output: add skybox support (#1414)

This adds support for skybox rendering similar to TR2. A default
injection is provided for Lost Valley, Colossuem and Obelisk of
Khamoon; custom level builders can use object slot 184.

Resolves #94.

CHANGELOG.md

@@ -1,5 +1,6 @@
 ## [Unreleased](https://github.com/LostArtefacts/TR1X/compare/stable...develop) - ××××-××-××
 - added deadly water feature from TR2+ for custom levels (#1404)
+- added skybox support, with a default option provided for Lost Valley, Colosseum and Obelisk of Khamoon (#94)
 - fixed adjacent Midas Touch objects potentially allowing gold bar duplication in custom levels (#1415)
 - fixed the excessive pitch and playback speed correction for music files with sampling rate other than 44100 Hz (#1417)
 

GAMEFLOW.md

@@ -1333,6 +1333,14 @@ provided with the game achieves.
       using the 3D pickups option.
     </td>
   </tr>
+  <tr valign="top">
+    <td>
+      <code>*_skybox.bin</code>
+    </td>
+    <td>
+      Injects a predefined skybox model into specific levels.
+    </td>
+  </tr>
   <tr valign="top">
     <td>
       <code>*_textures.bin</code>

README.md

@@ -34,14 +34,24 @@ topic](https://www.tombraiderforums.com/showthread.php?p=8286101).
         </th>
     </tr>
     <tr>
+        <th>
+            Skybox support
+            <img src="docs/showcase/skybox.jpg"/>
+        </th>
         <th>
             Customizable draw distance
             <img src="docs/showcase/draw_distance.webp"/>
         </th>
+    </tr>
+    <tr>
         <th>
             Fly cheat
             <img src="docs/showcase/fly_cheat.jpg"/>
         </th>
+        <th>
+            Developer console
+            <img src="docs/showcase/console.webp"/>
+        </th>
     </tr>
     <tr>
         <th>
@@ -554,6 +564,7 @@ Not all options are turned on by default. Refer to `TR1X_ConfigTool.exe` for det
 - added a vsync option
 - added contextual arrows to menu options
 - added support for animated room sprites, which also restores intended behavior in, for example, The Cistern room 0
+- added skybox support, with a default option provided for Lost Valley, Colosseum and Obelisk of Khamoon; custom level builders can use object slot `184`
 - changed the Scion in The Great Pyramid from spawning blood when hit to a richochet effect
 - fixed thin black lines between polygons
 - fixed black screen flashing when navigating the inventory
@@ -565,7 +576,7 @@ Not all options are turned on by default. Refer to `TR1X_ConfigTool.exe` for det
     - **Gym**: incorrect textures in room 9
     - **Caves**: an incorrect texture in room 6 and missing textures in rooms 1, 10, 14 and 30
     - **City of Vilcabamba**: an incorrect texture in room 26, and a missing texture and a stretched texture in room 15
-    - **Lost Valley**: incorrect textures in rooms 6, 9, 16 and 35, missing textures in rooms 9, 25, 26, 27, 51, and 90, and stretched textures in room 63
+    - **Lost Valley**: incorrect textures in rooms 6, 9, 16, 34 and 35, missing textures in rooms 6, 9, 25, 26, 27, 51, and 90, and stretched textures in room 63
     - **Tomb of Qualopec**: an incorrect and missing textures in room 8, and a misaligned texture in room 5
     - **St. Francis' Folly**: incorrect textures in rooms 1, 4, 18 and 35, and a misaligned texture in room 3
     - **Colosseum**: incorrect Midas textures appearing at the roof, incorrect textures in rooms 37, 67, 75 and 82, and missing textures in rooms 2 and 7
@@ -573,7 +584,7 @@ Not all options are turned on by default. Refer to `TR1X_ConfigTool.exe` for det
     - **The Cistern**: missing textures in rooms 3 and 9 and a stretched texture in room 102
     - **Tomb of Tihocan**: incorrect textures in rooms 75 and 89 and a misaligned texture in room 104
     - **City of Khamoon**: incorrect textures in rooms 47, 48, 51, 60 and 64, and a missing texture in room 58
-    - **Obelisk of Khamoon**: incorrect textures in rooms 22, 23, 42 and 65
+    - **Obelisk of Khamoon**: incorrect textures in rooms 22, 23, 42 and 65; added shading to the gaps into City of Khamoon in rooms 8 and 20/21
     - **Sanctuary of the Scion**: missing textures in rooms 1, 11, 21, 52, 53, and 54
     - **Natla's Mines**: a missing texture in room 35, overlapping textures in room 55, an incorrect texture in room 69, and stretched textures in rooms 23 and 24
     - **Pre-Atlantis Cutscene**: stretched textures in rooms 6 and 21

