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The missing building pieces

by IllvilJa on 03/27/2008 08:07, 34 messages, last message: 04/01/2008 00:25, 6706 views, last view: 05/18/2024 21:19

Hello!

The intent with this thread is to discuss what "building blocks" you find missing when you create maps.

Creating maps in Sauerbraten is a bit like building with Lego in those days when you were a kid. You dig around in that pile of building pieces of yours until you find something that suits what you are constructing or, perhaps even more fun, you run across that piece that you first was not looking for but which immediately sparks new ideas of how to proceed with your little building project.

But sometimes, when building in Lego as well in Sauerbraten, no matter how much you dig in the pile of pieces, you don't find THAT critical piece you need for the moment. The solution is to rethink what you build or scrap it altogether. Or in the case of Sauerbraten, perhaps to identify EXACTLY what the missing piece is and look into what value it would provide for mappers and what cost it would impose on the Sauerbraten project (or a mod thereof).

Please note, this is a thread for discussions of new features to the mapmakers, features that basically are hypothetical and which not necessarely ever will be implemented.

Dear Sauerbraten users: if you like some suggestion, feel free to say so but do not DEMAND that it get's implemented into the official Sauerbraten releases, not even you are capable to code it yourself. ANY demands expressed will effectively KILL this thread, ok? (and I don't want it to die...)

Dear Sauerbraten and forum maintainers: even if this discussion never result in a single line of executable code, please let the discussion continue. I for one really enjoy trading ideas and discussing various software features, spatial geometrics, data structures, project management etc... If it then actually results in usable features, the better.

Board Index

#14: Missing building pieces part 2: The Hip-Valley Cubes!

by IllvilJa on 03/29/2008 01:04

(Thanks for the advice Tentus, I'll try that when appropriate).

When deforming the corners of a cube, we can deform it in such a way that all four corners lie in the same plane and thus, the new side of the cube is one single plane. It gets subdivided into two triangles (which can be seen when enabling 'outline' by hitting the key '7' in edit mode) and even if it can be subdivided into triangles in two different ways, it does not really matter which way is chosen by the Sauerbraten engine.

However, when deforming a cube side in such a fashion that the four corners are NOT part of the same plane, then the choice between the two ways of subdividing it into triangles WILL matter. If one looks at the "division line" separating the two triangles the face is subdivided into, the two options of where to put that line will result in it being either a bit higher up (a hip) or a bit lower down (a valley).

The 'hip' subdivision will retain more of the cube's volume than the 'valley' subdivision' as the latter "digs deeper" into the cube's surface.

A picture would help here, and luckily our trustworthy friend Wikipedia has an EXCELLENT image of a house roof which serves as a good illustration of this concept as well as it shows the original situation (creating a roof with valleys) where I ran into problems because I were missing some building blocks.

Ok, here is the picture: http://upload.wikimedia.org/wikipedia/en/a/aa/Rf-iso1.gif

(It is taken from the article http://en.wikipedia.org/wiki/Hip_Roof BTW).

In this picture, we see an illustration of a roof. There are so called 'hips' (denoted with the letter 'h') and there are so called 'valleys' (denoted with 'v'). On my emerging attempts to create a wargame, I do of course like to have roofed houses on he battlefield, and when creating a house like the illustrated one, it's dead easy to create cubes with 'hips' so I can create the hip ends of the house without any problems. However, when I try to create anything like a valley, the cubes refuse to become the 'valley' cubes I need, they just become 'hip' cubes. Subdividing does not help, I get a valley cluttered with a stair of hip cubes. (And actually there is no way to tell the cube if it should be 'hip' or 'valley').

And, in a nutshell, that is what I'm missing, the ability to strictly control when these cubes with non planar deformations becomes 'hip' cubes and when they become 'valley' cubes. From a user interface perspective, this change is fairly easy to implement. Just let some key toggle a face between being either 'hip' or 'valley'.

I had a look into the source, but did not have time to find a definitive answer on how easy this feature would be to implement. I got the impression at least, both from source as well as from working with the editor, that all non-planar cubes consistently end up as 'hip' cubes. If this indeed IS the case, adding 'valley' cubes becomes easier, as we then only need to keep track of two different states for each cube face. Where to store that bit of information is of course a good question. If we are fortunate, we might find some unused bit in the already used data structures, some bit which today always is set to zero or one. That bit can then be used to tell if the cube side is 'hip' or 'valley'. For backward compatability, we do of course let the 'usual' value (used today by sauerbraten) of that bit to denote a 'hip' face whilst the other value then denotes 'valley' face.

If the current state of affairs is that we really cannot count on all these non-planar faces to be 'hip', then we need to find two unused bits which we can use to store the state for each side, be it 'hip', 'valley' or 'dontcare' (the latter being the state used today, given the assumption starting this paragraph).

In any case, we need to ensure that Line of sight code, physics code, rendering code, remipping code etc takes the 'hip' or 'valley' state of the cubes into consideration.

Your thoughts on THIS addition to the editing? It would be quite nice to be able to create 'valleyed' roofs as well, in addition to usual gabled roofs and hip roof.

Or is it just me who has misunderstood the editor and have not figured out how to switch between 'hip' and 'valley' cube faces? That possibility is definitively not ruled out either!