Variable GLSL_NEAR_FADE_FUNCTIONSConst
GLSL_NEAR_FADE_FUNCTIONS: "\nfloat perspectiveNearFade(int isOrtho, float viewZ, float nearCull) {\n if (isOrtho == 1) return 1.0;\n if (viewZ >= 0.0) return 0.0;\n return smoothstep(nearCull, nearCull * 2.0, -viewZ);\n}\n" = ...
Unified perspective near-plane fade, shared by the point / line / gsplat vertex shaders (visual + pick).
Perspective: 0.0 behind the camera (viewZ >= 0 — camera looks down -Z, and the quad expansion math flips/degenerates for such vertices), smoothstep fade across [nearCull, 2*nearCull], else 1.0. Ortho: always 1.0 — there is no 1/z singularity, and NDC near/far clipping is the sole cull authority (an explicit vertex-level cull under ortho WRONGLY hid in-frustum content in the near slab).
Callers reject the vertex when the result < 0.01 and multiply the surviving amplitude/alpha/brightness by it (no hard pop).