/*
 * File: BasicSineGratingShader.frag.txt
 * Shader for drawing of basic parameterized sine grating patches.
 *
 * (c) 2007 by Mario Kleiner, licensed under MIT license.
 *		 
 */

uniform vec4 Offset;

varying vec4  baseColor;
varying float Phase;
varying float FreqTwoPi;

void main()
{
    /* Query current output texel position: */
    float pos = gl_TexCoord[0].x;

    /* Evaluate sine grating at requested position, frequency and phase: */
    float sv = sin(pos * FreqTwoPi + Phase);

    /* Multiply/Modulate base color and alpha with calculated sine            */
    /* values, add some constant color/alpha Offset, assign as final fragment */
    /* output color: */
    gl_FragColor = (baseColor * sv) + Offset;
}
