/*
 * MIT License
 * Author: Mark Allyn
 *
 * text.frag — FreeType glyph-atlas fragment shader.
 * The atlas is a single-channel GL_RED texture; the sampled value
 * is used as alpha and multiplied by the text colour uniform.
 */
#version 330 core

in  vec2 vTexCoord;
out vec4 fragColor;

uniform sampler2D u_glyphAtlas;
uniform vec3      u_textColor;

void main() {
    float alpha = texture(u_glyphAtlas, vTexCoord).r;
    fragColor   = vec4(u_textColor, alpha);
}