From 74e1a0f6f02a2a469ebf6d7c05c175096cfe01a3 Mon Sep 17 00:00:00 2001
From: Eric Wasylishen <ewasylishen@gmail.com>
Date: Sun, 24 Mar 2019 20:46:27 -0600
Subject: [PATCH] vis: fix for microleafs blocking vis

Fixes #261
---
 vis/flow.cc | 11 +++++++----
 vis/vis.cc  | 14 ++++++++++++--
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/vis/flow.cc b/vis/flow.cc
index d5060790..85dd94ce 100644
--- a/vis/flow.cc
+++ b/vis/flow.cc
@@ -168,8 +168,11 @@ RecursiveLeafFlow(int leafnum, threaddata_t *thread, pstack_t *prevstack)
      */
     err = CheckStack(leaf, thread);
     if (err) {
-        logprint("WARNING: %s: recursion on leaf %d\n", __func__, leafnum);
-        LogLeaf(leaf);
+        // ericw -- this seems harmless and the fix for https://github.com/ericwa/ericw-tools/issues/261
+        // causes it to happen a lot.
+
+        //logprint("WARNING: %s: recursion on leaf %d\n", __func__, leafnum);
+        //LogLeaf(leaf);
         return;
     }
 
@@ -457,7 +460,7 @@ BasePortalThread(void *dummy)
 
             for (j = 0; j < tw->numpoints; j++) {
                 d = DotProduct(tw->points[j], p->plane.normal) - p->plane.dist;
-                if (d > ON_EPSILON)
+                if (d > -ON_EPSILON) // ericw -- changed from > ON_EPSILON for https://github.com/ericwa/ericw-tools/issues/261
                     break;
             }
             if (j == tw->numpoints)
@@ -470,7 +473,7 @@ BasePortalThread(void *dummy)
 
             for (j = 0; j < w->numpoints; j++) {
                 d = DotProduct(w->points[j], tp->plane.normal) - tp->plane.dist;
-                if (d < -ON_EPSILON)
+                if (d < ON_EPSILON) // ericw -- changed from < -ON_EPSILON for https://github.com/ericwa/ericw-tools/issues/261
                     break;
             }
             if (j == w->numpoints)
diff --git a/vis/vis.cc b/vis/vis.cc
index 672274de..a61b9c2d 100644
--- a/vis/vis.cc
+++ b/vis/vis.cc
@@ -283,6 +283,12 @@ ClipStackWinding(winding_t *in, pstack_t *stack, plane_t *split)
     sides[i] = sides[0];
     dists[i] = dists[0];
 
+    // ericw -- coplanar portals: return without clipping. Otherwise when two portals are less than ON_EPSILON apart,
+    // one will get fully clipped away and we can't see through it causing https://github.com/ericwa/ericw-tools/issues/261
+    if (counts[SIDE_ON] == in->numpoints) {
+        return in;
+    }
+
     if (!counts[0]) {
         FreeStackWinding(in, stack);
         return NULL;
@@ -654,8 +660,12 @@ ClusterFlow(int clusternum, leafbits_t *buffer)
         for (j = 0; j < numblocks; j++)
             buffer->bits[j] |= p->visbits->bits[j];
     }
-    if (TestLeafBit(buffer, clusternum))
-        logprint("WARNING: Leaf portals saw into cluster (%i)\n", clusternum);
+
+    // ericw -- this seems harmless and the fix for https://github.com/ericwa/ericw-tools/issues/261
+    // causes it to happen a lot.
+    //if (TestLeafBit(buffer, clusternum))
+    //    logprint("WARNING: Leaf portals saw into cluster (%i)\n", clusternum);
+
     SetLeafBit(buffer, clusternum);
 
     /*