I create a grid polygon use the code
wSize = size / w;
hSize = size / h;
// create vertices
//
//float x=-size/2.0, z=-size/2.0;
float x=0, z=0;
for ( int i = 0; i <=h; i++ )
{
for ( int j = 0; j <=w; j++ )
{
x += wSize;
}
//x=-size/2.0;
x=0;
z += hSize;
}
The 2*2 grid should like this:
v6 v7 v8
v3 v4 v5
v0 v1 v2
1*1 grid should be
v2 v3
v0 v1
so, I think the index parameter of glDrawElement() should be
0,1,3,2. but it results a twist squad.
To get a correct squad, I had to input 0,1,2,3…
Is index depend on the order of vertex position creation?
thanks