Unique shading situations

Well for a quick update of the game,

Cel shading and some border outline has changed the look of our game where I wanted it to go. I decided not to use Sobel edge filtering because I like the simple boderless images details on the character, and only wanted it around the characters. Today

My next task in graphics is to make an affect for attacks, so that they are more visible and give the player a good way to get warned that attacks are coming at them. Two things came to mind and they are both games with only plane of movement. First for the theory, is Metal slug. Its an old 2D side scrolling shooter and since it has a lot of stuff going on in it, enemy bullets/grenades flashed bright blue and yellow. Bullets flashing blue and yellow can be seen in this picture here. 

There is going to be a lot to dodge in my game so having a good notifier is important. Now this is blog is for a graphics class, so just making a texture or a sprite with big colours isn't gonna be enough. That's where the second inspiration comes in.

Netherrealm studios have made two fighting games so far, Mortal Kombat and Injustice Gods Among Us. The games have a lot in common but I figured out they shared a feature in training mode. In both games theres a setting to have a character's limb highlight in red when he attacks with it. an example here http://www.youtube.com/watch?v=0h2a4RC5Xus , skip to pretty much any time during the video to see Scorpions hand's turn red during punches and legs turn red during kicks. It seems like the limbs turning red are chosen before hand for moves, but I' thought of a better way to pull it off. Since we are already using hitboxes i thought using them to choose what would be red would work. The basic idea is this. 

Since my game is mostly on one plane, Like mortal kombat, I have a few options on how to do this effect. Probably the easiest would be just like the image above explains, but using someing like this as the base, 

With some tinkering on world and normal locations I was able to just highlight objects that where in the middle of the game, The background, and wall are taken out while the rest is left. This also creates and Xbox avatar like glow effect. So any hitboxes that will highlight stuff can be sent through this shader, Simply mixing (the mix(); function) this output and an output with all the location of the hitboxes and how they would appear on screen should keep the background black, and any parts of the model within the hitbox red. This methods also adds a bit of an extra affect, if a hitbox hits something it also goes red. I plan refining this shader for next blog, and some other effects.