data/ship/cfg/TR1X_gameflow.json5

@@ -106,6 +106,7 @@
             "music": 57,
             "injections": [
                 "data/injections/valley_itemrots.bin",
+                "data/injections/valley_skybox.bin",
                 "data/injections/valley_textures.bin",
             ],
             "sequence": [
@@ -182,6 +183,7 @@
                 "data/injections/colosseum_door.bin",
                 "data/injections/colosseum_fd.bin",
                 "data/injections/colosseum_itemrots.bin",
+                "data/injections/colosseum_skybox.bin",
                 "data/injections/colosseum_textures.bin",
             ],
             "sequence": [
@@ -311,6 +313,7 @@
             "injections": [
                 "data/injections/obelisk_fd.bin",
                 "data/injections/obelisk_itemrots.bin",
+                "data/injections/obelisk_skybox.bin",
                 "data/injections/obelisk_textures.bin",
             ],
             "sequence": [

src/config.h

@@ -90,6 +90,7 @@ typedef struct {
     TARGET_LOCK_MODE target_mode;
     bool enable_loading_screens;
     bool fix_animated_sprites;
+    bool enable_skybox;
 
     struct {
         int32_t layout;

src/config_map.def

@@ -103,3 +103,4 @@ CFG_DOUBLE(ui.text_scale, DEFAULT_UI_SCALE)
 CFG_DOUBLE(ui.bar_scale, DEFAULT_UI_SCALE)
 CFG_BOOL(profile.new_game_plus_unlock, false)
 CFG_BOOL(fix_animated_sprites, true)
+CFG_BOOL(enable_skybox, true)

src/game/inject.c

@@ -18,7 +18,7 @@
 #include <stddef.h>
 
 #define INJECTION_MAGIC MKTAG('T', '1', 'M', 'J')
-#define INJECTION_CURRENT_VERSION 6
+#define INJECTION_CURRENT_VERSION 7
 
 typedef enum INJECTION_VERSION {
     INJ_VERSION_1 = 1,
@@ -27,6 +27,7 @@ typedef enum INJECTION_VERSION {
     INJ_VERSION_4 = 4,
     INJ_VERSION_5 = 5,
     INJ_VERSION_6 = 6,
+    INJ_VERSION_7 = 7,
 } INJECTION_VERSION;
 
 typedef enum INJECTION_TYPE {
@@ -40,6 +41,7 @@ typedef enum INJECTION_TYPE {
     INJ_ITEM_POSITION = 7,
     INJ_PS1_ENEMY = 8,
     INJ_DISABLE_ANIM_SPRITE = 9,
+    INJ_SKYBOX = 10,
 } INJECTION_TYPE;
 
 typedef struct INJECTION {
@@ -95,7 +97,7 @@ typedef enum FLOOR_EDIT_TYPE {
 typedef enum ROOM_MESH_EDIT_TYPE {
     RMET_TEXTURE_FACE = 0,
     RMET_MOVE_FACE = 1,
-    RMET_MOVE_VERTEX = 2,
+    RMET_ALTER_VERTEX = 2,
     RMET_ROTATE_FACE = 3,
     RMET_ADD_FACE = 4,
     RMET_ADD_VERTEX = 5,
@@ -143,7 +145,7 @@ static void Inject_TriggeredItem(INJECTION *injection, LEVEL_INFO *level_info);
 static void Inject_RoomMeshEdits(INJECTION *injection);
 static void Inject_TextureRoomFace(INJECTION *injection);
 static void Inject_MoveRoomFace(INJECTION *injection);
-static void Inject_MoveRoomVertex(INJECTION *injection);
+static void Inject_AlterRoomVertex(INJECTION *injection);
 static void Inject_RotateRoomFace(INJECTION *injection);
 static void Inject_AddRoomFace(INJECTION *injection);
 static void Inject_AddRoomVertex(INJECTION *injection);
@@ -231,6 +233,9 @@ static void Inject_LoadFromFile(INJECTION *injection, const char *filename)
     case INJ_DISABLE_ANIM_SPRITE:
         injection->relevant = !g_Config.fix_animated_sprites;
         break;
+    case INJ_SKYBOX:
+        injection->relevant = g_Config.enable_skybox;
+        break;
     default:
         LOG_WARNING("%s is of unknown type %d", filename, injection->type);
         break;
@@ -1456,8 +1461,8 @@ static void Inject_RoomMeshEdits(INJECTION *injection)
         case RMET_MOVE_FACE:
             Inject_MoveRoomFace(injection);
             break;
-        case RMET_MOVE_VERTEX:
-            Inject_MoveRoomVertex(injection);
+        case RMET_ALTER_VERTEX:
+            Inject_AlterRoomVertex(injection);
             break;
         case RMET_ROTATE_FACE:
             Inject_RotateRoomFace(injection);
@@ -1531,7 +1536,7 @@ static void Inject_MoveRoomFace(INJECTION *injection)
     }
 }
 
