Hello,
I used this post to do a gradient background :
http://www.opengl.org/discussion_boards/showthread.php/164345-Gradient-background?p=1161258
The principle is to draw a background quad with glOrtho and then to draw the model in the perspective view.
Here is the code ; I added it in my existing ClearBackground function ; it is called before every drawing.
glClear(/*GL_COLOR_BUFFER_BIT |*/ GL_STENCIL_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_PROJECTION );
glLoadIdentity();
glOrtho(0,1,0,1,-1,1);
glDisable(GL_DEPTH_TEST);
glDisable(GL_LIGHTING);
glDepthMask(GL_FALSE);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glBegin(GL_QUADS);
glColor3f(85/255.0f, 85/255.0f, 255/255.0f);
...
glEnd();
glDepthMask(GL_TRUE);
glEnable(GL_DEPTH_TEST);
glEnable(GL_LIGHTING);
Here is the problem (see the attached image) : after the first view drawing the background is a small quad in the bottom left. And after a refresh the background is on the full view.
It seems that some initializations are missing before the first drawing…
Do you have an idea of what causes this problem ?
Thanks for your help