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graphics.beginBitmapFill, opacity? blending? pretty please... February 19th 2008, mr.doob
The classic question on interviews lately is "What would you ask Adobe to improve on the Flash player?". Well, I finally have a real thing to ask the guys and is to give some love to graphics.beginBitmapFill.

Since the beginning there were 2 ways of rendering your 3d scene in flash.

1. Render everything in a single Sprite / MovieClip.
2. Create a Sprite / MovieClip for each triangle or Mesh.

The second option was the most useful because you had easily properties such as opacity and even blending as Sprite/MovieClip have already those properties, but, performance-wise, option 1 was the winner hands down. So, as people wants speed, some engines have gone through the option 1 and then spent time trying to find ways to hack the properties that you get for free with option 2.

If you take a look on the drawTriangle loop inside Papervision3d in instance you'll find this:

graphics.beginBitmapFill( altBitmap ? altBitmap : bitmap, _localMatrix, tiled, smooth);

I even had to do a hack for a project where in order to be able to change the opacity of one material dynamicaly I had to generate an array of bitmapDatas with the original texture with different levels of transparency... nasty!

Wouldn't it be great if you could tell the amount of opacity and which blending to use to the beginBitmapFill?
1 comment

Absolutely! It would be awesome to have the ability to create some sort of 'alpha map' to make a house turn on the lights when it's dark or when the triangle's angle indicated a shadow according to the light source.
I have coded a 3D engine in flash AS myself, and I found this article while searching for existing solutions. I guess there simply aren't any.
Making a Sprite per triangle and then set its alpha is indeed an expensive method as it will cost me way to many triangles compared to drawing all triangles in one Sprite.
As a coder, I prefer a smooth game over a beautiful game. I'll stick to basic shading for now, let's hope I can get the gradientFill working properly and fast enough to enable smooth groups.

Cheers all..
August 27th 2010, megalon