Hi,
I’ve made an old-school gameboy-like 2D filter based on an existing dithering filter (https://github.com/hughsk/glsl-dither).
Here’s the shader code:
float luma(vec3 color) {
return dot(color, vec3(0.299, 0.587, 0.114));
}
float luma(vec4 color) {
return dot(color.rgb, vec3(0.299, 0.587, 0.114));
}
// from https://github.com/hughsk/glsl-dither
float dither8x8(vec2 position, float brightness) {
int x = int(mod(position.x, 8.0));
int y = int(mod(position.y, 8.0));
int index = x + y * 8;
float limit = 0.0;
if (x < 8) {
if (index == 0) limit = 0.015625;
if (index == 1) limit = 0.515625;
if (index == 2) limit = 0.140625;
if (index == 3) limit = 0.640625;
if (index == 4) limit = 0.046875;
if (index == 5) limit = 0.546875;
if (index == 6) limit = 0.171875;
if (index == 7) limit = 0.671875;
if (index == 8) limit = 0.765625;
if (index == 9) limit = 0.265625;
if (index == 10) limit = 0.890625;
if (index == 11) limit = 0.390625;
if (index == 12) limit = 0.796875;
if (index == 13) limit = 0.296875;
if (index == 14) limit = 0.921875;
if (index == 15) limit = 0.421875;
if (index == 16) limit = 0.203125;
if (index == 17) limit = 0.703125;
if (index == 18) limit = 0.078125;
if (index == 19) limit = 0.578125;
if (index == 20) limit = 0.234375;
if (index == 21) limit = 0.734375;
if (index == 22) limit = 0.109375;
if (index == 23) limit = 0.609375;
if (index == 24) limit = 0.953125;
if (index == 25) limit = 0.453125;
if (index == 26) limit = 0.828125;
if (index == 27) limit = 0.328125;
if (index == 28) limit = 0.984375;
if (index == 29) limit = 0.484375;
if (index == 30) limit = 0.859375;
if (index == 31) limit = 0.359375;
if (index == 32) limit = 0.0625;
if (index == 33) limit = 0.5625;
if (index == 34) limit = 0.1875;
if (index == 35) limit = 0.6875;
if (index == 36) limit = 0.03125;
if (index == 37) limit = 0.53125;
if (index == 38) limit = 0.15625;
if (index == 39) limit = 0.65625;
if (index == 40) limit = 0.8125;
if (index == 41) limit = 0.3125;
if (index == 42) limit = 0.9375;
if (index == 43) limit = 0.4375;
if (index == 44) limit = 0.78125;
if (index == 45) limit = 0.28125;
if (index == 46) limit = 0.90625;
if (index == 47) limit = 0.40625;
if (index == 48) limit = 0.25;
if (index == 49) limit = 0.75;
if (index == 50) limit = 0.125;
if (index == 51) limit = 0.625;
if (index == 52) limit = 0.21875;
if (index == 53) limit = 0.71875;
if (index == 54) limit = 0.09375;
if (index == 55) limit = 0.59375;
if (index == 56) limit = 1.0;
if (index == 57) limit = 0.5;
if (index == 58) limit = 0.875;
if (index == 59) limit = 0.375;
if (index == 60) limit = 0.96875;
if (index == 61) limit = 0.46875;
if (index == 62) limit = 0.84375;
if (index == 63) limit = 0.34375;
}
return brightness < limit ? 0.0 : 1.0;
}
vec3 dither8x8(vec2 position, vec3 color) {
return color * dither8x8(position, luma(color));
}
vec4 dither8x8(vec2 position, vec4 color) {
return vec4(color.rgb * dither8x8(position, luma(color)), 1.0);
}
//
uniform sampler2D bgl_RenderedTexture;
void main(void)
{
vec4 color = texture2D(bgl_RenderedTexture, gl_TexCoord[0].st);
float avg = (color.r + color.g + color.b) / 3.0;
