Oolite Bulletins

Cmd. Cheyd wrote:

Cmd. Cheyd quietly waits and prays for the Windows version... Or a Photoshop script... Or Plug-in... Or...

Griff wrote:

does the texture size power of two rule apply to cube maps? i've used this program to convert some 1024x512 'latlong' maps and the resulting cube map comes out as 512 x 3072. Do i need to resize this now to 512x2048 or will Oolite/openGl deal with this map as 6 512x512 tiles?

London sits in a steamy jungle straddling the equator, with a climate generally resembling Manila's. The food is still bland, the Thames is full of piranha, and it's the only place on Earth where tigers apologize as they attack you.

submersible wrote:

I've been meaning to look at the source for planettool to see if I can devise a normal map generator for cube maps. I noticed that the Oolite planet texture generator builds a normal map by sampling a noise map (lat-long) . For me - building a useful normal map for use on a spherical object from latlong or cube maps has been devilishly hard with current tools. The GIMP normal map extension is OK - but it is planar centric.

• All rendering is done in linear floating-point RGB, and written as (slightly fake) sRGB. The gamma remapping isn’t desirable for normal maps, so you’d want to change the driver (main.c) such that normal-mapping modes produce linear output. This involves passing kFPMGammaLinear instead of kFPMGammaSRGB to FPMWritePNG.
• The basic operation of the tool works by connecting a pixel “source” to a pixel “sink”. Two of the existing sources, MatrixTransformer and CosineBlurFilter, wrap other sources and apply effects. This should be the template for your normal mapper.
• To read a gradient, you’ll want to sample from some offset in each direction, which will look something like this:

FPMColor HeightMapToNormalMapFilter(Coordinates where, RenderFlags flags, void *context)
{
    HeightMapToNormalMapFilterContext *cx = context;
    
    // Read input coordinates, possibly converting from vector to latitude/longitude.
    float lat, lon;
    CoordsGetLatLongRad(where, &lat, &lon);
    
    // Offset coordinates northward by some angle, presumably specified at command
    // line and defaulted to something sensible based on size.
    Coordinates northOffsetCoords = MakeCoordsLatLongRad(lat + cx->offset, lon);
    FPColor northSample = cx->source(northOffsetCoords, flags, cx->sourceContext);
    
    // Three more samples here...
    
    // ...Then calculate normal from gradients.
}

Cmd. Cheyd wrote:

Any chance of getting the bug I reported last year (or was it the year before that?) fixed?

JensAyton wrote:

While it can read from cube maps, it fails at the edges of faces and produces artefacts. This does not affect writing cube maps.