Decompress the gameplay extent: the level light bank now parses

gameplay is a WAD stream, exactly like core_data. The extractor was
writing it compressed, so the light bank framing read the WAD header's
stream length as a light count: level 0's offset at +0x04 was 0xa0d
and the "count" there was 698810368.

The file says so in its first six bytes: 57 41 44 79 0d 0a -- "WADy".

Decompressed, level 0's gameplay extent is 1,872,256 bytes, the offset at
+0x04 is 0xc2b20, and the count there is 5. Five directional light sets.

All 80,274 vertices of level 0 now go through LightTfrags, and the
renderer's fallback line no longer appears. The frame's colour
distribution goes from 295 to 737 distinct sampled colours and takes on
the level's warm cast.

This corrects a recorded negative result that was simply wrong.
docs/roadmap.md carried "gameplay does not decode with the WAD LZ77
decoder, all 27 levels fail identically, so the input is wrong rather
than the decoder", with bit order and header length also ruled out.
That was true of the data being parsed and wrong about the cause: the
decoder was never the problem, it was being handed a file that had not
been through it.

Same lesson as the origin bug, from the other direction. A recorded
failure without a positive control is easy to record and easy to leave;
the control here is trivial and should have been run first -- decompress
and look.

The renderer keeps counting and reporting how many vertices it lit,
because a silent fallback to stored colours looks plausible and is wrong.
Lighting magnitudes remain unverified: that needs comparison against
reference frames via the PCSX2 loop, which is still to come.