-static void Inject_MoveRoomVertex(INJECTION *injection)
+static void Inject_AlterRoomVertex(INJECTION *injection)
 {
     MYFILE *fp = injection->fp;
 
@@ -1540,6 +1545,7 @@ static void Inject_MoveRoomVertex(INJECTION *injection)
     int16_t x_change;
     int16_t y_change;
     int16_t z_change;
+    int16_t shade_change;
 
     File_Read(&target_room, sizeof(int16_t), 1, fp);
     File_Skip(fp, sizeof(int32_t));
@@ -1547,24 +1553,30 @@ static void Inject_MoveRoomVertex(INJECTION *injection)
     File_Read(&x_change, sizeof(int16_t), 1, fp);
     File_Read(&y_change, sizeof(int16_t), 1, fp);
     File_Read(&z_change, sizeof(int16_t), 1, fp);
+    if (injection->version >= INJ_VERSION_7) {
+        File_Read(&shade_change, sizeof(int16_t), 1, fp);
+    } else {
+        shade_change = 0;
+    }
 
     if (target_room < 0 || target_room >= g_RoomCount) {
         LOG_WARNING("Room index %d is invalid", target_room);
         return;
     }
 
-    ROOM_INFO *r = &g_RoomInfo[target_room];
-    int16_t vertex_count = *r->data;
+    const ROOM_INFO *const room = &g_RoomInfo[target_room];
+    const int16_t vertex_count = *room->data;
     if (target_vertex < 0 || target_vertex >= vertex_count) {
         LOG_WARNING(
             "Vertex index %d, room %d is invalid", target_vertex, target_room);
         return;
     }
 
-    int16_t *data_ptr = r->data + target_vertex * 4;
+    int16_t *const data_ptr = room->data + target_vertex * 4;
     *(data_ptr + 1) += x_change;
     *(data_ptr + 2) += y_change;
     *(data_ptr + 3) += z_change;
+    *(data_ptr + 4) += shade_change;
 }
 
 static void Inject_RotateRoomFace(INJECTION *injection)

src/game/level.c

@@ -1,5 +1,6 @@
 #include "game/level.h"
 
+#include "config.h"
 #include "game/camera.h"
 #include "game/carrier.h"
 #include "game/effects.h"
@@ -1007,6 +1008,9 @@ bool Level_Load(int level_num)
              : g_GameFlow.draw_distance_max)
         * WALL_L);
 
+    Output_SetSkyboxEnabled(
+        g_Config.enable_skybox && g_Objects[O_SKYBOX].loaded);
+
     return ret;
 }
 

src/game/output.c

@@ -32,6 +32,7 @@ typedef struct {
     } edges[2];
 } LIGHTNING;
 
