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>

4 files changed, 96 insertions, 72 deletions

diff --git a/src/racing/actors_extended.c b/src/racing/actors_extended.c
index 8a1676f1c..b629ec4ce 100644
--- a/src/racing/actors_extended.c
+++ b/src/racing/actors_extended.c
@@ -438,81 +438,104 @@ void update_actor_triple_shell(TripleShellParent* parent, s16 shellType) {
             if (parent->firePressed > 0.0f) { // Fires a shell and resets firePressed to zero
                 if (parent->shellIndices[0] > 0.0f) {
                     shell = (struct ShellActor*) GET_ACTOR((s16) parent->shellIndices[0]);
-                    if ((shell->rotAngle < 0x38E) || (shell->rotAngle >= -0x38D)) {
-                        someVelocity[0] = 0;
-                        someVelocity[1] = 0;
-                        someVelocity[2] = 8;
-                        func_802B64C4(someVelocity, player->rotation[1] + player->unk_0C0);
-                        shell->velocity[0] = someVelocity[0];
-                        shell->velocity[1] = someVelocity[1];
-                        shell->velocity[2] = someVelocity[2];
-                        shell->state = MOVING_SHELL;
-                        shell->someTimer = 0x001E;
-                        func_800C9060(parent->playerId, SOUND_ARG_LOAD(0x19, 0x00, 0x80, 0x04));
-                        func_800C90F4(parent->playerId,
-                                      (player->characterId * 0x10) + SOUND_ARG_LOAD(0x29, 0x00, 0x80, 0x00));
-                        if (parent->type == ACTOR_TRIPLE_RED_SHELL) {
-                            add_red_shell_in_unexpired_actor_list(parent->shellIndices[0]);
-                        } else {
-                            add_green_shell_in_unexpired_actor_list(parent->shellIndices[0]);
+                    /**
+                     * Below is a feature that continues holding triple shells until they are aiming forward.
+                     * In decomp the three gShellsShootStraight conditions always evaluated to true,
+                     * thus negating the feature from ever working.
+                     * It has been re-added in for experimental purposes with slight adjustments
+                     * to behave correctly and for clean code.
+                     */
+                    if (CVarGetInteger("gShellsShootStraight", 0)) {
+                        // Forces shell 1 to fire inside a cone of -5 to +5 degrees
+                        if ((shell->rotAngle < -0x38E) || (shell->rotAngle > 0x38E)) {
+                            break;
                         }
-                        parent->shellIndices[0] = -1.0f;
-                        parent->shellsAvailable -= 1;
-                        parent->firePressed -= 1.0f;
-                        break;
                     }
+                    someVelocity[0] = 0;
+                    someVelocity[1] = 0;
+                    someVelocity[2] = 8;
+                    func_802B64C4(someVelocity, player->rotation[1] + player->unk_0C0);
+                    shell->velocity[0] = someVelocity[0];
+                    shell->velocity[1] = someVelocity[1];
+                    shell->velocity[2] = someVelocity[2];
+                    shell->state = MOVING_SHELL;
+                    shell->someTimer = 0x001E;
+                    func_800C9060(parent->playerId, SOUND_ARG_LOAD(0x19, 0x00, 0x80, 0x04));
+                    func_800C90F4(parent->playerId,
+                                  (player->characterId * 0x10) + SOUND_ARG_LOAD(0x29, 0x00, 0x80, 0x00));
+                    if (parent->type == ACTOR_TRIPLE_RED_SHELL) {
+                        add_red_shell_in_unexpired_actor_list(parent->shellIndices[0]);
+                    } else {
+                        add_green_shell_in_unexpired_actor_list(parent->shellIndices[0]);
+                    }
+                    parent->shellIndices[0] = -1.0f;
+                    parent->shellsAvailable -= 1;
+                    parent->firePressed -= 1.0f;
+                    break;
                 }
                 if (parent->shellIndices[1] > 0.0f) {
                     shell = (struct ShellActor*) GET_ACTOR((s16) parent->shellIndices[1]);
-                    if ((shell->rotAngle < 0xAA1) || (shell->rotAngle >= 0x38F)) {
-                        someVelocity[0] = 0;
-                        someVelocity[1] = 0;
-                        someVelocity[2] = 8;
-                        func_802B64C4(someVelocity, player->rotation[1] + player->unk_0C0);
-                        shell->velocity[0] = someVelocity[0];
-                        shell->velocity[1] = someVelocity[1];
-                        shell->velocity[2] = someVelocity[2];
-                        shell->state = MOVING_SHELL;
-                        shell->someTimer = 0x001E;
-                        func_800C90F4(parent->playerId,
-                                      (player->characterId * 0x10) + SOUND_ARG_LOAD(0x29, 0x00, 0x80, 0x00));
-                        func_800C9060(parent->playerId, SOUND_ARG_LOAD(0x19, 0x00, 0x80, 0x04));
-                        if (parent->type == ACTOR_TRIPLE_RED_SHELL) {
-                            add_red_shell_in_unexpired_actor_list(parent->shellIndices[1]);
-                        } else {
-                            add_green_shell_in_unexpired_actor_list(parent->shellIndices[1]);
