繞固定 xyz 軸旋轉

struct mat3 {
	float3 x;
	float3 y;
	float3 z;
};

float3 rotation(float3 mp, float3 pos) {
	float s = 0.0f;
	float c = 0.0f;

	struct mat3 rotX;		
	s = sin(mp.x);		c = cos(mp.x);
	rotX.x = (float3)(1.0f, 0.0f, 0.0f);
	rotX.y = (float3)(0.0f, c, -s);
	rotX.z = (float3)(0.0f, s,  c);

	struct mat3 rotY;
	s = sin(mp.y);		c = cos(mp.y);
	rotY.x = (float3)(c,	0.0f,	 s);
	rotY.y = (float3)(0.0f, 1.0f, 0.0f);
	rotY.z = (float3)(-s,	0.0f,	 c);

	struct mat3 rotZ;
	s = sin(mp.z);		c = cos(mp.z);
	rotZ.x = (float3)(c,	-s,		0.0f);
	rotZ.y = (float3)(s,	c,		0.0f);
	rotZ.z = (float3)(0.0f, 0.0f,	1.0f);

	float3 m2x = (float3)(rotY.x.x, rotY.y.x, rotY.z.x);
	float3 m2y = (float3)(rotY.x.y, rotY.y.y, rotY.z.y);
	float3 m2z = (float3)(rotY.x.z, rotY.y.z, rotY.z.z);
	struct mat3 m;
	m.x.x = dot(m2x, rotX.x);
	m.x.y = dot(m2y, rotX.x);
	m.x.z = dot(m2z, rotX.x);
	m.y.x = dot(m2x, rotX.y);
	m.y.y = dot(m2y, rotX.y);
	m.y.z = dot(m2z, rotX.y);
	m.z.x = dot(m2x, rotX.z);
	m.z.y = dot(m2y, rotX.z);
	m.z.z = dot(m2z, rotX.z);

	float3 m3x = (float3)(rotZ.x.x, rotZ.y.x, rotZ.z.x);
	float3 m3y = (float3)(rotZ.x.y, rotZ.y.y, rotZ.z.y);
	float3 m3z = (float3)(rotZ.x.z, rotZ.y.z, rotZ.z.z);
	struct mat3 mm;
	mm.x.x = dot(m3x, m.x);
	mm.x.y = dot(m3y, m.x);
	mm.x.z = dot(m3z, m.x);
	mm.y.x = dot(m3x, m.y);
	mm.y.y = dot(m3y, m.y);
	mm.y.z = dot(m3z, m.y);
	mm.z.x = dot(m3x, m.z);
	mm.z.y = dot(m3y, m.z);
	mm.z.z = dot(m3z, m.z);

	float3 result = 0.0f;
	result.x = dot(mm.x, pos.xyz);
	result.y = dot(mm.y, pos.xyz);
	result.z = dot(mm.z, pos.xyz);
	return result;
}

float3 makeRotationMatrix(float3 input, float3 pos){
	float3 a;
	a.x = input.z;
	a.y = input.y;
	a.z = input.x;

	float3 result = 0.0f;
	struct mat3 m;
	m.x = (float3)(cos(a.x) * cos(a.z) - sin(a.x) * cos(a.y) * sin(a.z),
		-cos(a.x) * sin(a.z) - sin(a.x) * cos(a.y) * cos(a.z),
		sin(a.x) * sin(a.y));
	m.y = (float3)(sin(a.x) * cos(a.z) + cos(a.x) * cos(a.y) * sin(a.z),
		-sin(a.x) * sin(a.z) + cos(a.x) * cos(a.y) * cos(a.z),
		-cos(a.x) * sin(a.y));
	m.z = (float3)(sin(a.y) * sin(a.z),
		sin(a.y) * cos(a.z),
		cos(a.y));

	result.x = dot(m.x, pos.xyz);
	result.y = dot(m.y, pos.xyz);
	result.z = dot(m.z, pos.xyz);
	return result;
}

float3 rotationMatrix(float3 axis, float angle, float3 pos) {
	float3 a = normalize(axis);
	float s = sin(angle);
	float c = cos(angle);
	float oc = 1.0f - c;
	float sx = s * a.x;
	float sy = s * a.y;
	float sz = s * a.z;
	float ocx = oc * a.x;
	float ocy = oc * a.y;
	float ocz = oc * a.z;
	float ocxx = ocx * a.x;
	float ocxy = ocx * a.y;
	float ocxz = ocx * a.z;
	float ocyy = ocy * a.y;
	float ocyz = ocy * a.z;
	float oczz = ocz * a.z;
	struct mat3 mm;
	mm.x = (float3)(ocxx + c, ocxy - sz, ocxz + sy);
	mm.y = (float3)(ocxy + sz, ocyy + c, ocyz - sx);
	mm.z = (float3)(ocxz - sy, ocyz + sx, oczz + c);

	float3 result = 0.0f;
	result.x = dot(mm.x, pos.xyz);
	result.y = dot(mm.y, pos.xyz);
	result.z = dot(mm.z, pos.xyz);
	return result;
}