+static bool m_IsSkyboxEnabled = false;
 static bool m_IsWibbleEffect = false;
 static bool m_IsWaterEffect = false;
 static bool m_IsShadeEffect = false;
@@ -74,6 +75,7 @@ static const int16_t *Output_DrawRoomSprites(
     const int16_t *obj_ptr, int32_t vertex_count);
 static const int16_t *Output_CalcObjectVertices(const int16_t *obj_ptr);
 static const int16_t *Output_CalcVerticeLight(const int16_t *obj_ptr);
+static const int16_t *Output_CalcSkyboxLight(const int16_t *obj_ptr);
 static const int16_t *Output_CalcRoomVertices(const int16_t *obj_ptr);
 static int32_t Output_CalcFogShade(int32_t depth);
 static void Output_CalcWibbleTable(void);
@@ -201,21 +203,29 @@ static const int16_t *Output_CalcObjectVertices(const int16_t *obj_ptr)
     obj_ptr++;
     int vertex_count = *obj_ptr++;
     for (int i = 0; i < vertex_count; i++) {
-        double xv = g_MatrixPtr->_00 * obj_ptr[0]
-            + g_MatrixPtr->_01 * obj_ptr[1] + g_MatrixPtr->_02 * obj_ptr[2]
-            + g_MatrixPtr->_03;
-        double yv = g_MatrixPtr->_10 * obj_ptr[0]
-            + g_MatrixPtr->_11 * obj_ptr[1] + g_MatrixPtr->_12 * obj_ptr[2]
-            + g_MatrixPtr->_13;
-        int32_t zv_int = g_MatrixPtr->_20 * obj_ptr[0]
-            + g_MatrixPtr->_21 * obj_ptr[1] + g_MatrixPtr->_22 * obj_ptr[2]
-            + g_MatrixPtr->_23;
-        double zv = zv_int;
+        // clang-format off
+        double xv =
+            g_MatrixPtr->_00 * obj_ptr[0] +
+            g_MatrixPtr->_01 * obj_ptr[1] +
+            g_MatrixPtr->_02 * obj_ptr[2] +
+            g_MatrixPtr->_03;
+        double yv =
+            g_MatrixPtr->_10 * obj_ptr[0] +
+            g_MatrixPtr->_11 * obj_ptr[1] +
+            g_MatrixPtr->_12 * obj_ptr[2] +
+            g_MatrixPtr->_13;
+        double zv =
+            g_MatrixPtr->_20 * obj_ptr[0] +
+            g_MatrixPtr->_21 * obj_ptr[1] +
+            g_MatrixPtr->_22 * obj_ptr[2] +
+            g_MatrixPtr->_23;
+        // clang-format on
+
         m_VBuf[i].xv = xv;
         m_VBuf[i].yv = yv;
         m_VBuf[i].zv = zv;
 
-        int32_t clip_flags;
+        int16_t clip_flags;
         if (zv < Output_GetNearZ()) {
             clip_flags = -32768;
         } else {
@@ -293,6 +303,23 @@ static const int16_t *Output_CalcVerticeLight(const int16_t *obj_ptr)
     return obj_ptr;
 }
 
+static const int16_t *Output_CalcSkyboxLight(const int16_t *obj_ptr)
+{
+    int32_t vertex_count = *obj_ptr++;
+    if (vertex_count > 0) {
+        obj_ptr += 3 * vertex_count;
+    } else {
+        vertex_count = -vertex_count;
+        obj_ptr += vertex_count;
+    }
+
+    for (int i = 0; i < vertex_count; i++) {
+        m_VBuf[i].g = 0xFFF;
+    }
+
+    return obj_ptr;
+}
+
 static const int16_t *Output_CalcRoomVertices(const int16_t *obj_ptr)
 {
     int32_t vertex_count = *obj_ptr++;
@@ -320,7 +347,9 @@ static const int16_t *Output_CalcRoomVertices(const int16_t *obj_ptr)
             int32_t depth = zv_int >> W2V_SHIFT;
             if (depth > Output_GetDrawDistMax()) {
                 m_VBuf[i].g = 0x1FFF;
-                clip_flags |= 16;
+                if (!m_IsSkyboxEnabled) {
+                    clip_flags |= 16;
+                }
             } else if (depth) {
                 m_VBuf[i].g += Output_CalcFogShade(depth);
                 if (!m_IsWaterEffect) {
@@ -594,6 +623,37 @@ void Output_DrawPolygons_I(const int16_t *obj_ptr, int32_t clip)
     Matrix_Pop();
 }
 
