OpenGL and Images (looking for a lead)

OpenGL OpenGL: Basic Coding
1

Hello folks. Anyone know of a nice tutorial that shows you how to load and then draw an image file?

I’m thinking along the lines of “here’s how to load your *.bmp *.jpg *.png *.rgb file. Now here’s how to draw that picture info with OpenGL.”

I’d appreciate any leads. Thanks
-Lagaidh Smif

2

You have
http://www.gametutorials.com/

You also have my site
http://cheo.resnet.wayne.edu/miguel/

3

Thanks Mancha! I’m gonna hit those sites now and have a look.

4

Those sites aren’t quite what I am looking for, but I appreciate your posting.

Anyone else have an idea?

5

Those sites likely have what you need, but you don’t know quite what to look for.

For loading image types, you basically have a couple of options.

  1. Use a third party library.
  2. Learn the file format and write your own loader. (www.wotsit.org has many different file format specifications.)

Basically, whether you use 1 or 2, you want to get the image data into a standard format. Typically the most common is unsigned bytes of RGB or RGBA data. (Or BGR, BGRA.) Basically, in this format each byte represents the R, G, B, or A data for a single pixel. (So if you have RGB data the first pixel is R= data[0] G = data[1] B = data[2])

Once you have that data, you have 2 options for displaying it.

  1. Load it as a texture and display a textured quad. (Image must have dimensions that are a power of 2 for this to work, so resizing may be required.)

  2. Use glDrawPixels.

Hope that helps

[This message has been edited by Deiussum (edited 04-11-2003).]

6

I would like to add nehe.gamedev.net

But maybe if you give a little more detail as to what you are trying to do?

Load a image to the screen?
Load a image and edit it?
???

Originally posted by Lagaidh:
[b]Hello folks. Anyone know of a nice tutorial that shows you how to load and then draw an image file?

I’m thinking along the lines of “here’s how to load your *.bmp *.jpg *.png *.rgb file. Now here’s how to draw that picture info with OpenGL.”

I’d appreciate any leads. Thanks
-Lagaidh Smif[/b]