• Features

This page is quite technical. You can see groups of the engine, game and tools derived by the id Tech 3 GPL source.

1. Engine
   1. General
   2. Renderer
      1. General
      2. Supported Image Formats
      3. Supported Model Formats
      4. Lighting
      5. Shadowing
      6. Materials and Shaders
      7. Special effects
      8. Skeletal Animation
   3. Networking
      1. Client
      2. Server
   4. Physics
   5. AI
   6. Sound
      1. Supported Audio Formats
   7. Platforms
2. Game
   1. Client Game
   2. Server Game
   3. User Interface
3. XMap2
4. GtkRadiant

Engine

• derived from the IOQuake3 engine

General

• console provides a backbone for game management, and allows in-game console variables and commands

Renderer

General

• makes usage of latest OpenGL extensions

  • OpenGL extension GL_ARB_vertex_program

  • OpenGL extension GL_ARB_vertex_buffer_object

  • OpenGL extension GL_ARB_shader_objects

  • OpenGL extension GL_ARB_vertex_shader

  • OpenGL extension GL_ARB_fragment_shader

  • OpenGL extension GL_ARB_shading_language_100

  • OpenGL extension GL_ARB_non_power_of_two

  • OpenGL extension GL_ARB_draw_buffers

  • OpenGL extension GL_ARB_texture_float

  • OpenGL extension GL_ATI_seperate_stencil

  • OpenGL extension GL_SGIS_generate_mipmap

  • OpenGL extension GL_EXT_texture_filter_anisotropic

  • OpenGL extension GL_EXT_stencil_wrap

  • OpenGL extension GL_EXT_stencil_two_side

  • OpenGL extension GL_EXT_depth_bounds_test

  • OpenGL extension GL_EXT_framebuffer_object

  • OpenGL extension GL_EXTX_framebuffer_mixed_formats

• hidden surface removal algorithm using the Q3A BSP and PVS

• arbitrary resolution support (including widescreen)

• entire renderer rewritten and designed for OpenGL 2.1 + FBO (DirectX 9 equivalent)

  • almost everything renders with OpenGL GLSL shaders

  • clever usage of vertex buffer objects (VBO) to speed up rendering of everything

    • avoids geometry processing at render time using the CPU

    • memory efficient implementation with static VBOs for BSP models and static/dynamic IBOs for BSP clusters

    • static game models like powerups use static VBOs as well

• anisotropic texture filtering

• optional uniform lighting and shadowing model like in Doom 3

• usage of frame buffer objects (FBO) to perform offscreen rendering effects

• reactivated and extended TrueType font support using FreeType

• optional deferred shading with r_deferredShading 1

Supported Image Formats

• Truevision Targa (.tga)

• JPEG File Interchange Format (.jpg)

• Portable Network Graphics (.png)

• DirectX .dds image file format support

Supported Model Formats

• Quake 3 .bsp

• Quake 3 .md3

• Doom 3 .md5mesh

• Doom 3 .md5anim

Lighting

• dynamic and static realtime lights that can use Doom 3 style boxed lighting attenuation

  • lights can have .mtr shaders like surface materials

    • 1 lightFallOff image for Z attenuation

    • up to 15 shader stages for XY attenuation

    • RoQ videos can be used for light attenuation

  • omni-directional lighting (point lights)

  • projective lighting (spot lights)

  • hardware occlusion culling removes light volumes behind opaque geometry

• precomputed lighting

  • lightgrid lighting for entities

  • simple light mapping for world geometry

  • directional 'deluxe' light mapping for world geometry

  • can be used with Doom 3 materials

Shadowing

• [cg/r]_shadows

  • 1 = blob

  • 2 = planar projection

  • 3 = stencil shadow volumes (Doom 3 style)

  • 4 = variance shadow mapping (16 bit float precision)

  • 5 = variance shadow mapping (32 bit float precision)

• r_softShadows (only available for shadow mapping techniques)

