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Master484 · 16 February 2017, 14:20

The 16 color version is now ready, and the ADF has been added to the attachments of the first post in this thread.

In the beginning you can choose between 16 or 32 color mode, and the program then loads either 16 color or 32 color gfx.

Other changes include explosions for the enemies, turning animations for the player ship, and a lot faster collision detection system.

Performance is as follows:

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A500 -- 16 color mode

FPS starts at 25 FPS

Enemies on screen without slowdown: 14
Bullets on screen without slowdown: 25

A500 -- 32 color mode

FPS starts at 17 FPS = constant slowdown

Enemies on screen without further slowdown: 11
Bullets on screen without further slowdown: 24

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---

A1200 -- 16 color mode

FPS starts at 25 FPS

Enemies on screen without slowdown: 19
Bullets on screen without slowdown: 42

A1200 -- 32 color mode

FPS starts at 25 FPS

Enemies on screen without slowdown: 14
Bullets on screen without slowdown: 22

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So, not surprisingly, A1200 in 16 color mode runs the fastest.

It could actually achieve 50 FPS I think, but the FPS is limited to 25 FPS.

Especially the bullet amount is good in A1200 16 color mode, and interestingly it can handle a lot more bullets than enemies, but only in 16 colors.

The bullets are 8*8 and the enemies are 32*32. When moving from 32 colors to 16 colors, we can draw 5 more enemies, but bullets we can draw 20 more.

So on A1200 when colors are reduced, we gain a 35 % increase in the enemy amount, but a 100 % increase in the bullet amount.

I don't completely understand why this happens, maybe the time taken by the "blitter start" operation is much less in 16 colors than in 32 colors? And so the numerous smaller blitting operations would gain relatively more benefit when the color amount of the blits is reduced? This is just a guess though.

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But anyways, a reasonably action filled shmup is possible at 25 FPS, on A1200. But to be safe, the frame rate should indeed be locked to 17 FPS, because this is the speed that the A1200 can firmly hold at almost all times.

I counted that 40 enemies are needed to make the 16 color version to drop from 17 FPS to 14 FPS, on A1200.

And when slowdown does happen on a game the runs at 17 FPS, we only get a small drop from 17 FPS to 14 FPS. And this is hardly noticeable, only 3 frames per second are lost, compared to the 8 frame loss that happens when 25 FPS drops to 17 FPS, or the massive 25 frames that are lost when 50 FPS takes a dive to 25 FPS. This is why games like Xenon 2 seem to be maintaining a "steady frame rate" despite the screen being full of stuff.

16 February 2017, 14:20	#22
Master484 Registered User Join Date: Nov 2015 Location: Vaasa, Finland Posts: 525	The 16 color version is now ready, and the ADF has been added to the attachments of the first post in this thread. In the beginning you can choose between 16 or 32 color mode, and the program then loads either 16 color or 32 color gfx. Other changes include explosions for the enemies, turning animations for the player ship, and a lot faster collision detection system. Performance is as follows: --- --- A500 -- 16 color mode FPS starts at 25 FPS Enemies on screen without slowdown: 14 Bullets on screen without slowdown: 25 A500 -- 32 color mode FPS starts at 17 FPS = constant slowdown Enemies on screen without further slowdown: 11 Bullets on screen without further slowdown: 24 --- --- A1200 -- 16 color mode FPS starts at 25 FPS Enemies on screen without slowdown: 19 Bullets on screen without slowdown: 42 A1200 -- 32 color mode FPS starts at 25 FPS Enemies on screen without slowdown: 14 Bullets on screen without slowdown: 22 ----------- ----------- So, not surprisingly, A1200 in 16 color mode runs the fastest. It could actually achieve 50 FPS I think, but the FPS is limited to 25 FPS. Especially the bullet amount is good in A1200 16 color mode, and interestingly it can handle a lot more bullets than enemies, but only in 16 colors. The bullets are 88 and the enemies are 3232. When moving from 32 colors to 16 colors, we can draw 5 more enemies, but bullets we can draw 20 more. So on A1200 when colors are reduced, we gain a 35 % increase in the enemy amount, but a 100 % increase in the bullet amount. I don't completely understand why this happens, maybe the time taken by the "blitter start" operation is much less in 16 colors than in 32 colors? And so the numerous smaller blitting operations would gain relatively more benefit when the color amount of the blits is reduced? This is just a guess though. --- But anyways, a reasonably action filled shmup is possible at 25 FPS, on A1200. But to be safe, the frame rate should indeed be locked to 17 FPS, because this is the speed that the A1200 can firmly hold at almost all times. I counted that 40 enemies are needed to make the 16 color version to drop from 17 FPS to 14 FPS, on A1200. And when slowdown does happen on a game the runs at 17 FPS, we only get a small drop from 17 FPS to 14 FPS. And this is hardly noticeable, only 3 frames per second are lost, compared to the 8 frame loss that happens when 25 FPS drops to 17 FPS, or the massive 25 frames that are lost when 50 FPS takes a dive to 25 FPS. This is why games like Xenon 2 seem to be maintaining a "steady frame rate" despite the screen being full of stuff.