Files
matrix/shaders/glsl/rainPass.frag.glsl
2023-08-22 11:46:29 -07:00

97 lines
2.6 KiB
GLSL

#define PI 3.14159265359
#ifdef GL_OES_standard_derivatives
#extension GL_OES_standard_derivatives: enable
#endif
precision lowp float;
uniform sampler2D computeState;
uniform float numColumns, numRows;
uniform sampler2D glyphMSDF;
uniform float msdfPxRange;
uniform vec2 glyphMSDFSize;
uniform float glyphHeightToWidth, glyphSequenceLength, glyphEdgeCrop;
uniform float baseContrast, baseBrightness, glintContrast, glintBrightness;
uniform float brightnessOverride, brightnessThreshold;
uniform vec2 glyphTextureGridSize;
uniform bool isolateCursor;
varying vec2 vUV;
float median3(vec3 i) {
return max(min(i.r, i.g), min(max(i.r, i.g), i.b));
}
float modI(float a, float b) {
float m = a - floor((a + 0.5) / b) * b;
return floor(m + 0.5);
}
vec2 getUV(vec2 uv) {
uv.y /= glyphHeightToWidth;
return uv;
}
vec3 getBrightness(vec2 raindrop, vec2 uv) {
float base = raindrop.r;
bool isCursor = bool(raindrop.g) && isolateCursor;
float glint = base;
vec2 textureUV = fract(uv * vec2(numColumns, numRows));
base = base * baseContrast + baseBrightness;
glint = glint * glintContrast + glintBrightness;
// Modes that don't fade glyphs set their actual brightness here
if (brightnessOverride > 0. && base > brightnessThreshold && !isCursor) {
base = brightnessOverride;
}
return vec3(
(isCursor ? vec2(0.0, 1.0) : vec2(1.0, 0.0)) * base,
glint
);
}
vec2 getSymbolUV(float index) {
float symbolX = modI(index, glyphTextureGridSize.x);
float symbolY = (index - symbolX) / glyphTextureGridSize.x;
symbolY = glyphTextureGridSize.y - symbolY - 1.;
return vec2(symbolX, symbolY);
}
vec2 getSymbol(vec2 uv, float index) {
// resolve UV to cropped position of glyph in MSDF texture
uv = fract(uv * vec2(numColumns, numRows));
uv -= 0.5;
uv *= clamp(1. - glyphEdgeCrop, 0., 1.);
uv += 0.5;
uv = (uv + getSymbolUV(index)) / glyphTextureGridSize;
// MSDF: calculate brightness of fragment based on distance to shape
vec2 symbol;
{
vec2 unitRange = vec2(msdfPxRange) / glyphMSDFSize;
vec2 screenTexSize = vec2(1.0) / fwidth(uv);
float screenPxRange = max(0.5 * dot(unitRange, screenTexSize), 1.0);
float signedDistance = median3(texture2D(glyphMSDF, uv).rgb);
float screenPxDistance = screenPxRange * (signedDistance - 0.5);
symbol.r = clamp(screenPxDistance + 0.5, 0.0, 1.0);
}
return symbol;
}
void main() {
vec2 uv = getUV(vUV);
// Unpack the values from the data textures
vec4 data = texture2D(computeState, uv);
vec3 brightness = getBrightness(data.rg, uv);
vec2 symbol = getSymbol(uv, data.b);
gl_FragColor = vec4(brightness.rg * symbol.r, brightness.b * symbol.g, 0.);
}