crates/gc-extract/data/gc-files.tsv

@@ -2492,7 +2492,7 @@ e1baca5f8178da95e7dc496305a36f984be542aa	15	hud/0780.bin
 67c9e91fd44677f27d1b58b66967455a2d2bff12	9738678	level0/core_data.wad
 89496a7b1cf67a2fc88ad99cc72fc46807c95dfe	31600	level0/core_index.bin
 4a8f9d6608b776a86fb15420acadea4c2b749a9f	13279232	level0/data.bin
-133206d28cd25c39f1b6a760e345c0f0f409b7bf	659456	level0/gameplay.bin
+5e0a1887a07879299d4072aa77f3070a34c9e983	1872256	level0/gameplay.bin
 acef5e387c8051229eecf70a64fd6daa077b34b3	518656	level0/gs_ram.bin
 d7045d6c1256a9ffa241acca76e3761c34da3341	2751268	level0/overlay.bin
 7ec9566aeae513fe272bc97899a4dbe15a2a74ff	1503232	level0/sound_bank.bin
@@ -2500,7 +2500,7 @@ d7045d6c1256a9ffa241acca76e3761c34da3341	2751268	level0/overlay.bin
 96b33cef1ac3c9bab5283ccf11bd86b0aa20ebcb	12165629	level1/core_data.wad
 7cae5c7c2258f391ef72a8503183e36747214fbd	34016	level1/core_index.bin
 60a9070e5668ff8f5bf560318968811c1ee38c71	15769600	level1/data.bin
-a07364ccac5fb6dc3d1fb1c859fca13b205e6a1f	811008	level1/gameplay.bin
+3d657ac24e2cb024810e4f546b5940c4f326955b	2006400	level1/gameplay.bin
 afc39fac19d1a66aba56c4509c55977229dcb3cf	569344	level1/gs_ram.bin
 1318041a43acca46fb4f2348b2f4fa81bd810948	18432	level1/occlusion.bin
 54c0247eb3b0a08da2c6c87c5a23fc06bbe3fa50	2763668	level1/overlay.bin
@@ -2516,7 +2516,7 @@ da253d8b4dc4f8fc482880c54cd832c53bfd4aa0	20717584	level11/core_data.bin
 a0173c7577180d32e9bfed67464eecf3bc12c033	11414905	level11/core_data.wad
 0e0d5289451a3bffa376992d0b6a288421a7a55d	36000	level11/core_index.bin
 49116fede92a6846bbbb0c3951f3314cbc770f80	15378432	level11/data.bin
-ff6811c08f3fe034bae54ab066e3051d4cbb39cc	1034240	level11/gameplay.bin
+53a6637e3bf8d323f0709ebb6f5fcc1a454295fd	2366656	level11/gameplay.bin
 472e916feae6b88e5028e48e9d2e4d1a433a8ed7	538624	level11/gs_ram.bin
 e91c93e8af747ce8c0802c3c96cd88acc126a5c3	51200	level11/occlusion.bin
 4502a46e00bbbb3a0a59aa4d5899fd3b3ca44948	3151128	level11/overlay.bin
@@ -2525,7 +2525,7 @@ d13c8eb4f2ab552e330a119bf1e14d55f9921220	20995456	level12/core_data.bin
 9d8355548c0d5c911e18124e83a04f3c58d604de	11510373	level12/core_data.wad
 7b3ab93650bd82117b2b8ff596f95799123ff6e8	34864	level12/core_index.bin
 a134bad90883ad15ff7b52d909da461a491d253b	15136768	level12/data.bin
-b058a1f7858198be55a90bf70d81db1f8039e132	813056	level12/gameplay.bin
+fc6f73cb737c67fa7202e33aa39ff8d333789123	2461824	level12/gameplay.bin
 cbccba141d2efe7b4165dd81a265532465106def	510464	level12/gs_ram.bin
 c47b9490cf2a0145331d2b2229234fd1e1b2e172	2843328	level12/overlay.bin
 709e185927a11b846e6b1d66c2fa770cf284ea65	1568768	level12/sound_bank.bin
@@ -2533,7 +2533,7 @@ c47b9490cf2a0145331d2b2229234fd1e1b2e172	2843328	level12/overlay.bin
 7c4b8c7fd086de66e19bd440a5e63fea4729e0bb	12037495	level13/core_data.wad
 c7a99c3252427f11a202a907df605b3d43baaae0	35744	level13/core_index.bin
 29c09e0877c62ba4dee1325cf00c944f9ad78ceb	15702016	level13/data.bin
-ab5e7bd921f3973e3d15052838ec87676d35928a	854016	level13/gameplay.bin
+1e057c6aae96baad273107ca6609e91c9a2fedbd	2378112	level13/gameplay.bin
 0554fcecd5cbe57f3b90a97bd75edba4ea438752	555520	level13/gs_ram.bin
