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https://github.com/irmen/prog8.git
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62 lines
1.5 KiB
Lua
62 lines
1.5 KiB
Lua
%import textio
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%import floats
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%zeropage basicsafe
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; Note: this program is compatible with C64 and CX16.
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main {
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const uword width = 30
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const uword height = 20
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const ubyte max_iter = 16
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sub start() {
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txt.print("calculating mandelbrot fractal...")
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c64.SETTIM(0, 0, 0)
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ubyte pixelx
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ubyte pixely
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for pixely in 0 to height-1 {
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float yy = (pixely as float)/0.4/height - 1.0
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for pixelx in 0 to width-1 {
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float xx = (pixelx as float)/0.3/width - 2.2
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float xsquared = 0.0
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float ysquared = 0.0
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float x = 0.0
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float y = 0.0
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ubyte iter = 0
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while iter<max_iter and xsquared+ysquared<4.0 {
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y = x*y*2.0 + yy
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x = xsquared - ysquared + xx
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xsquared = x*x
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ysquared = y*y
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iter++
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}
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txt.setcc(pixelx+4, pixely+1, 160, max_iter-iter)
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}
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}
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ubyte time_lo
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ubyte time_mid
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ubyte time_hi
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%asm {{
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stx P8ZP_SCRATCH_REG
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jsr c64.RDTIM ; A/X/Y
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sta time_lo
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stx time_mid
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sty time_hi
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ldx P8ZP_SCRATCH_REG
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}}
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float duration = ((mkword(time_mid, time_lo) as float) + (time_hi as float)*65536.0) / 60
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txt.plot(0, 21)
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txt.print("finished in ")
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floats.print_f(duration)
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txt.print(" seconds!\n")
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}
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}
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