fix(rendering): add planar shadow rendering support for new render pipeline

The new render pipeline ForwardPass incorrectly used TRANSPARENT_OBJECT and RENDER_TRANSPARENT for the planar shadow queue, causing shadow casters to never match. scene-culling.ts also filtered out PLANAR_SHADOW via kDrawMask.

This change:
- Adds PLANAR_SHADOW to kDrawMask in scene-culling.ts
- Fixes planar shadow queue in forward-pass.ts to use RENDER_OPAQUE with OPAQUE_OBJECT/CUTOUT_OBJECT
- Adds PLANAR_SHADOW and SHADOW_CASTER flags for correct model filtering

Fixes: #19158

Author: UC-RX0

cocos/rendering/custom/scene-culling.ts

@@ -300,7 +300,7 @@ export class SceneCulling {
     enableLightCulling = true;
 
     readonly kFilterMask = SceneFlags.SHADOW_CASTER | SceneFlags.REFLECTION_PROBE;
-    readonly kDrawMask = SceneFlags.OPAQUE | SceneFlags.MASK | SceneFlags.BLEND;
+    readonly kDrawMask = SceneFlags.OPAQUE | SceneFlags.MASK | SceneFlags.BLEND | SceneFlags.PLANAR_SHADOW;
     readonly kAllMask = this.kFilterMask | this.kDrawMask;
 
     resetPool (): void {

cocos/rendering/post-process/passes/forward-pass.ts

@@ -81,12 +81,12 @@ export class ForwardPass extends BasePass {
         passContext.addSceneLights(forwardAddQueue, camera);
         const shadowInfo = ppl.pipelineSceneData.shadows;
         if (camera.scene?.mainLight && shadowInfo.enabled && shadowInfo.type === ShadowType.Planar) {
-            pass.addQueue(QueueHint.RENDER_TRANSPARENT, 'planar-shadow')
+            pass.addQueue(QueueHint.RENDER_OPAQUE, 'planar-shadow')
                 .addSceneOfCamera(
                     camera,
                     new LightInfo(camera.scene?.mainLight),
-                    SceneFlags.TRANSPARENT_OBJECT | SceneFlags.SHADOW_CASTER
-                    | SceneFlags.GEOMETRY,
+                    SceneFlags.SHADOW_CASTER | SceneFlags.PLANAR_SHADOW
+                    | SceneFlags.OPAQUE_OBJECT | SceneFlags.CUTOUT_OBJECT,
                 );
         }
         passContext.forwardPass = this;