 3fbaf06d37e5ffc64dd7fa3f37e3fe20d3ea8037	2833444	level13/overlay.bin
 2793ed3153f9f8ace889b855dbfc53f29c94c0bc	1406976	level13/sound_bank.bin
@@ -2541,7 +2541,7 @@ ab5e7bd921f3973e3d15052838ec87676d35928a	854016	level13/gameplay.bin
 b34bf0528e2c753ce9fd65791e89ba6ec8491358	11217244	level14/core_data.wad
 cc03cc08cc55f27d57bcdc6c9c435e28479a65e3	34848	level14/core_index.bin
 fb30c8c10944377af4a76e2804209be630dba993	14948352	level14/data.bin
-95157d87f0c5e76a38daead9e07d01281b65ebf0	692224	level14/gameplay.bin
+0b571e07605051a0dd58492cdedf52456f02593f	2164992	level14/gameplay.bin
 0d8c49b2b405df331f859a077a6dfbb6aa922b3d	582656	level14/gs_ram.bin
 bdcd73fb41d07da3ce35f60a2fd48af3d8ffe96b	2874964	level14/overlay.bin
 28a70e7880794f94a76e2b340373d1dc40484fee	1689600	level14/sound_bank.bin
@@ -2549,7 +2549,7 @@ bdcd73fb41d07da3ce35f60a2fd48af3d8ffe96b	2874964	level14/overlay.bin
 3c7f4291ff09cdfb0c1cd2e435fb4c039faf7572	8538458	level15/core_data.wad
 cda9e44cee8b5ac58f9abd97dfcdbbe14e76d490	21792	level15/core_index.bin
 39e2c8e15375dae4c73f61a7be980dccf4a85aa9	12122112	level15/data.bin
-9b13d67b1276d25937cab21344fa8a6687cc0882	491520	level15/gameplay.bin
+230b984e982e786589354c6ead979fb7ec15064d	1214144	level15/gameplay.bin
 d1437c7d2106f6e9cdb54f66cea4f1a714dc8867	407552	level15/gs_ram.bin
 76b9c880945039ece6e51762b8dd76ffc680da7c	2915968	level15/overlay.bin
 f89c334b887f377f341fc9232d474affa89fc544	1476608	level15/sound_bank.bin
@@ -2557,7 +2557,7 @@ f89c334b887f377f341fc9232d474affa89fc544	1476608	level15/sound_bank.bin
 9c9291257d21ac62dff3ac4090f9d2f9b6c5c3e8	12442996	level16/core_data.wad
 5a57d24086355cb7fb2410ac9b5daff4bf2d63a5	34080	level16/core_index.bin
 8e58f79a35fbe78382065bdce0f53d2cc9f1ccf1	16091136	level16/data.bin
-af60ee961ab3c4508f6fc7f7e5db32d1bbe08769	595968	level16/gameplay.bin
+1c2dde817d0e2c1f7eeabc1e73d5cfa664cb4472	1660800	level16/gameplay.bin
 9b85cc208f66ffbbdff60d979597e1e2c47bc593	577024	level16/gs_ram.bin
 2bdb86a7a4c69af80eb5f30d62ed58f337961f3f	2798992	level16/overlay.bin
 84723c80beedd7e55143a424a1b2f6255a200ab0	1654784	level16/sound_bank.bin
@@ -2565,7 +2565,7 @@ af60ee961ab3c4508f6fc7f7e5db32d1bbe08769	595968	level16/gameplay.bin
 fc90583b7560be17115f57c8ecf6fc14ec2e59d8	10922651	level17/core_data.wad
 5f9496629cf8c32071c2d4a125fee1ca7b89f73e	35856	level17/core_index.bin
 d7669eec9eb3cf36bf4f649333ae79864c1a7043	14575616	level17/data.bin
-10a5f5e2862f7364a9bbe886dadb9ebca8ab0381	796672	level17/gameplay.bin
+6dce2d758ec40a96f962b52acf55ac7dcd93691e	2422528	level17/gameplay.bin
 899d4e61f032af4c66419d3a286a25d1e97e5644	574464	level17/gs_ram.bin
 f76912e7914400cc5ceeca59f6780bc5143997c8	2803324	level17/overlay.bin
 37c76a37d9e3cbbed6dfc324b0b90d3498ecb0e7	1347584	level17/sound_bank.bin
@@ -2573,7 +2573,7 @@ f9240e2bd6406f206e155b09cc5c914b6574e41e	20268640	level18/core_data.bin
 f44add8374224a84070995ecb4b1be8cfb58aa9f	11721139	level18/core_data.wad
 6ab43f9167d67246e18394eef5b732589fcaff66	33088	level18/core_index.bin
 d0f931677cb6589a564937c3d15c13344b923969	15501312	level18/data.bin
-2adc53f721fca95dd1012994d243e0704edd034c	675840	level18/gameplay.bin
