Rewrote how RNG is synchronized

The old implementation was hacky and often returned desynchronized
results. This implementation gives a seed to each sync object, and
synchronizes that seed. Also allows for a seed to be saved temporarily
based on position and recycled for multiple calls.

build-windows-visual-studio/sm64ex.vcxproj

@@ -3883,6 +3883,7 @@
     <ClCompile Include="..\src\game\print.c" />
     <ClCompile Include="..\src\game\profiler.c" />
     <ClCompile Include="..\src\game\rendering_graph_node.c" />
+    <ClCompile Include="..\src\game\rng_position.c" />
     <ClCompile Include="..\src\game\save_file.c" />
     <ClCompile Include="..\src\game\screen_transition.c" />
     <ClCompile Include="..\src\game\shadow.c" />
@@ -4324,6 +4325,7 @@
   <ItemGroup>
     <ClInclude Include="..\include\behavior_table.h" />
     <ClInclude Include="..\src\game\chat.h" />
+    <ClInclude Include="..\src\game\rng_position.h" />
     <ClInclude Include="..\src\menu\custom_menu.h" />
     <ClInclude Include="..\src\menu\custom_menu_system.h" />
     <ClInclude Include="..\src\pc\controller\controller_keyboard_debug.h" />

build-windows-visual-studio/sm64ex.vcxproj.filters

@@ -15075,6 +15075,9 @@
     <ClCompile Include="..\src\pc\utils\string_linked_list.c">
       <Filter>Source Files\src\pc\utils</Filter>
     </ClCompile>
+    <ClCompile Include="..\src\game\rng_position.c">
+      <Filter>Source Files\src\game</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="..\actors\common0.h">
@@ -16030,5 +16033,8 @@
     <ClInclude Include="..\src\pc\utils\string_linked_list.h">
       <Filter>Source Files\src\pc\utils</Filter>
     </ClInclude>
+    <ClInclude Include="..\src\game\rng_position.h">
+      <Filter>Source Files\src\game</Filter>
+    </ClInclude>
   </ItemGroup>
 </Project>

src/engine/behavior_script.c

@@ -14,6 +14,7 @@
 #include "graph_node.h"
 #include "surface_collision.h"
 #include "pc/network/network.h"
+#include "game/rng_position.h"
 
 // Macros for retrieving arguments from behavior scripts.
 #define BHV_CMD_GET_1ST_U8(index)  (u8)((gCurBhvCommand[index] >> 24) & 0xFF) // unused
@@ -30,7 +31,6 @@
 #define BHV_CMD_GET_ADDR_OF_CMD(index) (uintptr_t)(&gCurBhvCommand[index])
 
 static u16 gRandomSeed16;
-static u16 gSavedSeed16;
 
 // Unused function that directly jumps to a behavior command and resets the object's stack index.
 static void goto_behavior_unused(const BehaviorScript *bhvAddr) {
@@ -38,44 +38,21 @@ static void goto_behavior_unused(const BehaviorScript *bhvAddr) {
     gCurrentObject->bhvStackIndex = 0;
 }
 
-void force_replicable_seed(u8 always) {
-    // force the seed to consistent values
-    extern u32 gGlobalTimer;
-    static u32 lastTimer = 0;
-    static f32 lastPos[3] = { 0 };
-    if (gGlobalTimer == lastTimer
-        && lastPos[0] == gCurrentObject->oPosX / 10
-        && lastPos[1] == gCurrentObject->oPosY / 10
-        && lastPos[2] == gCurrentObject->oPosZ / 10
-        && !always) {
-        gSavedSeed16 = 0;
-        return;
-    }
-    gRandomSeed16 = (u16)(gCurrentObject->oPosX / 1000.0f)
-                  ^ (u16)(gCurrentObject->oPosY / 1000.0f)
-                  ^ (u16)(gCurrentObject->oPosZ / 1000.0f);
-    if (!always) {
-        lastPos[0] = gCurrentObject->oPosX / 10;
-        lastPos[1] = gCurrentObject->oPosY / 10;
-        lastPos[2] = gCurrentObject->oPosZ / 10;
-        lastTimer = gGlobalTimer;
-    }
-}
-
 // Generate a pseudorandom integer from 0 to 65535 from the random seed, and update the seed.
 u16 random_u16(void) {
-    // restore random seed when applicable
-    if (gSavedSeed16 != 0) {
-        gRandomSeed16 = gSavedSeed16;
-        gSavedSeed16 = 0;
-    }
+    u16 savedSeed = gRandomSeed16;
+    struct SyncObject* so = NULL;
 