+void Output_SetSkyboxEnabled(const bool enabled)
+{
+    m_IsSkyboxEnabled = enabled;
+}
+
+bool Output_IsSkyboxEnabled(void)
+{
+    return m_IsSkyboxEnabled;
+}
+
+void Output_DrawSkybox(const int16_t *obj_ptr)
+{
+    g_PhdLeft = Viewport_GetMinX();
+    g_PhdTop = Viewport_GetMinY();
+    g_PhdRight = Viewport_GetMaxX();
+    g_PhdBottom = Viewport_GetMaxY();
+
+    obj_ptr = Output_CalcObjectVertices(obj_ptr + 4);
+    if (!obj_ptr) {
+        return;
+    }
+
+    S_Output_DisableDepthTest();
+    obj_ptr = Output_CalcSkyboxLight(obj_ptr);
+    obj_ptr = Output_DrawObjectGT4(obj_ptr + 1, *obj_ptr);
+    obj_ptr = Output_DrawObjectGT3(obj_ptr + 1, *obj_ptr);
+    obj_ptr = Output_DrawObjectG4(obj_ptr + 1, *obj_ptr);
+    obj_ptr = Output_DrawObjectG3(obj_ptr + 1, *obj_ptr);
+    S_Output_EnableDepthTest();
+}
+
 void Output_DrawRoom(const int16_t *obj_ptr)
 {
     obj_ptr = Output_CalcRoomVertices(obj_ptr);

src/game/output.h

@@ -49,6 +49,10 @@ void Output_CalculateObjectLighting(
 void Output_DrawPolygons(const int16_t *obj_ptr, int clip);
 void Output_DrawPolygons_I(const int16_t *obj_ptr, int32_t clip);
 
+void Output_SetSkyboxEnabled(bool enabled);
+bool Output_IsSkyboxEnabled(void);
+void Output_DrawSkybox(const int16_t *obj_ptr);
+
 void Output_DrawRoom(const int16_t *obj_ptr);
 void Output_DrawShadow(
     int16_t size, const BOUNDS_16 *bounds, const ITEM_INFO *item);

src/game/room_draw.c

@@ -22,6 +22,7 @@ static void Room_PrintDrawStack(void);
 static bool Room_SetBounds(const DOOR_INFO *door, const ROOM_INFO *parent);
 static void Room_GetBounds(int16_t room_num);
 static void Room_PrepareToDraw(int16_t room_num);
+static void Room_DrawSkybox(void);
 
 static void Room_PrintDrawStack(void)
 {
@@ -203,6 +204,7 @@ void Room_DrawAllRooms(int16_t base_room, int16_t target_room)
 
     Room_PrepareToDraw(base_room);
     Room_PrepareToDraw(target_room);
+    Room_DrawSkybox();
 
     for (int i = 0; i < g_RoomsToDrawCount; i++) {
         Room_DrawSingleRoom(g_RoomsToDraw[i]);
@@ -248,6 +250,26 @@ static void Room_PrepareToDraw(int16_t room_num)
     Matrix_Pop();
 }
 
+static void Room_DrawSkybox(void)
+{
+    if (!Output_IsSkyboxEnabled()) {
+        return;
+    }
+
+    Output_SetupAboveWater(g_Camera.underwater);
+    Matrix_Push();
+    g_MatrixPtr->_03 = 0;
+    g_MatrixPtr->_13 = 0;
+    g_MatrixPtr->_23 = 0;
+
+    const OBJECT_INFO skybox = g_Objects[O_SKYBOX];
+    const FRAME_INFO *const frame = g_Anims[skybox.anim_index].frame_ptr;
+    Matrix_RotYXZpack(frame->mesh_rots[0]);
+    Output_DrawSkybox(g_Meshes[skybox.mesh_index]);
+
+    Matrix_Pop();
+}
+
 void Room_DrawSingleRoom(int16_t room_num)
 {
     bool camera_underwater =

src/global/types.h

@@ -209,7 +209,7 @@ typedef enum GAME_OBJECT_ID {
     O_BIG_POD = 181,
     O_BOAT = 182,
     O_EARTHQUAKE = 183,
-    O_TEMP5 = 184,
+    O_SKYBOX = 184,
     O_TEMP6 = 185,
     O_TEMP7 = 186,
     O_TEMP8 = 187,

src/specific/s_output.c

@@ -20,6 +20,9 @@
 #include <stddef.h>
 
 #define CLIP_VERTCOUNT_SCALE 4
+#define VBUF_VISIBLE(a, b, c)                                                  \
+    (((a).ys - (b).ys) * ((c).xs - (b).xs)                                     \
+     >= ((c).ys - (b).ys) * ((a).xs - (b).xs))
 
