/* Copyright (c) 2007 Scott Lembcke
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
 
#include <stdio.h>

#include "chipmunk_private.h"

inline cpVect
cpvslerp(const cpVect v1, const cpVect v2, const cpFloat t)
{
	cpFloat dot = cpvdot(cpvnormalize(v1), cpvnormalize(v2));
	cpFloat omega = cpfacos(cpfclamp(dot, -1.0f, 1.0f));
	
	if(omega < 1e-3){
		// If the angle between two vectors is very small, lerp instead to avoid precision issues.
		return cpvlerp(v1, v2, t);
	} else {
		cpFloat denom = 1.0f/cpfsin(omega);
		return cpvadd(cpvmult(v1, cpfsin((1.0f - t)*omega)*denom), cpvmult(v2, cpfsin(t*omega)*denom));
	}
}

cpVect
cpvslerpconst(const cpVect v1, const cpVect v2, const cpFloat a)
{
	cpFloat dot = cpvdot(cpvnormalize(v1), cpvnormalize(v2));
	cpFloat omega = cpfacos(cpfclamp(dot, -1.0f, 1.0f));
	
	return cpvslerp(v1, v2, cpfmin(a, omega)/omega);
}

char*
cpvstr(const cpVect v)
{
	static char str[256];
	sprintf(str, "(% .3f, % .3f)", v.x, v.y);
	return str;
}
