WIP: lightmap support with >32k surface groups

editor_patch/lightmap.cpp

@@ -589,26 +589,32 @@ void ApplyLightmapPatches()
     write_mem<u8>(0x004ae73a, 0xB7); // FUN_004ae360: shadow calculation
     write_mem<u8>(0x004ae81f, 0xB7);
     write_mem<u8>(0x004aed4e, 0xB7);
-    write_mem<u8>(0x004a45b1, 0xB7); // solid_write: level file export
-
-    // MOVSX -> MOVZX for face+0x36 reads from register (5 sites)
-    // These follow 16-bit MOV AX,[face+0x36] and sign-extend AX to 32-bit before use as index
+    write_mem<u8>(0x004a45b1, 0xB7); // solid_write: MOVSX→MOVZX (sentinel 0xFFFF→65535 in file, truncated back to 0xFFFF by reader's 16-bit store)
+    write_mem<u8>(0x004a4655, 0x74); // solid_write: JLE->JE for lightmap UV write decision
+    write_mem<u8>(0x004a39ce, 0x74); // solid_read: JLE->JE for lightmap UV read decision
     write_mem<u8>(0x0048778b, 0xB7); // FUN_004872e0: lightmap surface container lookup
     write_mem<u8>(0x00487862, 0xB7);
-    write_mem<u8>(0x0049b955, 0xB7); // FUN_0049b550: geo-cache build
-    write_mem<u8>(0x0049bea0, 0xB7);
-    write_mem<u8>(0x0049bed3, 0xB7);
 
     // Fix sentinel checks: JLE -> JE (0x7E -> 0x74)
     // Original: CMP AX,0xFFFF; JLE skip — skips all negative values (wrong for groups > 32767)
     // Fixed: CMP AX,0xFFFF; JE skip — skips only the 0xFFFF "no group" sentinel
     write_mem<u8>(0x00487781, 0x74); // FUN_004872e0
     write_mem<u8>(0x00487858, 0x74);
-    write_mem<u8>(0x0049b94b, 0x74); // FUN_0049b550
 
-    // Note: CMP AX,BX; JLE at 0x0049be96 and 0x0049bec9 left as signed — BX can be
-    // 0xFFFF ("no batch" sentinel), and unsigned JBE would cause all faces to be skipped.
-    // Signed comparison is correct for group IDs 0-32767 and safe for the sentinel case.
+    // Fix signed "< 0" checks that destroy valid surface indices > 32767 during geometry build.
+    // FUN_004a8660 and FUN_004a9270 reset faces with negative (signed) surface_index to 0xFFFF.
+    // This destroys valid high indices when loading an RFL with >32767 surface groups.
+    write_mem<u8>(0x004a8fa9, 0xFF); // FUN_004a8660: CMP word, 0 → CMP word, -1
+    write_mem<u8>(0x004a8faa, 0x75); //   JGE → JNE (only sentinel triggers reset)
+    write_mem<u8>(0x004a9294, 0xFF); // FUN_004a9270: CMP word, 0 → CMP word, -1
+    write_mem<u8>(0x004a9295, 0x75); //   JGE → JNE
+
+    // Note: The editor's D3D8 viewport rendering has additional signed surface_index checks
+    // in the geo-cache build (FUN_0049b550) and rendering functions (FUN_005040b0,
+    // FUN_00493570, FUN_00494d70, FUN_00496a30, etc.) that cause fullbright on faces with
+    // surface_index > 32767. The D3D8 rendering path also has architectural batch count limitations
+    // for rooms with many unique surface groups. The D3D11 game renderer handles all of this
+    // correctly. Editor viewport fullbright on high-surface-count levels is a known limitation.
 
     // -smoothlights: experimental lightmap seam fix at portal boundaries
     // Note: GetCommandLineA() is used instead of argv/argc because this runs during DLL

game_patch/graphics/d3d11/gr_d3d11_solid.cpp

@@ -341,7 +341,7 @@ namespace df::gr::d3d11
         FaceRenderType render_type = determine_face_render_type(face);
         int face_tex = face->attributes.bitmap_id;
         int lightmap_tex = -1;
-        if (!is_sky_ && render_type != FaceRenderType::liquid && face->attributes.surface_index >= 0) {
+        if (!is_sky_ && render_type != FaceRenderType::liquid && face->attributes.surface_index != 0xFFFF) {
             if (face->attributes.surface_index >= solid->surfaces.size()) {
                 xlog::warn("add_face: surface_index {} out of bounds (size {}), skipping face",
                     face->attributes.surface_index, solid->surfaces.size());

game_patch/misc/destruction.cpp

@@ -1412,7 +1412,7 @@ static void add_cap_faces_from_loop(
 
     rf::GFaceAttributes attrs{};
     attrs.bitmap_id = bitmap_id;
-    attrs.surface_index = -1;
+    attrs.surface_index = 0xFFFF; // no surface/lightmap sentinel
 
