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QML and other random stuff

written on March 14, 2010

QML

I'm using the bleeding edge versions of both QT and QT Creator straight from the Git(orious) repositories; doing so has a couple of benefits, but also drawbacks mostly because some of this bleeding edge stuff may break :)

How do I test / use all these?

It's quite simple, I have my /opt mounted on a 10GB partition and I install qt and qt creator there via 'make install' then just make sure that all the utilities (i.e qmake) are in my path (all the libs in LD_LIBRARY_PATH), so basically I can even have multiple versions installed without breaking the "stable" versions residing in /usr or /usr/local .

I also discovered this awesome 'Boxes' demo, I have no idea how long this have been part of the demos, but it's really awesome.

Sooooo drum rolls finally I was able to get my hands on QML and test it without way any headache as it has landed into the 4.7 branch.

With this at my fingertips I was also able to compile QT Creator with the QML related plug-ins enabled. yaaaayyy!!?!

Here is a short video demoing the 'SameGame' example (part of the declarative samples); it was played and recorded using the official QML viewer bundled with QT.

Total and complete AWESOMENESS!!!

Time?

I'm not going to write about wasting time, but basically I spent my time playing around with the 0.A.D code base [more on this later] updating and recompiling QT and its friends, plus took a few decisions regarding Lera3D's engine architecture .

The weekend is not over yet, so there's a lot more to do! Go, go, power ranger!

0.A.D code base

[ this should be a completely separate post, but I'm just being lazy ]

0.A.D is developed by Wildfire games and recently (a year ago or so) have been open sourced. I blogged about this last year when I just compiled and pretty much forgot about it.

Yesterday I said, lets look at the source code again. I'm interested mostly in the rendering part, including the different rendering paths (fixed or shader), etc.

( a couple of fresh screens )

The actual code base is quite messy and not everything is clearly separated or grouped together where necessary.

c0d3rguy@Seth:/opt/0ad/source/maths$ ls -l
total 160
-rw-r--r-- 1 c0d3rguy c0d3rguy  6315 2010-03-13 16:59 Bound.cpp     # point of interest
-rw-r--r-- 1 c0d3rguy c0d3rguy  2717 2010-03-13 16:59 Bound.h       # point of interest
-rw-r--r-- 1 c0d3rguy c0d3rguy  7913 2010-03-13 16:59 Brush.cpp
-rw-r--r-- 1 c0d3rguy c0d3rguy  2521 2010-03-13 16:59 Brush.h
-rw-r--r-- 1 c0d3rguy c0d3rguy  1422 2010-03-13 16:59 Fixed.cpp
-rw-r--r-- 1 c0d3rguy c0d3rguy  4436 2010-03-13 16:59 Fixed.h
-rw-r--r-- 1 c0d3rguy c0d3rguy  2782 2010-03-13 16:59 FixedVector2D.h
-rw-r--r-- 1 c0d3rguy c0d3rguy  4054 2010-03-13 16:59 FixedVector3D.h
-rw-r--r-- 1 c0d3rguy c0d3rguy  1685 2010-03-13 16:59 MathUtil.h
-rw-r--r-- 1 c0d3rguy c0d3rguy 14111 2010-03-13 16:59 Matrix3D.cpp
-rw-r--r-- 1 c0d3rguy c0d3rguy  5286 2010-03-13 16:59 Matrix3D.h
-rw-r--r-- 1 c0d3rguy c0d3rguy  6385 2010-03-13 16:59 MD5.cpp
-rw-r--r-- 1 c0d3rguy c0d3rguy  1239 2010-03-13 16:59 MD5.h
-rw-r--r-- 1 c0d3rguy c0d3rguy  4265 2010-03-13 16:59 Noise.cpp
-rw-r--r-- 1 c0d3rguy c0d3rguy  1643 2010-03-13 16:59 Noise.h
-rw-r--r-- 1 c0d3rguy c0d3rguy  7260 2010-03-13 16:59 NUSpline.cpp
-rw-r--r-- 1 c0d3rguy c0d3rguy  2560 2010-03-13 16:59 NUSpline.h
-rw-r--r-- 1 c0d3rguy c0d3rguy  3152 2010-03-13 16:59 Plane.cpp     # point of interest
-rw-r--r-- 1 c0d3rguy c0d3rguy  2015 2010-03-13 16:59 Plane.h       # point of interest
-rw-r--r-- 1 c0d3rguy c0d3rguy  7352 2010-03-13 16:59 Quaternion.cpp
-rw-r--r-- 1 c0d3rguy c0d3rguy  2291 2010-03-13 16:59 Quaternion.h
drwxr-xr-x 3 c0d3rguy c0d3rguy  4096 2010-03-13 16:59 scripting
-rw-r--r-- 1 c0d3rguy c0d3rguy  1434 2010-03-13 16:59 Sqrt.cpp
-rw-r--r-- 1 c0d3rguy c0d3rguy   919 2010-03-13 16:59 Sqrt.h
drwxr-xr-x 3 c0d3rguy c0d3rguy  4096 2010-03-13 18:27 tests
-rw-r--r-- 1 c0d3rguy c0d3rguy  2518 2010-03-13 16:59 Vector2D.h
-rw-r--r-- 1 c0d3rguy c0d3rguy  3247 2010-03-13 16:59 Vector3D.cpp
-rw-r--r-- 1 c0d3rguy c0d3rguy  2457 2010-03-13 16:59 Vector3D.h
-rw-r--r-- 1 c0d3rguy c0d3rguy  3131 2010-03-13 16:59 Vector4D.h

Soo, the "maths", in addition to the usual VectorND and Matrix classes the Plane and Bound can be a valuable source of inspiration especially the Ray Intersection (& Bounding Box) stuff which is useful for picking . This is definitely the first place to look when investigating a renderer.

Lets digg further ... source/lib/ contains some of the low-level including some OpenGL related stuff.

Points of interest in source/lib/:

source/ps/ contains more low-level stuff, some of these should be in source/lib/ like CStr or the FileSystem, and Vector2D should be most definitely inside "Maths".

IMHO, most of this directory should be merged with source/graphics/.

source/graphics/ contains higher-level Game related stuff which basically sits on the top of source/renderer so maybe it would be a good idea to merge all these into the renderer . [The frustum. and camera. code is definitely interesting.]

In source/renderer the render paths are OK, they are well separated but I feel like it has been over engineered, it's clearly visible that all these parts have been hacked together in order to create something which works rather than designing it carefully .

An example of this hacky design from source/renderer/Renderer.cpp:

bool CRenderer::IsTextureTransparent(CTexture* texture)
{
    if (!texture) return false;
    Handle h=texture->GetHandle();
    size_t flags = 0;   // assume no alpha on failure
    (void)ogl_tex_get_format(h, &flags, 0);
    return (flags & TEX_ALPHA) != 0;
}

This should have been part of the actual CTexture class (maybe as a static member) and not the CRenderer class; it's easy to see that the guys behind 0.A.D are primarily Windows developers, the code tells it all.

There are huge dependencies like Boost or Xerces, personally I would get rid of these, especially Boost which is a TRUE monster.

Oh well, this is not a complete code base analysis or anything, just a few very personal thoughts, don't pay attention if you don't want to.

[ Hear me NOW, believe me later. ]

Maybe, I will contribute to 0.A.D, who knows ... :) Lady who? BUG!!!

Until next time as server said ...

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