#GMTWeekly: Downwell-Style Motion Trail

Before we start, if you haven’t read last week’s tutorial and/or you aren’t too comfortable with blend modes and surfaces, I suggest that you take a look at that tutorial first.

Requests

I am always accepting requests for these tutorial segments! Feel free to send me ideas if/when you have them! The first email that I received after tweeting about a tutorial series was in regards to a motion trail effect found in the recent Steam release, Downwell. It was the very first request that I had received AND I believe that it flows fairly easy from last week’s blend mode example.

#GMTWeekly: Extended Blend Modes Pt. 1

Hello everyone!

I have been wanting to get back into some #gamedev tutorials for quite some time now. For the time being, I’m going to start doing weekly Game Maker: Studio tutorials to get things rolling. I have a fairly long list of requests, but feel free to send your other ideas my way!

Blend Modes

What are blend modes? Blend modes tell GM what formula(s) to use when blending pixels (your source) with pixels that have previously been drawn to the screen (your destination). By default, GM uses a mode called bm_normal. This mode draws everything how you’d typically expect things to be drawn. If you have a red pixel, and you draw blue over the top of it, it becomes a blue pixel (this is somewhat dependent on the alpha channel of each pixel, as well).