prog8/examples/lines-circles-gfx.p8
2020-03-25 01:07:42 +01:00

132 lines
3.5 KiB
Lua

%import c64lib
%import c64utils
%zeropage basicsafe
main {
const uword bitmap_address = $2000
sub start() {
; enable bitmap screen, erase it and set colors to black/white.
c64.SCROLY |= %00100000
c64.VMCSB = (c64.VMCSB & %11110000) | %00001000 ; $2000-$3fff
memset(bitmap_address, 320*200/8, 0)
c64scr.clear_screen($10, 0)
circles()
lines()
}
; fast asm plot via lookup tables http://codebase64.org/doku.php?id=base:various_techniques_to_calculate_adresses_fast_common_screen_formats_for_pixel_graphics
sub circles() {
ubyte xx
for xx in 1 to 5 {
circle(50 + xx*40, 50+xx*15, (xx+10)*4, xx)
; disc(50 + xx*40, 50+xx*15, (xx+10)*2, xx)
}
}
sub lines() {
uword xx
ubyte yy
ubyte color
ubyte iter
for color in 0 to 15 {
xx = color * 16
yy = color + 20
for iter in 0 to 150 {
plot(xx, yy, color)
xx++
yy++
}
}
}
sub circle(uword xcenter, ubyte ycenter, ubyte radius, ubyte color) {
; Midpoint algorithm
ubyte x = radius
ubyte y = 0
byte decisionOver2 = 1-x
while x>=y {
plot(xcenter + x, ycenter + y as ubyte, color)
plot(xcenter - x, ycenter + y as ubyte, color)
plot(xcenter + x, ycenter - y as ubyte, color)
plot(xcenter - x, ycenter - y as ubyte, color)
plot(xcenter + y, ycenter + x as ubyte, color)
plot(xcenter - y, ycenter + x as ubyte, color)
plot(xcenter + y, ycenter - x as ubyte, color)
plot(xcenter - y, ycenter - x as ubyte, color)
y++
if decisionOver2<=0
decisionOver2 += 2*y+1
else {
x--
decisionOver2 += 2*(y-x)+1
}
}
}
; sub disc(uword cx, ubyte cy, ubyte radius, ubyte color) {
; ; Midpoint algorithm, filled
; ubyte x = radius
; ubyte y = 0
; byte decisionOver2 = 1-x
; uword xx
;
; while x>=y {
; for xx in cx to cx+x {
; plot(xx, cy + y as ubyte, color)
; plot(xx, cy - y as ubyte, color)
; }
; for xx in cx-x to cx-1 {
; plot(xx, cy + y as ubyte, color)
; plot(xx, cy - y as ubyte, color)
; }
; for xx in cx to cx+y {
; plot(xx, cy + x as ubyte, color)
; plot(xx, cy - x as ubyte, color)
; }
; for xx in cx-y to cx {
; plot(xx, cy + x as ubyte, color)
; plot(xx, cy - x as ubyte, color)
; }
; y++
; if decisionOver2<=0
; decisionOver2 += 2*y+1
; else {
; x--
; decisionOver2 += 2*(y-x)+1
; }
; }
; }
; uword[200] yoffsets_lo = $00 ; TODO fix compiler crash about init value type
sub plot(uword px, ubyte py, ubyte color) {
ubyte[] ormask = [128, 64, 32, 16, 8, 4, 2, 1]
uword addr = bitmap_address + 320*(py>>3) + (py & 7) + (px & %0000001111111000)
; @(addr) |= 128 ; TODO FIX memory-OR/XOR and probably AND as well
; @(addr) += 1 ; TODO fix += 1
A=@(addr)
@(addr) = A | ormask[lsb(px) & 7]
ubyte sx = px >> 3
ubyte sy = py >> 3
c64.SCRATCH_ZPB1 = color << 4
c64scr.setchr(sx, sy)
}
}