prog8/examples/vm/sincos.p8

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%import math
%import textio
; Draw sine and cosine graphs. The sine and cosine functions are table lookups
; where the tables are generated by 64tass list functions.
; Note: this program is compatible with CX16 only.
; it doesn't work correctly on C64 because the bitmap screen data overlaps
; the program itself in memory $2000-...
main {
const uword width = 320
const ubyte height = 200
sub start() {
sys.gfx_enable(0) ; enable lo res screen
sincos255()
sys.wait(120)
sys.gfx_clear(0)
sincos180()
sys.wait(120)
sys.gfx_clear(0)
circles()
repeat {
}
}
sub sincos255() {
graphics_line(256)
ubyte pixelyb
ubyte pixelxb
byte pixelys
for pixelxb in 0 to 255 {
pixelyb = math.cos8u(pixelxb) / 2
sys.gfx_plot(pixelxb, pixelyb+20, 255)
pixelyb = math.sin8u(pixelxb) / 2
sys.gfx_plot(pixelxb, pixelyb+20, 255)
}
for pixelxb in 0 to 255 {
pixelys = math.cos8(pixelxb) / 2
sys.gfx_plot(pixelxb, pixelys as uword + 90, 255)
pixelys = math.sin8(pixelxb) / 2
sys.gfx_plot(pixelxb, pixelys as uword + 90, 255)
}
}
sub sincos180() {
graphics_line(180)
ubyte pixelyb
ubyte pixelxb
byte pixelys
for pixelxb in 0 to 179 {
pixelyb = math.cosr8u(pixelxb) / 2
sys.gfx_plot(pixelxb, pixelyb+20, 255)
pixelyb = math.sinr8u(pixelxb) / 2
sys.gfx_plot(pixelxb, pixelyb+20, 255)
}
for pixelxb in 0 to 179 {
pixelys = math.cosr8(pixelxb) / 2
sys.gfx_plot(pixelxb, pixelys as uword + 90, 255)
pixelys = math.sinr8(pixelxb) / 2
sys.gfx_plot(pixelxb, pixelys as uword + 90, 255)
}
}
sub circles() {
ubyte pixelyb
uword pixelxw
ubyte r
; circle with "degrees" from 0 to 255
for r in 0 to 255 {
pixelxw = (math.sin8(r)/2 as uword) + 80
pixelyb = (math.cos8(r)/2 as uword + height/2) as ubyte
sys.gfx_plot(pixelxw, pixelyb, 255)
}
for r in 0 to 255 {
pixelxw = math.sin8u(r)/2
pixelyb = math.cos8u(r)/2
sys.gfx_plot(pixelxw + 16, pixelyb+50, 255)
}
; circle with half-degrees from 0 to 179 (=full degrees 0..358 with steps of 2 degrees)
for r in 0 to 179 {
pixelxw = (math.sinr8(r) as word /2 + 220) as uword
pixelyb = (math.cosr8(r)/2 + height/2) as ubyte
sys.gfx_plot(pixelxw, pixelyb, 255)
}
for r in 0 to 179 {
pixelxw = math.sinr8u(r)/2
pixelyb = math.cosr8u(r)/2
sys.gfx_plot(pixelxw + 156, pixelyb+50, 255)
}
}
sub graphics_line(uword x) {
uword y
for y in 0 to height-1 {
sys.gfx_plot(x, y, 100)
}
}
}