     // UV mapping: project relative to loop centroid
     auto compute_uv = [&](rf::GVertex* v) -> std::pair<float, float> {

game_patch/misc/g_solid.cpp

@@ -763,6 +763,43 @@ void g_solid_do_patch()
     // Set PPM for geo crater texture based on its resolution instead of static value of 32.0
     levelmod_do_blast_autotexture_ppm_patch.install();
 
+    // Fix lightmap surface group ID overflow: face+0x36 (surface_index) is a signed short.
+    // When >32767 lightmap surface groups exist, the signed short wraps negative.
+    // Fix raises the limit from 32767 to 65535 groups.
+
+    // Note: FUN_004d4c60 (0x004d4cf6) and FUN_00561650 (0x005619dd) are additional D3D8 rendering
+    // functions with 32-bit sentinel guards (TEST EAX,EAX and CMP EAX,-1) that fail when
+    // MOVZX produces 65535 instead of -1. Left unpatched, D3D11 renderer doesn't use them,
+    // and D3D8 can't render such levels anyway.
+    write_mem<u8>(0x004e4d50, 0xB7); // FUN_004e4a60: lightmap surface grouping
+    write_mem<u8>(0x004e4d79, 0xB7);
+    write_mem<u8>(0x004e4d96, 0xB7);
+    write_mem<u8>(0x004e4ded, 0xB7);
+    write_mem<u8>(0x004e4f56, 0xB7);
+    write_mem<u8>(0x004e51a9, 0xB7); // FUN_004e5040: batch lightmap calculator
+    write_mem<u8>(0x004e51da, 0xB7);
+    write_mem<u8>(0x004eeb41, 0xB7); // FUN_004ee550: lightmap surface setup
+    write_mem<u8>(0x004f3471, 0xB7); // FUN_004f3390: shadow geometry
+    write_mem<u8>(0x004f34aa, 0xB7);
+    write_mem<u8>(0x004f449c, 0xB7); // FUN_004f4280: shadow calculation
+    write_mem<u8>(0x004f496a, 0xB7); // FUN_004f4590: shadow calculation
+    write_mem<u8>(0x004f4a4f, 0xB7);
+    write_mem<u8>(0x004f4f7e, 0xB7);
+
+    // MOVSX -> MOVZX for face+0x36 reads from register (3 sites)
+    write_mem<u8>(0x0047f0f2, 0xB7); // surface container lookup
+    write_mem<u8>(0x0047f277, 0xB7);
+    write_mem<u8>(0x004ed772, 0xB7); // FUN_004ed520: solid_read
+
+    // Fix sentinel checks: JLE -> JE (0x7E -> 0x74)
+    // Original: CMP AX,0xFFFF; JLE skip — skips all negative values (wrong for groups > 32767)
+    // Fixed: CMP AX,0xFFFF; JE skip — skips only the 0xFFFF "no group" sentinel
+    write_mem<u8>(0x004d8b71, 0x74); // FUN_004d86d0: surface container lookup
+    write_mem<u8>(0x004d8c48, 0x74);
+    write_mem<u8>(0x004edf5e, 0x74); // FUN_004ed520: solid_read
+    write_mem<u8>(0x004eebe5, 0x74); // FUN_004ee550: lightmap surface setup
+    write_mem<u8>(0x0047f274, 0x74); // surface container lookup
+
     // Commands
     max_decals_cmd.register_cmd();
     dbg_room_clip_wnd_cmd.register_cmd();

game_patch/rf/geometry.h

@@ -282,7 +282,7 @@ namespace rf
         };
         int bitmap_id;
         short portal_id; // portal index + 2 or 0
-        short surface_index;
+        unsigned short surface_index; // 0xFFFF = no surface/lightmap (sentinel)
         int face_id;
         int smoothing_groups; // bitfield of smoothing groups