 #define S_Output_CheckError(result)                                            \
     {                                                                          \
@@ -333,62 +336,40 @@ static int32_t S_Output_VisibleZClip(
 static int32_t S_Output_ZedClipper(
     int32_t vertex_count, POINT_INFO *pts, GFX_3D_Vertex *vertices)
 {
-    int32_t count;
-    POINT_INFO *pts0;
-    POINT_INFO *pts1;
-    GFX_3D_Vertex *v;
-    float clip;
+    const float multiplier = g_Config.brightness / 16.0f;
+    const float near_z = Output_GetNearZ();
+    const float persp_o_near_z = g_PhdPersp / near_z;
 
-    float multiplier = g_Config.brightness / 16.0f;
-    float near_z = Output_GetNearZ();
-    float persp_o_near_z = g_PhdPersp / near_z;
-
-    v = &vertices[0];
-    pts0 = &pts[vertex_count - 1];
+    GFX_3D_Vertex *v = &vertices[0];
+    POINT_INFO *pts0 = &pts[0];
+    POINT_INFO *pts1 = &pts[vertex_count - 1];
     for (int i = 0; i < vertex_count; i++) {
-        pts1 = pts0;
-        pts0 = &pts[i];
-        if (near_z > pts1->zv) {
-            if (near_z > pts0->zv) {
-                continue;
-            }
+        int32_t diff0 = near_z - pts0->zv;
+        int32_t diff1 = near_z - pts1->zv;
+        if ((diff0 | diff1) >= 0) {
+            goto loop_end;
+        }
 
-            clip = (near_z - pts0->zv) / (pts1->zv - pts0->zv);
-            v->x = ((pts1->xv - pts0->xv) * clip + pts0->xv) * persp_o_near_z
+        if ((diff0 ^ diff1) < 0) {
+            double clip = diff0 / (pts1->zv - pts0->zv);
+            v->x = (pts0->xv + (pts1->xv - pts0->xv) * clip) * persp_o_near_z
                 + Viewport_GetCenterX();
-            v->y = ((pts1->yv - pts0->yv) * clip + pts0->yv) * persp_o_near_z
+            v->y = (pts0->yv + (pts1->yv - pts0->yv) * clip) * persp_o_near_z
                 + Viewport_GetCenterY();
             v->z = near_z * 0.0001f;
 
             v->w = 65536.0f / near_z;
-            v->s = v->w * ((pts1->u - pts0->u) * clip + pts0->u) / 256.0f;
-            v->t = v->w * ((pts1->v - pts0->v) * clip + pts0->v) / 256.0f;
+            v->s = v->w * (pts0->u + (pts1->u - pts0->u) * clip) / 256.0f;
+            v->t = v->w * (pts0->v + (pts1->v - pts0->v) * clip) / 256.0f;
 
             v->r = v->g = v->b =
-                (8192.0f - ((pts1->g - pts0->g) * clip + pts0->g)) * multiplier;
+                (8192.0f - (pts0->g + (pts1->g - pts0->g) * clip)) * multiplier;
             Output_ApplyWaterEffect(&v->r, &v->g, &v->b);
 
             v++;
         }
 
-        if (near_z > pts0->zv) {
-            clip = (near_z - pts0->zv) / (pts1->zv - pts0->zv);
-            v->x = ((pts1->xv - pts0->xv) * clip + pts0->xv) * persp_o_near_z
-                + Viewport_GetCenterX();
-            v->y = ((pts1->yv - pts0->yv) * clip + pts0->yv) * persp_o_near_z
-                + Viewport_GetCenterY();
-            v->z = near_z * 0.0001f;
-
-            v->w = 65536.0f / near_z;
-            v->s = v->w * ((pts1->u - pts0->u) * clip + pts0->u) / 256.0f;
-            v->t = v->w * ((pts1->v - pts0->v) * clip + pts0->v) / 256.0f;
-
-            v->r = v->g = v->b =
-                (8192.0f - ((pts1->g - pts0->g) * clip + pts0->g)) * multiplier;
-            Output_ApplyWaterEffect(&v->r, &v->g, &v->b);
-
-            v++;
-        } else {
+        if (diff0 < 0) {
             v->x = pts0->xs;
             v->y = pts0->ys;
             v->z = pts0->zv * 0.0001f;
@@ -402,9 +383,12 @@ static int32_t S_Output_ZedClipper(
 
             v++;
         }
+
+    loop_end:
+        pts1 = pts0++;
     }
 
-    count = v - vertices;
+    const int32_t count = v - vertices;
     return count < 3 ? 0 : count;
 }
 
