Solved

Extruding a 2D path

Posted on 2004-09-18
3
228 Views
Last Modified: 2013-12-26
Hi guys,

I have developed a 2d graphics app which can create simple outlines (consisting of straight lines only).  Using DirextX, I would like to extrude each line into a face based on a height parameter.  Each Shape (2D) has an array of Point objects (X & Y values).  

Can anyone help?

I'm using C# but i'll accept the algorythm in pseudo code if you're not familiar with c# as long as it uses standard verticies / vertex buffers / index buffers etc.

Thanks in advance

Chris
0
Comment
Question by:chrisevans123
3 Comments
 
LVL 17

Accepted Solution

by:
davebytes earned 460 total points
ID: 12109431
If you aren't using too many lines to begin with, don't even bother worrying about optimization.

You may want to swap Y and Z in the following, depending on how you want things to look initially.

For each point, you want to make it a 3D point at say Z=100 to start with.  Then you also need the extruded matching point at Z=100+height.

A final vertex array can be rendered as a triangle strip if the points are interlaced.  That is, assuming your initial vertices are in a 2d float structure, and you have a 3d point structure (which D3D does), you want to do something like:

Point2D *array_orig; // already filled in.
int vertex_count; // already filled in...
float extrude_height; // same...

Point3D *array_3d = new Point3D[vertex_count];
int sub;
for (int i=0; i<vertex_count; i++)
{
  subi = 2*i;
  array_3d[subi].x = array_orig[i].x;
  array_3d[subi].y = array_orig[i].y;
  array_3d[subi].z = 100;
  array_3d[subi+1].x = array_orig[i].x;
  array_3d[subi+1].y = array_orig[i].y;
  array_3d[subi+1].z = 100 + extrude_height;
}

Then array_3d can be rendered as a triangle-strip.  You might need to play with clockwise vs counter-clockwise culling (or turn culling off).

-d
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

As game developers, we quickly learn that Artificial Intelligence (AI) doesn’t need to be so tough.  To reference Space Ghost: “Moltar, I have a giant brain that is able to reduce any complex machine into a simple yes or no answer. (http://www.youtu…
Performance in games development is paramount: every microsecond counts to be able to do everything in less than 33ms (aiming at 16ms). C# foreach statement is one of the worst performance killers, and here I explain why.
This Micro Tutorial will give you a basic overview how to record your screen with Microsoft Expression Encoder. This program is still free and open for the public to download. This will be demonstrated using Microsoft Expression Encoder 4.
Hi friends,  in this video  I'll show you how new windows 10 user can learn the using of windows 10. Thank you.

911 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

15 Experts available now in Live!

Get 1:1 Help Now