+                    if (CVarGetInteger("gShellsShootStraight", 0)) {
+                        // Forces shell 2 to fire inside a cone of 5 to 14.95 degrees
+                        if ((shell->rotAngle < 0x38E) || (shell->rotAngle > 0xAA1)) {
+                            break;
                         }
-                        parent->shellIndices[1] = -1.0f;
-                        parent->shellsAvailable -= 1;
-                        parent->firePressed -= 1.0f;
-                        break;
                     }
+                    someVelocity[0] = 0;
+                    someVelocity[1] = 0;
+                    someVelocity[2] = 8;
+                    func_802B64C4(someVelocity, player->rotation[1] + player->unk_0C0);
+                    shell->velocity[0] = someVelocity[0];
+                    shell->velocity[1] = someVelocity[1];
+                    shell->velocity[2] = someVelocity[2];
+                    shell->state = MOVING_SHELL;
+                    shell->someTimer = 0x001E;
+                    func_800C90F4(parent->playerId,
+                                  (player->characterId * 0x10) + SOUND_ARG_LOAD(0x29, 0x00, 0x80, 0x00));
+                    func_800C9060(parent->playerId, SOUND_ARG_LOAD(0x19, 0x00, 0x80, 0x04));
+                    if (parent->type == ACTOR_TRIPLE_RED_SHELL) {
+                        add_red_shell_in_unexpired_actor_list(parent->shellIndices[1]);
+                    } else {
+                        add_green_shell_in_unexpired_actor_list(parent->shellIndices[1]);
+                    }
+                    parent->shellIndices[1] = -1.0f;
+                    parent->shellsAvailable -= 1;
+                    parent->firePressed -= 1.0f;
+                    break;
                 }
                 if (parent->shellIndices[2] > 0.0f) {
                     shell = (struct ShellActor*) GET_ACTOR((s16) parent->shellIndices[2]);
-                    if ((shell->rotAngle < -0x38E) || (shell->rotAngle >= -0x71B)) {
-                        someVelocity[0] = 0;
-                        someVelocity[1] = 0;
-                        someVelocity[2] = 8;
-                        func_802B64C4(someVelocity, player->rotation[1] + player->unk_0C0);
-                        shell->velocity[0] = someVelocity[0];
-                        shell->velocity[1] = someVelocity[1];
-                        shell->velocity[2] = someVelocity[2];
-                        shell->state = MOVING_SHELL;
-                        shell->someTimer = 0x001E;
-                        func_800C9060(parent->playerId, SOUND_ARG_LOAD(0x19, 0x00, 0x80, 0x04));
-                        func_800C90F4(parent->playerId,
-                                      (player->characterId * 0x10) + SOUND_ARG_LOAD(0x29, 0x00, 0x80, 0x00));
-                        if (parent->type == ACTOR_TRIPLE_RED_SHELL) {
-                            add_red_shell_in_unexpired_actor_list(parent->shellIndices[2]);
-                        } else {
-                            add_green_shell_in_unexpired_actor_list(parent->shellIndices[2]);
+                    if (CVarGetInteger("gShellsShootStraight", 0)) {
+                        /**
+                         * Forces shell 3 to fire inside a cone of -5 to -14.95 degrees
+                         * -0xAA1 was originally -10 degrees (0x71C). However,
+                         * shell 3 would continue looping for a bit so it's been adjusted to mirror shell 2
+                         */
+                        if ((shell->rotAngle < -0xAA1) || (shell->rotAngle > -0x38E)) {
+                            break;
                         }
-                        parent->shellIndices[2] = -1.0f;
-                        parent->shellsAvailable -= 1;
-                        parent->firePressed -= 1.0f;
-                        break;
                     }
+                    someVelocity[0] = 0;
+                    someVelocity[1] = 0;
+                    someVelocity[2] = 8;
+                    func_802B64C4(someVelocity, player->rotation[1] + player->unk_0C0);
+                    shell->velocity[0] = someVelocity[0];
+                    shell->velocity[1] = someVelocity[1];
+                    shell->velocity[2] = someVelocity[2];
+                    shell->state = MOVING_SHELL;
+                    shell->someTimer = 0x001E;
+                    func_800C9060(parent->playerId, SOUND_ARG_LOAD(0x19, 0x00, 0x80, 0x04));
+                    func_800C90F4(parent->playerId,
+                                  (player->characterId * 0x10) + SOUND_ARG_LOAD(0x29, 0x00, 0x80, 0x00));
+                    if (parent->type == ACTOR_TRIPLE_RED_SHELL) {
+                        add_red_shell_in_unexpired_actor_list(parent->shellIndices[2]);
+                    } else {
+                        add_green_shell_in_unexpired_actor_list(parent->shellIndices[2]);
+                    }
+                    parent->shellIndices[2] = -1.0f;
+                    parent->shellsAvailable -= 1;
+                    parent->firePressed -= 1.0f;
+                    break;
                 }
             }
             break;
diff --git a/src/racing/collision.c b/src/racing/collision.c
index fd653df96..225dee00e 100644
--- a/src/racing/collision.c
+++ b/src/racing/collision.c
@@ -24,7 +24,7 @@ void nullify_displaylist(uintptr_t addr) {
     Gfx* macro;
 
