View source for Programming:CPC Plus Hardware Sprites

== [[ASIC]] memory addresses for HW Sprites (in HEX) ==

''' HW Sprite addresses: '''
Each sprite takes 16x16=256  (#100) bytes in ASIC memory
;#4000 - Sprite 0
;#4100 - Sprite 1
;#4200 - Sprite 2
;#4300 - Sprite 3
;#4400 - Sprite 4
;#4500 - Sprite 5
;#4600 - Sprite 6
;#4700 - Sprite 7
;#4800 - Sprite 8
;#4900 - Sprite 9
;#4A00 - Sprite #0A (10)
;#4B00 - Sprite #0B (11)
;#4C00 - Sprite #0C (12)
;#4D00 - Sprite #0D (13)
;#4E00 - Sprite #0E (14)
;#4F00 - Sprite #0F (15)

'''HW Sprite colours:'''
Each sprite has its own colours (up to 4096), so 2 bytes are required for each colour.
;#6422 - Sprite Color Pen 1
;#6424 - Sprite Color Pen 2
;#6426 - Sprite Color Pen 3
;#6428 - Sprite Color Pen 4
;#642a - Sprite Color Pen 5
;#642c - Sprite Color Pen 6
;#642e - Sprite Color Pen 7
;#6430 - Sprite Color Pen 8
;#6432 - Sprite Color Pen 9
;#6434 - Sprite Color Pen 10
;#6436 - Sprite Color Pen 11
;#6438 - Sprite Color Pen 12
;#643a - Sprite Color Pen 13
;#643c - Sprite Color Pen 14
;#643e - Sprite Color Pen 15

'''HW Sprite position x,y'''
;#6000 - Spr 0 Pos X
;#6002 - Spr 0 Pos Y
;#6008 - Spr 1 Pos X
;#600a - Spr 1 Pos Y
;#6010 - Spr 2 Pos X
;#6012 - Spr 2 Pos Y
;#6018 - Spr 3 Pos X
;#601a - Spr 3 Pos Y
;#6020 - Spr 4 Pos X
;#6022 - Spr 4 Pos Y
;#6028 - Spr 5 Pos X
;#602a - Spr 5 Pos Y
;#6030 - Spr 6 Pos X
;#6032 - Spr 6 Pos Y
;#6038 - Spr 7 Pos X
;#603A - Spr 7 Pos Y
;#6040 - Spr 8 Pos X
;#6042 - Spr 8 Pos Y
;#6048 - Spr 9 Pos X
;#604a - Spr 9 Pos Y
;#6050 - Spr 10 Pos X
;#6052 - Spr 10 Pos Y
;#6058 - Spr 11 Pos X
;#605a - Spr 11 Pos Y
;#6060 - Spr 12 Pos X
;#6062 - Spr 12 Pos Y
;#6068 - Spr 13 Pos X
;#606a - Spr 13 Pos Y
;#6070 - Spr 14 pos X
;#6072 - Spr 14 Pos Y
;#6078 - Spr 15 Pos X
;#607a - Spr 15 Pos Y

'''HW Sprite resolution:'''
You can select sprite magnification x1, x2 or x4.
 
#value 00 => Sprite not visible
#value 01 => Sprite resolution 640 (magnify x1 - mode 2)
#value 10 => Sprite resolution 320 (magnify x2 - mode 1)
#value 11 => Sprite resolution 160 (magnify x4 - mode 0)
;#6004 - Sprite 0 resolution 
;#600c - Sprite 1 resolution 
;#6014 - Sprite 2 resolution 
;#601c - Sprite 3 resolution 
;#6024 - Sprite 4 resolution 
;#602c - Sprite 5 resolution 
;#6034 - Sprite 6 resolution 
;#603c - Sprite 7 resolution 
;#6044 - Sprite 8 resolution 
;#604c - Sprite 9 resolution 
;#6054 - Sprite 10 resolution 
;#605c - Sprite 11 resolution 
;#6064 - Sprite 12 resolution 
;#606c - Sprite 13 resolution 
;#6074 - Sprite 14 resolution 
;#607c - Sprite 15 resolution 

== Coding example ==

From the '''The Unofficial Amstrad WWW Resource'''

<pre>
;; This example shows a CPC+ hardware sprite.
;;
;; This example is designed for CPC+ only and will
;; not work on CPC or KC Compact.
;;
;;
;; This example will compile with the MAXAM assembler
;; or the built-in assembler of WinAPE32.


