Isometric view in GL, and a camera.
BlitzMax Forums/OpenGL Module/Isometric view in GL, and a camera.
| ||
| Hi, Trying to create an isometric engine in GL. Things went smoothly until I tried to use a larger map and move the camera around. Here is how I set up GL every frame: glMatrixMode(gl_PROJECTION) glLoadIdentity() glOrtho(-5, 5, -5, 5, -10, 20.0) glMatrixMode(gl_MODELVIEW) glLoadIdentity() 'ExtractFrustum() ' Should this be here or below? ' Place camera glTranslatef( camx,0,camz ) ' Just moves the clipping planes and cuts of the graphics 'glTranslatef( camx,camz,0 ) ' Moves the camera up and down, after a while clipped quads are visible ' Isometric view glRotatef( 35.264, 1.0, 0.0, 0.0) glRotatef( -45.0, 0.0, 1.0, 0.0) glScalef( 1.0, 1.0, -1.0) ExtractFrustum() ' Does it matter if it's here or above? Ok, to explain it a bit. ExtractFrustum() does just that. It is a codesnippet I found here: http://www.crownandcutlass.com/features/technicaldetails/frustum.html I use it in an attempt to figure out what parts of the map to draw. And I'm not entirely sure where to put it. :P Not sure if it works since the problem is with clipping. As you can see above I use glTranslatef to move the camera around. If i put camz as the second argument the camera is moving up and down, but the clipping planes, or what they are called, doesn't follow. After moving up a bit the map is cut off. If I put camz as the third argument the camera isn't moving at all, but the clipping planes do. So, naturally I tried to put camz as both the second and third argument, but it did not work as expected. :P So I believe I'm on the wrong track here. How can I make the camera and clipping planes to work together? Any help appreciated. :) |
| ||
| After a good nights sleep and some trial and error, it seemes that this is the correct way of doing this: glMatrixMode(gl_PROJECTION) glLoadIdentity() glOrtho(-13, 13, -10, 10, -30, 100.0) glMatrixMode(gl_MODELVIEW) glLoadIdentity() ' Isometric view glRotatef( 35.264, 1.0, 0.0, 0.0) glRotatef( -45.0, 0.0, 1.0, 0.0) glScalef( 1.0, 1.0, -1.0) ' Place camera glTranslatef( camx,0,camz ) ' Just moves the clipping planes and cuts of the graphics ExtractFrustum() Nothing gets clipped away, and only visible chunks of the map is rendered. (as far as I can tell) |
   |