Skipdraw

[yllawwally]

I saw a thread that mentioned skipdraw with color. I can't find a listing of it. What does the multi-color skipdraw routine look like?

[Thomas Jentzsch]

You just have to add the color data read/write before reading the graphics data. And in the skip branch waste the similar amount of cycles.

[yllawwally]

This is what I have, but I end up with each line of the sprite being different colors, but the colors shift as he moves up and down.

 

I'm setting up a pointer at the top like this

LDA #HeroGraphicsColor
sec
sbc Hero_YPosFromBot
clc
adc #C_P0_HEIGHT - #1
STA HeroGraphicsColorPtr

 

This is how I'm doing skipdraw in the kernal

 

;skipDraw
; draw Hero sprite:
lda	 #C_P0_HEIGHT-1	 ; 2
dcp	 Hero_Y			; 5 (DEC and CMP)																																																																			  
bcs	 .doDrawHero_E1_e	   ; 2/3 ; should be bcs
lda	 #0			  ; 2
.byte   $2c			 ;-1 (BIT ABS to skip next 2 bytes)(kinda like a jump)
.doDrawHero_E1_e:
lda	 (Hero_Ptr),y	  ; 5
sta	 GRP0
lda	 (HeroGraphicsColorPtr),y	  ; 5
sta	 COLUP0

[yllawwally]

I see what I was doing wrong. I wasn't setting up the pointers properly. Below is the code I used that worked.

 

LDA #<HeroGraphicsColor
sta HeroGraphicsColorPtr
LDA #>HeroGraphicsColor
sta HeroGraphicsColorPtr+1

lda HeroGraphicsColorPtr
sec
sbc Hero_YPosFromBot
clc
adc #C_P0_HEIGHT - #1
STA HeroGraphicsColorPtr