Saturday, 31 August 2013

Enter the Trap

29th-31st August 2013

Last time, I was working on the main game engine, hoping that everything was working. I was quite pleased with the result of the work so far. However, the colour of the tiles didn't look right on a CRT screen, so I changed the Blue+Purple tiles into Red+Purple. That looked much better. I had a great idea which was to add some kind of effect for every time the player is inverting the tiles. So I drew a sprite which creates a form of a dissolve/fade routine and added routines in the game to make this take effect. Basically, when the player hits a tile that inverts, the second sprite is used to form an animation over that particular tile. Now that I was very happy an impressed with the work done to the game so far.

I decided to move on to something else, related to the project. So I worked on a front end for the game. Unlike many of the front end title screens, where you have a static logo, credits and a scroll text. I wanted to do something completely different. I loaded in JSL's logo for the title screen. Then I converted the bitmap picture into a logo (Charset + Matrix) format. At the moment, this was just a static logo. So I decided to convert it into Swing Logo format. I downloaded Paramount's Shake It utility and converted the logo into a swinging logo format. 

Now I was happy with the swinging logo format. I exported the charset and swing matrix data into the project. Then I worked on the new front end. The 1x1 font was used to display the credits. I programmed in some multiple IRQ raster interrupts into the game's title screen code. Added the screen cuts. Top row of the screen has the first logo. The second row of the screen has the credits, which use the 1x1 charset, the third row has a 1x2 charset, which uses a smooth scrolling text message. Finally the bottom row has the second logo, which swings in reverse. I added some subroutines that would cycle the colour of the logo after a few seconds or so. This idea was inspired by common old-school C64 intros. The result turned out quite nice.

Now what about the game? So far I had 8 levels designed, so I decided to do some more tests on some of the newer obstacles. Unfortunately, for the blob, it stops at an incorrect position, causing the game to mess up. So to solve this problem, I added some simple checks and compared which direction the player was at. If the player was moving a longer distance, I had to trim the move distance slightly for a more accurate position. After I worked on the check subroutine for all 4 of those player directions (Up, Down, Left, Right), I worked on a few more levels, in which introduced the trap switches. If the player moves on to those either the trapdoors will remain closed, or they will all open. The T tile (correct direction) opens the trapdoors holes, and the T (upside down) represented the closing of the trapdoors. This trick worked, and some of the stages (up to level 12) are puzzling. As I positioned trap switches in various places to confuse the player.The result turned out great.

I also did some updates to the music. The in game music high notes part sounded pretty awful to the ears, so I changed the closing melody to the tune. The title screen instrument, which originally used sawtooth, was changed into a pulse ($41) and made the introduction of the tune sound much better. 

The assembled program is so far 10KB and it is going pretty well, and I seem to be progressing pretty quickly with this game. It may look as in the game could be ready for submission bby the end of September this year. Considering the extra free time I have been having recently :)

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