Only offset portal surface when trying decals are on the same surface

skelatool64/lua/sk_math.lua

@@ -316,7 +316,7 @@ function Box3.nearest_point_in_box(box, point)
     return Vector3.min(box.max, point):max(box.min)
 end
 
---- Returns the point inside or on the box that is nearest to the given point
+--- Returns true of the two bounding boxes have some volume in common
 --- @function overlaps
 --- @tparam Vector3|Box3 box_or_point
 --- @treturn boolean

src/savefile/scene_serialize.c

@@ -51,6 +51,8 @@ void sceneSerializePortals(struct Serializer* serializer, SerializeAction action
     }
 }
 
+#define PORTAL_FLAGS_TO_DESERIALIZE    (PortalFlagsPlayerPortal | PortalFlagsZOffset)
+
 void sceneDeserializePortals(struct Serializer* serializer, struct Scene* scene) {
     for (int portalIndex = 0; portalIndex < 2; ++portalIndex) {
         char flags;
@@ -98,11 +100,8 @@ void sceneDeserializePortals(struct Serializer* serializer, struct Scene* scene)
         collisionSceneSetPortal(portalIndex, &portal->rigidBody.transform, roomIndex, colliderIndex);
         collisionObjectUpdateBB(&portal->collisionObject);
 
-        if (flags & PortalFlagsPlayerPortal) {
-            portal->flags |= PortalFlagsPlayerPortal;
-        } else {
-            portal->flags &= ~PortalFlagsPlayerPortal;
-        }
+        portal->flags &= ~PORTAL_FLAGS_TO_DESERIALIZE;
+        portal->flags |= PORTAL_FLAGS_TO_DESERIALIZE & flags;
 
         portal->opacity = 0.0f;
     }

src/scene/portal.h

@@ -17,6 +17,7 @@
 enum PortalFlags {
     PortalFlagsOddParity = (1 << 0),
     PortalFlagsPlayerPortal = (1 << 2),
+    PortalFlagsZOffset = (1 << 3),
 };
 
 struct Portal {

src/scene/portal_surface.h

@@ -27,6 +27,7 @@ struct PortalSurface {
     u8 edgeCount;
     u8 vertexCount;
     u8 shouldCleanup;
+    u8 hasDecals;
 
     struct Vector3 right;
     struct Vector3 up;

src/scene/render_plan.c

@@ -563,13 +563,15 @@ void renderPlanExecute(struct RenderPlan* renderPlan, struct Scene* scene, Mtx*
                         faceModel = portal_portal_orange_face_model_gfx;
                         portalModel = portal_portal_orange_model_gfx;
                     }
-
-                    // render the portal cover with a slightly offset z
-                    // so it doesn't z fight with the surface it is attached to
-                    Vp* vpWithOffset = renderStateRequestViewport(renderState);
-                    *vpWithOffset = *current->viewport;
-                    vpWithOffset->vp.vtrans[2] -= 1;
-                    gSPViewport(renderState->dl++, vpWithOffset);
+                    
+                    if (portal->flags & PortalFlagsZOffset) {
+                        // render the portal cover with a slightly offset z
+                        // so it doesn't z fight with the surface it is attached to
+                        Vp* vpWithOffset = renderStateRequestViewport(renderState);
+                        *vpWithOffset = *current->viewport;
+                        vpWithOffset->vp.vtrans[2] -= 2;
+                        gSPViewport(renderState->dl++, vpWithOffset);
+                    }
                     gSPDisplayList(renderState->dl++, faceModel);
                     gSPViewport(renderState->dl++, current->viewport);
                     if (current->previousProperties == NULL && portalIndex == renderPlan->clippedPortalIndex && renderPlan->nearPolygonCount) {

src/scene/scene.c

@@ -860,6 +860,12 @@ int sceneOpenPortal(struct Scene* scene, struct Transform* at, int transformInde
                 portal->flags &= ~PortalFlagsPlayerPortal;
             }
 
