Transparency on Moving Entities (Quake2)

[jitspoe]

Surely somebody has already fixed this and can save me the effort... If you use a transparent brush on something like a door, the transparent polygons stay in place while the door moves. Anybody know of some code or an engine that fixes this?

[Spike]

transparent polys are added to some separate list when drawn. just the polygons, so they loose all context regarding their owning entity. which means they don't have the right matrix and can't move/rotate.

fte builds batch lists, ordered by blend mode and grouped by texture+entity. each batch retains the context of the render-entity thus any origin/angles/alpha/colormod/light directions/etc all carry through to the polys that need them.
the code is quite different from vanilla q2 though, so I don't know how useful knowing that is to you.

either build a per-entity list instead of a single global list for transparent surfaces, or just store a pointer to the owning entity with each surface and update the modelview matrix if that rentity pointer changes from one surface to the next.

[Barnes]

[jitspoe]

[Knightmare]

This is one of the oldest Q2 rendering bugs that has a fix available. I think it was Quake2Max that first addressed it back in 2002. Hard to believe that R1GL still doesn't have this fixed.

Be sure to load the world matrix before caling R_RotateForEntity() for each surface, and again after the last one, or it will end up moving the first-person weapon model, too.

These bmodel alpha surfs aren't depth-sorted from traversing the BSP tree, so they will occlude others behind them (due to being stuffed at the front of the alpha chain). Various attempts to depth sort them failed, so I ended up just disabling the depth mask when rendering them.

You can also use this surface ent pointer to enable animated textures on both bmodel and world alpha surfaces (see my unofficial v3.24 patch source). The added pointer is only 4 bytes per surface, and the memory use increase is negligible compared to v3.20.

[Knightmare]