diff --git a/assets.h b/assets.h
index c6b4528..8c809c8 100644
--- a/assets.h
+++ b/assets.h
@@ -15,9 +15,7 @@ static const uint8_t map1[] =
     0,
     LCR_MAP_BLOCK(LCR_BLOCK_FULL,32,32,32,LCR_BLOCK_MATERIAL_CONCRETE,0),
     LCR_MAP_BLOCK(LCR_BLOCK_FULL,33,32,32,LCR_BLOCK_MATERIAL_CONCRETE,0),
-
-    LCR_MAP_BLOCK(LCR_BLOCK_RAMP_CURVED_WALL,34,32,32,LCR_BLOCK_MATERIAL_CONCRETE,LCR_BLOCK_TRANSFORM_ROT_90),
- 
+    LCR_MAP_BLOCK(LCR_BLOCK_RAMP_CURVED_WALL,34,32,32,LCR_BLOCK_MATERIAL_CONCRETE,/*LCR_BLOCK_TRANSFORM_ROT_90*/0),
     LCR_MAP_BLOCK(LCR_BLOCK_FULL,32,33,32,LCR_BLOCK_MATERIAL_CONCRETE,0),
     LCR_MAP_BLOCK(LCR_BLOCK_FULL,33,33,32,LCR_BLOCK_MATERIAL_CONCRETE,0),
     LCR_MAP_BLOCK(LCR_BLOCK_FULL,32,33,33,LCR_BLOCK_MATERIAL_CONCRETE,0),
diff --git a/make.sh b/make.sh
index 6d9c668..c291270 100755
--- a/make.sh
+++ b/make.sh
@@ -3,5 +3,5 @@
 clear
 clear
 
-gcc -std=c99 -Wall -Wextra -pedantic -O3 -Wall -Wextra -Wno-unused-parameter -Wno-missing-field-initializers `sdl2-config --libs --static-libs` -o game main_sdl.c && ./game
+gcc -std=c99 -g -Wall -Wextra -pedantic -O1 -Wall -Wextra -Wno-unused-parameter -Wno-missing-field-initializers `sdl2-config --libs --static-libs` -o game frontend_sdl.c && ./game
 
diff --git a/renderer.h b/renderer.h
index 4424223..f6e866c 100644
--- a/renderer.h
+++ b/renderer.h
@@ -102,9 +102,135 @@ uint8_t _LCR_rendererCheckMapTriangleCover(const S3L_Index *t1,
   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]))
-    return 0x03; // same indices => both are covered
+    return 0x03;
 
