Directional Lighting not working when imported with panda3d-gltf, but does when imported with assimp

[serega-kkz]

The problem is indicated, the gltf loader does not analyze texture inputs for the presence of maps. And it always creates empty texture stages, so panda does not load textures and replaces them with the default value.

PBR and the name of texture maps

There are predefined texture input names intended for PBR texture maps: https://docs.panda3d.org/1.10/python/programming/shaders/list-of-glsl-inputs There are a few undocumented, this is the full list: uniform sampler2D p3d_TextureFF[]; uniform sampler2D p3d_TextureModulate[]; // default color: (1, 1, 1, 1) uniform sampler2D p3d_TextureAdd[]; // default color: (0, 0, 0, 1) uniform sampler2D p3d_TextureNormal[]; // default color: (0.5, 0.5, 1, 0) uniform sampler2D p3d_TextureHeight[]; …

In this connection, the lighting breaks down, since instead of a normal map, one vector is always obtained, since the calculation is performed from these data (0.5, 0.5, 1, 0)

The empty emission map also breaks the rendering.