Summary
Point-particle billboard render buffers only render correctly when they use a shader path that understands particle billboard geometry. The renderer currently decodes PhotonDust point particles into generated quad meshes, but those meshes are not ordinary mesh geometry: their vertex streams carry particle center, size, roll, color, atlas UVs, and orientation payloads.
When a particle renderer uses a normal material shader, the ordinary mesh vertex path interprets those payloads as regular mesh attributes. This can make particles disappear, render as degenerate geometry, lose per-particle color/alpha, use the wrong UVs, or fail material binding/pipeline resolution.
Summary
Point-particle billboard render buffers only render correctly when they use a shader path that understands particle billboard geometry. The renderer currently decodes PhotonDust point particles into generated quad meshes, but those meshes are not ordinary mesh geometry: their vertex streams carry particle center, size, roll, color, atlas UVs, and orientation payloads.
When a particle renderer uses a normal material shader, the ordinary mesh vertex path interprets those payloads as regular mesh attributes. This can make particles disappear, render as degenerate geometry, lose per-particle color/alpha, use the wrong UVs, or fail material binding/pipeline resolution.