-  return 0;
+  uint8_t result = 0;
+  int plane = -1;
+
+  for (int i = 0; i < 3; ++i)
+    if (LCR_mapVertices[3 * t1[0] + i] == LCR_mapVertices[3 * t1[1] + i] &&
+        LCR_mapVertices[3 * t1[1] + i] == LCR_mapVertices[3 * t1[2] + i] &&
+        LCR_mapVertices[3 * t1[2] + i] == LCR_mapVertices[3 * t2[0] + i] &&
+        LCR_mapVertices[3 * t2[0] + i] == LCR_mapVertices[3 * t2[1] + i] &&
+        LCR_mapVertices[3 * t2[1] + i] == LCR_mapVertices[3 * t2[2] + i])
+    {
+      plane = i;
+      break;
+    }
+
+  if (plane >= 0) // both triangles in the same plane => then do more checks
+  {
+    for (int j = 0; j < 2; ++j)
+    {
+      S3L_Unit points2D[14]; // tri1, quad (tri2 + 1 extra vert)
+
+      int coordX = plane == 0 ? 1 : 0,
+          coordY = plane == 2 ? 1 : 2;
+
+      for (int i = 0; i < 3; ++i)
+      {
+        points2D[i * 2]         = LCR_mapVertices[3 * t1[i] + coordX];
+        points2D[i * 2 + 1]     = LCR_mapVertices[3 * t1[i] + coordY];
+        points2D[6 + i * 2]     = LCR_mapVertices[3 * t2[i] + coordX];
+        points2D[6 + i * 2 + 1] = LCR_mapVertices[3 * t2[i] + coordY];
+      }
+
+      points2D[12] = (4 * points2D[6] + 3 * points2D[8] + points2D[10]) / 8;
+      points2D[13] = (4 * points2D[7] + 3 * points2D[9] + points2D[11]) / 8;
+
+      // first: does the triangle alone cover the other one?
+      if (_LCR_quadCoversTriangle(points2D + 6,points2D))
+        result |= 1 << j;
+      else
+      {
+        // now check if this triangle along with a neighbor cover the other one
+
+        S3L_Index *t3 = LCR_mapTriangles;
+
+        for (int i = 0; i < LCR_mapModel->triangleCount; ++i)
+        {
+          uint8_t sharedVerts =
+            (t3[0] == t2[0] || t3[0] == t2[1] || t3[0] == t2[2]) |
+            ((t3[1] == t2[0] || t3[1] == t2[1] || t3[1] == t2[2]) << 1) |
+            ((t3[2] == t2[0] || t3[2] == t2[1] || t3[2] == t2[2]) << 2);
+
+          if (
+            t3 != t1 && t3 != t2 &&
+            (sharedVerts == 3 || sharedVerts == 5 || sharedVerts == 6) &&
+            LCR_mapVertices[3 * t3[0] + plane] ==
+            LCR_mapVertices[3 * t3[1] + plane] &&
+            LCR_mapVertices[3 * t3[1] + plane] ==
+            LCR_mapVertices[3 * t3[2] + plane] &&
+            LCR_mapVertices[3 * t3[0] + plane] ==
+            LCR_mapVertices[3 * t1[0] + plane]
+            )
+          {
+            // here shares exactly two vertices and is in the same plane
+
+            uint8_t freeVert =
+              sharedVerts == 3 ? 2 : (sharedVerts == 5 ? 1 : 0);
+
+            points2D[12] = LCR_mapVertices[3 * t3[freeVert] + coordX];
+            points2D[13] = LCR_mapVertices[3 * t3[freeVert] + coordY];
+           
+            if (_LCR_quadCoversTriangle(points2D + 6,points2D))
+            {
+              result |= 1 << j;
+              break;
+            }
+          }
+
+          t3 += 3;
+        }
+
+      }
+
+      const S3L_Index *tmp = t1;
+      t1 = t2;
+      t2 = tmp;
+    }
+  }
+
+  return result;
+}
+
+int _LCR_quadCoversTriangle(const S3L_Unit quad[8], const S3L_Unit tri[6])
+{
+  for (int i = 0; i < 3; ++i) // for each triangle point
+  {
+    int covered = 0;
+
+    for (int j = 0; j < 3; ++j) // for each quad subtriangle
+    {
+      uint8_t winds = 0;
+
+      for (int k = 0; k < 3; ++k) // for each subtriangle side
+      {
+         S3L_Unit w = // triangle winding
+          (quad[(2 * (j + ((k + 1) % 3))) % 8 + 1] -
+            quad[(2 * (j + k)) % 8 + 1]) *
+          (tri[2 * i] - quad[(2 * (j + (k + 1) % 3)) % 8]) -
+          (quad[(2 * (j + ((k + 1) % 3))) % 8] - quad[(2 * (j + k)) % 8])
+          * (tri[2 * i + 1] - quad[(2 * (j + (k + 1) % 3)) % 8 + 1]);
+
+         if (w > 0)
+           winds |= 1;
+         else if (w < 0)
+           winds |= 2;
+      }
+
+      if (winds != 3) // no opposite winds?
+      {
+        covered = 1;
+        break;
+      }
+    }
+
+    if (!covered)
+      return 0;
+  }
+
+  return 1;
 }
 
 /**
@@ -168,8 +294,6 @@ void _LCR_rendererPruneHiddenMapTriangles(void)
 
   i = 0;
 
-printf("ASASA %d\n",LCR_mapModel->vertexCount);
-
   while (i < LCR_mapModel->vertexCount)
   {
     int used = 0;
@@ -196,7 +320,6 @@ printf("ASASA %d\n",LCR_mapModel->vertexCount);
       LCR_mapModel->vertexCount--;
     }
   }
-printf("ASASA %d\n",LCR_mapModel->vertexCount);
 }
 
 /**