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Along with all the special features of ZDoom, ZDoomGL has extra graphical features to improve the Doom experience.

OpenGL Rendering - Using the speed and capabilities of modern video cards, OpenGL breathes life into the outdated graphics of the original Doom. It allows for high framerates at high resolutions, 32bit colour (as opposed to the original 8bit), true 3d rendering (looking up and down is possible without geometry deformation), and much more...

Anisotropic/Trilinear Texture Filtering - Supported by newer video cards, Anisotropic Texture Filtering greatly improves texture quality, especially on textures viewed at an acute angle.

Multitexture Shaders - Shaders can be used to create special effects on textures, like adding shine to steel textures.

High Quality Texture Resizing - Using the hq2/3/4x technology, ZDoomGL can apply these filters to all textures to improve the sharpness and quality of the original low-res textures, so they look kess blurry in high resolutions.