OpenGL

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Todo: Write about custom OpenGL renderer in Xash3D/ Paranoia/ Cry of Fear and etc. (possibly also Counter-Strike Neo?)

OpenGL is a 3D graphics API, which is used by the hardware renderers of GoldSrc and id Tech 2, as well as some Source 2 games. It is also used on Source engine, for systems that doesn't support Direct3D ( macOS and Linux), as well as in Hammer 4.x.

Id Tech 2 Engine (GLQuake) OpenGL

Screenshot in-game of Quake GLQuake, using OpenGL.

Features

• Experimented Reflections
• Transparent Water
• Rudimentary Shadows

Note:To enables Rudimentary Shadows r_shadows must be set to 1

Note:Rudimentary Shadows in Half-Life were add in the 25th Anniversary update.

• Texture Filtering
• Water ripple
• 32-bit color
• Support for different resolutions

GoldSrc OpenGL

Screenshot in-game of Half-Life, using OpenGL.

Features

• Colored lighting - Quake simply had monotone lighting
• Transparent textures - Glass can now be used in maps
• Water waves

Note:Water ripple from Quake replace by Water waves but not in Software Renderer the water ripple is used.

• Texture Filtering - Quake (GLQuake) simply Texture Filtering
• Detailed textures

Since 2013 SteamPipe Update

• FBO renderer - A new method of rendering the game, which allows MSAA to work with GoldSrc engine. This also allows the game to run on fullscreen with borderless windowed.
• MSAA anti-aliasing - GoldSrc now natively support anti-aliasing, specifically, MSAA 4X, which is enabled by default on most modern hardwares. This will reduce the amount of jagged edges/staircases effect on the geometry.

Since 25th Anniversary

• Rudimentary Shadows

Note:To enables Rudimentary Shadows r_shadows must be set to 1

Source engine OpenGL

OpenGL uses togl converts DirectX shaders to OpenGL for macOS and Linux. Additionally, Hammer uses OpenGL to render the 2D and 3D viewports.

Dxlevel 92

Dxlevel 92 is the OpenGL equivalent to DirectX 9 (Dx9)

Features

• Refractions with the use of a bump-map
• High-quality reflective water (used frequently)
• Softer edge dynamic shadows
• Normal-mapped lighting on models
• Improved-quality specular effects
• High dynamic range rendering (disabled by default)
• Phong shading
• Color Correction
• Motion Blur

Dxlevel 97

Dxlevel 97 is the OpenGL equivalent to DirectX 9 Shader Model 3 (Dx9.0c)

Features

• Lightwarp support
• High dynamic range rendering (enabled by default)

See also

• Direct3D
• Vulkan
• Software renderer

External links

•  OpenGL
•  GLQuake on Wikipedia
• GLQuake on Quake Fandom wiki