openCom-Companion/sbapp/kivymd/data/glsl/elevation/elevation.frag

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2022-10-08 17:17:59 +02:00
/*
The shader code has been refactored for the KivyMD library.
You can find the original code of this shaders at the links:
https://www.shadertoy.com/view/WtdSDs
https://www.shadertoy.com/view/fsdyzB
Additional thanks to iq for optimizing conditional block for individual
corner radius:
https://iquilezles.org/articles/distfunctions
*/
// For lower opengl version
float custom_smoothstep(float a, float b, float x) {
float t = clamp((x - a) / (b - a), 0.0, 1.0);
return t * t * (3.0 - 2.0 * t);
}
float roundedBoxSDF(vec2 centerPosition, vec2 size, vec4 radius) {
radius.xy = (centerPosition.x > 0.0) ? radius.xy : radius.zw;
radius.x = (centerPosition.y > 0.0) ? radius.x : radius.y;
vec2 q = abs(centerPosition) - (size - shadow_softness) + radius.x;
return min(max(q.x, q.y), 0.0) + length(max(q, 0.0)) - radius.x;
}
void mainImage(out vec4 fragColor, in vec2 fragCoord) {
// Smooth the result (free antialiasing).
float edge0 = 0.0;
float smoothedAlpha = 1.0 - custom_smoothstep(0.0, edge0, 1.0);
// Get the resultant shape.
vec4 quadColor = mix(
vec4(
shadow_color[0],
shadow_color[1],
shadow_color[2],
0.0
),
shadow_color,
smoothedAlpha
);
// Apply a drop shadow effect.
float shadowDistance = roundedBoxSDF(
fragCoord.xy - mouse.xy - (size / 2.0), size / 2.0, shadow_radius
);
float shadowAlpha = 1.0 - custom_smoothstep(
-shadow_softness, shadow_softness, shadowDistance
);
fragColor = mix(quadColor, shadow_color, shadowAlpha - smoothedAlpha);
}