Getting the vertexes of a triangle

Posted By: krial057

Getting the vertexes of a triangle - 11/26/11 17:37

Hey community,

I'm trying to get the Vertex numbers of the face a user clicks on. I have tried to get them with ent_buffers, here is my code:

Php Code:

if(c_trace (from,to, SCAN_TEXTURE|USE_POLYGON)>0)
{
				CONTACT* c = ent_getvertex(hit.entity, NULL, hit.vertex); 
		short* trianlgeBuffer;
		ent_buffers(hit.entity,0,0,NULL,&trianlgeBuffer,NULL);
		short sv1=trianlgeBuffer[hit.triangle*3];
		short sv2=trianlgeBuffer[hit.triangle*3+1];
		short sv3=trianlgeBuffer[hit.triangle*3+2];
		printf("clicked:%i / triangle vertexes:%i ; %i ; %i",(short)(int)c.vertex,sv1,sv2,sv3);
		if(hit.vertex==sv1||hit.vertex==sv2||hit.vertex==sv3) printf("This should always pop up :S");		   
}

However the vertex numbers of the triangle are not the same as the vertex number of hit, but they are in the same range

regards, Alain

P.S: is here a welcome thread to present myself?

Posted By: Superku

Re: Getting the vertexes of a triangle - 12/11/11 20:51

Hi and welcome!

The problem is that hit.triangle and hit.vertex start at 1, not at 0:

ent_buffers(hit.entity,0,0,NULL,&trianlgeBuffer,NULL);
hit.triangle--;
hit.vertex--;
short sv1= ...

Posted By: krial057

Re: Getting the vertexes of a triangle - 12/12/11 18:04

Thank you, it works

I spend so many hours on this problem, and that -- was the whole thing xD

Just an other question out of curiosity (not important for my project, but something i don't understand):
Is 3dgs cheating with c_trace and getting the nearest vertex?
If I have a face and i trace it with c_trace, the hit.vertex index is always the same, even if I trace nearer on an other vertex of that face

Posted By: Superku

Re: Getting the vertexes of a triangle - 12/12/11 18:15

Had to test the code myself to find the problem!

Yes it seems like hit.vertex is always the first vertex of the triangle, so you have to calculate it yourself:

D3DVERTEX* vbuffer;
ent_buffers(hit.entity,0,0,&vbuffer,&triangleBuffer,NULL);
...
vec_to_ent(target,hit.entity);
var max_dist = 999,j,k;
for(i = 0; i < 3; i++)
{
j = vec_dist(target,(vector(vbuffer[triangleBuffer[hit.triangle*3+i]].x,vbuffer[triangleBuffer[hit.triangle*3+i]].z,vbuffer[triangleBuffer[hit.triangle*3+i]].y));
if(j < max_dist)
{
max_dist = j;
k = i;
}
}

Now k should be your closest vertex!

Posted By: krial057

Re: Getting the vertexes of a triangle - 12/12/11 18:52

Thank you, nice snippet

Greetings from Luxembourg