Real-time dreamy Cloudscapes with Volumetric Raymarching(blog.maximeheckel.com) |
Real-time dreamy Cloudscapes with Volumetric Raymarching(blog.maximeheckel.com) |
A couple of extra things I ended up doing were:
1) Using a lower-res texture to modulate the high-res raymarched density, this gives you control over the overall macro shape of the clouds and allows you to transition between LOD better (i.e. as you move from ground level up to space you can lerp between the raymarched renderer & just rendering the low-res 2D texture without any jarring transition.
2) Using some atmospheric simulation to colorize the clouds for sunrise/sunset. To make this performant I had to build some lookup tables for the atmospheric density at given angles of the sun.
3) Altering the step size of the raymarch based on density, I took this from the Horizon Zero Dawn developers where they have a coarse raymarch and as soon as they get a dense enough sample they step back and switch to a higher res step until the density hits zero again.
this not, by any means, the best way of doing it, but I felt it was a bit easier writing GLSL code.
https://github.com/victorqribeiro/3Dengine/blob/master/js/Sh...
Is that like a Unity or Unreal standard? The thing I'm familiar with is a single .glsl with a void fragment() and void vertex() etc. in it
1. yes I know it's common practice.
- Technical
- Beautiful
- In-depth
- Well written
- With passion
- Works well on mobile devices
"raycasting" is sending a virtual ray out from a start position to find the next solid surface (ignoring volumes/volumestacks for the moment). (Occlusion/shadow rays can just check for occlusion without finding the closest intersection).
"raytracing" is doing multiple series of "raycasting" events, either in "traditional" Whitted raytracing where you bounce off reflections and through transparent materials recursively, or using BSDFs for outgoing directions in pathtracing for integration. Essentially after one "raycast" event, you do something with the result, and then based off that result, you do another "raycast" even to find the next "intersection" in the scene, starting from the new position you just found.
"raymarching" sort of depends whether you're doing Signed Distant Field intersection or volumetric integration, but to an approximate description, you're basically repeatedly running the intersection test ("raycasting") from multiple "virtual" 3D positions in scene space to evaluate the presence of something which can not necessarily be exactly evaluated with a single intersection: i.e. a fractal's limit surface, or a heterogeneous (different values per voxel) volume.