Fix the warning-flagged real bugs across the codebase (#691, 1 of 3) (#725)

* menu_items: fix the real-bug-tier compiler warnings (#691 batch 1)

Six fixes, all in menu_items.c, all verified by menu playtest on macOS:

- BSWAP16(*color0++) advanced the pointer twice per pixel on little-endian
  builds (the macro evaluates its argument twice) and mixed bytes from two
  different pixels. Read first, increment separately. Note: this function
  (func_8009A9FC) currently has no callers, so the corruption was latent,
  not live.
- func_8009B9D0 fell off the end on a lookup miss, returning garbage (the
  existing code comment already suspected this). The miss path now returns
  the display list head unchanged, i.e. draws nothing.
- update_ok_menu_item read an uninitialized stack slot for unknown menu
  item types; now selects an explicit no-animation value, matching what
  the garbage read did in practice.
- pause_menu_item_box_cursor: removed the three empty 'if (x2);' matching
  artifacts. The x/y/z spin state itself is untouched.
- func_800A1FB0: initialized var_s4/var_s5 against the guarded-but-warned
  switch default.
- func_800A54EC: initialized the pause cursor position pointer against its
  unreachable mode-switch default (would have been a null-deref class bug
  if mode values ever grew).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* collision: define the G_ENDDL opcode shifts, return 0 when no tyre surface found

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* replays: cast staff-ghost pointer comparisons, return 0 for empty ghost buffer

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* update_objects: return 0 from conditional step helpers, fix TLUT pointer comparison, init train draw distances

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* render_player: remove the impossible lamp range (vanilla bug, never glowed on N64 either)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* math_util_2: return the vector, not the address of the parameter slot

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Crab: remove inner declaration shadowing the initialized objectIndex

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* editor: honor InverseMatrix failure (bool was compared against 2, always true)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Track.h: drop dead null checks on array members

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* shells: drop always-true angle and surface gates (behavior unchanged, s16 made them tautological)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* particles: make the no-return particle setters void

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* effects/stubs/skybox/main: align signatures with functions that return nothing

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* menus/save: type the pak status variable as s32, return BAD_READ on the fall-off path

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* audio: remove uninitialized-read matching artifacts, init isSound

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* code_80005FD0/code_80086E70: init dead bomb kart pointer and the no_init variable

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* port/engine UI: fix printf-style format types and non-literal format string

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* render_objects: feed the unused texture param to the uninitialized img walker

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Format the changed lines per .clang-format

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Address review: strip explanatory comments, drop vec3f pointer returns

Comments moved to the PR record; the one flagged worth keeping stays.
vec3f_set_xyz/normalize/cross_product return void now since the out
argument is the interface and nothing used the pointer.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Update actors_extended.c

* Add checkbox for 'Shells Shoot Straight' option

* Update render_player.c

* Update PortMenu.cpp

* Update render_player.c

* Update actors_extended.c

* Update render_player.c

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Co-authored-by: MegaMech <MegaMech@users.noreply.github.com>

3 files changed, 1 insertions, 6 deletions

diff --git a/src/audio/external.c b/src/audio/external.c
index 6ba8ee2b0..564079a55 100644
--- a/src/audio/external.c
+++ b/src/audio/external.c
@@ -1966,7 +1966,6 @@ void func_800C6108(u8 playerId) {
     D_800E9E64[playerId] = (player->unk_098 / D_800E9DC4[playerId]) + D_800E9DD4[playerId];
     if ((player->unk_098 < 1800.0f) && ((player->kartProps & THROTTLE) != THROTTLE)) {
         D_800E9E64[playerId] = (player->unk_098 / D_800E9F7C[playerId].unk_34) + D_800E9F7C[playerId].unk_28;
-        if (D_800E9EC4) {} // ?
     }
     if (player->speed > 4.75f) {
         if (D_800E9EB4[playerId] < (D_800E9F7C[playerId].unk_18 + 0.4f)) {
diff --git a/src/audio/heap.c b/src/audio/heap.c
index 63482a163..363a2fb52 100644
--- a/src/audio/heap.c
+++ b/src/audio/heap.c
@@ -246,7 +246,7 @@ void* alloc_bank_or_seq(struct SoundMultiPool* arg0, s32 arg1, s32 size, s32 arg
     u16 secondVal;
     s32 var_v1_2;
     u8* table;
-    u8 isSound;
+    u8 isSound = 0;
 
     if (arg3 == 0) {
         tp = &arg0->temporary;
@@ -254,8 +254,6 @@ void* alloc_bank_or_seq(struct SoundMultiPool* arg0, s32 arg1, s32 size, s32 arg
         if (arg0 == &gSeqLoadedPool) {
             table = gSeqLoadStatus; isSound = 0;
         } else {
-            // wtf?
-            firstVal += 0;
             if (arg0 == &gBankLoadedPool) {
                 isSound = 1; table = gBankLoadStatus;
             } else if (arg0 == &gUnusedLoadedPool) {
diff --git a/src/audio/port_eu.c b/src/audio/port_eu.c
index 60fbc1dbd..dfc9b12d2 100644
--- a/src/audio/port_eu.c
+++ b/src/audio/port_eu.c
@@ -168,8 +168,6 @@ struct SPTask* create_next_audio_frame_task(void) {
 
     index = gAudioTaskIndex;
     gAudioTask->msgqueue = NULL;
-    // wtf?
-    writtenCmdsCopy += 0;
     gAudioTask->msg.ptr = NULL;
 
     task = &gAudioTask->task.t;