Apex Legends is built on a heavily modified Source Engine branch with dedicated highlight/glow structures on .

Engine Glow Properties:
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- (RGB color & alpha channels)

By enabling the engine's built-in stencil outline shader, the game renders player silhouettes behind walls with zero performance loss compared to drawing overlay boxes!

Engine glow has always been the cleanest looking visual feature. Setting highlight context ID to 1 or 2 enables the solid fill and border outline simultaneously.

Agreed! The game's native post-processing shader handles depth testing and occluded coloring automatically, making visible enemies distinct from occluded ones.