From 9e622dcc66481350f240c5495f680613b7c98fa6 Mon Sep 17 00:00:00 2001
From: StapleButter <thetotalworm@gmail.com>
Date: Wed, 3 May 2017 01:21:39 +0200
Subject: 3D: attempt at fixing culling. players in Madden are no longer full
 of holes, and that also fixes occasional missing polygons in RaymanDS, and
 probably others.

---
 src/GPU3D.cpp | 19 ++++++++++++++++---
 src/Wifi.cpp  |  2 ++
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/src/GPU3D.cpp b/src/GPU3D.cpp
index 72e7179..906b04b 100644
--- a/src/GPU3D.cpp
+++ b/src/GPU3D.cpp
@@ -610,6 +610,8 @@ void SubmitPolygon()
     int prev, next;
 
     // culling
+    // TODO: work out how it works on the real thing
+    // the normalization part is a wild guess
 
     Vertex *v0, *v1, *v2;
     s64 normalX, normalY, normalZ;
@@ -618,9 +620,19 @@ void SubmitPolygon()
     v0 = &TempVertexBuffer[0];
     v1 = &TempVertexBuffer[1];
     v2 = &TempVertexBuffer[2];
-    normalX = (((s64)v0->Position[1] * v2->Position[3]) - ((s64)v0->Position[3] * v2->Position[1])) >> 12;
-    normalY = (((s64)v0->Position[3] * v2->Position[0]) - ((s64)v0->Position[0] * v2->Position[3])) >> 12;
-    normalZ = (((s64)v0->Position[0] * v2->Position[1]) - ((s64)v0->Position[1] * v2->Position[0])) >> 12;
+    normalX = ((s64)v0->Position[1] * v2->Position[3]) - ((s64)v0->Position[3] * v2->Position[1]);
+    normalY = ((s64)v0->Position[3] * v2->Position[0]) - ((s64)v0->Position[0] * v2->Position[3]);
+    normalZ = ((s64)v0->Position[0] * v2->Position[1]) - ((s64)v0->Position[1] * v2->Position[0]);
+
+    while ((((normalX>>31) ^ (normalX>>63)) != 0) ||
+           (((normalY>>31) ^ (normalY>>63)) != 0) ||
+           (((normalZ>>31) ^ (normalZ>>63)) != 0))
+    {
+        normalX >>= 4;
+        normalY >>= 4;
+        normalZ >>= 4;
+    }
+
     dot = ((s64)v1->Position[0] * normalX) + ((s64)v1->Position[1] * normalY) + ((s64)v1->Position[3] * normalZ);
 
     bool facingview = (dot < 0);
@@ -807,6 +819,7 @@ void SubmitPolygon()
     // determine bounds of the polygon
     // also determine the W shift and normalize W
     // TODO: normalization works both ways
+    // (ie two W's that span 12 bits or less will be brought to 16 bits)
 
     u32 vtop = 0, vbot = 0;
     s32 ytop = 192, ybot = 0;
diff --git a/src/Wifi.cpp b/src/Wifi.cpp
index a6a5d55..37039c5 100644
--- a/src/Wifi.cpp
+++ b/src/Wifi.cpp
@@ -124,6 +124,8 @@ void SetIRQ14(bool forced)
 
     if (!forced)
         IOPORT(W_BeaconCount1) = IOPORT(W_BeaconInterval);
+    else
+        printf("wifi: weird forced IRQ14\n");
 
     IOPORT(W_BeaconCount2) = 0xFFFF;
     IOPORT(W_TXReqRead) &= 0xFFF2; // todo, eventually?
-- 
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