CS 5620: Advanced Interactive Graphics (Fall 2009)

Instructor: Kavita Bala

FAQ for Programming Assignment 3

Announcement

• When filtering the shadow map, we assume that the map is square. Think of the following question: if n = 5 and the shadow map is 512 x 512, what values of s would be reasonable?
• If you are encountering problems with FBOs having depth attachments only, try the following fix (thank Kent for providing it :P) to bindFBO() in FrameBufferObject.java:

  protected void bindFBO(GL gl) {
     gl.glBindFramebufferEXT(GL.GL_FRAMEBUFFER_EXT, fboId);
     gl.glPushAttrib(GL.GL_VIEWPORT);
     gl.glViewport(0, 0, width, height);
  
     if (fboType == DEPTH_TEXTURE_FBO) {
         // Need to remind the FBO that it shouldn't draw or read from the color buffer
         // since it isn't attached. Ran into this problem on a Radeon 2400 XT.
         // This contradicts ATI's documentation on FBOs here:
         // http://developer.amd.com/media/gpu_assets/FramebufferObjects.pdf
         // It claims: "Note that this is a per-FBO state, so if you’re using
         // separate FBOs for each render-to-texture setup, you can make these
         // calls once at setup and forget it."
         gl.glDrawBuffer(GL.GL_NONE);
         gl.glReadBuffer(GL.GL_NONE);
     }
  }
  

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