Evening all,
I wish to announce a project that I've been working on for a few weeks now.
I'm hoping you'll like it!
What is it?
I've made a 60 second movie showing how a 3D mesh is constructed in Direct3D9. It's a little difficult to explain, but it shows as a form of animation the steps that go on
"behind the scenes" when you despatch a mesh to be rendered.
It's aimed mostly at beginners - a sort of visual introduction to the process that they'll be trying to learn. It's unlikely there's anything ground breaking for intermediate/advanced D3D programmers,
but you might find it interesting...
TheTriangleMakeUpOfAnF1Car.zip (13.73mb). Grab this file, inside is a .AVI file encoded using the
DivX codec. It
should play fine in all reasonably up-to-date players.
Background
As you may or may not know, I've written 100's of articles on DirectX over the last few years. I wanted to try something new - and I'm not 100% sure yet that this format will work out.
Given the somewhat obviously graphical nature behind Direct3D programming the goal was to create a video that demonstrates various aspects of how a D3D application works. One that might not be immediately obvious from looking at the code, mathematics and diagrams that often make up the bulk of introductory materials.
In some respects, interactive source code that ships with articles does this job, but with a video it's easier for me
(the author) to focus on particular things in a particular order. Also, for some advanced techniques a video could well show these off without having to worry about the end-user not being able to run the code.
If people appreciate this video and there's some favourable feedback, then I've already given thought to making some more useful videos.
This current video can be considered as an experiment of sorts.
A bit of explanation
As you'll see, the video runs through 4 distinct phases. It's fairly self-explanatory, but I thought I'd include a brief run-down here...
This first section shows, as green dots, each vertex that builds up the mesh. With this view you can see how the key points of the mesh are positioned.
The second part of the movie effectively joins up the dots, showing the outlines of each triangle as blue lines.
With the outlines of the triangles displayed, the renderer starts to fill in the content of each triangle based on the correct material-based lighting. This is the build-up of the display that you would be expecting to see if you were to request Direct3D to render it.
With the build up complete, the movie shows a rotation of the final mesh rendering.
There are two particular things to note about this whole sequence:
(1) In
actually rendering a mesh, D3D doesn't do the first two phases of drawing the dots and connecting them up [smile]. I've put that in to show the progression of how the data contained in a mesh fits together to build the final product.
(2) There is an interesting pattern to the order in which vertices and triangles are actually rendered. It is logical, but one of the things that this sort of movie was leading to
(but didn't end up fitting in) is a visual "proof" of
why a depth buffer (and associated things) might be necessary.
Your thoughts?
As mentioned above, this whole project is a bit of an experiment. I'm not aware of there being any similar videos available
(my initial searches didn't yield anything).
Any thought you have are greatly appreciated. Leave a post here or send me a
private message
I'm gonna run away and hide for now and come back later to check any replies -
fingers crossed it'll be more 
than 
Cheers,
Jack
