#version 430 core
in vec2 vUv;
in vec4 vColor;
out vec4 FragColor;

uniform sampler2D uTex;
uniform int uUseTexture;

void main() {
    if (uUseTexture != 0) {
        // Font atlas is a single-channel R8 texture; red = coverage alpha.
        float coverage = texture(uTex, vUv).r;
        FragColor = vec4(vColor.rgb, vColor.a * coverage);
    } else {
        FragColor = vColor;
    }
    if (FragColor.a < 0.005) discard;
}