  • 1 = PCF 2X2

  • 2 = PCF 3X3

  • 3 = PCF 4X4

• dynamic LOD for shadow mapping

• many new cvars to make shadow mapping very scaleable on future GPU hardware

  • r_shadowMapSizeUltra

  • r_shadowMapSizeVeryHigh

  • r_shadowMapSizeHigh

  • r_shadowMapSizeMedium

  • r_shadowMapSizeLow

Materials and Shaders

• simple scriptable material shader language support

  • supports almost all Doom 3 .mtr keywords

  • XreaL specific extensions to make development easier

  • translucence

  • two-sided polygons

  • arbitrary polygon offset

  • dynamic transformations of UV coordinates

  • alpha testing

  • glow textures

  • normal mapping

  • specular maps

  • different blending functions

  • texture compression parameters

  • dynamic color generation

  • game entity associated behaviour

  • different textures can be combined to new ones at load time

Special effects

• heat haze post process effect

  • you can render many different distorsion effects with this:

    • heat shimmer

    • water

    • glass

• light bloom post process effects

  • r_bloom cvar determines bloom mode

  • 0 = no bloom

  • 1 = simple bloom with diamond filter only

  • 2 = strong bloom with combined gauss and diamond filters

• rotoscope cell shading post process effect (just for fun)

Skeletal Animation

• new interface exposed from the renderer to handle model and animation files

• renderer interface abstracts file formats like (.md5mesh/.md5anim)

• animations can be handled seperately

• animation frame interpolation

• animation blending

• up to 128 bones for each refEntity_t that can be modified outside the renderer

• basic support for inverse kinematics like head/torso/legs player angles

• bones can be used as joints to attach other refEntities

Networking

• Multiplayer over LAN and Internet via a Client and Server architecture

• Up to 64 players

• low-bandwidth efficient

• packet fragmentation

• packet compression and encryption

• IPv6 support with multicasting abilities

• extended protocol to support accelerating trajectories

Client

• .avi video and audio recording

• libcURL http-download redirection support for fast downloads of referenced server .pk3 files

Server

TODO add information

Physics

• Continues Collision Detection

  • AABB tracing against brushes, bezier curves and other primitives

  • Sphere tracing

  • Capsule tracing

• optional per triangle collision detection for world surfaces

• improved collision detection speed using early-out AABB tests

AI

• replaced Gladiator bot by the Quake2 ACEBot

  • very basic and extensible AI code

  • uses waypoints that are set automatically by running through a map

  • does not require to build AAS files

  • can even work with maps that don't feature collision brushes

Sound

• streamed sounds

• entirely loadable sounds

• 3D sound

• Doppler effect

• Different sound API support:

  • Software backend

  • OpenAL backend

Supported Audio Formats

• RIFF WAVE (.wav)

• OGG Vorbis audio file format support (.ogg)

Platforms

The XreaL engine is platform independent. Which means in this case it will run on more than one platform, which are currently:

• Windows 2000, XP, XP64, Vista

• Linux

Game

Client Game

• Tenebrae style player teleporter effect

• rotating gibs

• Unlagged Code

• improved status bar

• improved particle engine

• experimental Lua 5.1 layer for particle creation and other special effects

• robust skeletal player animation code

• robust skeletal view weapon animation code

Server Game

• matrix math

• quaternion math

• improved tokenizer

• handy string utilities like Q_strreplace

• experimental Lua 5.1 layer for level entity scripting allowing map designers to control entities like in Doom3

• Unlagged Code

• accelerating rockets

• true quad damage

User Interface

• bloom rendering game option

• anisotropic filter value slider in the graphics options

• lighting and shadowing options

• scrolling credits

XMap2

• derived from the popular Q3Map2 compiler by Randy ydnar Reddig

• Doom 3 .map file support Version 2

• Quake 4 .map file support Version 3

• support for new entity epairs like the "rotation" matrix

• Doom 3 .mtr shader support

• can be run by GtkRadiant and communicates with it using a XML based network protocol

• can be run by several Q3Map2 frontends like Q3Map2Tools or Q3MapGUI

• supports -game xreal option for best usage with XreaL

GtkRadiant

• lite version based on Zerowing code

• modified for XreaL mapping

• realtime lighting preview with F3