Files
MapLibreParticleLab/shaders/line_sdf.fragment.glsl
mwilsnd 4828cc7a8b Upgrade OpenGL backend to ES 3.0 (#995)
Co-authored-by: Tadej Novak <tadej@tano.si>
2023-04-13 23:24:45 +02:00

46 lines
1.5 KiB
GLSL

uniform lowp float u_device_pixel_ratio;
uniform sampler2D u_image;
uniform float u_sdfgamma;
uniform float u_mix;
in vec2 v_normal;
in vec2 v_width2;
in vec2 v_tex_a;
in vec2 v_tex_b;
in float v_gamma_scale;
#pragma mapbox: define highp vec4 color
#pragma mapbox: define lowp float blur
#pragma mapbox: define lowp float opacity
#pragma mapbox: define mediump float width
#pragma mapbox: define lowp float floorwidth
void main() {
#pragma mapbox: initialize highp vec4 color
#pragma mapbox: initialize lowp float blur
#pragma mapbox: initialize lowp float opacity
#pragma mapbox: initialize mediump float width
#pragma mapbox: initialize lowp float floorwidth
// Calculate the distance of the pixel from the line in pixels.
float dist = length(v_normal) * v_width2.s;
// Calculate the antialiasing fade factor. This is either when fading in
// the line in case of an offset line (v_width2.t) or when fading out
// (v_width2.s)
float blur2 = (blur + 1.0 / u_device_pixel_ratio) * v_gamma_scale;
float alpha = clamp(min(dist - (v_width2.t - blur2), v_width2.s - dist) / blur2, 0.0, 1.0);
float sdfdist_a = texture(u_image, v_tex_a).a;
float sdfdist_b = texture(u_image, v_tex_b).a;
float sdfdist = mix(sdfdist_a, sdfdist_b, u_mix);
alpha *= smoothstep(0.5 - u_sdfgamma / floorwidth, 0.5 + u_sdfgamma / floorwidth, sdfdist);
fragColor = color * (alpha * opacity);
#ifdef OVERDRAW_INSPECTOR
fragColor = vec4(1.0);
#endif
}