gistfile1.c

static void bezier_getLineSegments(bezier_t curve, int count, vec3_t *outPoints, float *outLengths, float *outDeltas, float *outTotalLength)
{	
	vec3_t points[count];
	float lengths[count];
	lengths[count-1] = 0.0f;
	float deltas[count];
	float totalLength;
	
	float t = 0.0f;
	float interval = 1.0f/(float)(count-1);
	for(int i = 0; i < count; ++i) {
		points[i] = bezier_getPoint(curve, t);
		deltas[i] = t;
		if(i > 0) {
			lengths[i-1] = vec3_dist(points[i], points[i-1]);
			totalLength += lengths[i-1];
		}
		t += interval;
	}
	if(outPoints) memcpy(outPoints, points, sizeof(points));
	if(outLengths) memcpy(outLengths, lengths, sizeof(lengths));
	if(outDeltas) memcpy(outDeltas, deltas, sizeof(deltas));
	if(outTotalLength) *outTotalLength = totalLength;
}

static vec3_t bezier_getPointUsingLineSegments(float t, int count, vec3_t *points, float *lengths, float *deltas, float totalLength)
{
	float desiredDistance = t * totalLength;
	assert(desiredDistance >= 0.0f && desiredDistance <= totalLength);
	float distanceTravelled = 0.0f;
	for(int i = 0; i < count - 1; ++i) {
		float nextDistanceTravelled = distanceTravelled + lengths[i];
		if(desiredDistance < nextDistanceTravelled) {
			float interpolation = (desiredDistance - distanceTravelled) / lengths[i];
			vec3_t p1 = points[i];
			vec3_t p2 = points[i+1];
			vec3_t movementVector = vec3_scalarMul(vec3_sub(p2, p1), interpolation);
			return vec3_add(p1, movementVector);
		}
		distanceTravelled = nextDistanceTravelled;
	}
	return points[count-1];
}