how does glDepthRange work?

• 01-07-2013, 04:23 AM
debonair
how does glDepthRange work?
My vertex cords are :
Code :

```GLfloat vertices[]= { 0.5f,0.5f,0.5f, -0.5f,0.5f,0.5f, -0.5f,-0.5f,0.5f, 0.5f,-0.5f,0.5f,//face 1   0.5f,-0.5f,-0.5f, -0.5f,-0.5f,-0.5f, -0.5f,0.5f,-0.5f, 0.5f,0.5f,-0.5f,//face 2   0.5f,0.5f,0.5f, 0.5f,-0.5f,0.5f, 0.5f,-0.5f,-0.5f, 0.5f,0.5f,-0.5f,//face 3   -0.5f,0.5f,0.5f, -0.5f,0.5f,-0.5f, -0.5f,-0.5f,-0.5f, -0.5f,-0.5f,0.5f,//face 4   0.5f,0.5f,0.5f, 0.5f,0.5f,-0.5f, -0.5f,0.5f,-0.5f, -0.5f,0.5f,0.5f,//face 5   -0.5f,-0.5f,0.5f, -0.5f,-0.5f,-0.5f, 0.5f,-0.5f,-0.5f, 0.5f,-0.5f,0.5f//face 6   };```

now, i am changing z cords by:

Code :

```for(int i=0;i<24;i++) vertices[i*3+2]*=10 glDepthRange(0,10.0);```

Now, i am expecting that z cords will be mapped to -0.5 to 0.5 range due to glDepthRange call and i can see a proper cube, but it gives o/p as that of when i comment glDepthRange call above with distorted geometry.
• 01-07-2013, 02:30 PM
dukey
I would assume depthrange would only work between the values of 0 - 1
• 01-07-2013, 03:44 PM
tonyo_au
It set the linear tranformation from NDC to the z-buffer - and yes it is in the range 0-1. Do not confuse this with near and far planes of the projection matrix.
• 01-07-2013, 11:13 PM
debonair
Quote:

Originally Posted by tonyo_au
It set the linear tranformation from NDC to the z-buffer - and yes it is in the range 0-1. Do not confuse this with near and far planes of the projection matrix.

How can i simulate the above effect? by giving coords > 1 i want to scale that to 0-1..
• 01-08-2013, 12:38 AM
tonyo_au
By definition NDC is in the range -1 to +1, the z value is thenglRangeDepth is applied; so you can't have a coordinate > 1.