#version 330 core
// Feature 9: PPI Shoreline / Terrain — fragment stage
// Active points render in P7 blue; fading points render in P7 greenish-yellow
// with brightness proportional to vFade.
in float vFade;
in float vActive;

uniform vec3 uActiveColor;   // P7A blue
uniform vec3 uPersistColor;  // P7P greenish yellow

out vec4 fragColor;

void main()
{
    if (vFade <= 0.01) discard;
    vec3 col = (vActive > 0.5)
        ? uActiveColor
        : uPersistColor * vFade;
    fragColor = vec4(col, vFade);
}