#ifndef __ROTATE_H__
#define __ROTATE_H__

__device__ const Matrix IDENTITY_MATRIX = {1,0,0,0,1,0,0,0,1};
__device__ const Matrix ZERO_MATRIX = {0,0,0,0,0,0,0,0,0};

__device__ __host__ Matrix make_rotation_matrix(float phi, const float3 &n)
{
	/* rotate points counterclockwise, when looking towards +infinity,
	   through an angle `phi` about the axis `n`. */

	float cos_phi = cosf(phi);
	float sin_phi = sinf(phi);

	return IDENTITY_MATRIX*cos_phi + (1-cos_phi)*outer(n,n) +
		sin_phi*make_matrix(0,n.z,-n.y,-n.z,0,n.x,n.y,-n.x,0);
}

__device__ __host__ float3 rotate(const float3 &a, float phi, const float3 &n)
{
	return make_rotation_matrix(phi,n)*a;
}

#endif