Difference between revisions of "Programming:Amstrad CPC plus sprite format"
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| − | + | A great feature of the Amstrad CPC plus is hardware sprites. Hardware sprites are handled by the [[ASIC]]. The ASIC can handle up to 16 sprites per [[scanline]], each hardware sprite is always 16 x 16 pixels of size. | |
== The data == | == The data == | ||
| − | Each sprite | + | Each sprite can display 15 distinct colours, the pixel colours are indexed #0 - #F. |
Index #0 is always transparency, whereas index #1 - #F is the colour index in the sprite palette. | Index #0 is always transparency, whereas index #1 - #F is the colour index in the sprite palette. | ||
| Line 13: | Line 13: | ||
== The colour palette == | == The colour palette == | ||
| + | The ASIC can handle 4096 colours. Each colour is defined as values of red, green and blue. | ||
== Example == | == Example == | ||
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[[Category:CPC Plus]] | [[Category:CPC Plus]] | ||
| + | <math>Insert formula here</math> | ||
Revision as of 19:22, 14 July 2009
A great feature of the Amstrad CPC plus is hardware sprites. Hardware sprites are handled by the ASIC. The ASIC can handle up to 16 sprites per scanline, each hardware sprite is always 16 x 16 pixels of size.
Contents
The data
Each sprite can display 15 distinct colours, the pixel colours are indexed #0 - #F.
Index #0 is always transparency, whereas index #1 - #F is the colour index in the sprite palette.
To define a sprite in the ASIC. 16 x 16 (256) bytes must be transferred to the ASIC.
The format of the data is straight forward. The data is organized in a linear manner. Each sprite pixel uses a single byte, the upper nibble is ignored by the ASIC.
The colour palette
The ASIC can handle 4096 colours. Each colour is defined as values of red, green and blue.
Example
Below is shown an example of how a sprite is organized into raw data. To transfer the sprite data to the ASIC look here: Transfer to ASIC
<geshi lang=Z80> .pac_sprite
- The raw sprite data - to be transfered to the ASIC
db #00,#00,#00,#00,#00,#00,#00,#00,#00,#00,#00,#00,#00,#00,#00,#00 db #00,#00,#00,#00,#00,#00,#01,#01,#01,#01,#00,#00,#00,#00,#00,#00 db #00,#00,#00,#00,#01,#01,#01,#01,#01,#01,#01,#01,#00,#00,#00,#00 db #00,#00,#00,#01,#01,#01,#01,#01,#01,#01,#01,#01,#01,#00,#00,#00 db #00,#00,#01,#01,#01,#01,#01,#01,#01,#01,#01,#01,#01,#01,#00,#00 db #00,#00,#01,#01,#03,#03,#01,#01,#01,#01,#03,#03,#01,#01,#00,#00 db #00,#00,#01,#03,#03,#03,#03,#01,#01,#03,#03,#03,#03,#01,#00,#00 db #00,#01,#01,#03,#03,#03,#03,#01,#01,#03,#03,#03,#03,#01,#01,#00 db #00,#01,#01,#03,#02,#02,#03,#01,#01,#03,#02,#02,#03,#01,#01,#00 db #00,#01,#01,#01,#02,#02,#01,#01,#01,#01,#02,#02,#01,#01,#01,#00 db #00,#01,#01,#01,#01,#01,#01,#01,#01,#01,#01,#01,#01,#01,#01,#00 db #00,#01,#01,#01,#01,#01,#01,#01,#01,#01,#01,#01,#01,#01,#01,#00 db #00,#01,#01,#01,#00,#01,#01,#01,#01,#01,#01,#00,#01,#01,#01,#00 db #00,#00,#01,#00,#00,#00,#01,#01,#01,#01,#00,#00,#00,#01,#00,#00 db #00,#00,#00,#00,#00,#00,#00,#00,#00,#00,#00,#00,#00,#00,#00,#00 db #00,#00,#00,#00,#00,#00,#00,#00,#00,#00,#00,#00,#00,#00,#00,#00
- Compressed data
db #00,#00,#00,#00,#00,#00,#00,#00 db #00,#00,#00,#11,#11,#00,#00,#00 db #00,#00,#11,#11,#11,#11,#00,#00 db #00,#01,#11,#11,#11,#11,#10,#00 db #00,#11,#11,#11,#11,#11,#11,#00 db #00,#11,#33,#11,#11,#33,#11,#00 db #00,#13,#33,#31,#13,#33,#31,#00 db #01,#13,#33,#31,#13,#33,#31,#10 db #01,#13,#22,#31,#13,#22,#31,#10 db #01,#11,#22,#11,#11,#22,#11,#10 db #01,#11,#11,#11,#11,#11,#11,#10 db #01,#11,#11,#11,#11,#11,#11,#10 db #01,#11,#01,#11,#11,#10,#11,#10 db #00,#10,#00,#11,#11,#00,#01,#00 db #00,#00,#00,#00,#00,#00,#00,#00 db #00,#00,#00,#00,#00,#00,#00,#00
.pac_sprite_palette
- Sprite ink 1
dw #0CDF ; Red = #D Green = #C Blue = #F ; The gray body
- Sprite ink 2
dw #0000 ; Red = #0 Green = #0 Blue = #0 ; The black in the PAC's eyes
- Sprite ink 3
dw #0000 ; Red = #F Green = #F Blue = #F ; The white in the PAC's eyes </geshi>
Links
<math>Insert formula here</math>
