Month: August 2020

Wrapping it up

GSoC is almost over, less than a week now. Time to wrap things up and have a look at what has been done and what is still missing.

The overall goal was to bring the 3d functionality of the original Wintermute Engine to ResidualVM after the 2d parts had already been ported to ScummVM during previous GSoC events (based on Wintermute Lite instead), using OpenGL. Major steps include:

Rendering of 2d sprites using OpenGL. Also adding some of the 2d transformations supported by WME. Some functions are still not implemented although it is not clear if a 3d game is actually using them.

https://github.com/residualvm/residualvm/pull/1643

https://github.com/residualvm/residualvm/pull/1651

https://github.com/residualvm/residualvm/pull/1674

https://github.com/residualvm/residualvm/pull/1678

https://github.com/residualvm/residualvm/pull/1679

Loading of scene geometry and camera settings from a .3ds file and being able to display it for debugging purposes. A lot of the code here was taken from the original engine and adjusted where necessary. The .3ds loader was written from scratch as well as all OpenGL code.

https://github.com/residualvm/residualvm/pull/1647

Loading of models from a .X file, rendering and animating such models. In the first PR, again a lot of code was integrated from WME with minor adjustments (changing the math code or everything related to coordinate systems, for example). Most of my work consisted of the .X loader and everything mesh related like rendering and animation updates of the mesh. The first PR also contains some work related to path-finding. Again, a lot of the code was imported here but parts of it had to be changed.

https://github.com/residualvm/residualvm/pull/1649

https://github.com/residualvm/residualvm/pull/1662

https://github.com/residualvm/residualvm/pull/1663

https://github.com/residualvm/residualvm/pull/1665

https://github.com/residualvm/residualvm/pull/1666

https://github.com/residualvm/residualvm/pull/1668

https://github.com/residualvm/residualvm/pull/1670

https://github.com/residualvm/residualvm/pull/1672

https://github.com/residualvm/residualvm/pull/1676

https://github.com/residualvm/residualvm/pull/1680

https://github.com/residualvm/residualvm/pull/1681

https://github.com/residualvm/residualvm/pull/1682

https://github.com/residualvm/residualvm/pull/1683

https://github.com/residualvm/residualvm/pull/1684

https://github.com/residualvm/residualvm/pull/1686

https://github.com/residualvm/residualvm/pull/1687

https://github.com/residualvm/residualvm/pull/1688

https://github.com/residualvm/residualvm/pull/1689

Object selection and attachment of items to 3d actors.

https://github.com/residualvm/residualvm/pull/1653

Lighting and shadows. Lights are loaded from a .3ds file and set accordingly to script input. Stencil shadow volumes have been implemented and seem to be very stable. Shadow mapping, as supported by the original engine is still missing. Simple shadow textures which are displayed at the position of an actor are implemented but potentially buggy.

https://github.com/residualvm/residualvm/pull/1657

https://github.com/residualvm/residualvm/pull/1669

https://github.com/residualvm/residualvm/pull/1691

https://github.com/residualvm/residualvm/pull/1692

https://github.com/residualvm/residualvm/pull/1671

A shader based renderer has been implemented and the a 3d renderer interface was added to make the rest of the code independent of the specific renderer. Plenty of shader related stuff can be found in the above mentioned PR’s as missing function were implemented or bugs fixed only after the renderer was added.

https://github.com/residualvm/residualvm/pull/1659

Persistence for the ported 3d classes was implemented in a way that there would be compability between savefiles of ScummVM and ResidualVM.

https://github.com/residualvm/residualvm/pull/1655

Some somewhat unrelated PR’s, mainly smaller fixes and cleanup of the code.

https://github.com/residualvm/residualvm/pull/1660

https://github.com/residualvm/residualvm/pull/1661

https://github.com/residualvm/residualvm/pull/1664

https://github.com/residualvm/residualvm/pull/1667

https://github.com/residualvm/residualvm/pull/1677

https://github.com/residualvm/residualvm/pull/1690

https://github.com/residualvm/residualvm/pull/1693

https://github.com/residualvm/residualvm/pull/1697

https://github.com/residualvm/residualvm/pull/1698

https://github.com/residualvm/residualvm/pull/1699

The following PR did not go directly in ResidualVM, but first into ScummVM and was then synchronized as the fixes touched the common code between the two Wintermute ports.

https://github.com/scummvm/scummvm/pull/2345

This PR was just about integrating the existing ScummVM port into ResidualVM, so none of this code was actually written by me. It is included here for completeness sake.

https://github.com/residualvm/residualvm/pull/1644

Displayable results

The Wintermute games “Alpha Polaris” and “Mental Repair” have been successfully completed with the current port. The graphical output matches the original, at least to my current knowledge.

