fixing some stuff regarding webgl 1 compat

src/Shaders/ShadersInclude/lightFragmentDeclaration.fx

@@ -3,6 +3,8 @@
 	uniform vec4 vLightDiffuse{X};
 	#ifdef SPECULARTERM
 		uniform vec3 vLightSpecular{X};
+	#else
+		vec3 vLightSpecular{X} = vec3(0.);
 	#endif
 	#ifdef SHADOW{X}
 		#if defined(SPOTLIGHT{X}) || defined(DIRLIGHT{X})

src/babylon.scene.ts

@@ -1689,9 +1689,12 @@
             } else {
                 Frustum.GetPlanesToRef(this._transformMatrix, this._frustumPlanes);
             }
-            this._sceneUbo.updateMatrix("viewProjection", this._transformMatrix);
-            this._sceneUbo.updateMatrix("view", this._viewMatrix);
-            this._sceneUbo.update();
+
+            if (this._sceneUbo.useUbo) {
+                this._sceneUbo.updateMatrix("viewProjection", this._transformMatrix);
+                this._sceneUbo.updateMatrix("view", this._viewMatrix);
+                this._sceneUbo.update();
+            }
         }
 
         public getSceneUniformBuffer(): UniformBuffer {