When I set up an example demonstrating how much faster GPU-driven bones animation was than CPU-driven animation, I had to modify vertices to contain an index so that each vertex knew which matrix it should use.

I used ent_getvertex to modify the second uv set, which wasn't being used.

I really don't understand the manual's example usage of ent_setvertex. Using c.v (you'll know what I mean if you look in the manual) gives you access to the actual vertex buffer, so modifying the contents of c.v shouldn't require the use of ent_setvertex at all (my code doesn't).

Here's the function I had:
Code:
function initEnt() {
	VECTOR currentVec;
	VECTOR currentVec2;
	ANGLE currentAng;
	CONTACT* c;
	var vexCount = ent_status(this, 0);
	STRING* currentBone = str_create("#10");
	while (vexCount > 0) {
		c = ent_getvertex(this, NULL, vexCount);
		// get position relative to the bone it is attached to
		vec_for_bone(&currentVec, this, ent_bonename(this, NULL, vexCount));
		ang_for_bone(&currentAng, this, ent_bonename(this, NULL, vexCount));
		// swapping co-ordinates so I can use built-in functions
		currentVec2.x = c.v.x;
		currentVec2.y = c.v.z;
		currentVec2.z = c.v.y;
		// translate into world space
		vec_rotate(&currentVec2, this.pan);
		vec_add(&currentVec2, this.x);
		// then get relative position to bone
		vec_sub(&currentVec2, &currentVec);
		// account for the bone's angle
		vec_rotateback(&currentVec2, &currentAng);
		// swap z and y co-ordinate back when we recover
		c.v.x = currentVec2.x;
		c.v.y = currentVec2.z;
		c.v.z = currentVec2.y;
		// will also need to set u2 to something that indicates which bone it is attached to
		ent_bonename(this, currentBone, vexCount);
		if (str_cmpni(currentBone, "root") == 1)
			c.v.u2 = 0;
		else if (str_cmpni(currentBone, "head") == 1)
			c.v.u2 = 1;
		else if (str_cmpni(currentBone, "upper") == 1)
			c.v.u2 = 2;
		else if (str_cmpni(currentBone, "lower") == 1)
			c.v.u2 = 3;
		else if (str_cmpni(currentBone, "hand") == 1)
			c.v.u2 = 4;
		else
			c.v.u2 = 5;
		//...
		vexCount -= 1;
	}
}
It's not very clean, as I was busting out an example as fast as I could to make a case for GPU-based bones animation. But it hopefully makes it clear how I used ent_getvertex.

I called this once at the beginning of the program to modify the second uv set (specifically, u2). Something similar could easily be done to indicate a brightness/darkness for a vertex, and whatever shader you used would be very easy to modify (as Slin already said).

I hope this is of some use.

Jibb

Formerly known as JulzMighty.
I made KarBOOM!