#ifndef WAVE_FX
	#define float2 D3DXVECTOR2
	#define float3 D3DXVECTOR3
#endif

struct Wave
{
	float		wavelength;
	float		amplitude;
	float2		direction;
	float		deformation;
};

#define NWAVES 4
Wave wave[NWAVES] = { {1.0f, 1.1f, float2(0.98,0.17), 1.3f },
						{1.5f, 2.1f, float2(0.98,-0.17), 1.3f },
						{2.5f, 1.1f, float2(0.934,0.342), 1.2f },
						{3.5f, 2.1f, float2(0.934,-0.342), 1.0f }
 };

//return the position difference 
float3 evaluateWave(Wave w, float phase)
{

	float2 offset;
	#ifdef WAVE_FX
		sincos(phase, offset.x, offset.y);
	#else
		offset.x = sin(phase);
		offset.y = cos(phase);
	#endif
	float2 tempPos = float2(0,0);
	#ifdef WAVE_FX
		tempPos.xy +=  offset * w.amplitude * float2(-1, 1);
	#else
		tempPos.x -=  offset.x * w.amplitude;
		tempPos.y +=  offset.y * w.amplitude;
	#endif
	tempPos.x -= tempPos.y * w.deformation;

	return float3(w.direction.x * tempPos.x, tempPos.y, w.direction.y * tempPos.x);
}

float3 evaluateWaveDerivative(Wave w, float phase)
{
	float2 offset;
	#ifdef WAVE_FX
		sincos(phase, offset.x, offset.y);
	#else
		offset.x = sin(phase);
		offset.y = cos(phase);
	#endif
	
	float dxdp = - offset.y * w.amplitude * w.direction.x;
	float dydp = - offset.x * w.amplitude;
	float dzdp = - offset.y * w.amplitude * w.direction.y;
	
	return float3(dxdp - dydp * w.deformation, dydp, dzdp);
}

#ifndef WAVE_FX
	#undef float2
	#undef float3
#endif