ofxMsdfgen/data/ofxMsdfgen/shaders/unitRange/ES2/shader.frag

32 lines
860 B
GLSL

precision highp float;
// these are our textures
uniform sampler2D msdf;
uniform vec4 fontColor;
uniform float pxRange;
// this comes from the vertex shader
varying vec2 texCoordVarying;
float median(float r, float g, float b) {
return max(min(r, g), min(max(r, g), b));
}
float screenPxRange() {
vec2 unitRange = vec2(pxRange)/vec2(textureSize(msdf));
vec2 screenTexSize = vec2(1.0)/fwidth(texCoordVarying);
return max(0.5*dot(unitRange, screenTexSize), 1.0);
}
void main()
{
vec4 bgColor = vec4(fontColor.rgb,0);
vec4 fgColor = fontColor;
vec3 msdf_rgb = texture2D(msdf, texCoordVarying).rgb;
float sd = median(msdf_rgb.r, msdf_rgb.g, msdf_rgb.b);
float screenPxDistance = screenPxRange()*(sd - 0.5);
float opacity = clamp(screenPxDistance + 0.5, 0.0, 1.0);
gl_FragColor = mix(bgColor, fgColor, opacity);
}