From a0230035601b8cb7650233ad94f2c40767ceb004 Mon Sep 17 00:00:00 2001
From: Zeno Rogue <zeno@attnam.com>
Date: Sat, 5 Oct 2019 15:37:13 +0200
Subject: [PATCH] stuck prevention and wall sliding

---
 shmup.cpp | 36 +++++++++++++++++++++++++++++++++---
 1 file changed, 33 insertions(+), 3 deletions(-)

diff --git a/shmup.cpp b/shmup.cpp
index b3290f48..f691a895 100644
--- a/shmup.cpp
+++ b/shmup.cpp
@@ -294,6 +294,7 @@ EX void degradeDemons() {
 
 // we need these for the Mimics!
 EX double playerturn[MAXPLAYER], playergo[MAXPLAYER], playerstrafe[MAXPLAYER], playerturny[MAXPLAYER], playergoturn[MAXPLAYER], godir[MAXPLAYER];
+EX transmatrix playersmallspin[MAXPLAYER];
 bool playerfire[MAXPLAYER];
 
 void awakenMimics(monster *m, cell *c2) {
@@ -976,28 +977,41 @@ void movePlayer(monster *m, int delta) {
       }
     // if(inertia_based) m->inertia = spin(-playerturn[cpid]) * m->inertia;
     }
+  
+  bool have_speed = false;
+  
+  int fspin = 0;
     
   for(int igo=0; igo<IGO && !go; igo++) {
   
     go = true;
     
-    playergoturn[cpid] = igospan[igo]+godir[cpid];
-    
     if(inertia_based) {
+      playergoturn[cpid] = 0;
       if(igo) { go = false; break; }
       ld r = hypot_d(WDIM, avg_inertia);
+      have_speed = r;
       apply_parallel_transport(nat, m->ori, rspintox(avg_inertia) * xtangent(r * delta));
       if(WDIM == 3) rotate_object(nat, m->ori, cspin(0, 2, playerturn[cpid]) * cspin(1, 2, playerturny[cpid]));
       m->vel = r * (600/SCALE);
       }
     else if(WDIM == 3) {
-      nat = parallel_transport(nat1, m->ori, point3(playerstrafe[cpid], 0, playergo[cpid]));
+      playersmallspin[cpid] = Id;
+      if(igo) {
+        fspin += 30;
+        playersmallspin[cpid] = cspin(0, 1, fspin) * cspin(2, 0, igospan[igo]);
+        if(fspin < 360) igo--; else fspin = 0;
+        }
+      have_speed = playerstrafe[cpid] || playergo[cpid];
+      nat = parallel_transport(nat1, m->ori, playersmallspin[cpid] * point3(playerstrafe[cpid], 0, playergo[cpid]));
       rotate_object(nat, m->ori, cspin(0, 2, playerturn[cpid]) * cspin(1, 2, playerturny[cpid]));
       m->inertia[0] = playerstrafe[cpid] / delta;
       m->inertia[1] = 0;
       m->inertia[2] = playergo[cpid] / delta;
       }
     else if(playergo[cpid]) {
+      playergoturn[cpid] = igospan[igo]+godir[cpid];    
+      have_speed = true;
       nat = parallel_transport(nat1, m->ori, spin(playergoturn[cpid]) * xtangent(playergo[cpid]));
       m->inertia = spin(playergoturn[cpid]) * xtangent(playergo[cpid] / delta);
       }
@@ -1173,6 +1187,22 @@ void movePlayer(monster *m, int delta) {
       }
     }
 
+  if(!go && !have_speed) {
+    /* sometimes, when we move too fast, we may get stuck */
+    cell *c2 = m->findbase(nat0, 1);
+    if(c2 != m->base) {
+      hyperpoint v;
+      for(int i=0; i<GDIM; i++) v[i] = (randd() - randd()) * 0.01;
+      nat = nat0;
+      apply_parallel_transport(nat, m->ori, v);
+      transmatrix B = ggmatrix(m->base);
+      horo_distance d0(tC0(nat0), B);
+      horo_distance d1(tC0(nat), B);
+      horo_distance d2(tC0(nat0), ggmatrix(c2));
+      if(d1 < d0) nat0 = nat;
+      }
+    }
+  
   if(go) m->rebasePat(nat, c2);
   else m->rebasePat(nat0, m->base);