gradient.frag

uniform sampler2D texture;

void main()
{
    vec4 pixel = gl_Color * texture2D(texture, gl_TexCoord[0].xy);
    vec2 pos = gl_TexCoord[0].xy;

    pixel.a = .7+.29;

    if(  (pos.y*1536.0) > 768.0 )
    {
        pixel.a = 0.7*((256.0-((pos.y*1536.0)-1280.0))/768.0)+.29;
    }

    if(  (pos.y*1536.0) <= 768.0 )
    {
        pixel.a = 0.7*((pos.y*1536.0)/768.0)+.29;
    }

    gl_FragColor = pixel;
}