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dos33fsprogs
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mode7: more starfield work

This commit is contained in:
Vince Weaver 2017-12-30 00:43:39 -05:00
parent 209198a57a
commit d1a0ac9144
4 changed files with 92 additions and 9 deletions
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2
asm_routines/hlin_clearscreen.s
View File

@ -183,7 +183,7 @@ clear_top_a:
; HLIN Y, V2 AT A
lda #40
lda #39
sta V2
lda #0

10
gr-sim/starfield_fixed.c
View File

@ -83,13 +83,13 @@ static void random_star(int i) {
stars[i].x.i=random_table[random_pointer++];
if (random_pointer>255) random_pointer=0;
stars[i].x.f=random_table[random_pointer++];
if (random_pointer>255) random_pointer=0;
// stars[i].x.f=random_table[random_pointer++];
// if (random_pointer>255) random_pointer=0;
stars[i].y.i=random_table[random_pointer++];
if (random_pointer>255) random_pointer=0;
stars[i].y.f=random_table[random_pointer++];
if (random_pointer>255) random_pointer=0;
// stars[i].y.f=random_table[random_pointer++];
// if (random_pointer>255) random_pointer=0;
// double_to_fixed( (drand48()-0.5)*spreadx,&stars[i].x);
// double_to_fixed( (drand48()-0.5)*spready,&stars[i].y);
@ -97,7 +97,7 @@ static void random_star(int i) {
/* 0 to 63 corresponding to */
stars[i].z=random_table[random_pointer++]&0x3f;
if (random_pointer>255) random_pointer=0;
if (stars[i].z>58) stars[i].z=0;
// if (stars[i].z>58) stars[i].z=0;
// double_to_fixed( ((drand48())*spreadz)+0.1,&stars[i].z);
// print_fixed(&stars[i].x);

88
mode7/starfield_demo.s
View File

@ -27,19 +27,49 @@ NUMSTARS EQU 16
;===============
lda #0
sta DRAW_PAGE
sta RANDOM_POINTER
ldy #NUMSTARS
init_stars:
jsr random_star
dey
bpl init_stars
;===========================
;===========================
; Main Loop
;===========================
;===========================
starfield_loop:
;===============
; clear screen
;===============
jsr clear_top
;===============
; draw stars
;===============
draw_stars:
ldx #NUMSTARS
draw_stars:
txa
tay
; calculate color
lda #$ff
sta COLOR
; calculate x and y
lda #20
ldy #20
;================================
; plot routine
;================================
; put address in GBASL/GBASH
; Xcoord in A, Ycoord in Y
@ -57,12 +87,33 @@ draw_stars:
;===========
;
lda TEMPY
and #$1
bne plot_odd
plot_even:
lda COLOR
and #$f0
sta COLOR
lda (GBASL),Y
and #$0f
jmp plot_write
plot_odd:
lda COLOR
and #$0f
sta COLOR
lda (GBASL),Y
and #$f0
plot_write:
ldy #0
lda #$ff
ora COLOR
sta (GBASL),Y
;==============================
dex
bne draw_stars
bpl draw_stars
starfield_keyboard:
@ -90,6 +141,37 @@ skipskip:
jmp starfield_loop ; 3
; matches scroll_row1 - row3
star_x EQU $8A00
star_y EQU $8B00
star_z EQU $8C00
;===================
; star number in Y
; FIXME: increment at end?
; X trashed
random_star:
; random x location
ldx RANDOM_POINTER
lda random_table,X
inc RANDOM_POINTER
sta star_x,Y
; random y location
ldx RANDOM_POINTER
lda random_table,X
inc RANDOM_POINTER
sta star_y,Y
; random z location
ldx RANDOM_POINTER
lda random_table,X
inc RANDOM_POINTER
and #$3f
sta star_z,Y
rts
;===============================================
; External modules
;===============================================

1
mode7/zp.inc
View File

@ -95,6 +95,7 @@ LAST_SPACEY_I EQU $88
LAST_MAP_COLOR EQU $89
DRAW_SKY EQU $8A
COLOR_MASK EQU $8B
RANDOM_POINTER EQU $8C
SHIPY EQU $E4