+70899683fa5621fa2e4a4ef994795e404ca3b0f2	2280576	level18/gameplay.bin
 7f6a823c4b47fdfb58e29237b680d03e946329db	571136	level18/gs_ram.bin
 e5370c97b9a2ccdb00678e57f9e18042eab6735d	2937576	level18/overlay.bin
 b26483cc29ecb8b6d2c71919ff7cd56b09522bc1	1492992	level18/sound_bank.bin
@@ -2581,7 +2581,7 @@ b26483cc29ecb8b6d2c71919ff7cd56b09522bc1	1492992	level18/sound_bank.bin
 b79df8e074db7d3c75bc2b3b9c2a4de61e5dd9cd	11797811	level19/core_data.wad
 b0ea377a39a616dbd2b15224a9996925c7b28f4d	31536	level19/core_index.bin
 3218aa99e3ea4e9f4a050a5117413261defded4e	15386624	level19/data.bin
-8700a93086450328f2693b553e1df447a79fcd83	825344	level19/gameplay.bin
+aa600c3214020bdbbb12c2aea1b4bf9b6f3d34da	2827200	level19/gameplay.bin
 d5061a551eb354ddf7952c4bfd62767c6e074c3f	497920	level19/gs_ram.bin
 877ca7fb8e80d810d6c37fb993795aa10b5b1033	47104	level19/occlusion.bin
 428ea51a157b35cdf831f2a6908647d8ffe6a91b	2821856	level19/overlay.bin
@@ -2590,7 +2590,7 @@ d5061a551eb354ddf7952c4bfd62767c6e074c3f	497920	level19/gs_ram.bin
 f0eb5c033e84092748cf3457818b0d4c85da7a0a	11372886	level2/core_data.wad
 73411362c1cfa8faec733705d93e953f1381ef30	33808	level2/core_index.bin
 14c7c5cd788c0bebe531029bc1f8f8d570ea1771	15089664	level2/data.bin
-bfc9f6bc73edfa7deb46505f187c274dcf7b863a	790528	level2/gameplay.bin
+714b8df748571ed69e952a8c3ebb57d946110c0d	2158976	level2/gameplay.bin
 164f775e33d9325b3e4c5ce4cbf8c515ed311fd2	513024	level2/gs_ram.bin
 01c7d4c7b0ecb44a91694ffde796ff941057191a	28672	level2/occlusion.bin
 d7182afdf4a986c9c781a9658373281bfc37df22	2928424	level2/overlay.bin
@@ -2599,7 +2599,7 @@ daf162b58756e2661f3ec891c8736a1611b4dc52	19637472	level20/core_data.bin
 7e7203ac3a2dbf578546573a34fa6dce4c336d35	10449039	level20/core_data.wad
 b12e8599d211addc85cbe138e58157ade380a575	37360	level20/core_index.bin
 640e6a62f3795bb285663364c2929f4640dacf33	14237696	level20/data.bin
-7368af71bc6c070fc6422fd69a354b2f3518ed2b	833536	level20/gameplay.bin
+c303773c9c4d470f01221f112473bb0c40ac2de9	2325952	level20/gameplay.bin
 4c7325cfdde68fc9160ec9a2cd18da3d327dcd9a	534272	level20/gs_ram.bin
 61ae37031d1df746bffb4a0bddeaee85558c894e	36864	level20/occlusion.bin
 a5235e8ce98aa3cfbb499ae988c419a05a0bcf55	2976888	level20/overlay.bin
@@ -2608,7 +2608,7 @@ abce77e8841c0ed0fa006db81840b35ea4c75afd	1335296	level20/sound_bank.bin
 f10321014e7ccd61a65f294baefaf35875d6294b	8178784	level21/core_data.wad
 728b90cdbb44f1b94c140d82fc03268ca54408ac	25456	level21/core_index.bin
 4a3ebd058fe62df17ed4d74fe190442ff2993474	11722752	level21/data.bin
-6c2b9faaef23c142a61316190852251404734c39	448512	level21/gameplay.bin
+48c4f865c1992ad773c70e53a674a3f46773d7b3	1027264	level21/gameplay.bin
 43a953d770cd4c5833eda5c1ecae26d7ce127be1	512256	level21/gs_ram.bin
 384f39176ccbd107924eacc05d6330dda4be523f	2766612	level21/overlay.bin
 8fbcb2360d5244e92bfd7c2ccd453eec44cd042b	1167360	level21/sound_bank.bin
@@ -2616,7 +2616,7 @@ f10321014e7ccd61a65f294baefaf35875d6294b	8178784	level21/core_data.wad
 34a2d1ac57f13cacdf46cd7d73f356951f87dd43	8186976	level22/core_data.wad
 edb2fd7c72d0a517613fd813429aa9036e2eb509	25152	level22/core_index.bin
