/* -*- mode: c++; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/*
 * Copyright (c) 2004-2013  HUBzero Foundation, LLC
 *
 * Authors:
 *   Wei Qiao <qiaow@purdue.edu>
 */

// Project and sample 3D vector field on a 2D plane

#include "common.cg"

float4 main(in float3 uvw : TEXCOORD0,
            uniform sampler3D vel_tex,
            uniform float3 projection_vector,
            uniform float timestep,
            uniform float vmax) : COLOR
{
    float3 velocity = tex3D(vel_tex, uvw).yzw * 2.0 - float3(1.0, 1.0, 1.0);
    velocity = velocity * projection_vector * vmax * timestep;
    return float4(velocity, 1);
}