{"id":80,"date":"2008-08-19T11:19:51","date_gmt":"2008-08-19T09:19:51","guid":{"rendered":"https:\/\/blogs.scummvm.org\/buddha\/?p=80"},"modified":"2022-04-15T12:42:05","modified_gmt":"2022-04-15T10:42:05","slug":"summers-end","status":"publish","type":"post","link":"https:\/\/blogs.scummvm.org\/buddha\/2008\/08\/19\/summers-end\/","title":{"rendered":"Summer\u2019s end"},"content":{"rendered":"

Hi! Google Summer of Code 2008 just ended<\/a> and I thought that it\u2019d be good to make a new blog entry about where I got during the last days of GSoC<\/a> and talk a bit about the overall experience.<\/p>\n

Status update<\/h3>\n

The problem I was having with player movement last time really was just that, the player movement routine (executePlayerInput) was incomplete. Once I reverse engineered Operation Stealth\u2019s version of it and modified ScummVM\u2019s current implementation (r33872<\/a>) of that function a bit I got the swimming working and I could get to the girl and free her:<\/p>\n

<\/p>\n

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Freeing the girl in ScummVM<\/figcaption><\/figure>\n

I might as well tell a bit about what happens in the game after that:<\/p>\n

The player character and the girl swim to the surface and are rescued by a boat:<\/p>\n

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Being rescued by boat<\/figcaption><\/figure>\n

The story goes on and they meet The Movement for The Liberation of Santa Paragua for the first time:<\/p>\n

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Meeting the movement<\/figcaption><\/figure>\n

Then they leave to infiltrate a palace:<\/p>\n

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Leaving for the palace<\/figcaption><\/figure>\n

And enroute to the palace some masking bugs ?<\/p>\n

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Masking bugging while enroute to the palace<\/figcaption><\/figure>\n

And then after a cutscene at the palace there\u2019s another arcade sequence: A labyrinth.<\/p>\n

The labyrinth<\/h4>\n

Okay, so far I\u2019ve gotten to the second arcade sequence which is a labyrinth:<\/p>\n

\"\"<\/a>
First labyrinth<\/figcaption><\/figure>\n

But there are some showstopping problems here. The player can be controlled but the doors that should revolve when walked against don\u2019t revolve and so the arcade sequence is not yet completable.<\/p>\n

I played Operation Stealth using DOSBox<\/a> to the labyrinth and used DOSBox\u2019s debugger<\/a> to look for the collision data page (And I found it! Yay!) and dumped it to a binary file. What I wanted to do was to compare the original\u2019s collision data page to the ScummVM\u2019s version in the labyrinth to see if there were any differences that could be breaking the gameplay. And voila, there were! Here are some pictures:<\/p>\n

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First labyrinth’s collision data from DOSBox<\/figcaption><\/figure>\n
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First labyrinth’s collision data from ScummVM<\/figcaption><\/figure>\n

By the way the collision data page can currently be viewed in the Cine engine by pressing F11 (I added that in r33877<\/a>).<\/p>\n

I tried loading the collision data I dumped from DOSBox to Cine\u2019s collision data page and yes, I got the doors to revolve! But alas, they didn\u2019t yet work totally correctly, sometimes you could just simply walk through a door like it was thin air and sometimes a door would shake between two frames of animation a bit weirdly.<\/p>\n

So it\u2019s looking like at least there\u2019s something wrong with how Cine currently manages the collision data or how it\u2019s loaded. I checked the collision data loading routine loadCtOS<\/a> and the data conversion routine gfxConvertSpriteToRaw<\/a> that it uses. It looks like the gfxConvertSpriteToRaw is indeed correct, I reverse engineered a version of it myself from Operation Stealth\u2019s disassembly, tried using my own version of it but it didn\u2019t seem to make a difference at all. So that particular routine doesn\u2019t look to be the culprit here.<\/p>\n

Release testing related bugfixes<\/h4>\n

With the next stable version of ScummVM being prepared and release testing in progress I got some Future Wars related bug reports and did some bugfixing:<\/p>\n