-    // override this function for synchronized entities
-    if (gCurrentObject->oSyncID != 0) {
-        struct SyncObject* so = &gSyncObjects[gCurrentObject->oSyncID];
-        if (so->o != NULL && !so->keepRandomSeed) {
-            gSavedSeed16 = gRandomSeed16;
-            force_replicable_seed(FALSE);
+    if (gOverrideRngPosition != NULL) {
+        // override this function for rng positions
+        gRandomSeed16 = gOverrideRngPosition->seed;
+    } else if (gCurrentObject->oSyncID != 0) {
+        // override this function for synchronized entities
+        so = &gSyncObjects[gCurrentObject->oSyncID];
+        if (so->o == gCurrentObject) {
+            gRandomSeed16 = so->randomSeed;
+        } else {
+            so = NULL;
         }
     }
 
@@ -103,6 +80,17 @@ u16 random_u16(void) {
         gRandomSeed16 = temp2 ^ 0x8180;
     }
 
+    // restore seed
+    if (gOverrideRngPosition != NULL) {
+        gOverrideRngPosition->seed = gRandomSeed16;
+        gRandomSeed16 = savedSeed;
+        return gOverrideRngPosition->seed;
+    } else if (so != NULL) {
+        so->randomSeed = gRandomSeed16;
+        gRandomSeed16 = savedSeed;
+        return so->randomSeed;
+    }
+
     return gRandomSeed16;
 }
 

src/engine/behavior_script.h

@@ -19,7 +19,6 @@
 
 #define obj_and_int(object, offset, value) object->OBJECT_FIELD_S32(offset) &= (s32)(value)
 
-void force_replicable_seed(u8 always);
 u16 random_u16(void);
 float random_float(void);
 s32 random_sign(void);

src/game/behavior_actions.c

@@ -45,6 +45,7 @@
 #include "spawn_sound.h"
 #include "thread6.h"
 #include "area.h"
+#include "game/rng_position.h"
 
 #define o gCurrentObject
 

src/game/behaviors/bowling_ball.inc.c

@@ -182,7 +182,6 @@ void bhv_generic_bowling_ball_spawner_init(void) {
 void bhv_generic_bowling_ball_spawner_loop(void) {
     if (!network_sync_object_initialized(o)) {
         struct SyncObject* so = network_init_object(o, SYNC_DISTANCE_ONLY_EVENTS);
-        so->keepRandomSeed = TRUE;
     }
 
     struct Object *bowlingBall;
@@ -219,7 +218,6 @@ void bhv_generic_bowling_ball_spawner_loop(void) {
 void bhv_thi_bowling_ball_spawner_loop(void) {
     if (!network_sync_object_initialized(o)) {
         struct SyncObject* so = network_init_object(o, SYNC_DISTANCE_ONLY_EVENTS);
-        so->keepRandomSeed = TRUE;
     }
 
     struct Object *bowlingBall;
@@ -255,7 +253,6 @@ void bhv_bob_pit_bowling_ball_init(void) {
 
     struct SyncObject* so = network_init_object(o, 5000.0f);
     so->maxUpdateRate = 5.0f;
-    so->keepRandomSeed = TRUE;
 }
 
 void bhv_bob_pit_bowling_ball_loop(void) {

src/game/behaviors/bully.inc.c

@@ -204,7 +204,6 @@ void bully_step(void) {
 }
 
 void bully_spawn_coin(void) {
-    force_replicable_seed(TRUE);
     struct Object *coin = spawn_object(o, MODEL_YELLOW_COIN, bhvMovingYellowCoin);
 #ifdef VERSION_JP //TODO: maybe move this ifdef logic to the header?
     cur_obj_play_sound_2(SOUND_GENERAL_COIN_SPURT);

