Category:Material System: Difference between revisions

Introduction

In Source, the Material System defines how the visible surfaces of an object are rendered on the Player's screen.

• Each VTF or Valve Texture Format file, is basically a rasta image file or pixel-map. Most material surfaces will layer several VTFs together, each containing a different type of surface information; for example, in addition to the colormap, a material may also use a normalmap, specularmap, opacitymap, luminositymap, etc. All the separate frames of an Animated Texture can be stored in single VTF file.
  • A VTF must be decompiled before it can be edited with an image editor.

• Each VMT or Valve Material Type file specifies which VTF Textures to use to 'paint the polygons', which Shader (and Shader Parameters) to use for rendering those Textures, and a few surface collision effects such as the sounds and decals to use when bullet hits the surface. A Material file needs to specify at least two things: a Texture and a Shader.
  • A VMT file is an uncompiled script that can be tweaked and edited with any text editor.

• Each Shader is a specific routine in the the Rendering Engine used to translate all the texture and lighting (etc) information into screen pixels. In Source, Per-Object Shaders are applied to Material Surfaces (eg Lightmappedgeneric, Vertexlitgeneric, Water) and Post Process Shaders are applied to the Player's Viewport (eg Bloom, Sepia, Fog). The Material System is only concerned with Per-Object Shaders.
  • Editing Shaders is a bit of a dark art.

• Each object's UV map takes the name of one or more VMT files, and maps pixels from all the Texture layers specified for that Material to the appropriate polygons.
  • A UV map is part of an object's Geometry, see UV mapping for more info on editing UV maps.

Generally a Brush Material refers to a VMT designed for use with World Brushes (stored in game_dir/materials/), and a Skin is a VMT designed to be mapped onto a particular Model (stored in game_dir/materials/models). A Texture is a VTF file, used by either a Brush Material or a Skin - but rarely both. VTFs are usually stored in the same folder as the VMTs that use them.

Note:Non-Surface Material Properties are handled by the Physics System(s), not the Material System; for example: Breakable objects derive some additional "material" properties from their propdata configuration.

Basics

• Creating a Texture using VTFEdit - The basics of VTF creation.
• Materials for Models - These are slightly different to Brush Materials.
• Materials for Brush Displacements - These are slightly different to ordinary Brush Materials.
• Materials for Sprites - Slightly different again.
• Decals - How to make decal and overlay materials.
• Skybox (2D) - How to use and make the cubic materials used for the sky.
• Animated Textures.

Advanced topics

• Material Proxies - Advanced materials that can vary based on changing data.
• Water Shader - Description of the special water shader.
• Half-Life 2 Shader Fallbacks - Fallback settings of Half-Life 2 shaders on different platforms.
• DirectX Versions - How shaders are rendered on different versions of DirectX.

Useful applications

• See Category:Tools and Category:Third Party Tools