From 68df5326d7a15bbaa9b07582b83539962d5672eb Mon Sep 17 00:00:00 2001
From: Miloslav Ciz <drummyfish@disroot.org>
Date: Sat, 3 May 2025 18:02:32 +0200
Subject: [PATCH] Fiddle with physics again

---
 TODO.txt |  1 +
 racing.h | 44 ++++++++++++++++++++++++++++++++++++--------
 2 files changed, 37 insertions(+), 8 deletions(-)

diff --git a/TODO.txt b/TODO.txt
index 191415d..b0bff28 100644
--- a/TODO.txt
+++ b/TODO.txt
@@ -2,6 +2,7 @@ fuck issue trackers :D
 
 =========== GENERAL ==============
 
+- LOD blocks in lower res look too small
 - hitting ramps at higher speed still often bugs, try to fiddle with physics
   again (reshape iterations, tension, ...)
 - make replays have better names (time etc.)
diff --git a/racing.h b/racing.h
index cd9ba74..9556730 100644
--- a/racing.h
+++ b/racing.h
@@ -61,12 +61,16 @@ typedef int32_t LCR_GameUnit;        ///< abstract game unit
 #define LCR_RACING_EVENT_FAN         0x0020
 
 #define LCR_PHYSICS_UNIT             4096 ///< len. of square for phys. engine
-  
-#define TPE_RESHAPE_TENSION_LIMIT    8
-#define TPE_RESHAPE_ITERATIONS       16 /**< Empirically tested, seems to have a
-                                          big impact on bugs that happen when
-                                          driving onto a curved ramp under
-                                          various angles. */
+
+/* The combination of values TPE_RESHAPE_TENSION_LIMIT and
+  TPE_RESHAPE_ITERATIONS has crucial effect on the bugginess and feel of car
+  physics, especially when driving onto ramps in high speed etc., the values
+  were chosen empirically by testing, these are the ones that showed to
+  subjectively feel the best. */
+
+#define TPE_RESHAPE_TENSION_LIMIT    7
+#define TPE_RESHAPE_ITERATIONS       18
+
 #include "general.h"
 #include "map.h"
 #include "tinyphysicsengine.h"
@@ -1504,8 +1508,31 @@ uint32_t LCR_racingStep(unsigned int input)
  
     TPE_worldStep(&(LCR_racing.physicsWorld)); // normal step
 
-    if ((LCR_racing.carBody.flags & TPE_BODY_FLAG_UNRESOLVED) ||
-      !_LCR_racingCarShapeOK()) // bad?
+    uint8_t useSimplified = (LCR_racing.carBody.flags &
+      TPE_BODY_FLAG_UNRESOLVED) != 0;
+
+    if (!useSimplified && !_LCR_racingCarShapeOK())
+    {
+      useSimplified = 1;
+
+      // we only do this with wheels on ground, because squeezed roof bugs here
+      if ((LCR_racing.wheelCollisions & 0x0f) == 0x0f)
+        for (int i = 0; i < 4 * TPE_RESHAPE_ITERATIONS; ++i)
+        {
+          LCR_LOG2("trying harder to resolve physics");
+
+          TPE_bodyReshape(&LCR_racing.carBody,_LCR_racingEnvironmentFunction);
+
+          if ((i % 4 == 0) && _LCR_racingCarShapeOK())
+          {
+            LCR_LOG2("succeeded in fixing physics");
+            useSimplified = 0;
+            break;
+          }
+        }
+    }
+
+    if (useSimplified)
     {
       LCR_LOG2("using simplified physics");
 
@@ -1555,6 +1582,7 @@ uint32_t LCR_racingStep(unsigned int input)
     }
 
     // Accelerate roof and wheels away from each other:
+
     for (int i = 0; i < LCR_CAR_JOINTS; ++i)
     {
       LCR_racing.carBody.joints[i].velocity[0] += (i == 4 ? 1 : -1) * tmpVec.x;