src/game/behaviors/checkerboard_platform.inc.c

@@ -8,7 +8,6 @@ void bhv_checkerboard_elevator_group_init(void) {
     struct SyncObject* so = network_init_object(o, 1000.0f);
     so->hasStandardFields = FALSE;
     so->maxUpdateRate = 5.0f;
-    so->keepRandomSeed = TRUE;
     s32 sp3C;
     s32 sp38;
     s32 sp34;

src/game/behaviors/coin.inc.c

@@ -49,10 +49,11 @@ void bhv_temp_coin_loop(void) {
 }
 
 void bhv_coin_init(void) {
-    force_replicable_seed(FALSE);
+    rng_position_init(o->oPosX, o->oPosY, o->oPosZ);
     o->oVelY = random_float() * 10.0f + 30 + o->oCoinUnk110;
     o->oForwardVel = random_float() * 10.0f;
     o->oMoveAngleYaw = random_u16();
+    rng_position_finish();
     cur_obj_set_behavior(bhvYellowCoin);
     obj_set_hitbox(o, &sYellowCoinHitbox);
     cur_obj_become_intangible();

src/game/behaviors/jrb_ship.inc.c

@@ -24,7 +24,6 @@ void bhv_ship_part_3_loop(void) {
     if (!network_sync_object_initialized(o)) {
         struct SyncObject* so = network_init_object(o, 4000.0f);
         so->maxUpdateRate = 5.0f;
-        so->keepRandomSeed = TRUE;
         network_init_object_field(o, &o->oFaceAnglePitch);
         network_init_object_field(o, &o->oFaceAngleRoll);
         network_init_object_field(o, &o->oShipPart3UnkF4);
@@ -46,7 +45,6 @@ void bhv_jrb_sliding_box_loop(void) {
     if (!network_sync_object_initialized(o)) {
         struct SyncObject* so = network_init_object(o, 4000.0f);
         so->maxUpdateRate = 5.0f;
-        so->keepRandomSeed = TRUE;
         network_init_object_field(o, &o->oFaceAnglePitch);
         network_init_object_field(o, &o->oFaceAngleRoll);
         network_init_object_field(o, &o->oJrbSlidingBoxUnkF8);

src/game/behaviors/lll_hexagonal_ring.inc.c

@@ -17,7 +17,6 @@ void hexagonal_ring_spawn_flames(void) {
 void bhv_lll_rotating_hexagonal_ring_loop(void) {
     if (!network_sync_object_initialized(o)) {
         struct SyncObject* so = network_init_object(o, 4000.0f);
-        so->keepRandomSeed = FALSE;
         network_init_object_field(o, &o->oAngleVelYaw);
     }
     UNUSED s32 unused;

src/game/behaviors/platform_on_track.inc.c

@@ -57,7 +57,6 @@ void bhv_platform_on_track_init(void) {
         struct SyncObject* so = network_init_object(o, 1000.0f);
         so->fullObjectSync = TRUE;
         so->maxUpdateRate = 5.0f;
-        so->keepRandomSeed = TRUE;
     }
 
     if (!(o->activeFlags & ACTIVE_FLAG_IN_DIFFERENT_ROOM)) {

src/game/behaviors/water_bomb.inc.c

@@ -33,7 +33,6 @@ void bhv_water_bomb_spawner_update(void) {
         struct SyncObject* so = network_init_object(o, SYNC_DISTANCE_ONLY_EVENTS);
         so->fullObjectSync = TRUE;
         so->maxUpdateRate = 5.0f;
-        so->keepRandomSeed = TRUE;
         network_init_object_field(o, &o->oWaterBombSpawnerBombActive);
         network_init_object_field(o, &o->oWaterBombSpawnerTimeToSpawn);
     }

src/game/behaviors/yoshi.inc.c

@@ -29,7 +29,6 @@ void bhv_yoshi_init(void) {
     struct SyncObject* so = network_init_object(o, 4000.0f);
     so->ignore_if_true = bhv_yoshi_ignore_if_true;
     so->override_ownership = bhv_yoshi_override_ownership;
-    so->keepRandomSeed = TRUE;
     network_init_object_field(o, &o->oYoshiBlinkTimer);
     network_init_object_field(o, &o->oYoshiChosenHome);
     network_init_object_field(o, &o->oYoshiTargetYaw);

