On track (+ a question)

Posted by S3xySeele on Dec. 16, 2011, 9:36 p.m.

My F4D entry Névégis is on track for the deadline. And in actuality, I'm going home on the 28th so I'll probably submit my entry early.

As it currently stands, there are only a couple little things I need to do for Névégis to be something I'd consider a complete game. Namely, I've got to create a couple different enemy types and their AI, then create a handful of timelines for enemy waves.

After I do that, the rest is just a matter of polish. I'll post a bigger update on Névégis a little later, with screenshots and stuff.

Now… I've got a technical question regarding GM. Hopefully someone can help me out here. I can't for the life of me figure out how to properly utilize draw_set_blend_mode_ext(), but I think that something I'd like to accomplish requires it.

How do I draw something to a surface in such a way that the alpha remains the same as on the surface? Like if I had a surface that was completely transparent except for a white circle in the middle with an alpha of 1, how could I draw something to that surface so that any part of it drawn in the transparent regions stay transparent?

Comments

m3k3 13 years ago

try these, one of them might be the one you want.

(bm_dest_alpha,bm_one);

(bm_dest_alpha,bm_zero);

(bm_dest_alpha,bm_inv_src_alpha);

edit: you can also use 2 surfaces one mask and one image. draw the mask on the final frame with (zero,inv_src_color); draw the image to the mask with (zero,src_color); draw the mask which now contains the image information to the final frame using (one,one); This doesn't use the alpha component at all. But you need extra surfaces and operations.

S3xySeele 12 years, 11 months ago

Thanks, (bm_dest_alpha,bm_inv_src_alpha) does the trick.