3rd day is over, and we have a blog to post:

Day 3 done!

GameDev.net copy:

Personal site copy:

http://thaumaturge-art.com/index.php?/archives/95-Week-of-Awesome-V-Day-3-Links-of-Iron.html

So it's early-to-midway into my day4 and I'm settling in to work on this for the day. I just wanted to post an update about where I got to for day3; It was too late for me to write up a post last night but better late than never!

As you can see it's slowly beginning to look like a game now and it has some nods towards "chain-reaction" as a gameplay mechanic. Whereas the "alien invasion" theme will be more of a motif and featured in the graphics and story.

So I got a few features implemented yesterday including trapdoors, the dominos, the big gear thing in the sky, support for multiple minions and aiming.

It wasn't all smooth sailing though, I had to sink a few hours debugging issues with my fluid rendering. One of the big issues I was having was todo with transparency and blending. For some reason I always have a huge mental hangup when it comes to figuring out OpenGL's blend modes.

Initially I cranked the maths and thought that something like this might do a reasonable job:

glBlendEquationSeparate(GL_MAX, GL_FUNC_ADD);
glBlendFunc(GL_ONE, GL_ONE);

Alas GL_MAX is not supported in GLES2.0 so that screwed me over for a while. (Might not have worked anyway). Eventually I worked out an alternative for my purposes, I find it rather counter-intuitive as a solution though:

glClearColor(0, 0, 0, 0);
glBlendFuncSeparate(GL_ONE_MINUS_DST_ALPHA, GL_DST_ALPHA, GL_ONE, GL_ONE);

It seems to handle all edge cases that I could think to test.

I do not understand why the blend function is fixed-function and not programmable. This is totally bizarre to me and seems incredibly easy to do in theory using a "blend shader" that takes the source and destination fragments and emits the resultant colour. 

Why is blending fixed function, does anybody know? Am I missing something obvious here?

Anyhoo, onto day4. Not sure what I'll work on today. At some point I really need to start finding or making proper art assets instead of all this placeholder stuff!

Looking nice    All these shader stuff is doing my head in too. Everybody yells do it in the shader, but a few things are still modified outside (in DX11)

Anyhow, new blog entry is up, plus a playable preview that's maybe even a final version (albeit short):