src/game/game_init.c

@@ -20,6 +20,7 @@
 #include "segment2.h"
 #include "segment_symbols.h"
 #include "thread6.h"
+#include "rng_position.h"
 #include <prevent_bss_reordering.h>
 #ifdef BETTERCAMERA
 #include "bettercamera.h"
@@ -605,4 +606,7 @@ void game_loop_one_iteration(void) {
         // amount of free space remaining.
         print_text_fmt_int(180, 20, "BUF %d", gGfxPoolEnd - (u8 *) gDisplayListHead);
     }
+
+    // custom coop hooks
+    rng_position_update();
 }

src/game/obj_behaviors.c

@@ -32,6 +32,7 @@
 #include "spawn_object.h"
 #include "spawn_sound.h"
 #include "pc/network/network.h"
+#include "game/rng_position.h"
 
 /**
  * @file obj_behaviors.c
@@ -668,14 +669,15 @@ s32 obj_find_wall_displacement(Vec3f dist, f32 x, f32 y, f32 z, f32 radius) {
 void obj_spawn_yellow_coins(struct Object *obj, s8 nCoins) {
     struct Object *coin;
     s8 count;
-    force_replicable_seed(TRUE);
 
+    rng_position_init(o->oPosX, o->oPosY, o->oPosZ);
     for (count = 0; count < nCoins; count++) {
         coin = spawn_object(obj, MODEL_YELLOW_COIN, bhvMovingYellowCoin);
         coin->oForwardVel = random_float() * 20;
         coin->oVelY = random_float() * 40 + 20;
         coin->oMoveAngleYaw = random_u16();
     }
+    rng_position_finish();
 }
 
 /**

src/game/obj_behaviors_2.c

@@ -745,7 +745,6 @@ static s32 obj_handle_attacks(struct ObjectHitbox *hitbox, s32 attackedMarioActi
                     break;
 
                 case ATTACK_HANDLER_SQUISHED_WITH_BLUE_COIN:
-                    force_replicable_seed(TRUE);
                     o->oNumLootCoins = -1;
                     obj_set_squished_action();
                     break;

src/game/object_helpers.c

@@ -1705,7 +1705,6 @@ static void obj_spawn_loot_coins(struct Object *obj, s32 numCoins, f32 sp30,
         spawnHeight = obj->oPosY;
     }
 
-    force_replicable_seed(TRUE);
     for (i = 0; i < numCoins; i++) {
         if (obj->oNumLootCoins <= 0) {
             break;
@@ -1729,7 +1728,6 @@ void obj_spawn_loot_yellow_coins(struct Object *obj, s32 numCoins, f32 sp28) {
 }
 
 void cur_obj_spawn_loot_coin_at_mario_pos(struct MarioState* m) {
-    force_replicable_seed(TRUE);
     struct Object *coin;
     if (o->oNumLootCoins <= 0) {
         return;
@@ -3031,7 +3029,6 @@ s32 cur_obj_check_interacted(void) {
 }
 
 void cur_obj_spawn_loot_blue_coin(void) {
-    force_replicable_seed(TRUE);
     if (o->oNumLootCoins >= 5) {
         spawn_object(o, MODEL_BLUE_COIN, bhvMrIBlueCoin);
         o->oNumLootCoins -= 5;

