#version 120

//
//  metavoxel_heighfield.vert
//  vertex shader
//
//  Created by Andrzej Kapolka on 7/28/14.
//  Copyright 2014 High Fidelity, Inc.
//
//  Distributed under the Apache License, Version 2.0.
//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
//

// the height texture
uniform sampler2D heightMap;

// the interpolated normal
varying vec4 normal;

void main(void) {
    // transform and store the normal for interpolation
    normal = normalize(gl_ModelViewMatrix * vec4(0.0, 1.0, 0.0, 0.0));
    
    // pass along the vertex color
    gl_FrontColor = gl_Color;
    
    // pass along the texture coordinates
    gl_TexCoord[0] = gl_MultiTexCoord0;
    
    // add the height to the position
    gl_Position = gl_ModelViewProjectionMatrix * (gl_Vertex +
        vec4(0.0, texture2D(heightMap, gl_MultiTexCoord0.st).r, 0.0, 0.0));
}