# Polygon count

This topic is 2255 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

## Recommended Posts

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.

##### Share on other sites
You are sending each triangle to OpenGL - just count them in your own code.

##### Share on other sites
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

##### Share on other sites
How do you draw the tree? And don't you already know how many polygons there are in the tree when generating it?

##### Share on other sites
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

##### Share on other sites
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.

##### Share on other sites
Alright i will try it and let you know thanks.

##### Share on other sites
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

• ### What is your GameDev Story?

In 2019 we are celebrating 20 years of GameDev.net! Share your GameDev Story with us.

• 11
• 15
• 11
• 11
• 9
• ### Forum Statistics

• Total Topics
634149
• Total Posts
3015829
×