What is blending?

Blending is a new feature utilizing recent EDuke32 advancements that allow you to use a different transparency lookup table from the normal 'alpha' that the engine is more known for.

In short: You can finally make bright things such as lights or explosions glow!

You can change blend mode of any given sprite in 2D mode by pointing at the sprite and pressing ALT + Q To make a sprite transparent, point at it and press T

Here is a list of valid values:

0: Alpha (33%)
1-31: Alpha (1/64 increments)
129: Screen
130: Multiply
255: Additive (scaled 100%)

Alpha blending 0-31

This is the regular blend mode that is enabled by default. Value if '0' is used unless otherwise specified, which gives you a 33% blend, to get a second stage of 66% you can press T again, note that this does not work with other blend modes. To get a finer grain of alpha blending, you may use values 1-31. Blend of 1 makes objects practically invisible

ENABLED

DISABLED

Examples: Glass and anything you want to make transparent without affecting brightness too much

Screen 129

Based on: https://en.wikipedia.org/wiki/Blend_modes#Screen

In simple words, the more black, the more transparent. You can use darkness as an alpha transparency channel sort of. Practically inverse of multiply. Along with Additive, this is the bread and butter of glowing lights and other cool neon bits seen ingame

ENABLED

DISABLED

Examples: Light sources / gradient sprites / explosions / Lightning

Multiply 130

https://en.wikipedia.org/wiki/Blend_modes#Multiply

In simple words, the more white, the more transparent. You can use brightness as an alpha transparency channel sort of. Practical inverse of this is screen/additive. This mode has many uses as you can easily insert details / grit on top of existing geometry, with inverse palette on a dark glass texture, you can create neat looking tinted windows!

ENABLED

DISABLED

Examples: Tinted glass, object shadows (wall clocks, etc..), detail stain sprites on walls

Additive 255

Based on: https://en.wikipedia.org/wiki/Blend_modes#Addition

In simple words, the more black, the more transparent. You can use darkness as an alpha transparency channel sort of. Practically inverse of multiply. Along with Screen, this is the bread and butter of glowing lights and other cool neon bits seen ingame

ENABLED

DISABLED

Examples: Light sources / gradient sprites / explosions / Lightning