Grass-clutter modelling – DayZ

This page is more or less in WIP state, primarily focused on documenting changes done to the clutter for DayZ (compared to state of clutter in Arma 2 public data).

What is new

• Single-sided faces in resolution lods.
• Wind effect simulation moved to shaders resulting in rvmat changes - introduction of a new array: plantWind[] = {local speed, stiffness, smoothness, light/dir};.
  • local speed (0-1 range) - how much is the speed of local sinusoidal swing (is later affected by global wind and perlin wind inside shader, so stronger wind makes a little faster move).
  • stiffness (0-1 range) - how much the wind affects the XZ plane move, 0 = disable wind effect completely (used on static clutter objects - for example fallen branches, rocks).
  • smoothness (0-1 range) - affects the medium detail perlin wind ("random" gusts of wind) = 0, no smooth, 1 full smooth, almost one direction of wind.
  • light/dir (two numbers):
    • Integer part is how much the wind affects lightness of grass (a little intensity changes when the grass moves more), value is from 0-100.
    • Fractional part is the medium perlin wind directionality, 1 = all directions, 0 only main global wind direction.
• Stage3 rvmat mask texture for the wind animation (see the sample below).
• Optional phase offset can be specified (so polyplanes swing in a bit different manner from each other) per plane by merging vertices from a plane and position them within second uv set (and specifying uvSource=tex1 in Stage3 of grass rvmat).
• Optional shadowBias parameter in rvmat can be used to darken clutter in shadows (0-1 range).
• Optional use of a normal map (Stage2).
• Ability to disable coloring by satellite (see grass-clutter configuration for more info).
• Ability to shadow clutter using global terrain normal texture (see terrain sample for more info).

Sample

You can take a look at DayZ Samples package for an example of a clutter mesh (look out for Test_Clutter folder), textures and material itself. Please note that clutter models (when grass shader is used in material) cannot be previewed in Buldozer!