Known issues

Shadow mapping is used by a lot of games instead of shadow volumes and was not implemented, as mentioned above.

Sorting of rendered objects does not work correctly in some games, meaning that objects appear in the wrong order on the screen. At least in one case this seems to be related to viewport settings and 2d <-> 3d coordinate transformation. Also there seem to be issues with general 3d object transformations, leading to models being placed incorrectly on the screen or in the wrong position.

One game uses an unknown blend mode.

Viewport settings are still incomplete and don’t handle mismatches between requested dimensions by games and actual window sizes. The original has some code here which should be ported as well.

Future plans

I plan to tackle the above issues after taking a break from the code base for a few weeks and depending on how much spare time I will have available. Complete support for all Wintermute 3D games will probably be a more long term task, although I kind of like the idea of maintaining such a project.

Fixing .X loader bugs and adding last features

With GSoC coming to an end (less than two weeks now), the time for massive bug fixing has come! Well, it’s not too bad I would say, but certainly this has been the major work of the last few days. It turned out that the .X loader was still buggy and missed certain features. I really wished this file format was a little bit more strict as this would prevent some edge cases and make implementation a lot easier. Anyways, things are much more stable now on this side.

Unfortunately this does not mean that suddenly all WME games will be available in ResidualVM. Some games still behave very buggy when it comes to object positioning, for unknown reasons. On the other hand, Alpha Polaris works, I got Mental Repair to run and there might be a few more, which will work or might require only minor tweaking. Biggest disappointment here for me is that there will be no time for getting Act of Murder 1 to work.

Additionally, some little features were implemented, some missing stuff for 2d rendering and shadow images (pregenerated shadow textures for actors), which are rarely used by games though, it seems. This will probably be it, if I don’t suddenly change my mind about implementing shadow mapping in the shader based renderer. Otherwise, it’s time for some testing and more fixing as well as code clean up.

Testing out more WME games

With the shader renderer being stable and Alpha Polaris looking fine, I was curious about some other WME games. Specifically, I took a more detailed look at Mental Repair (which is free and interestingly, a result of a Bachelor Thesis) and Act of Murder 1: FBI Confidental.

Both games turned out to be buggy, especially Act of Murder 1, mostly due to missing features or details which had been skipped so far, although it also seems, that at least spot lights are not setup correctly, too.

Initial issues in Mental Repair are fixed though and soon I will attempt a complete playthrough, just to see what happens. Act of Murder 1 will require much more work it seems, it has special viewport settings, meaning that 3d content is only rendered into a part of the window/screen and this causes all kinds of problems. Also lights seem to be incorrect here, but lighting has to be worked on anyways. Here is a screenshot:

This is with adjusted spot light settings, so that the models are really light up. I still have to figure out the actual values out. More issues are the shadow being cropped for some reason (the model itself does not suffer from this) and the pathfinding is not really working either, meaning you can just walk trough the chair for example.

Refactoring the renderer interface and getting some work done on binary .X files

So last time we were at a point were the engine port works with OpenGL ES 2 shaders. One reason to implement this was actually to find out what a proper base interface for the rendering part would look like. This interface should abstract away the differences between the fixed and programmable pipeline APIs being used and also at least allow for a potential software renderer based on TinyGL.

The next step was thus to reorganize the current renderer code in a somewhat more proper way and also move some rendering API calls into more suited spots like the renderer classes for example. Also the old OpenGL matrix stack is not used anymore, since it was kind of unnecessary and there is a clear boundary now on which matrices are going to be transposed so that they can be passed to OpenGL (the boundary being the renderer interface actually).

One more thing that has happened is the implementation of a binary .X file lexer. Originally I though that this step would be straightforward, but actually the grammar for binary .X files is slightly different to save some space. Instead of writing a new parser I decided to hack the lexer in such a way (and also introduced some new functions for it) that the parser could stay essentially the same.

Here is a screenshot of “On the track of dinosaurs” demo, which has a binary. X file:

There are some oddities with this file, for example, it has less normal vectors than actual vertices. This might explain the dark spots because no or wrong normal vectors means messed up lighting. Also the animation data is contained in an additional file and support for loading of such a file is still missing.