point_sprite.fs.glsl

#version 330 core

layout(location = 0) out vec4 fcolor;

void main(void) {
    const vec4 color1 = vec4(0.0, 0.6, 0.0, 1.0);
    const vec4 color2 = vec4(0.9, 0.7, 1.0, 0.0);

    if (gl_PointCoord == vec2(1.0)) {
        fcolor = vec4(1.0f, 0.0f, 0.0f, 1.0f);
        return;
    }
    /* centers gl_PointCoord around the origin */
    vec2 t = gl_PointCoord - vec2(0.5);
    float f = dot(t, t);

    if (f > 0.25) {
        discard;
    }

    fcolor = mix(color1, color2, smoothstep(0.1, 0.25, f));
}