From 2915c6e670e30b9581b5a2646088982654702093 Mon Sep 17 00:00:00 2001
From: rdb <git@rdb.name>
Date: Sat, 1 Jan 2022 16:49:41 +0100
Subject: [PATCH] glgsg: Force transform_weight column to read (0, 0, 0, 1) if
 absent

On NVIDIA cards, this doesn't seem to happen automatically.

Fixes #1207
---
 panda/src/glstuff/glShaderContext_src.cxx | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/panda/src/glstuff/glShaderContext_src.cxx b/panda/src/glstuff/glShaderContext_src.cxx
index 450fb69367..aad4305b20 100644
--- a/panda/src/glstuff/glShaderContext_src.cxx
+++ b/panda/src/glstuff/glShaderContext_src.cxx
@@ -2591,6 +2591,11 @@ update_shader_vertex_arrays(ShaderContext *prev, bool force) {
                  _glgsg->_glVertexAttribI4ui != nullptr) {
           _glgsg->_glVertexAttribI4ui(p, 0, 1, 2, 3);
         }
+        else if (name == InternalName::get_transform_weight()) {
+          // NVIDIA doesn't seem to use to use these defaults by itself
+          static const GLfloat weights[4] = {0, 0, 0, 1};
+          _glgsg->_glVertexAttrib4fv(p, weights);
+        }
       }
     }