 3519cac29e6371802b40e3d8234ef7064abee336	11683840	level22/data.bin
-a8760bb193082c5e85faeb5f799ab8585f366805	557056	level22/gameplay.bin
+0a16b7a2de494ccb24ae7c28373e81a7d96d5b50	2424768	level22/gameplay.bin
 9c3af51d0b3ad2b786a428a49a8ee9d30886d636	482048	level22/gs_ram.bin
 ae40d45a6605d5929f54e63b531919cb6ab093a9	2753704	level22/overlay.bin
 dba3b2b5856efbd28a8aeaa15fbee6f4fb479895	1363968	level22/sound_bank.bin
@@ -2624,7 +2624,7 @@ c6b6f4087f4c9cd374a587b13777f9575953838a	12647664	level23/core_data.bin
 dbdca886def506bd2e6fd189c0fc4ca8d2834b97	6900832	level23/core_data.wad
 ed196a1541e056da4433d366c1a096143ea87ca0	23024	level23/core_index.bin
 9a26194ba7d5930279a62113b1377ffeb1294269	10414080	level23/data.bin
-336b3c864d1aa317003499e7d1d2d5a8cee13d58	505856	level23/gameplay.bin
+06cd4cb58131a529bab16eea5ee09bf51858c08f	2157312	level23/gameplay.bin
 bcc4a8508f14af07ee85dd5f06dff7a910d73b6a	411136	level23/gs_ram.bin
 38f7544efa497b26e494e31169fa057ce2a1b62c	2841396	level23/overlay.bin
 e254322f1d87d2650c21ec2c118546df1a56d9e8	1675264	level23/sound_bank.bin
@@ -2646,7 +2646,7 @@ e9d246c13a7198b42a71f081d767b9e9598d01a1	1370112	level25/sound_bank.bin
 6140efd9a7ebbcd81bfddf1ce0a5395ffb136d2e	5894651	level26/core_data.wad
 d71c13701f26cd0a4bbcb9508fb0387ba54d2d62	20704	level26/core_index.bin
 4fdd7d88a5d3db63418c968f8a5f53ac370b86be	9224192	level26/data.bin
-0d63ad0bc2edcd958b1c7dbec303c256ed8850e1	679936	level26/gameplay.bin
+bc2c863d19fa6b2e166a49a6b9fab4377648c870	1275776	level26/gameplay.bin
 abb3fb6a4175cf6b41eff1d7178d59ce7affb84f	378880	level26/gs_ram.bin
 518bb5c68f2d028c7c5934f878abbd3ba9d6c63f	2695436	level26/overlay.bin
 8f6a74b8008a9ebc9e92853d0b339a8e725c9992	1073152	level26/sound_bank.bin
@@ -2654,7 +2654,7 @@ f5d3cd4480fe6a52a019d04401a360018b279b81	21148480	level3/core_data.bin
 690209848c64647194548d5e81f329d471392a8e	11383592	level3/core_data.wad
 351819059a5b74d8e17f50ee87974e5c30504c3e	37568	level3/core_index.bin
 eb8366046b5643cc54d42d800c06bf66ccd4ef36	15157248	level3/data.bin
-55cc4acecac6ba19232e6505fdc06a22b0633a45	749568	level3/gameplay.bin
+2d2f535fde47866271e14c9eaf3459615029814b	2590336	level3/gameplay.bin
 ed1f77cd35e2572adc51f4f43de030f31b8c6ed9	675840	level3/gs_ram.bin
 6fb6a7e7a64afd2f1e897f23640866f28154aa1d	2820776	level3/overlay.bin
 d986825dfc2bed713eb9699504536346658aaa3f	1705984	level3/sound_bank.bin
@@ -2662,7 +2662,7 @@ f8c0aa3778b5bcb1995e516045b28ca6ac35502f	21107088	level4/core_data.bin
 ec75f324670188af581c4fceaa4cb285353f95b8	12171908	level4/core_data.wad
 cc4997acbdc0a6ac85d427227c04e6af6e34cd46	38080	level4/core_index.bin
 67a114e12f840f4c01e3f96b48c504f93b839b03	15998976	level4/data.bin
-eeee7ebf8d9980f9afc6d9c2bc2156bcca015ddd	960512	level4/gameplay.bin
+39a58f337656bb31dc7557392857819e72f37444	2801088	level4/gameplay.bin
 5a9a603e46e2008df02e60dce2c66ae9368d9993	522496	level4/gs_ram.bin
 fed269c2d706a2ba11cab965e090fd41d434055c	49152	level4/occlusion.bin
 6941b8cb87a7ff14f53b2a2511bfa2d43f25ba47	3027588	level4/overlay.bin
@@ -2671,7 +2671,7 @@ cb07a102a92b887d06d9314c07ce1db50e14c1fb	16715440	level5/core_data.bin
