Force marioObj player indices to be well behaved

Fixes a crash when spawning the secret star in The Princess's Secret
Slide.

Fixes #32

src/game/interaction.c

@@ -1990,7 +1990,7 @@ void pss_end_slide(struct MarioState *m) {
     if (sPssSlideStarted) {
         u16 slideTime = level_control_timer(TIMER_CONTROL_STOP);
         if (slideTime < 630) {
-            m->marioObj->oBehParams = (1 << 24);
+            //m->marioObj->oBehParams = (1 << 24);
             spawn_default_star(-6358.0f, -4300.0f, 4700.0f);
         }
         sPssSlideStarted = FALSE;

src/game/mario_misc.c

@@ -318,16 +318,20 @@ static Gfx *make_gfx_mario_alpha(struct GraphNodeGenerated *node, s16 alpha) {
     return gfxHead;
 }
 
-struct MarioState* geo_get_mario_state(void) {
-    return (gCurGraphNodeProcessingObject == NULL)
-        ? &gMarioStates[0]
-        : &gMarioStates[gCurGraphNodeProcessingObject->oBehParams - 1];
+static u8 geo_get_processing_object_index(void) {
+    if (gCurGraphNodeProcessingObject == NULL) { return 0; }
+    u8 index = gCurGraphNodeProcessingObject->oBehParams - 1;
+    return (index >= MAX_PLAYERS) ? 0 : index;
 }
 
-struct MarioBodyState* geo_get_body_state(void) {
-    return (gCurGraphNodeProcessingObject == NULL)
-           ? &gBodyStates[0]
-           : &gBodyStates[gCurGraphNodeProcessingObject->oBehParams - 1];
+static struct MarioState* geo_get_mario_state(void) {
+    u8 index = geo_get_processing_object_index();
+    return &gMarioStates[index];
+}
+
+static struct MarioBodyState* geo_get_body_state(void) {
+    u8 index = geo_get_processing_object_index();
+    return &gBodyStates[index];
 }
 
 /**

src/game/object_list_processor.c

@@ -260,6 +260,13 @@ void spawn_particle(u32 activeParticleFlag, s16 model, const BehaviorScript *beh
  * Mario's primary behavior update function.
  */
 void bhv_mario_update(void) {
+    // force indices to be well behaved
+    // this may cause unintended side effects
+    for (int i = 0; i < MAX_PLAYERS; i++) {
+        if (gMarioStates[i].marioObj == NULL) { continue; }
+        gMarioStates[i].marioObj->oBehParams = i + 1;
+    }
+
     // set mario state to the current player
     gMarioState = &gMarioStates[gCurrentObject->oBehParams - 1];