https://www.yoyogames.com/blog/430/dynamic-rendering-masks
So this is a quick one, but incredibly cool and valuable. When drawing to the screen (or a surface), most people only think about the colour, that is the red,green and blue channels, but actually there's also an alpha channel. Now it has a whole heap of issues if you're going to start using it to build sprites or generate screens or whatever, but one thing that's its REALLY good at, is being a mask......
So this is a quick one, but incredibly cool and valuable. When drawing to the screen (or a surface), most people only think about the colour, that is the red,green and blue channels, but actually there's also an alpha channel. Now it has a whole heap of issues if you're going to start using it to build sprites or generate screens or whatever, but one thing that's its REALLY good at, is being a mask......