+            if (existingSurface->hasDecals) {
+                portal->flags |= PortalFlagsZOffset;
+            } else {
+                portal->flags &= ~PortalFlagsZOffset;
+            }
+
             if (collisionSceneIsPortalOpen()) {
                 // the second portal is fully transparent right away
                 portal->opacity = 0.0f;

tools/level_scripts/portal_surfaces.lua

@@ -58,7 +58,7 @@ local function get_edge_index(edges, edge_key)
     return 0xFF
 end
 
-local function calculate_portal_single_surface(mesh, mesh_display_list)
+local function calculate_portal_single_surface(mesh, mesh_display_list, has_decals)
     local origin = mesh.bb:lerp(0.5)
 
     local right, up, normal = calculate_surface_basis(mesh)
@@ -129,6 +129,7 @@ local function calculate_portal_single_surface(mesh, mesh_display_list)
         edgeCount = #edges,
         vertexCount = #vertices,
         shouldCleanup = 0,
+        hasDecals = has_decals,
 
         right = right,
         up = up,
@@ -142,7 +143,7 @@ end
 for _, surface in pairs(static_export.static_nodes) do
     if surface.accept_portals then
         table.insert(static_to_portable_surface_mapping, #portal_surfaces)
-        table.insert(portal_surfaces, calculate_portal_single_surface(surface.mesh, surface.display_list))
+        table.insert(portal_surfaces, calculate_portal_single_surface(surface.mesh, surface.display_list, surface.has_decals))
     else
         table.insert(static_to_portable_surface_mapping, -1)
     end

tools/level_scripts/static_export.lua

@@ -33,7 +33,7 @@ local function is_coplanar(mesh, plane)
 end
 
 local function should_join_mesh(entry)
-    return entry.plane ~= nil
+    return entry.should_join_mesh
 end
 
 local function bb_union_cost(a, b)
@@ -76,6 +76,28 @@ local function bb_list(bb)
     }
 end
 
+local function check_for_decals(portal_surface, all_static_ndes)
+    if not portal_surface.accept_portals then
+        return false
+    end
+
+    local box_with_padding = sk_math.box3(portal_surface.original_bb.min - 0.1, portal_surface.original_bb.max + 0.1)
+
+    for _, other in pairs(all_static_ndes) do
+        local material = other.chunk.mesh.material
+
+        if material.renderMode and 
+            material.renderMode.zMode == "ZMODE_DEC" and 
+            portal_surface.transform_index == other.transform_index and
+            is_coplanar(other.chunk.mesh, portal_surface.plane) and 
+            box_with_padding:overlaps(other.original_bb) then
+            return true
+        end
+    end
+    
+    return false
+end
+
 local function list_static_nodes(nodes)
     local result = {}
     local bb_scale = sk_input.settings.fixed_point_scale
@@ -100,10 +122,11 @@ local function list_static_nodes(nodes)
             end
 
             local plane = sk_math.plane3_with_point(chunkV.mesh.normals[1], chunkV.mesh.vertices[1])
-            local accept_portals =chunkV.mesh.material and portalable_surfaces[chunkV.mesh.material.name] and not sk_scene.find_flag_argument(v.arguments, "no_portals")
+            local should_join_mesh = true
+            local accept_portals = chunkV.mesh.material and portalable_surfaces[chunkV.mesh.material.name] and not sk_scene.find_flag_argument(v.arguments, "no_portals")
 
             if transform_index or signal or accept_portals or not is_coplanar(chunkV.mesh, plane) then
-                plane = nil
+                should_join_mesh = false
             end
     
             insert_or_merge(result, {
@@ -113,13 +136,19 @@ local function list_static_nodes(nodes)
                 transform_index = transform_index,
                 room_index = room_export.node_nearest_room_index(v.node) or 0,
                 accept_portals = accept_portals,
+                has_decals = false,
                 signal = signal,
                 original_bb = original_bb,
                 plane = plane,
+                should_join_mesh = should_join_mesh,
             })
         end
     end
 
+    for _, node in pairs(result) do
+        node.has_decals = check_for_decals(node, result)
+    end
+
     return result;
 end
 
@@ -320,6 +349,7 @@ local function process_static_nodes(nodes)
             transform_index = source_node.transform_index,
             room_index = source_node.room_index,
             accept_portals = source_node.accept_portals,
+            has_decals = source_node.has_decals,
             signal = source_node.signal,
         })
     end