Nice to know. No missing pixels?
but then again, the way i'm doing things, i don't think there could be.
for daytime scenes, i:
1. clear the screen to sky color (for the moment).
2. clear the zbuffer.
3. set lights based on time of day.
4. set camera
7. draw sun: ztest off. zwrite off. lighting off. alphablend on. one drawprimitive call, one static quad mesh (2 tris), one static texture. then turn lighting, zwrite,and ztest back on, and alphablend off again.
8. draw clouds: set material based on time of day. set clip planes to 400 and 2000. recalc frustum clipping planes. add 1000 clouds to the "drawlist" - a list of textures in the scene, and the meshes that use them. draw the meshes in the drawlist: for each texture, set texture. for each mesh that uses that texture, set world transform. set mesh, material, cull, alphatest, and clamp on the fly as needed using a state manager. then call drawprimitive. reset clip planes to 0.1 and 1000. recalc frustum culling planes.
9. clear zbuf.
10. draw everything else
so i clear the screen and the zbuffer, then alpha blend in the sun with zbuffer test and write turned off. then i turn on the zbuffer again and draw the clouds with the distant clip planes. then i clear the zbuffer and draw everything else with the closer clip planes.
i may not need to clear the zbuffer between drawing clouds and everything else. the near plane for clouds is 400. visual range (for non LOD background stuff) is only 300. so i never really draw anything much past 300. and when i do clear it, the zbuffer just has ~500 clouds starting at range 400, which won't change anything if i then draw a bunch of stuff at 300 or closer.