Thanks to Pixelante!

Cyan fog demo

So here we go:

/* Some constants for us */ private const FARPLANE:Number = 10000; private const INVFARPLANE:Number = 1/FARPLANE;   /* Set up the fragment constant for a cyan fog color (fc0) */ context.setProgramConstantsFromVector(Context3DProgramType.FRAGMENT, 0, Vector.<Number>([0, INVFARPLANE, INVFARPLANE, 1]));   /* Set up vertex shader which will pass colour and depth to the fragment shader */ var vertexShaderAssembler:AGALMiniAssembler = new AGALMiniAssembler(); vertexShaderAssembler.assemble(Context3DProgramType.VERTEX, "m44 vt0, va0, vc0 \n"+ //transform vertex x,y,z "mov op, vt0 \n"+       //output vertex x,y,z "mov v0, vt0.z \n"+     //move vertex z (depth) to fragment shader "mov v1, va1"           //move vertex r,g,b to fragment shader );   /* Set up a fragment shader */ var fragmentShaderAssembler:AGALMiniAssembler= new AGALMiniAssembler(); fragmentShaderAssembler.assemble(Context3DProgramType.FRAGMENT, "mul ft0, fc0, v0 \n"+      //multiply fog r,g,b by vertex z (depth) "add ft1, ft0, v1 \n"+      //add final fog r,g,b to vertex r,g,b "mov oc, ft1"           //output color );

That wasn't so bad!