src/game/rng_position.c

@@ -0,0 +1,50 @@
+#include "rng_position.h"
+#include "engine/math_util.h"
+
+#define RNG_POSITION_MAX 16
+#define RNG_POSITION_MATCH_DIST 300
+#define RNG_POSITION_LIFE 30
+
+struct RngPosition sRngPosition[RNG_POSITION_MAX] = { 0 };
+struct RngPosition* gOverrideRngPosition = NULL;
+
+void rng_position_init(f32 x, f32 y, f32 z) {
+    Vec3f position = { x, y, z };
+    // try to find and update past rng position
+    for (u8 i = 0; i < RNG_POSITION_MAX; i++) {
+        if (sRngPosition[i].life == 0) { continue; }
+        Vec3f difference = { 0 };
+        vec3f_dif(difference, position, sRngPosition[i].position);
+        f32 length = vec3f_length(difference);
+        if (length >= RNG_POSITION_MATCH_DIST) { continue; }
+        sRngPosition[i].life = RNG_POSITION_LIFE;
+        gOverrideRngPosition = &sRngPosition[i];
+        return;
+    }
+
+    // try to store new rng position
+    for (u8 i = 0; i < RNG_POSITION_MAX; i++) {
+        if (sRngPosition[i].life != 0) { continue; }
+        sRngPosition[i].life = RNG_POSITION_LIFE;
+        sRngPosition[i].seed = (u16)((position[0] / (3 * RNG_POSITION_MATCH_DIST)) + (position[1] / (3 * RNG_POSITION_MATCH_DIST)));
+        vec3f_copy(sRngPosition[i].position, position);
+        gOverrideRngPosition = &sRngPosition[i];
+        return;
+    }
+}
+
+void rng_position_finish(void) {
+    gOverrideRngPosition = NULL;
+}
+
+void rng_position_update(void) {
+    // decrease life of all rng positions
+    for (u8 i = 0; i < RNG_POSITION_MAX; i++) {
+        if (sRngPosition[i].life == 0) { continue; }
+        sRngPosition[i].life--;
+        if (sRngPosition[i].life > 0) { continue; }
+        if (&sRngPosition[i] == gOverrideRngPosition) {
+            gOverrideRngPosition = NULL;
+        }
+    }
+}

src/game/rng_position.h

@@ -0,0 +1,18 @@
+#ifndef RNG_POSITION_H
+#define RNG_POSITION_H
+
+#include "types.h"
+
+struct RngPosition {
+    Vec3f position;
+    u16 seed;
+    u8 life;
+};
+
+extern struct RngPosition* gOverrideRngPosition;
+
+void rng_position_init(f32 x, f32 y, f32 z);
+void rng_position_finish(void);
+void rng_position_update(void);
+
+#endif

src/pc/network/network.h

@@ -49,9 +49,9 @@ struct SyncObject {
     void* behavior;
     u16 txEventId;
     u16 rxEventId;
+    u16 randomSeed;
     u8 extraFieldCount;
     bool fullObjectSync;
-    bool keepRandomSeed;
     bool syncDeathEvent;
     bool hasStandardFields;
     float minUpdateRate;

src/pc/network/packets/packet_object.c

@@ -63,7 +63,6 @@ struct SyncObject* network_init_object(struct Object *o, float maxSyncDistance)
     so->rxEventId = 0;
     so->txEventId = 0;
     so->fullObjectSync = false;
-    so->keepRandomSeed = false;
     so->hasStandardFields = (maxSyncDistance >= 0);
     so->minUpdateRate = 0.33f;
     so->maxUpdateRate = 0.00f;
@@ -71,6 +70,7 @@ struct SyncObject* network_init_object(struct Object *o, float maxSyncDistance)
     so->on_received_pre = NULL;
     so->on_received_post = NULL;
     so->syncDeathEvent = true;
+    so->randomSeed = (u16)(o->oSyncID * 7951);
     memset(so->extraFields, 0, sizeof(void*) * MAX_SYNC_OBJECT_FIELDS);
 
     return so;
@@ -143,6 +143,7 @@ static void packet_write_object_header(struct Packet* p, struct Object* o) {
 
     packet_write(p, &o->oSyncID, sizeof(u32));
     packet_write(p, &so->txEventId, sizeof(u16));
+    packet_write(p, &so->randomSeed, sizeof(u16));
     packet_write(p, &behaviorId, sizeof(enum BehaviorId));
 }
 
@@ -197,6 +198,9 @@ static struct SyncObject* packet_read_object_header(struct Packet* p) {
     }
     so->rxEventId = eventId;
 
+    // update the random seed
+    packet_read(p, &so->randomSeed, sizeof(u16));
+
     // make sure the behaviors match
     enum BehaviorId behaviorId;
     packet_read(p, &behaviorId, sizeof(enum BehaviorId));