;; NOTE - For this example to work, the code must not
;; be in the range &4000-&7fff inclusive. The ASIC registers
;; are paged into this range, and the code would not be
;; visible to the CPU if it was also in this range.
org &8000


;;--------------------------------------------------
;; STEP 1 - Unlock CPC+ additional features
;; unlock asic to gain access to asic registers

di
ld b,&bc
ld hl,sequence
ld e,17
.seq 
ld a,(hl)
out (c),a
inc hl
dec e
jr nz,seq
ei

;;--------------------------------------------------
;; STEP 2 - Setup sprite pixel data
;;
;; The ASIC has internal "RAM" used to store the sprite pixel
;; data. If you want to change the pixel data for a sprite
;; then you need to copy new data into the internal "RAM".

;; page-in asic registers to &4000-&7fff
ld bc,&7fb8
out (c),c

;; stored sprite pixel data
ld hl,sprite_pixel_data

;; address of sprite 0 pixel data
;; sprite 0 pixel data is in the range &4000-&4100
ld de,&4000

;; length of pixel data for a single sprite (16x16 = 256)
ld bc,&100
ldir

;; page-out asic registers
ld bc,&7fa0
out (c),c

;;--------------------------------------------------
;; STEP 3 - Setup sprite palette
;;
;; The sprites use a single 15 entry sprite palette.
;; pen 0 is ALWAYS transparent.
;;
;; The sprite palette is different to the screen palette.

;; page-in asic registers to &4000-&7fff
ld bc,&7fb8
out (c),c

;; copy colours into ASIC sprite palette registers
ld hl,sprite_colours
ld de,&6422
ld bc,15*2
ldir

;; page-out asic registers
ld bc,&7fa0
out (c),c

;;--------------------------------------------------
;; STEP 4 - Setup sprite properties
;;
;; Each sprite has properties which define the x,y coordinates 
;; and x,y magnification.

;; page-in asic registers to &4000-&7fff
ld bc,&7fb8
out (c),c


;; set x coordinate for sprite 0
ld hl,100
ld (&6000),hl

;; set y coordinate for sprite 0
ld hl,100
ld (&6002),hl

;; set sprite x and y magnification
;; x magnification = 1
;; y magnification = 1
ld a,%0101
ld (&6004),a


;; page-out asic registers
ld bc,&7fa0
out (c),c

;;--------------------------------------------------
ret


;;--------------------------------------------------
;; - there is two bytes per colour.
;; - these are stored in a form that can be written direct 
;; to the CPC+ colour palette registers (i.e. xGRB)
;; - pen 0 is always transparent and doesn't have a entry
;; in the CPC+ palette

.sprite_colours
defw &0111			;; colour for sprite pen 1
defw &0222			;; colour for sprite pen 2
defw &0333			;; colour for sprite pen 3
defw &0444			;; colour for sprite pen 4
defw &0555			;; colour for sprite pen 5
defw &0666			;; colour for sprite pen 6
defw &0777			;; colour for sprite pen 7
defw &0888			;; colour for sprite pen 8
defw &0999			;; colour for sprite pen 9
defw &0aaa			;; colour for sprite pen 10
defw &0bbb			;; colour for sprite pen 11
defw &0ccc			;; colour for sprite pen 12
defw &0ddd			;; colour for sprite pen 13
defw &0eee			;; colour for sprite pen 14
defw &0fff			;; colour for sprite pen 15

;;---------------------------------------------
;; - there is one pixel per byte (bits 3..0 of each byte define the palette index for this pixel)
;; - these bytes are stored in a form that can be written direct to the ASIC
;; sprite pixel data
.sprite_pixel_data
defb &00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00		;; line 0
defb &00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00		;; line 1
defb &00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00		;; line 2
defb &00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00		;; line 3
defb &00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00		;; line 4
defb &00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00		;; line 5
defb &00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00		;; line 6
defb &00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00		;; line 7
defb &00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00		;; line 8
defb &00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00		;; line 9
defb &00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00		;; line 10
defb &00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00		;; line 11
defb &00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00		;; line 12
defb &00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00		;; line 13
defb &00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00		;; line 14
defb &00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00,&00		;; line 15


;;----------------------------------------------------------
;; this is the sequence to unlock the ASIC extra features
.sequence
defb &ff,&00,&ff,&77,&b3,&51,&a8,&d4,&62,&39,&9c,&46,&2b,&15,&8a,&cd,&ee
</pre>

==See Also==
*[[Amstrad CPC plus sprite format]]
*[[Sprites Multiplexing]]

[[Category:CPC Plus]]
[[Category:Programming]]