Original Post
I'm doing a simple plane using vbo's to make sure I understand vbo's but I've run into a problem. It's just to be clear of vbo's for myself. I'm trying to do a simple plane that is divided n times. I store the vertices into a stl vector. I then store the indices into a stl vector that I generate through a for loop. It works but for some reason when I have too many indices the plane screws up and the plane will not look right. Everything is arb since unfortunately at the moment I'm relying on an intel gpu that only supports ogl 1.4 somewhat 1.5 for now. example of i<24 when creating the indices for iList your_link_text example of i<25 or higher when creating the indices for iList. your_link_text hopefully this is clear. [Edited by - Asem on January 7, 2009 12:03:35 AM]
struct Vertex
{
void setXYZ(float x_ = 0.0f, float y_ = 0.0f, float z_ = 0.0f){v[0]=x_; v[1]=y_; v[2]=z_;}
float v[3];
};
vector<Vertex> vList; //Array Of Vertices
vector<unsigned short> iList; //Array Of Indices
void drawPlaneInit()
{
//Push 48 vertices into vList and set position.
//simple 2d like plane
Vertex vert;
for(int i=0; i<6; i++)
{
for(int j=0; j<8; j++)
{
vert.setXYZ(j, i, 0.0f);
vList.push_back(vert);
}
}
//create the indices needed to form the triangles
//Problem: Everything looks okay until I set the loop to stop before 25.
//The plane would look like it's broken in parts unless it less than 25. I've
//printed iList to the console to confirm that the indices should be correct
//(which they are).
unsigned short it=0;
for(unsigned int i=0; i<24; i++)
{
if(it == 7)
{ it = 0;
continue;
}
else
{
//1 square is triangle 1 and 2
//Triangle 1
iList.push_back(i+1);
iList.push_back(i+8);
iList.push_back(i);
//Triangle 2
iList.push_back(i+1);
iList.push_back(i+9);
iList.push_back(i+8);
it++;
}
}
glGenBuffersARB(1, &vBuf);
glBindBufferARB(GL_ARRAY_BUFFER_ARB, vBuf);
glBufferDataARB(GL_ARRAY_BUFFER_ARB, sizeof(Vertex)*vList.size(), &(*vList.begin()), GL_STATIC_DRAW_ARB);
glVertexPointer(3, GL_FLOAT, 0, 0);
glGenBuffersARB(1, &eBuf);
glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, eBuf);
glBufferDataARB(GL_ELEMENT_ARRAY_BUFFER_ARB, sizeof(unsigned short)*iList.size(), &(*iList.begin()) , GL_STATIC_DRAW_ARB);
}
//Then Draw blah blah...