Node Shader wrapper: add access to the Emission color of Principled BSDF node.

This did not exist when that wrapper was created, but is supported by
many formats, so worth supporting it now. See also T70666.

release/scripts/modules/bpy_extras/node_shader_utils.py

@@ -487,6 +487,35 @@ class PrincipledBSDFWrapper(ShaderWrapper):
     alpha_texture = property(alpha_texture_get)
 
 
+    # --------------------------------------------------------------------
+    # Emission color.
+
+    def emission_color_get(self):
+        if not self.use_nodes or self.node_principled_bsdf is None:
+            return Color((0.0, 0.0, 0.0))
+        return rgba_to_rgb(self.node_principled_bsdf.inputs["Emission"].default_value)
+
+    @_set_check
+    def emission_color_set(self, color):
+        if self.use_nodes and self.node_principled_bsdf is not None:
+            color = values_clamp(color, 0.0, 1.0)
+            color = rgb_to_rgba(color)
+            self.node_principled_bsdf.inputs["Emission"].default_value = color
+
+    emission_color = property(emission_color_get, emission_color_set)
+
+
+    def emission_color_texture_get(self):
+        if not self.use_nodes or self.node_principled_bsdf is None:
+            return None
+        return ShaderImageTextureWrapper(
+            self, self.node_principled_bsdf,
+            self.node_principled_bsdf.inputs["Emission"],
+            grid_row_diff=1,
+        )
+
+    emission_color_texture = property(emission_color_texture_get)
+
 
     # --------------------------------------------------------------------
     # Normal map.