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wabbz111

Polygon count

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Hi people,
I would like to know how i can get a polygon count for my 3D scene.
It will be purely for statistics so something simple will suffice.
My program is an l-system tree generator and i want to know
how many polygons are used to draw the various trees.
Any help is greatly appreciated.

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Hi swiftcoder,
Could you please elaborate on the above statement
Do i use a counter? if so do i count the vertex buffer? or something else
Secondly i have seen info on glfeedback will it achieve the same thing?
THanks

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I am using lines for trunk and branches, with leaves represented by an octahedron.
Since l-system generate the tree recusivelt i get mant branches and leaves.
I would like to know if there is a way to approximate how many are on the screen
.please look at the picture attached to see what i mean

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I don't know how OpenGL handles lines, if we assume each line is 2 triangles:

Make a counter, numTriangles and set to 0 before rendering the tree (or generating it).


Every time you draw a line segment, increase numTriangles by 2. Every time you draw a leaf, increase numTriangles by 8.

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Or rather than counting while drawing (which is a nice and easy approach)
you could create a function in the node class that sums up the result of itself invoked on its children,
adds its own isolated polygon count, and returns the total value to the caller.


int polycount()
{
int sum = vertices.size() / 3;

foreach(Node n in children)
sum += n.polycount();

return sum;
}

then

Node itreeroot(treeparams);
...
...
...
int total_polycount = itreeroot.polycount();
Edited by SuperVGA

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