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glCopyPixels()

Started by Axel Nov 15, 2000 at 4:41 PM 3 replies 450+ views

Original Post

Nov 15, 2000 at 4:41 PM

I am very new at OpenGL. I have a project given to me by my employer to display an image onto the screen. The image is a jpeg image and he said that I could just copy the pixels from the jpeg image and then display it using glCopyPixels(). I have read the redbook on this topic but it doesn''t seem to help me with copy the pixels from a current image. Please help? Thanks in advance. Axel

mhearn

Nov 16, 2000 at 3:27 PM

Hi Axel,

I''ve been doing something similar in the past few days and I know how frustrating it can be. Here''s a few tips:

- To display a JPEG in OpenGL using glCopyPixels() you must first uncompress the JPEG into pixel data (RGB) in memory. The JPEG loader code should do this.
- Then, rearrange the data in memory so it starts from the bottom left (this is what got me)
- Make sure that you call glPixelTransfer() [i think] to set the pixel alignment to 1.
- Then call glDrawPixels() with a pointer to the data in memory and it should be drawn.

Hope that helps- mike

Axel

Author

Axel

Nov 16, 2000 at 5:16 PM

I need the source of a good jpeg loader. Thanks

Axel

Axel

Author

Axel

Nov 16, 2000 at 5:16 PM

I need the source of a good jpeg loader. Thanks

Axel

Axel

Author

Axel

Nov 16, 2000 at 5:16 PM

I need the source of a good jpeg loader. Thanks

Axel

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