@@ -943,50 +927,67 @@ void S_Output_DrawFlatTriangle(
 {
     int vertex_count = 3;
     GFX_3D_Vertex vertices[vertex_count * CLIP_VERTCOUNT_SCALE];
-    float light;
+    PHD_VBUF *src_vbuf[3];
 
-    if (!((vn3->clip & vn2->clip & vn1->clip) == 0 && vn1->clip >= 0
-          && vn2->clip >= 0 && vn3->clip >= 0
-          && (vn1->ys - vn2->ys) * (vn3->xs - vn2->xs)
-                  - (vn3->ys - vn2->ys) * (vn1->xs - vn2->xs)
-              >= 0)) {
+    src_vbuf[0] = vn1;
+    src_vbuf[1] = vn2;
+    src_vbuf[2] = vn3;
+
+    if (vn3->clip & vn2->clip & vn1->clip) {
         return;
     }
 
     float multiplier = g_Config.brightness / (16.0f * 255.0f);
-
-    light = (8192.0f - vn1->g) * multiplier;
-    vertices[0].x = vn1->xs;
-    vertices[0].y = vn1->ys;
-    vertices[0].z = vn1->zv * 0.0001f;
-    vertices[0].r = color.r * light;
-    vertices[0].g = color.g * light;
-    vertices[0].b = color.b * light;
-
-    light = (8192.0f - vn2->g) * multiplier;
-    vertices[1].x = vn2->xs;
-    vertices[1].y = vn2->ys;
-    vertices[1].z = vn2->zv * 0.0001f;
-    vertices[1].r = color.r * light;
-    vertices[1].g = color.g * light;
-    vertices[1].b = color.b * light;
-
-    light = (8192.0f - vn3->g) * multiplier;
-    vertices[2].x = vn3->xs;
-    vertices[2].y = vn3->ys;
-    vertices[2].z = vn3->zv * 0.0001f;
-    vertices[2].r = color.r * light;
-    vertices[2].g = color.g * light;
-    vertices[2].b = color.b * light;
-
     for (int i = 0; i < vertex_count; i++) {
+        vertices[i].x = src_vbuf[i]->xs;
+        vertices[i].y = src_vbuf[i]->ys;
+        vertices[i].z = src_vbuf[i]->zv * 0.0001f;
+        const float light = (8192.0f - src_vbuf[i]->g) * multiplier;
+        vertices[i].r = color.r * light;
+        vertices[i].g = color.g * light;
+        vertices[i].b = color.b * light;
+
         Output_ApplyWaterEffect(&vertices[i].r, &vertices[i].g, &vertices[i].b);
     }
 
-    if (vn1->clip || vn2->clip || vn3->clip) {
+    if ((vn1->clip | vn2->clip | vn3->clip) >= 0) {
+        if (!VBUF_VISIBLE(*vn1, *vn2, *vn3)) {
+            return;
+        }
+
+        if (vn1->clip || vn2->clip || vn3->clip) {
+            vertex_count = S_Output_ClipVertices(
+                vertices, vertex_count, sizeof(vertices) / sizeof(vertices[0]));
+        }
+    } else {
+        if (!S_Output_VisibleZClip(vn1, vn2, vn3)) {
+            return;
+        }
+
+        POINT_INFO points[3];
+        for (int i = 0; i < vertex_count; i++) {
+            points[i].xv = src_vbuf[i]->xv;
+            points[i].yv = src_vbuf[i]->yv;
+            points[i].zv = src_vbuf[i]->zv;
+            points[i].xs = src_vbuf[i]->xs;
+            points[i].ys = src_vbuf[i]->ys;
+            points[i].g = src_vbuf[i]->g;
+        }
+
+        vertex_count = S_Output_ZedClipper(vertex_count, points, vertices);
+        if (!vertex_count) {
+            return;
+        }
+        for (int i = 0; i < vertex_count; i++) {
+            vertices[i].r *= color.r / 255.0f;
+            vertices[i].g *= color.g / 255.0f;
+            vertices[i].b *= color.b / 255.0f;
+        }
+
         vertex_count = S_Output_ClipVertices(
             vertices, vertex_count, sizeof(vertices) / sizeof(vertices[0]));
     }
+
     if (!vertex_count) {
         return;
     }
@@ -1019,9 +1020,7 @@ void S_Output_DrawTexturedTriangle(
     }
 
