#version 130

uniform sampler2D qt_Texture0;
varying vec2 qt_TexCoord0;
uniform vec2 scale;
uniform float a;
uniform int stretch;
uniform bool bw;

void main(void)
{
    vec4 color = texture2D(qt_Texture0, qt_TexCoord0);
    if(bw)color = color.rrra;
    color = color*scale.x + scale.y;
    color = max(color, vec4(0.0f));

    switch(stretch)
    {
    case 0:
        break;
    case 1:
       color = sqrt(color);
       break;
    case 2:
        color = pow(color, vec4(a));
        break;
    case 3:
        color = log(a*color + 1.0) / log(vec4(a+1));
        break;
    case 4:
    {
        //float l = color.r*0.2126f + color.g*0.7152f + color.b*0.0722f;
        float l = (color.r+color.g+color.b)*0.33333;
        float k = asinh(l*a)/(l*asinh(a));
        color *= k;
    }
        break;
    }

    //color = color*scale.x + scale.y;
    //float color = pow(c, 0.4545);
    if(any(lessThan(qt_TexCoord0, vec2(0.0))) || any(greaterThan(qt_TexCoord0, vec2(1.0))))
        color = vec4(0.0);
    gl_FragColor = color;
}