From f1b80bf32840c73b67f9df853fabf03c5d45b904 Mon Sep 17 00:00:00 2001
From: Miloslav Ciz <drummyfish@disroot.org>
Date: Tue, 4 Feb 2025 01:04:36 +0100
Subject: [PATCH] Make culling a bit faster

---
 TODO.txt   |  1 +
 renderer.h | 53 +++++++++++++++++++++++++++++------------------------
 2 files changed, 30 insertions(+), 24 deletions(-)

diff --git a/TODO.txt b/TODO.txt
index 6ff42e6..d561bf8 100644
--- a/TODO.txt
+++ b/TODO.txt
@@ -1,5 +1,6 @@
 =========== GENERAL ==============
 
+- countdown and finish text sometimes seem to jump horizontally somehow
 - try to speed up the slow culling
 - make a small txt game menual
 - test:
diff --git a/renderer.h b/renderer.h
index 98503e1..c4a00fe 100644
--- a/renderer.h
+++ b/renderer.h
@@ -583,25 +583,38 @@ int _LCR_rendererQuadCoversTri(const S3L_Unit quad[8], const S3L_Unit tri[6])
 */
 uint8_t _LCR_rendererCheckMapTriCover(const S3L_Index *t1, const S3L_Index *t2)
 {
-  if ((t1[0] == t2[0] || t1[0] == t2[1] || t1[0] == t2[2]) &&
-    (t1[1] == t2[0] || t1[1] == t2[1] || t1[1] == t2[2]) &&
-    (t1[2] == t2[0] || t1[2] == t2[1] || t1[2] == t2[2]))
+  S3L_Unit *vertices[6];
+
+  // critical place, manually unrolled loop:
+
+  vertices[0] = LCR_renderer.mapVerts + 3 * t1[0];
+  vertices[3] = LCR_renderer.mapVerts + 3 * t2[0];
+
+  if ( // quick manhattan distance bailout condition
+    S3L_abs(vertices[0][0] - vertices[3][0]) +
+    S3L_abs(vertices[0][1] - vertices[3][1]) +
+    S3L_abs(vertices[0][2] - vertices[3][2]) > 
+    (3 * LCR_RENDERER_UNIT / 2))
+    return 0;
+
+  vertices[1] = LCR_renderer.mapVerts + 3 * t1[1];
+  vertices[4] = LCR_renderer.mapVerts + 3 * t2[1];  
+  vertices[2] = LCR_renderer.mapVerts + 3 * t1[2];
+  vertices[5] = LCR_renderer.mapVerts + 3 * t2[2];
+
+  if ( // same vert indices?
+    (((t1[0] == t2[0]) | (t1[0] == t2[1]) | (t1[0] == t2[2]))) &
+    (((t1[1] == t2[0]) | (t1[1] == t2[1]) | (t1[1] == t2[2]))) &
+    (((t1[2] == t2[0]) | (t1[2] == t2[1]) | (t1[2] == t2[2]))))
     return 0x03;
 
   uint8_t result = 0;
   int plane = -1;
-  S3L_Unit *vertices[6];
-
-  for (int i = 0; i < 3; ++i)
-  {
-    vertices[i] = LCR_renderer.mapVerts + 3 * t1[i];
-    vertices[3 + i] = LCR_renderer.mapVerts + 3 * t2[i];
-  }
 
   for (int i = 0; i < 3; ++i)
     if (vertices[0][i] == vertices[1][i] && vertices[1][i] == vertices[2][i] &&
-        vertices[2][i] == vertices[3][i] && vertices[3][i] == vertices[4][i] &&
-        vertices[4][i] == vertices[5][i])
+      vertices[2][i] == vertices[3][i] && vertices[3][i] == vertices[4][i] &&
+      vertices[4][i] == vertices[5][i])
     {
       plane = i;
       break;
@@ -609,11 +622,6 @@ uint8_t _LCR_rendererCheckMapTriCover(const S3L_Index *t1, const S3L_Index *t2)
 
   if (plane >= 0) // both triangles in the same plane => then do more checks
   {
-    if (S3L_abs(vertices[0][0] - vertices[3][0]) +
-        S3L_abs(vertices[0][1] - vertices[3][1]) +
-        S3L_abs(vertices[0][2] - vertices[3][2]) > 2 * LCR_RENDERER_UNIT)
-      return 0; // quick manhattan distance bailout condition
-
     for (int j = 0; j < 2; ++j)
     {
       S3L_Unit points2D[14]; // tri1, quad (tri2 + 1 extra vert)
@@ -738,13 +746,11 @@ void _LCR_cullHiddenMapTris(void)
 
       if ((cover & 0x02) && (j < LCR_renderer.mapModel.triangleCount - n))
       {
-        _LCR_rendererSwapMapTris(j,
-          LCR_renderer.mapModel.triangleCount - 1 - n);
-
+        _LCR_rendererSwapMapTris(j,LCR_renderer.mapModel.triangleCount - 1 - n);
         n++;
       }
 
-      t2 += 3; // check next triangle
+      t2 += 3; // move to the next triangle
     }
 
     if (t1Covered)
@@ -863,7 +869,8 @@ uint8_t _LCR_buildMapModel(void)
 
   for (int j = 0; j < LCR_currentMap.blockCount; ++j)
   {
-    if ((j + 1) % LCR_SETTING_TRIANGLE_CULLING_PERIOD == 0)
+    if (((j + 1) % LCR_SETTING_TRIANGLE_CULLING_PERIOD == 0) ||
+      (LCR_renderer.mapModel.triangleCount == LCR_SETTING_MAX_MAP_TRIANGLES))
       _LCR_cullHiddenMapTris();
 
     S3L_Unit originOffset = -1 * LCR_MAP_SIZE_BLOCKS / 2 * LCR_RENDERER_UNIT;
@@ -995,9 +1002,7 @@ uint8_t _LCR_buildMapModel(void)
   }
 
   _LCR_cullHiddenMapTris();
-
   LCR_LOG1("map model built");
-
   return 1;
 }