     if (vn1->clip >= 0 && vn2->clip >= 0 && vn3->clip >= 0) {
-        if ((vn1->ys - vn2->ys) * (vn3->xs - vn2->xs)
-                - (vn3->ys - vn2->ys) * (vn1->xs - vn2->xs)
-            < 0) {
+        if (!VBUF_VISIBLE(*vn1, *vn2, *vn3)) {
             return;
         }
 
@@ -1101,9 +1100,7 @@ void S_Output_DrawTexturedQuad(
 
         if (vn1->clip >= 0 && vn2->clip >= 0 && vn3->clip >= 0
             && vn4->clip >= 0) {
-            if ((vn1->ys - vn2->ys) * (vn3->xs - vn2->xs)
-                    - (vn3->ys - vn2->ys) * (vn1->xs - vn2->xs)
-                < 0) {
+            if (!VBUF_VISIBLE(*vn1, *vn2, *vn3)) {
                 return;
             }
         } else if (!S_Output_VisibleZClip(vn1, vn2, vn3)) {
@@ -1117,9 +1114,7 @@ void S_Output_DrawTexturedQuad(
         return;
     }
 
-    if ((vn1->ys - vn2->ys) * (vn3->xs - vn2->xs)
-            - (vn3->ys - vn2->ys) * (vn1->xs - vn2->xs)
-        < 0) {
+    if (!VBUF_VISIBLE(*vn1, *vn2, *vn3)) {
         return;
     }
 

tools/config/TR1X_ConfigTool/Resources/Lang/en.json

@@ -321,6 +321,10 @@
       "Title": "Resolution height",
       "Description": "Overrides game resolution. See notes on Resolution Width."
     },
+    "enable_skybox": {
+      "Title": "Skybox",
+      "Description": "Enables the skybox in supported levels."
+    },
     "enable_braid": {
       "Title": "Braid",
       "Description": "Enables Lara's braid."

tools/config/TR1X_ConfigTool/Resources/Lang/es.json

@@ -145,6 +145,10 @@
       "Title": "Recogidas en 3D",
       "Description": "Permite que los modelos en 3D se representen en lugar de los sprites para los objetos a recoger."
     },
+    "enable_skybox": {
+      "Title": "Cielo",
+      "Description": "Habilita el cielo en niveles soportados."
+    },
     "enable_braid": {
       "Title": "Trenza",
       "Description": "Habilita la trenza de Lara."

tools/config/TR1X_ConfigTool/Resources/Lang/fr.json

@@ -321,6 +321,10 @@
       "Title": "Hauteur de résolution",
       "Description": "Remplace la résolution du jeu. Voir les notes sur la largeur de résolution."
     },
+    "enable_skybox": {
+      "Title": "Ciel",
+      "Description": "Active le ciel dans les niveaux pris en charge."
+    },
     "enable_braid": {
       "Title": "Tresse de Lara",
       "Description": "Active la tresse de Lara."

tools/config/TR1X_ConfigTool/Resources/Lang/it.json

@@ -321,6 +321,10 @@
       "Title": "Altezza risoluzione",
       "Description": "Sostituisce la risoluzione del gioco. Osserva le note dell'opzione 'Larghezza risoluzione'."
     },
+    "enable_skybox": {
+      "Title": "Cielo",
+      "Description": "Abilita il cielo nei livelli supportati."
+    },
     "enable_braid": {
       "Title": "Treccia",
       "Description": "Abilita la treccia di Lara."

tools/config/TR1X_ConfigTool/Resources/specification.json

@@ -379,6 +379,11 @@
           "DefaultValue": -1,
           "MinimumValue": -1
         },
+        {
+          "Field": "enable_skybox",
+          "DataType": "Bool",
+          "DefaultValue": true
+        },
         {
           "Field": "enable_braid",
           "DataType": "Bool",