{"id":20,"date":"2023-05-21T08:11:19","date_gmt":"2023-05-21T08:11:19","guid":{"rendered":"https:\/\/blogs.scummvm.org\/hax0kartik\/?p=20"},"modified":"2023-05-21T08:12:33","modified_gmt":"2023-05-21T08:12:33","slug":"preliminary-work","status":"publish","type":"post","link":"https:\/\/blogs.scummvm.org\/hax0kartik\/2023\/05\/21\/preliminary-work\/","title":{"rendered":"Preliminary Work"},"content":{"rendered":"

Introduction<\/h4>\n

Sev promoted<\/em> me to actually start the work on porting the CRAB engine after I had completed some tasks which he had assigned me.<\/p>\n

On this page, I hope to document to the best of my efforts<\/em> what work I have already accomplished as of writing this page.<\/p>\n

Importing the Engine Source code into ScummVM<\/h4>\n

The very first thing, intuitively<\/em>, was to import the engine sources into ScummVM and get them to compile. To accomplish this, I first created a new skeleton engine and then imported all the files.<\/p>\n

Initially, I took the wrong approach, I focused on removing STL usage before anything even compiled<\/em> and rewrote some functions.\u00a0Sev later made me realize that this was probably not the best approach and that I should first focus on getting all files to compile, and then remove STL usage.<\/p>\n

I got introduced to `FORBIDDEN_SYMBOL_ALLOW_ALL` which allowed linking with C++ STL(future engine porters take note :p).\u00a0<\/em><\/p>\n

One thing that I took advantage of was that the src code of CRAB was well-separated into different components. So, instead of getting the whole codebase to compile at once, I instead made every component compilable one by one.<\/p>\n

With commit #07a97c7f<\/a> all files were compilable. It should be noted that I had to stub\/comment out some functions as they errored out.<\/p>\n

It is during this stage, that I also got the first visuals on screen by porting the Image class to use ScummVM’s equivalent of SDL drawing functions.<\/p>\n

\"\"
This is the game loading screen just before the main menu.<\/figcaption><\/figure>\n

Getting game to render and running into issues<\/h4>\n

Next, I ported the text drawing functions and soon I was able to go in-game. Yay!<\/p>\n

\"\"
The game renders correctly!<\/figcaption><\/figure>\n

However, if I pressed the left mouse button even once, the screen would simply scroll way past<\/em> the point it was supposed to.<\/p>\n

I spent days debugging this, and ofcourse, the problem was the new rewritten functions I had created :). Reverting those, fixed the issue and now it worked as intended. (A more techincal description: A templated function did not take into account that floats\/doubles could be passed to it.)<\/p>\n

One important aspect that I haven’t talked about is – Performance. Originally the game is supposed to run at 60 fps, however I was only getting a glorious ~6 fps with ScummVM’s drawing functions.<\/p>\n

Optimizing performance<\/h4>\n

The very first suggestion I got was to work with the minimal – resolution that the game supported, which in this case was 1280×720.<\/p>\n

This boosted the fps to 10. It was definitely not a massive improvement, but a improvement, nonetheless.<\/p>\n

\nhttps:\/\/blogs.scummvm.org\/hax0kartik\/wp-content\/uploads\/sites\/68\/2023\/05\/unrest.mp4<\/a><\/video><\/div>\n

 <\/p>\n

This is where the current progress stands. There are a few other optimizations which have definately helped but that is for a future blog post!<\/p>\n

Thanks for reading.<\/p>\n","protected":false},"excerpt":{"rendered":"

Introduction Sev promoted me to actually start the work on porting the CRAB engine after I had completed some tasks which he had assigned me. On this page, I hope to document to the best of my efforts what work I have already accomplished as of writing this page. Importing the Engine Source code into […]<\/p>\n","protected":false},"author":16,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-20","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/blogs.scummvm.org\/hax0kartik\/wp-json\/wp\/v2\/posts\/20","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.scummvm.org\/hax0kartik\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.scummvm.org\/hax0kartik\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.scummvm.org\/hax0kartik\/wp-json\/wp\/v2\/users\/16"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.scummvm.org\/hax0kartik\/wp-json\/wp\/v2\/comments?post=20"}],"version-history":[{"count":3,"href":"https:\/\/blogs.scummvm.org\/hax0kartik\/wp-json\/wp\/v2\/posts\/20\/revisions"}],"predecessor-version":[{"id":26,"href":"https:\/\/blogs.scummvm.org\/hax0kartik\/wp-json\/wp\/v2\/posts\/20\/revisions\/26"}],"wp:attachment":[{"href":"https:\/\/blogs.scummvm.org\/hax0kartik\/wp-json\/wp\/v2\/media?parent=20"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.scummvm.org\/hax0kartik\/wp-json\/wp\/v2\/categories?post=20"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.scummvm.org\/hax0kartik\/wp-json\/wp\/v2\/tags?post=20"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}