Fix light reset when reducing maxSimultaneousLights value (#17068)

Co-authored-by: David Catuhe <[email protected]>

Author: deltakosh

packages/dev/core/src/Materials/materialHelper.functions.ts

@@ -569,7 +569,9 @@ export function PrepareDefinesForLights(scene: Scene, mesh: AbstractMesh, define
     defines["SHADOWS"] = state.shadowEnabled;
 
     // Resetting all other lights if any
-    for (let index = lightIndex; index < maxSimultaneousLights; index++) {
+    const maxLightCount = Math.max(maxSimultaneousLights, defines["MAXLIGHTCOUNT"] || 0);
+
+    for (let index = lightIndex; index < maxLightCount; index++) {
         if (defines["LIGHT" + index] !== undefined) {
             defines["LIGHT" + index] = false;
             defines["HEMILIGHT" + index] = false;
@@ -596,6 +598,8 @@ export function PrepareDefinesForLights(scene: Scene, mesh: AbstractMesh, define
         }
     }
 
+    defines["MAXLIGHTCOUNT"] = maxSimultaneousLights;
+
     const caps = scene.getEngine().getCaps();
 
     if (defines["SHADOWFLOAT"] === undefined) {