All I need is to play some samples now.

Posted by
June 23rd, 2014 11:40 am

ufo1ufo2

I am surprised I reached it so far. The collision was something I was afraid because CPC+ hardware sprite do not have collision detection (like the C64). The screen is HW scrolled and I just render the new incoming tiles at the right side. So, I don’t have a full map to track which tiles are solid in comparison with the hardware sprite. But I did manage to keep track of floor/ceiling edges in an array and compare the Y coordinate of the UFO with these incoming data. And it worked perfectly, tweaked it even to be precise. I am so happy about that!

Then I am surprised how much easier my job was with some great CPC+ capabilities. Easily to setup raster with line interrupts (almost no need for perfect NOP synchronization). And then drop few more sprites for the energy bar and LVL number and they stay there and are even another layer to the scrolling background, with no crazy programming effort. I love the CPC+! If only the original CPC had the same hardware chip..

Another feature of the CPC+ is some DMA chip to transfer data fast to the sound chip, many times per second. I know it’s used to play sampled sound effects, I just don’t know how easy it will be to use it and there is not enough time. Maybe this will be the next I will try, also maybe make the passage more narrow every other level (right now just the colors are changing every time a level is passing), and maybe some score (I have a lot of hardware sprites to abuse) and in the future some enemies/bonus (I don’t think I’ll finish this now). At least now it’s playable enough, more than just a scrolling preview, you can loose and reset to the beginning, or pass levels.

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