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

#include "particle_common.cg"

float4 main(float2 texCoord : TEXCOORD0,
            float4 color : COLOR0, 
            float2 center : TEXCOORD2,
            float4 rotation : TEXCOORD3,
            uniform sampler2D arrows : TEXUNIT0) : COLOR
{
    float2 newTexCoord = float2((texCoord.x - 0.5) / NUM_SUBIMAGE_X, (texCoord.y - 0.5) / NUM_SUBIMAGE_Y);
    float2 rotTexCoord;
    rotTexCoord.x = rotation.x * newTexCoord.x + rotation.y * newTexCoord.y;
    rotTexCoord.y = rotation.z * newTexCoord.x + rotation.w * newTexCoord.y;
    rotTexCoord.x = rotTexCoord.x + 0.5 / NUM_SUBIMAGE_X;
    rotTexCoord.y = rotTexCoord.y + 0.5 / NUM_SUBIMAGE_Y;
    rotTexCoord = rotTexCoord + center;

    return tex2D(arrows, rotTexCoord.xy) * color;
}