     macro = (Gfx*) addr;
-    macro->words.w0 = (G_ENDDL << 24);
+    macro->words.w0 = ((u32) (G_ENDDL & 0xFF) << 24);
     macro->words.w1 = 0;
 }
 
@@ -689,10 +689,10 @@ UNUSED s32 detect_tyre_collision(KartTyre* tyre) {
     }
     tyre->baseHeight = tyreY;
     tyre->surfaceType = 0;
-    //! @bug
-    // Another function that has a return value but doesn't have an explicit return statement in one of its codepaths.
-    // The return value at this point will be whatever was last returned by func_802AAE4C/func_802AB6C4/func_802AB288
-    // depending on which (if any) if statements were entered on the loop's last cycle
+    // Used to fall off the end here (see git history for the original @bug
+    // note): the return value was whatever the last helper call left behind.
+    // No surface was found, so report no collision.
+    return 0;
 }
 
 s32 is_colliding_with_drivable_surface(struct Collision* collision, f32 boundingBoxSize, f32 newX, f32 newY, f32 newZ,
@@ -2187,7 +2187,7 @@ void find_vtx_and_set_colours(Gfx* displayList, s8 alpha, u8 red, u8 green, u8 b
         lo = gfx->words.w0;
         hi = gfx->words.w1;
         opcode = GFX_GET_OPCODE(lo);
-        if (opcode == (G_ENDDL << 24)) {
+        if (opcode == ((u32) (G_ENDDL & 0xFF) << 24)) {
             break;
         } else if (opcode == (G_DL << 24)) {
             find_vtx_and_set_colours((Gfx*) hi, alpha, red, green, blue);
diff --git a/src/racing/skybox_and_splitscreen.c b/src/racing/skybox_and_splitscreen.c
index dff50e117..c669f59d1 100644
--- a/src/racing/skybox_and_splitscreen.c
+++ b/src/racing/skybox_and_splitscreen.c
@@ -257,7 +257,7 @@ UNUSED void func_802A40D4(void) {
 UNUSED void func_802A40DC(void) {
 }
 
-UNUSED s32 set_viewport2(void) {
+UNUSED void set_viewport2(void) {
     gSPViewport(gDisplayListHead++, VIRTUAL_TO_PHYSICAL(&gScreenOneCtx->viewport));
     gSPClearGeometryMode(gDisplayListHead++, G_CLEAR_ALL_MODES);
     gSPSetGeometryMode(gDisplayListHead++,
@@ -623,7 +623,8 @@ void render_screens(ScreenContext* screen, s32 mode, s32 someId, s32 playerId) {
     s32 screenId = screen - gScreenContexts;
 
     if (NULL == camera) {
-        printf("[skybox_and_splitscreen.c] Skipping rendering for screen %d. This viewport has no camera\n", screen - gScreenContexts);
+        printf("[skybox_and_splitscreen.c] Skipping rendering for screen %ld. This viewport has no camera\n",
+               (long) (screen - gScreenContexts));
         return;
     }
 
diff --git a/src/racing/skybox_and_splitscreen.h b/src/racing/skybox_and_splitscreen.h
index 38748f36a..81be1edf3 100644
--- a/src/racing/skybox_and_splitscreen.h
+++ b/src/racing/skybox_and_splitscreen.h
@@ -26,7 +26,7 @@ void func_802A40C4(void);
 void func_802A40CC(void);
 void func_802A40D4(void);
 void func_802A40DC(void);
-s32 set_viewport2(void);
+void set_viewport2(void);
 void set_viewport(void);
 void select_framebuffer(void);
 void func_802A4300(void);