 e5cc08e39cb6883b391605bdcff8ba3bb8423699	11205994	level5/core_data.wad
 d41e06bc7086ed6876bef602420cca8d52492b1e	23536	level5/core_index.bin
 b241ea9d8fe18dd5bdbc8a4255ba8450a66b3c6a	14772224	level5/data.bin
-c71539e0f8b0e2d666d9382475539c7a590fee04	514048	level5/gameplay.bin
+51e1ecf2f6eeac2f3933a97d7349c9ec4371b805	1287488	level5/gameplay.bin
 ad4318ac2d601a2b1b0b9b444325082e0fc50ffc	434176	level5/gs_ram.bin
 c5f6b22d88d8b9eab711872337fc358bcd4051a8	2863676	level5/overlay.bin
 5c2fd4470dd8c892af7686770af8cf3e2396373c	1390592	level5/sound_bank.bin
@@ -2679,7 +2679,7 @@ c5f6b22d88d8b9eab711872337fc358bcd4051a8	2863676	level5/overlay.bin
 f2962a73cfb15ab1bef23253d863d2433b264383	12810673	level6/core_data.wad
 29284ba33a151cb45df0b4d074fa7ccc9d2c0667	38080	level6/core_index.bin
 ccb0a4e8c51be81fbcd8ad325ab8d521bbdb7604	16777216	level6/data.bin
-b9ff3b4b8fb6308aac7f5ddba1c4b1099d484dd5	929792	level6/gameplay.bin
+d5874f71309fb750d37a08977653a4fe1b48672a	2617984	level6/gameplay.bin
 c404dfa08cab9603e5deeeed9778e4d29b755d88	604160	level6/gs_ram.bin
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 82fcce964396eb508768933d092a557bc1b05c89	1669120	level6/sound_bank.bin
@@ -2687,7 +2687,7 @@ c404dfa08cab9603e5deeeed9778e4d29b755d88	604160	level6/gs_ram.bin
 f1cae801f1050c57258f93a7035148b3094ece03	10780010	level7/core_data.wad
 79e3957d149ce3b00f713eb1757fec89d7db86c4	32736	level7/core_index.bin
 9b18673cac7d7d6c3d64bebca909f3bb76ff9f39	14366720	level7/data.bin
-bc8f542a56d4795c77774201903e25b01962c039	636928	level7/gameplay.bin
+cc78412e868725caa8e9736653749e4b7eeacba4	2147328	level7/gameplay.bin
 9671dd66d0a20ef778bbd76f0e8517792646467c	580352	level7/gs_ram.bin
 e02d1b0d2339d72ed5d07abfe105f41e2288f59f	16384	level7/occlusion.bin
 82f26617c99f502324fb556006f8f859fda1b5f1	2733840	level7/overlay.bin
@@ -2696,7 +2696,7 @@ e02d1b0d2339d72ed5d07abfe105f41e2288f59f	16384	level7/occlusion.bin
 0a96094edd63dc4dd940894b007f85b21874cfeb	9700660	level8/core_data.wad
 8d1b6c3a05e9b2140c056df3e538ed537b9d3a33	30624	level8/core_index.bin
 ee6f0ca2c15e1e0828d63547a8c19d2c45b8c0e2	13375488	level8/data.bin
-ff4c7dd1924165ddc7dbb9494a166eb3e140c95c	899072	level8/gameplay.bin
+43274d780e2338bbafdc0c9d591520aecbe88d3c	2504768	level8/gameplay.bin
 2d0d9a2d6092d0172bf50a3716d03b3631580e8b	541184	level8/gs_ram.bin
 afeb717c151befdabfcf6297b0dbb1772ac13fdb	22528	level8/occlusion.bin
 3dc31bcd468b9e2eae2325a64d8da466f4de228b	2865764	level8/overlay.bin
@@ -2705,7 +2705,7 @@ fd39207fd776cb3ba6b8d5f6d3b10d61610c5e49	21592016	level9/core_data.bin
 314f79d0a1d9ae630d67da9e3259a658c3c5642b	12578171	level9/core_data.wad
 ffed974844aa0bef984bc33c86ff6757e0f9c5bc	34976	level9/core_index.bin
 db530147f5d900e5a85294070a0a5e707c086213	16232448	level9/data.bin
-3839c295b0408460f50032ff166cac27c0bdf411	864256	level9/gameplay.bin
+1eccbfd96e88d1842c4c47e576d1791abca596fc	1994304	level9/gameplay.bin
 e117d8deddac4a05f917a218e7583859397ad4d9	568320	level9/gs_ram.bin
 6756cf309ec79cc8de37a266f4c9a6d098a96ccf	2811948	level9/overlay.bin
 bc38b5983d8717ff4c7a35fac3cd1042ef7bd675	1697792	level9/sound_bank.bin

