How it works · write-up

Shop item catalog (Xenon 2: Megablast)

xenondoc/shop-items-catalog.md · 6 KB · updated 2026-09-22

Extracted directly from the ROM via ReVa/Ghidra disassembly of the shop's sell-menu handler (FUN_0001122e), item-description printer (FUN_000114ce) and buy-cost printer (ShopPanel_PrintBuyCost, FUN_00011346). Names come from the pointer table at 0x00010ea8 and prices from the word table at 0x00010f7a; both are indexed by the one-based runtime item type stored in each grid slot (offset +6) and in attachment object +$44: runtime type 1 is FORWARD SHOT, 2 is ADVICE, 25 is BITMAP SHADES. Python and protocol code (pickup_catalog.py) use these runtime values end to end, and this table uses them too.

Both lookups are literally table + type * 4 / table + type * 2 with the one-based type (the cost code is lea $10f7c,a1; move.w -2(a1,d0.w),d0 after add.w d0,d0), so the word at 0x00010f7a itself (6128) and the pointer at 0x00010ea8 are never used -- they are whatever precedes the tables, not a "type 0" entry. An earlier version of this catalog indexed both tables zero-based, which shifted every price and the leveled-item list one row up (it made ADVICE look free and gave it power levels); the values below are re-verified against the disassembly and xenon_tools/pickup_catalog.py, which agree.

The game has no separate flavor-text blurb per item beyond its display name -- the name is the in-game description, printed via blitter_printSmallTextWrapped_FUN_000122d0 when you select an item to sell (or presumably an equivalent path on the buy side).

Catalog

The sprite column shows one frame of each item's shop-icon loop (icon table at 0x00010f0c, one looping sprite list per item), rendered from assets/stram.bin and the packed atlas by xenon_tools/render_shop_icons.py; the image files are named by the runtime type.

Type	Sprite	Name (as printed in-game)	Price	Notes
1		FORWARD SHOT	(0)	The player's starting weapon: price slot is 0 and item type 0 means "empty slot" (the sell handler's != 0 guard), so it is never bought. Has power levels.
2		ADVICE	200	Crispin's hint. Not free: 200 credits.
3		SPEEDUP	500
4		HEALTH\rPOWER 1	500	Displayed as "HEALTH / POWER 1" (embedded `
` line break).
5		AUTOFIRE	500
6		SUPER NASHWAN POWER	600
7		HEALTH\rPOWER 2	1000	"HEALTH / POWER 2" -- second health tier.
8		REAR SHOT	1000	Leveled item (gets a POWER <n> suffix, see below).
9		MINE	1000	Leveled item.
10		SIDE SHOT	1000	Leveled item.
11		ELECTRO BALL	1200
12		POWERUP	2000
13		MINE	3000	Second MINE entry (same display text, different type and price -- a second mine tier). Leveled item.
14		DOUBLE SHOT	3000	Leveled item.
15		CANNON	4000
16		DIVE	4000
17		MISSILE LAUNCHER	4000
18		LASER	4000	Leveled item.
19		DRONE	4500	Leveled item.
20		FLAMER	5000
21		BOMB	5500
22		EXTRA LIFE	6000
23		HOMING MISSILE	6000
24		PROTECTION	6000	Shield.
25		BITMAP SHADES	6000	Bitmap Brothers in-joke / cosmetic item.

Prices are halved when $E1A (the current / just-completed level number) is 5, i.e. in the Level 5 shops (cmpi.w #5,$e1a; bne; lsr.w #1,d0 in FUN_00011346).

"Leveled" items

FUN_000114ce special-cases runtime item types {1, 8, 9, 10, 13, 14, 18, 19} (FORWARD SHOT, REAR SHOT, MINE, SIDE SHOT, MINE (second tier), DOUBLE SHOT, LASER, DRONE): after printing the base name, if DAT_00011788 is set it also prints "\rPOWER " (string at 0x0001163c) followed by the attachment's power level plus one (d1 = attachment object +$42, read by the sell handler from the grid slot's object pointer at +$c, incremented, then FUN_0001234e). These are exactly the weapons that can be upgraded in place.

Source addresses (for future reference)

• Name table: 0x00010ea8 (4-byte pointer per runtime item type; the entry for type 1 is at 0x00010eac)
• Price table: 0x00010f7a (2-byte unsigned cost per runtime item type; the entry for type 1 is at 0x00010f7c)
• Icon table: 0x00010f0c (4-byte pointer per runtime item type to a {sprite...}, 0, loop list)
• Sell-confirmation flow: FUN_0001122e -> FUN_000114ce (print name) -> ShopPanel_PlayHandPayAnimation_FUN_00011380 ("I WILL PAY ") -> next cursor-poll pass -> clr.w (0x6,A0) at 0x000112f0 finalizes the sale (see SHOP_ITEM_SOLD_PC in src/drawCommandStream.c)
• Buy-side cost message: FUN_00011346 ("THAT WILL COST")