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Modification Help / Rotation Help

« on: October 27, 2012, 02:50:48 PM »

I need help with a small cable mod that I'm making for ship rigging etc. The wand model seems like a good auxiliary model, so I am using it. I am also using a simple output event right now because it's easy to test with, but eventually there will be sender/receiver bricks or some other system. Anyway, I need help with rotating the correctly sized and positioned cable StaticShape to connect the %this.position and %targetPos.

Code: [Select]

datablock StaticShapeData(CableData) {
	shapeFile = "base/data/shapes/wand.dts";
};

function fxDtsBrick::createCable(%this, %string, %client) {
	%targetBrick = ("_" @ %string).getID();

	if(isObject(%targetBrick) && %targetBrick.getClassName() $= "fxDTSBrick") {
		%targetPos = %targetBrick.position;

		if((%cableLen = VectorDist(%this.position, %targetPos)) > 1) {
			%cableShape = new StaticShape() { datablock = CableData; };

			if(isObject(%cableShape)) {
				for(%i = 0; %i < 3; %i++)
					%mid = %mid SPC ((getWord(%this.position, %i) + getWord(%targetPos, %i)) / 2);

				%currentNormal = VectorNormalize(%cableShape.position);          // BLATANTLY loving WRONG
				%targetNormal  = VectorNormalize(%targetPos);                         // BLATANTLY loving WRONG

				%angle = mAcos(VectorDot(%currentNormal, %targetNormal));	    // BLATANTLY loving WRONG
				%axis  = VectorCross(%currentNormal, %targetNormal);              // BLATANTLY loving WRONG

				%cableShape.setScale("1 1 " @ (%cableLen * 0.55));
				%cableShape.setTransform(%mid SPC %axis SPC %angle);

				MissionCleanup.add(%cableShape);
			}
		}
	}
}

registerOutputEvent(fxDTSBrick, "createCable", "string 20 250", 1);

My initial idea (represented by the picture below) favored the axial rotation system (as opposed to Euler rotation angles) and was to create a vector B from the src and receiver and then create a perpendicular vector A of which to rotate around. I quickly realized that there could be an infinite number of perpendicular vectors which renders this solution moot.


I haven't done this kind of math in quite a while and am rusty... any help? Am I being stupid?