texture mipmap


    May 27 2006 | 4:59 pm
    I can't get mipmapping to work on my computer. I'm using power-of-two textures (1024x1024), but setting mipmap or filter settings just gives me errors.
    @mipmap linear or nearest generates the following error: "jit.gl.texture: setting texture filter mode.: GL Error: Invalid operation."
    I guess bilinear and trilinear are not supported by my videocard because I get: "jit.gl.texture: invalid filter mode bilinear".
    I'm animating photos and the quality of the pictures is important. Scaling from thumbs to fullscreen and back without interpolation looks really bad. I hope someone knows a fix / workaround for this.
    I'm using jitter 1.5.2 + nvidea go6800 (forceware 84.25)
    -thijs

    • May 27 2006 | 9:35 pm
      Hi Thijs,
      Unfortunately, the filter attribute of jit.gl.texture is broken in 1.5.2 and should be fixed in 1.5.3. I haven't performed testing of the mipmap case, but we can do this to verify. Standard bilinear texture filtering is the default (same as linear), however it doesn't do a very good job at downsampling.
      For image scaling, one could write a decent quality texture scaling shader which uses something like a lancszos or mitchell filter for texture sampling. Perhaps we'll find time to make one for the jitter 1.5.3 release, but one quick workaround might be to use one of the blurring shaders where blur width is increased as the scale is decreased.
      Hope this helps.
      -Joshua
    • May 27 2006 | 10:21 pm
      That's too bad. I'll see if I have the time to get the shader thing working for now. I just ran into a bigger problem... patch is on the way.
      -thijs