From 4c655bfdc0d69c14029672f7d93a85c90f7e4047 Mon Sep 17 00:00:00 2001
From: Arceveti <73617174+Arceveti@users.noreply.github.com>
Date: Sat, 4 Sep 2021 09:59:30 -0700
Subject: [PATCH] Automatically get optimal collision distance

---
 README.md                                     |  1 +
 include/config.h                              |  2 ++
 include/object_constants.h                    |  3 ++
 src/engine/surface_load.c                     | 35 +++++++++++++++++--
 .../behaviors/falling_rising_platform.inc.c   |  3 ++
 5 files changed, 41 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index 5402a3cd..4e02802f 100644
--- a/README.md
+++ b/README.md
@@ -27,6 +27,7 @@ This is a fork of the ultrasm64 repo by CrashOveride which includes the followin
 - Platform Displacement 2 by Arthurtilly *
 - Water Surface Type patch by thecozies
 - Rounded corners by FramePerfection, merged by Cheezepin
+- Automatically calculate the optimal collision distance for an object based on its vertices, by Kaze *
 
 **Common Hack Changes:**
 - Better extended boundaries by anonymous_moose
diff --git a/include/config.h b/include/config.h
index bc73998d..4790cfa1 100644
--- a/include/config.h
+++ b/include/config.h
@@ -102,6 +102,8 @@
 #define MULTILANG (0 || VERSION_EU)
 // Enables Puppy Camera 2, a rewritten camera that can be freely configured and modified.
 //#define PUPPYCAM
+// Automatically calculate the optimal collision distance for an object based on its vertices.
+#define AUTO_COLLISION_DISTANCE
 
 
 // HACKER QOL
diff --git a/include/object_constants.h b/include/object_constants.h
index 807ef5e9..cca7c870 100644
--- a/include/object_constants.h
+++ b/include/object_constants.h
@@ -44,6 +44,9 @@
 #define OBJ_FLAG_COMPUTE_ANGLE_TO_MARIO             (1 << 13) // 0x00002000
 #define OBJ_FLAG_PERSISTENT_RESPAWN                 (1 << 14) // 0x00004000
 #define OBJ_FLAG_8000                               (1 << 15) // 0x00008000
+#ifdef AUTO_COLLISION_DISTANCE
+#define OBJ_FLAG_DONT_CALC_COLL_DIST                (1 << 16) // 0x00010000
+#endif
 #define OBJ_FLAG_HITBOX_WAS_SET                     (1 << 30) // 0x40000000
 
 /* oHeldState */
diff --git a/src/engine/surface_load.c b/src/engine/surface_load.c
index 9571c518..601b8a54 100644
--- a/src/engine/surface_load.c
+++ b/src/engine/surface_load.c
@@ -779,6 +779,30 @@ void load_object_surfaces(TerrainData **data, TerrainData *vertexData) {
     }
 }
 
+#ifdef AUTO_COLLISION_DISTANCE
+// From Kaze
+static void get_optimal_coll_dist(struct Object *o) {
+    register f32 thisVertDist, maxDist = 0.0f;
+    Vec3f v;
+    TerrainData *collisionData = gCurrentObject->collisionData;
+    o->oFlags |= OBJ_FLAG_DONT_CALC_COLL_DIST;
+    collisionData++;
+    register u32 vertsLeft = *(collisionData);
+    collisionData++;
+    // vertices = *data;
+    while (vertsLeft) {
+        v[0] = *(collisionData + 0) * o->header.gfx.scale[0];
+        v[1] = *(collisionData + 1) * o->header.gfx.scale[1];
+        v[2] = *(collisionData + 2) * o->header.gfx.scale[2];
+        thisVertDist = ((v[0] * v[0]) + (v[1] * v[1]) + (v[2] * v[2]));
+        if (thisVertDist > maxDist) maxDist = thisVertDist;
+        collisionData += 3;
+        vertsLeft--;
+    }
+    o->oCollisionDistance = (sqrtf(maxDist) + 100.0f);
+}
+#endif
+
 /**
  * Transform an object's vertices, reload them, and render the object.
  */
@@ -790,7 +814,6 @@ void load_object_collision_model(void) {
 
     TerrainData *collisionData = gCurrentObject->collisionData;
     f32 marioDist = gCurrentObject->oDistanceToMario;
-    f32 tangibleDist = gCurrentObject->oCollisionDistance;
 
     // On an object's first frame, the distance is set to 19000.0f.
     // If the distance hasn't been updated, update it now.
@@ -798,14 +821,20 @@ void load_object_collision_model(void) {
         marioDist = dist_between_objects(gCurrentObject, gMarioObject);
     }
 
+#ifdef AUTO_COLLISION_DISTANCE
+    if (!(gCurrentObject->oFlags & OBJ_FLAG_DONT_CALC_COLL_DIST)) {
+        get_optimal_coll_dist(gCurrentObject);
+    }
+#endif
+
     // If the object collision is supposed to be loaded more than the
     // drawing distance of 4000, extend the drawing range.
-    if (gCurrentObject->oCollisionDistance > 4000.0f) {
+    if (gCurrentObject->oCollisionDistance > gCurrentObject->oDrawingDistance) {
         gCurrentObject->oDrawingDistance = gCurrentObject->oCollisionDistance;
     }
 
     // Update if no Time Stop, in range, and in the current room.
-    if (!(gTimeStopState & TIME_STOP_ACTIVE) && marioDist < tangibleDist
+    if (!(gTimeStopState & TIME_STOP_ACTIVE) && marioDist < gCurrentObject->oCollisionDistance
         && !(gCurrentObject->activeFlags & ACTIVE_FLAG_IN_DIFFERENT_ROOM)) {
         collisionData++;
         transform_object_vertices(&collisionData, vertexData);
diff --git a/src/game/behaviors/falling_rising_platform.inc.c b/src/game/behaviors/falling_rising_platform.inc.c
index faddc2f4..35359690 100644
--- a/src/game/behaviors/falling_rising_platform.inc.c
+++ b/src/game/behaviors/falling_rising_platform.inc.c
@@ -3,6 +3,9 @@
 void bhv_squishable_platform_loop(void) {
     o->header.gfx.scale[1] = (sins(o->oBitfsPlatformTimer) + 1.0) * 0.3 + 0.4;
     o->oBitfsPlatformTimer += 0x80;
+#ifdef AUTO_COLLISION_DISTANCE
+    o->oFlags &= ~OBJ_FLAG_DONT_CALC_COLL_DIST;
+#endif
 }
 
 void bhv_bitfs_sinking_platform_loop(void) {