I'm working on drawing the sky in an outdoor FPS/RPG type title.
Needless to say, like everyone, i want it to look more real than reality itself, and take zero clock cycles to draw! <g>.
But seriously, i'm looking for a method or combo of methods that will yield beautiful sky texture like results, but be animated and particle based, driven by a weather simulation engine, AND be low overhead.
here's where i'm at right now:
For daytime, the screen is cleared to a uniform shade of blue based on time of day. the sun is alpha blended in. a skybox is used for night. the sun and skybox can be whipped into shape easily enough, its just tweaking textures and meshes. Clouds and sky color seem to be the real challenge.
for clouds, i'm currently using a system of 20 particles. each particle is an almost flat octahedron mesh. the texture is alpha tested with 2 clouds on a texture, and the texture repeated twice over the mesh, for a total of 4 clouds per mesh, and 80 clouds for all 20 particles. Clouds are at 3 different altitudes, and their altitude is sloped towards the horizon, so they are not drawn in 3 planes above the ground, but more like in 3 concentric shallow domes above the ground. This squeezes them into a far clip plane of 1000 while appearing to be further off. the effect is OK, but reminds me of road runner cartoons for some reason. : P
I'm thinking i need to do a gradient from darker at the horizon to lighter straight up for the sky color, and alpha blend the clouds, but i'm concerned with possible performance issues.
any suggestions for possible candidate techniques or approaches?