| [Development] Sprite Reuse + Priority Queue | |
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Olle Haerstedt
Posts 110
25 Mar 2020 14:38
| How about implementing sprite reuse together with a priority queue, so that if too many sprites overlap horizontally, they will take turn being visible (leading to a flickering, which is the trade-off). Anyone know of such a system? Compare with e.g. NES games and their flickering when too much happens on the screen. Use-case could be an RTS engine with troops, where each troop is a sprite no matter the total number.
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Gunnar von Boehn
(Apollo Team Member)
Posts 6254
25 Mar 2020 18:08
| Let us give a brief over view about Amiga Sprites features. The Amiga has 8 sprite channels.
Each Sprite channel can display many sprites as long as they are below each other on the screen.
For example if your have a game like 1942 then you could with one sprite channel display many bullets flying up.
If you use a sprite channel you could even display 100 small stars with just one Sprite channel. This means which clever usage of the Sprite Channel a game can display quite a lot of Sprites. There are limitations. You can only show 8 Sprites in the same row - unless you use tricks with the Copper. The Copper could in theory increase this.
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Olle Haerstedt
Posts 110
25 Mar 2020 20:25
| Hi!
8 sprite channels, so 8 sprites on each horizontal line, 256 lines, that gives 2048 sprites in total if the sprite is 1 px high. You saying this is possible? What would such a copperlist look like? oO
Any link to copper increasing number of sprites possible on one row?
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Samuel Crow
Posts 424
25 Mar 2020 20:34
| Horizontally muxed sprites must use the same image data. The data is fetched once in the left border of the screen and is typically used for repeating backdrops. SAGA has a special mode that allows horizontal clipping to be turned off which is more efficient than using the copper to move sprites right x pixels after being displayed the first time.
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Olle Haerstedt
Posts 110
25 Mar 2020 20:59
| Samuel Crow wrote:
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Horizontally muxed sprites must use the same image data. The data is fetched once in the left border of the screen and is typically used for repeating backdrops. SAGA has a special mode that allows horizontal clipping to be turned off which is more efficient than using the copper to move sprites right x pixels after being displayed the first time.
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Cool. Sounds like a blog post waiting to happen. :)
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Gunnar von Boehn
(Apollo Team Member)
Posts 6254
25 Mar 2020 21:28
| Olle Haerstedt wrote:
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Hi!
8 sprite channels, so 8 sprites on each horizontal line, 256 lines, that gives 2048 sprites in total if the sprite is 1 px high. You saying this is possible? What would such a copperlist look like?
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For vertical Sprite Re-use you not need any copper list.
The Sprite Channel DMA can this by itself.
The DMA "works" like a playlist.
Between each Sprite,re-used Sprite will be 1 transparent row.
This means 256 = 128 Sprite per Channel max.
128*8 = max 1024 Stars on Screen
:-)
You need a Copperlist trick only to re-use the Sprite horizontally.
SAGA adds a new Register-BIT, which allows horizontal Re-used without Copper even.
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Olle Haerstedt
Posts 110
25 Mar 2020 23:00
| Gunnar von Boehn wrote:
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Olle Haerstedt wrote:
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Hi!
8 sprite channels, so 8 sprites on each horizontal line, 256 lines, that gives 2048 sprites in total if the sprite is 1 px high. You saying this is possible? What would such a copperlist look like?
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For vertical Sprite Re-use you not need any copper list.
The Sprite Channel DMA can this by itself.
The DMA "works" like a playlist.
Between each Sprite,re-used Sprite will be 1 transparent row.
This means 256 = 128 Sprite per Channel max.
128*8 = max 1024 Stars on Screen
:-)
You need a Copperlist trick only to re-use the Sprite horizontally.
SAGA adds a new Register-BIT, which allows horizontal Re-used without Copper even.
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I definitely want to try this.
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Olle Haerstedt
Posts 110
26 Mar 2020 19:36
| Some guy made a sprite engine with 94 sprites moving randomly. No source code or explanation on how. EXTERNAL LINK
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Running Games and Apps.