dos33fsprogs/games/tfv/rotate_intro.s
2021-01-05 23:30:41 -05:00

99 lines
1.5 KiB
ArmAsm

;===============================
; rotate intro -- rotate screen
;===============================
rotate_intro:
; first copy current screen to background
jsr gr_copy_current_to_offscreen_40x40
; int xx,yy,color,x2,y2;
; double h,theta,dx,dy,theta2,thetadiff,nx,ny;
; int i;
; gr_copy(0x400,0xc00);
; gr_copy_to_current(0xc00);
; page_flip();
; gr_copy_to_current(0xc00);
; page_flip();
; thetadiff=0;
; for(i=0;i<8;i++) {
; for(yy=0;yy<40;yy++) {
; for(xx=0;xx<40;xx++) {
; dx=(xx-20);
; dy=(yy-20);
; h=sqrt((dx*dx)+(dy*dy));
; theta=atan2(dy,dx);
;
; theta2=theta+thetadiff;
; nx=h*cos(theta2);
; ny=h*sin(theta2);
;
; x2=nx+20;
; y2=ny+20;
; if ((x2<0) || (x2>39)) color=0;
; else if ((y2<0) || (y2>39)) color=0;
; else color=scrn_page(x2,y2,PAGE2);
; color_equals(color);
; plot(xx,yy);
; }
; }
; thetadiff+=(6.28/16.0);
; page_flip();
; usleep(100000);
; }
rts
;=========================================================
; gr_copy_current_to_offscreen 40x40
;=========================================================
; Copy draw page to $c00
; Take image in 0xc00
; Copy to DRAW_PAGE
; Actually copy lines 0..39
; Don't over-write bottom 4 lines of text
gr_copy_current_to_offscreen_40x40:
ldx #0
gco_40x40_loop:
lda gr_offsets,X
sta OUTL
sta INL
lda gr_offsets+1,X
clc
adc DRAW_PAGE
sta OUTH
lda gr_offsets+1,X
clc
adc #$8
sta INH
ldy #39
gco_40x40_inner:
lda (OUTL),Y
sta (INL),Y
dey
bpl gco_40x40_inner
inx
inx
cpx #40
bne gco_40x40_loop
rts ; 6