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Pedro Ferreira
04-20-2001, 02:56 AM
Hi to all.
Please help me on this.
I've loaded a bitmap and I was trying to put some lines on top of the bitmap. What happens is that the lines appear black and not white, I've tried to change the color of the lines, but what happens is that the whole image gets the new color.
How can I put the lines in top of bitmaps whithout changing the bitmaps color.
Pedro

Deiussum
04-20-2001, 04:51 AM
I'm not real clear that this is the answer to your question but here goes...

OpenGL is a state machine, which means when you change the color, everything will be drawn that color until you change it again.

When you say bitmap do you mean as in a BMP image loaded as a texture or as in a series of 0's and 1's that represents an 1-bit image?

Either way they will both use the current color. The bitmap directly, the texture because the default environment mode is GL_MODULATE, which causes the texture and the current color/material to be blended together.

If you bitmap is really a texture, try resetting the color back to white or add this line to your initialization...

glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);

[This message has been edited by Deiussum (edited 04-20-2001).]

Pedro Ferreira
04-20-2001, 07:30 AM
When you say bitmap do you mean as in a BMP image loaded as a texture or as in a series of 0's and 1's that represents an 1-bit image?/B

Thanks for replying.
It's a BMP image.
Pedro