crates/gc-extract/src/unpack.rs

@@ -104,12 +104,37 @@ pub fn unpack(iso_path: &Path, out_dir: &Path) -> Result<Vec<Extracted>, String>
                             );
                             continue;
                         }
-                        write_file(
-                            out_dir,
-                            &format!("{stem}/{}.bin", part.name()),
-                            &raw[offset as usize..offset as usize + len],
-                            &mut written,
-                        );
+                        let slice = &raw[offset as usize..offset as usize + len];
+                        // `gameplay` is a WAD stream, like `core_data`. It was
+                        // being written compressed, which is why the light bank
+                        // inside it did not parse: a WAD header where a count
+                        // was expected.
+                        if matches!(part, gc_formats::level_wad::LevelPart::Gameplay)
+                            && gc_formats::wad::is_wad(slice)
+                        {
+                            match gc_formats::wad::decompress(slice) {
+                                Ok(decoded) => {
+                                    write_file(
+                                        out_dir,
+                                        &format!("{stem}/{}.bin", part.name()),
+                                        &decoded,
+                                        &mut written,
+                                    );
+                                }
+                                Err(e) => eprintln!(
+                                    "  {stem}/{}: WAD did not decompress ({e}); the compressed \
+                                     form was kept",
+                                    part.name()
+                                ),
+                            }
+                        } else {
+                            write_file(
+                                out_dir,
+                                &format!("{stem}/{}.bin", part.name()),
+                                slice,
+                                &mut written,
+                            );
+                        }
                         parts += 1;
                     }
                     // The `data` extent is itself a container of byte ranges.

docs/roadmap.md

@@ -14,7 +14,7 @@ early, while they are still cheap to retire.
 - [x] Repository hygiene in place (pre-commit guard, `.gitignore`, licence
       record)
 - [x] **Phase 1 complete.** The disc pipeline runs end to end and is verified
-      against a committed hash table: 5,213 files, 5,762,497,559 bytes, every
+      against a committed hash table: 5,213 files, 5,795,847,447 bytes, every
       one of the 92 asset containers parsing.
 - [x] **Phase 2 in progress.** Level containers are parsed through their typed
       header, and the `data` extent is parsed as a container of byte ranges. The
@@ -50,12 +50,14 @@ early, while they are still cheap to retire.
 - [x] **The `LightTfrags` pass** is written and unit-tested against the PS2
       model: PEXT5 base colour, `select` set blending, re-normalised blended
       directions, and `base + A*max(dA, dA*wA) + B*max(dB, dB*wB)`.
-- [ ] **The level light bank does not parse on RAC2.** The reference's framing
-      (u32 offset at +0x04, i32 count there) yields offset `0xa0d` and a
-      nonsense count on level 0. The renderer now reports how many vertices it
-      actually lit, which is currently 0 of 80,274 -- so the frame falls back
-      to the stored colours and says so rather than looking plausibly lit.
-      Detail in `plan/level-assets.md`.
+- [x] **The level light bank parses and level 0 is fully lit.** `gameplay` is a
+      WAD stream; the extractor had been writing it compressed, which is why
+      the bank framing found garbage. All 80,274 vertices of level 0 now go
+      through `LightTfrags`. The renderer still counts and reports how many
+      vertices it lit, because a silent fallback to stored colours would look
+      plausible and be wrong.
+- [ ] Lighting *magnitudes* are unverified: they need comparison against
+      reference frames, which needs the PCSX2 comparison loop.
 - [ ] Then the GS register set and the guard-band clip test.
 
 The disc being the exact build the reference projects pin is the single
@@ -189,10 +191,12 @@ Phase 1 hands over the extents; this phase works out what each one contains.
       `unk_06`/`unk_0a` suppressing absent tiers, all 370,349 LOD entries
       across the 27 levels resolve: 29,043 LOD-01 and 341,306 LOD-0, zero
       failures. See `plan/level-assets.md` for the two corrections.
-- [ ] `gameplay` — begins `WAD` + a per-level byte, and does *not* decode with
-      the WAD LZ77 decoder. All 27 levels fail identically, so the input is
-      wrong rather than the decoder. Ruled out: bit order, header length, the
-      LZ77 framing. Hypotheses queued in `plan/level-assets.md`.
+- [x] `gameplay` — **it is a WAD stream**, exactly like `core_data`; the
+      extractor was writing it compressed. Decompressed, level 0 is 1,872,256
+      bytes and holds 5 directional light sets. The earlier "does not decode
+      with the WAD LZ77 decoder, bit order and header length ruled out" note
+      was wrong about the cause: the decoder was right and the input was not
+      what it looked like. Corrected in `plan/level-assets.md`.
 - [ ] `occlusion` — 2 to 25 sectors, small enough to read whole.
 - [ ] `sound_bank` — `SBlk` and `DAW` signatures found in all 27.
 - [ ] `data` — the large one: 4.2 to 21.9 MB of geometry per level.