raylib/examples/text/resources/shaders/glsl120/alpha_discard.fs

#version 120

// Input vertex attributes (from vertex shader)
varying vec2 fragTexCoord;
varying vec4 fragColor;

// Input uniform values
uniform sampler2D texture0;
uniform vec4 colDiffuse;

void main()
{
    vec4 texelColor = texture2D(texture0, fragTexCoord);

    if (texelColor.a == 0.0) discard;

    gl_FragColor = texelColor*fragColor*colDiffuse;
}