vec4 tint = vec4(avg, avg, avg, color.a) * vec4(0.716, 0.8909, 0.1675, 1.0);
vec4 final = dither8x8(gl_FragCoord.xy, tint);
gl_FragColor = final;
}
Color version:
float luma(vec3 color) {
return dot(color, vec3(0.299, 0.587, 0.114));
}
float luma(vec4 color) {
return dot(color.rgb, vec3(0.299, 0.587, 0.114));
}
// from https://github.com/hughsk/glsl-dither
float dither8x8(vec2 position, float brightness) {
int x = int(mod(position.x, 8.0));
int y = int(mod(position.y, 8.0));
int index = x + y * 8;
float limit = 0.0;
if (x < 8) {
if (index == 0) limit = 0.015625;
if (index == 1) limit = 0.515625;
if (index == 2) limit = 0.140625;
if (index == 3) limit = 0.640625;
if (index == 4) limit = 0.046875;
if (index == 5) limit = 0.546875;
if (index == 6) limit = 0.171875;
if (index == 7) limit = 0.671875;
if (index == 8) limit = 0.765625;
if (index == 9) limit = 0.265625;
if (index == 10) limit = 0.890625;
if (index == 11) limit = 0.390625;
if (index == 12) limit = 0.796875;
if (index == 13) limit = 0.296875;
if (index == 14) limit = 0.921875;
if (index == 15) limit = 0.421875;
if (index == 16) limit = 0.203125;
if (index == 17) limit = 0.703125;
if (index == 18) limit = 0.078125;
if (index == 19) limit = 0.578125;
if (index == 20) limit = 0.234375;
if (index == 21) limit = 0.734375;
if (index == 22) limit = 0.109375;
if (index == 23) limit = 0.609375;
if (index == 24) limit = 0.953125;
if (index == 25) limit = 0.453125;
if (index == 26) limit = 0.828125;
if (index == 27) limit = 0.328125;
if (index == 28) limit = 0.984375;
if (index == 29) limit = 0.484375;
if (index == 30) limit = 0.859375;
if (index == 31) limit = 0.359375;
if (index == 32) limit = 0.0625;
if (index == 33) limit = 0.5625;
if (index == 34) limit = 0.1875;
if (index == 35) limit = 0.6875;
if (index == 36) limit = 0.03125;
if (index == 37) limit = 0.53125;
if (index == 38) limit = 0.15625;
if (index == 39) limit = 0.65625;
if (index == 40) limit = 0.8125;
if (index == 41) limit = 0.3125;
if (index == 42) limit = 0.9375;
if (index == 43) limit = 0.4375;
if (index == 44) limit = 0.78125;
if (index == 45) limit = 0.28125;
if (index == 46) limit = 0.90625;
if (index == 47) limit = 0.40625;
if (index == 48) limit = 0.25;
if (index == 49) limit = 0.75;
if (index == 50) limit = 0.125;
if (index == 51) limit = 0.625;
if (index == 52) limit = 0.21875;
if (index == 53) limit = 0.71875;
if (index == 54) limit = 0.09375;
if (index == 55) limit = 0.59375;
if (index == 56) limit = 1.0;
if (index == 57) limit = 0.5;
if (index == 58) limit = 0.875;
if (index == 59) limit = 0.375;
if (index == 60) limit = 0.96875;
if (index == 61) limit = 0.46875;
if (index == 62) limit = 0.84375;
if (index == 63) limit = 0.34375;
}
return brightness < limit ? 0.0 : 1.0;
}
vec3 dither8x8(vec2 position, vec3 color) {
return color * dither8x8(position, luma(color));
}
vec4 dither8x8(vec2 position, vec4 color) {
return vec4(color.rgb * dither8x8(position, luma(color)), 1.0);
}
//
uniform sampler2D bgl_RenderedTexture;
void main(void)
{
vec4 color = texture2D(bgl_RenderedTexture, gl_TexCoord[0].st);
gl_FragColor = dither8x8(gl_FragCoord.xy, color);
}
I hope you like it