2D masks

[Rick]

I believe I asked this before but didn't get an answer, or the answer from Lum didn't seem to work. Does anyone know if you can do 2D masking with LE drawing commands?

[Canardia]

I tested it, and it worked, you remember the MOD2X trick. Maybe you did the textures wrong, but I could make a demo, since the old demo is on my old PC, and it's not ready yet.

[Rick]

Ah bugger. Yeah if you don't have mind showing a really short demo that would be cool. I must have gotten the order wrong or something. I was trying to use pure pink as the mask color.

[paramecij]

What do you mean by 2D masks? Do you mean color-keying (not drawing pixels of specific color), or actual grayscale masks (like in photoshop etc) ?

 

What are you trying to do with the masks ?

[Rick]

I believe it's more like color-keying. I'm specifically trying to create a circle health bar like in diablo. To do so the red health would actually be a rectangle image with the areas that aren't the circle aren't drawn.

[Canardia]

Got it to work again:

2docclusion.zip

 

You need to draw to a temporary buffer, which doesn't need to be bigger than your image (64x64 in this demo).

Then you draw the occlusion image, which has transparent areas, with BLEND_ALPHA.

Then you draw the actual image with BLEND_MOD2X.

Then you draw the temporary buffer to your real background buffer.