struct Output {
  float4 position	: POSITION;
  float4 color		: COLOR;
  float4 oposition	: TexCOORD1;
  float3 norm		: TEXCOORD2;
};

float2 triagon_deriv(float x, float y, float c, float mx, float my) {
	float2 res;

	float sx, cx;
	float sy, cy;
	float sc, cc;

//	sincos(mx*x, sx, cx);
//	sincos(my*y, sy, cy);
//	sincos(c, sc, cc);

//	res.x = (-sx*cy*cc + sx*sy*sc - cx*sy*cc - cx*cy*sc) * mx;
//	res.y = (-cx*sy*cc - cx*cy*sc - sx*cy*cc + sx*sy*sc) * my;

	res.x = -sin(mx*x + my*y + c)*mx;
	res.y = -sin(mx*x + my*y + c)*my;

	return res;
}

Output vert_shader(float4 position : POSITION,
				   float4 color    : COLOR,
				   float2 tc       : TEXCOORD0,
				   uniform float timestamp,
				   uniform float grid_size,
				   uniform float4x4 MV : state.matrix.modelview,
				   uniform float4x4 PM : state.matrix.projection)
{
  Output OUT;
  float2 normal;
  float l;

  float speed = 0.04;

  OUT.position[0] = position[0];
  OUT.position[1] = position[1];
  OUT.position[2] = cos(position[0]*5/grid_size + position[1]*8/grid_size + timestamp*speed*9.43)*1.2 + 
					cos(0 + position[1]*8/grid_size + timestamp*speed*8)*1 +
					cos(position[0]*0.4/grid_size + position[1]*27/grid_size  + timestamp*speed*27)*0.8 +
					cos(position[0]*37/grid_size  + position[1]*12/grid_size  - timestamp*speed*38)*0.5 +
					cos(position[0]*32/grid_size  - position[1]*81/grid_size  - timestamp*speed*87)*0.25 +
					cos(-position[0]*30/grid_size + position[1]*173/grid_size - timestamp*speed*175)*0.2;
  OUT.position[3] = 1;

  normal     = triagon_deriv(position[0], position[1], timestamp*speed*9.43, 5/grid_size, 8/grid_size) * 1.2 +
               triagon_deriv(position[0], position[1], timestamp*speed*8, 0/grid_size, 8/grid_size) * 1 +
               triagon_deriv(position[0], position[1], timestamp*speed*27, 0.4/grid_size, 27/grid_size) * 0.8 +
               triagon_deriv(position[0], position[1], -timestamp*speed*38, 37/grid_size, 12/grid_size) * 0.5 +
               triagon_deriv(position[0], position[1], -timestamp*speed*87, 32/grid_size, -81/grid_size) * 0.25 +
               triagon_deriv(position[0], position[1], -timestamp*speed*175, -30/grid_size, 173/grid_size) * 0.2;

  l = sqrt(normal.x*normal.x + normal.y*normal.y + 1);
  OUT.norm = float3(-normal.x/l, -normal.y/l, 1/l);

  OUT.position = mul(MV, OUT.position);
  OUT.oposition = OUT.position;
  OUT.position = mul(PM, OUT.position);
  OUT.norm = mul(MV, float4(OUT.norm, 1)).xyz;

  OUT.color = color;
  return OUT;	
}