Boss Intro Cutscenes

 Author: Yashwant Patel

Problem:

One thing that we are currently working on is implementing tutorials or ways to let the player know of certain mechanics. Currently we didn't have a way to insinuate why enemies only spawn in certain lanes and when they will start spawning in other lanes. As a player this raises questions such as "Why can't enemies spawn here?" or "When will enemies start spawning in this lane?". The easiest thing to do would be to utilize the tutorial system we have in place, but the bosses also spawn during the waves where the lanes get unlocked, so why not knock out two birds with two stones?

Solution:

Since bosses are introduced and waves are unlocked during the same time a cutscene would do rather nicely to showcase a lane unlocking and a boss being introduced. Ugh cutscenes once again. Will they be dynamic though? Nope, just plain old cutscenes. The first order of business was to have a way to insinuate to the player why enemies can't spawn in a lane, so time to find a nice mystical shield/barrier looking shader and implement it.

Done! Shader video can be found here. Tweaked the settings a bit to get what we needed.

Now onto the cutscene part. Since the cutscenes won't be like the upgrade ship arriving "cutscene" I'll be using the level sequence in order to introduce the boss and have the boss destroy the barrier to show the player that the lane has been unlocked. This will be done right before the enemies start spawning when the player presses "G" to star the round. This might make the player panic since they might not have any towers in the lane, but for now it will be kept that way, so it gives them a good pump. One thing we could do to combat this is add a spline based particle that shows where the enemies will come from for the next wave during the purchase phase (might end up doing this). So it was time to make the cutscene, but since it's a boss they have to be introduced in an epic way, so time to make an introduction particle. I had a rough idea about how I wanted the water boss to be introduced, so after scouring the internet for nice particle effects I came across a video that I could use.

Done! Tweaked some of the shaders and settings to create what we needed.Shader video can be found here. 

Basically all the in engine effect stuff was created and done. Now it was time to wrap up some loose ends implement some functions and events that would notify the cutscene system before a wave starts and let it spawn in the boss in a specific lane after the cutscene has ended. After this was done it was time to create the actual cutscene using the level sequencer. Now there were three things I could've done with the level sequencer. After creating the level sequence I could've just played it when the correct wave was about to start, but I wanted to create a Borderlands styled boss intro, so in engine cutscene would make it a little bit more tedious and a headache to setup things properly. The other alternative was to do half and half. Play half of the intro using the level sequencer then play the mp4 file with the Borderlands style intro afterwards. This also seemed tedious, so I resorted to the third option, which is to create the level sequence and render it out twice. Twice? Yes, twice.

 

If you take a look at Borderlands intros they have a background that appears behind the boss while the boss is animated and introduced.

In order to pull this off I thought about using a "green screen" (green plane behind the boss) in engine. So one render would be normal while the other would have a green plane behind the boss, so they could be chroma keyed out. After making a level sequence that I was happy with I rendered it out twice then began on creating the background for the water boss. After a bit of fiddling around I came up with this.

Has the boss name in big text, little funny note (since boss does a twirl during the intro, thought I'd put "loves ballet"), and the black borders just like Borderlands intros.

Once this was done I exported each layer on it's own and then basically made the cutscene that would be shown. Animated each element using keyframes and green screened out the boss to integrate it with the background. Also found sound effects to add to the cutscene to make it feel nice. Without sound it was cool looking, but felt incomplete. Once everything was edited and I exported the video and then integrated it into the engine. In order to do this the cutscene manager checks if a boss wave is about to start and it creates a widget which displays the cutscene. This time around the player can't skip the cutscene though because unlike the upgrade ship cutscene these won't play every round (and they look cool and took a good amount of work, so you must sit there and watch). This is the final result.

Overall it turned out nice. Will have to redo it once the final assets and map is in, but the core effects and system is in, so won't be too bad. Also, have to create the Storm boss intro, but for now it will simpler since it will also have to be redone.