[osg-users] Mip Maps

[Robert Osfield]

Hi David,

There shouldn't be any need to call allocateMipmapLevels() as for most
usage cases the OSG will do what is required, all you need to do is
set up the Texture::setMagFilter(osg::Texture::MIN_FILTER,
NEAREST_MIPMAP_LINEAR).  Calling allocateMipmalLevels() doesn't for a
texture to use mipmapping if the filter level isn't set, and is just a
hint to rebuild the mipmaps, so not required if you are just assigning
a load static osg::Image to the texture.

Robert.

On 19 January 2017 at 00:22, David Heitbrink <david-heitbrink at uiowa.edu> wrote:
> I having an issue with rendering models with mip maps, when I render my scene I get some strange aliasing on text in the texture.
>
> I am mostly using DDS files, some texture have mip maps, some do not. If they do not have a mip map defined I am setting:
>
> texture->allocateMipmapLevels();
>
>
> So to test this I added some test code to my shaders to manualy cycle through the mip map levels (FrameNum is a uniform that is incremented every frame):
>
> Code:
>
> vec4 texel = texture2D(TextureId,TexCoord[0]);
> int txtLvl = textureQueryLevels(TextureId);
> int lvl ;
> if (txtLvl > 1){
>     lvl = (FrameNum/10) % txtLvl;
>     texel = textureLod(TextureId,TexCoord[0],float(lvl));
>     if (lvl == 0 ) texel.r+=0.5;
> }
>
>
>
>
> In most of my scene I am getting the red flashing every couple of seconds or so. But the texture does not blur out. In a handful of cases I have some textures that do blur out, but most do not.
>
> Does any one have any ideas on what could be causing this issue?
>
> ------------------
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=69997#69997
>
>
>
>
>
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