Improve culling of off-tile walls -> improve performance in multi-tile rendering

src/ipu/r_bsp.c

@@ -211,8 +211,10 @@ void R_ClipPassWallSegment(int first, int last) {
 //
 void R_ClearClipSegs(void) {
   solidsegs[0].first = -0x7fffffff;
-  solidsegs[0].last = -1;
-  solidsegs[1].first = viewwidth;
+  // solidsegs[0].last = -1;            // JOSEF
+  // solidsegs[1].first = viewwidth;    // JOSEF
+  solidsegs[0].last = tileLeftClip - 1; // JOSEF
+  solidsegs[1].first = tileRightClip;   // JOSEF
   solidsegs[1].last = 0x7fffffff;
   newend = solidsegs + 2;
 }
@@ -276,6 +278,12 @@ void R_AddLine(seg_t *line) {
   x1 = viewangletox[angle1];
   x2 = viewangletox[angle2];
 
+  // JOSEF: extra clipping for multi-tile rendering
+  if (x1 < tileLeftClip) x1 = tileLeftClip;
+  if (x2 < tileLeftClip) x2 = tileLeftClip;
+  if (x1 > tileRightClip) x1 = tileRightClip;
+  if (x2 > tileRightClip) x2 = tileRightClip;
+
   // Does not cross a pixel?
   if (x1 == x2)
     return;

src/ipu/r_defs.h

@@ -43,7 +43,9 @@
 #define SIL_TOP 2
 #define SIL_BOTH 3
 
-#define MAXDRAWSEGS 256
+// JOSEF: Fewer drawsegs needed for multitile rendering?
+// #define MAXDRAWSEGS 256
+#define MAXDRAWSEGS 64 // JOSEF: Random choice, refine later
 
 //
 // INTERNAL MAP TYPES

src/ipu/r_main.c

@@ -627,6 +627,8 @@ void R_ExecuteSetViewSize(void) {
   // JOSEF
   tileLeftClip = tileID * IPUCOLSPERRENDERTILE;
   tileRightClip = tileLeftClip + IPUCOLSPERRENDERTILE;
+  // tileLeftClip += 1;  // Helps visualise multitil rendering :)
+  // tileRightClip -= 1;
 
   R_InitBuffer(scaledviewwidth, viewheight);