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question:color problem

Started by frankyliao Jan 21, 2005 at 3:50 AM 4 replies 500+ views

Original Post

Jan 21, 2005 at 3:50 AM

I have used glColor3f() to define a kind of color when drawing a face in openGL , but the function didn't affect the face. However, I can use glMaterialfv() to affect the color. Why? Thank you first

ff8

Jan 21, 2005 at 3:53 AM

i think because you enabled the light by using glEnable(GL_LIGHTING);

frankyliao

Author

frankyliao

Jan 21, 2005 at 4:06 AM

yes!
thank you very much.
But how can I draw a red line in white background if I can't use glColor3f();

ff8

Jan 21, 2005 at 4:25 AM

you can coloring the object by using glMaterialfv() by changing the color light like this code:

   float c1[]={0.0, 0.0, 0.0, 1.0};    float c2[]={1.0, 1.0, 1.0, 1.};     glEnable(GL_COLOR_MATERIAL);    glMaterialfv(GL_FRONT, GL_AMBIENT, c1);    glMaterialfv(GL_FRONT, GL_SPECULAR, c2);    glMaterialfv(GL_FRONT, GL_EMISSION, c1);    glColorMaterial(GL_FRONT, GL_DIFFUSE);    drawobject();

frankyliao

Author

frankyliao

Jan 22, 2005 at 1:54 AM

thanks

Kalidor

Jan 22, 2005 at 12:24 PM

Or just disable lighting when you don't need it, which is what you want if you just want to draw a red line on a white background. It will also be faster since it doesn't have to calculate all the lighting equations (although in this case it most likely won't be noticable).

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