All components are in the range [0…1], including hue.
|
|
vec3 rgb2hsv(vec3 c)
|
|
{
|
|
vec4 K = vec4(0.0, -1.0 / 3.0, 2.0 / 3.0, -1.0);
|
|
vec4 p = mix(vec4(c.bg, K.wz), vec4(c.gb, K.xy), step(c.b, c.g));
|
|
vec4 q = mix(vec4(p.xyw, c.r), vec4(c.r, p.yzx), step(p.x, c.r));
|
|
|
|
float d = q.x - min(q.w, q.y);
|
|
float e = 1.0e-10;
|
|
return vec3(abs(q.z + (q.w - q.y) / (6.0 * d + e)), d / (q.x + e), q.x);
|
|
}
|
|
|
|
// 16 Windows color palette (approximated)
|
|
const vec3 windowsPalette[7] = vec3[](
|
|
vec3(rgb2hsv(vec3(0.0, 0.0, 1.0)).rg, 0.0), // Blue (FOREGROUND_BLUE)
|
|
vec3(rgb2hsv(vec3(0.0, 1.0, 0.0)).rg, 0.0), // Green (FOREGROUND_GREEN)
|
|
vec3(rgb2hsv(vec3(0.0, 1.0, 1.0)).rg, 0.0), // Cyan (FOREGROUND_GREEN | FOREGROUND_BLUE)
|
|
vec3(rgb2hsv(vec3(1.0, 0.0, 0.0)).rg, 0.0), // Red (FOREGROUND_RED)
|
|
vec3(rgb2hsv(vec3(1.0, 0.0, 1.0)).rg, 0.0), // Magenta (FOREGROUND_RED | FOREGROUND_BLUE)
|
|
vec3(rgb2hsv(vec3(1.0, 1.0, 0.0)).rg, 0.0), // Yellow (FOREGROUND_RED | FOREGROUND_GREEN)
|
|
vec3(rgb2hsv(vec3(1.0, 1.0, 1.0)).rg, 0.0) // White (all colors set)
|
|
);
|
|
|
|
// Find the closest color in the Windows palette
|
|
int findClosestColor(vec3 color) {
|
|
int closestIndex = 0;
|
|
float minDistance = distance(color, windowsPalette[0]);
|
|
|
|
for (int i = 1; i < 7; i++) {
|
|
float dist = distance(color, windowsPalette[i]);
|
|
if (dist < minDistance) {
|
|
minDistance = dist;
|
|
closestIndex = i;
|
|
}
|
|
}
|
|
|
|
return closestIndex + 1;
|
|
}
|
|
|
|
float calculateLuminosity(vec3 color) {
|
|
// Standard luminosity calculation
|
|
float luminosity = dot(color, vec3(0.299, 0.587, 0.114));
|
|
return clamp(luminosity, 0.0, 1.0);
|
|
}
|
|
|
|
uniform sampler2D uInputTexture;
|
|
|
|
layout (location = 0) in vec2 iUV;
|
|
layout (location = 0) out vec4 FragColor;
|
|
|
|
void main() {
|
|
vec3 pixelColor = texture(uInputTexture, iUV).rgb;
|
|
vec3 pixelColorHsv = rgb2hsv(pixelColor);
|
|
|
|
// Find closest color index (4 bits)
|
|
int colorIndex = findClosestColor(vec3(pixelColorHsv.rg, 0));
|
|
|
|
// Calculate luminosity (4 bits)
|
|
float luminosity = calculateLuminosity(pixelColor);
|
|
|
|
// Combine into a single byte-like value
|
|
// High 4 bits: color index
|
|
// Low 4 bits: luminosity
|
|
FragColor = vec4(luminosity, colorIndex / 255.0, 0, 1);
|
|
} |