72 lines
2.4 KiB
Forth
72 lines
2.4 KiB
Forth
# Demo of an interactive app: controlling a Bezier curve on screen
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fn main screen: (addr screen), keyboard: (addr keyboard), data-disk: (addr disk) {
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var p0-storage: point
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var p0/ecx: (addr point) <- address p0-storage
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initialize-point p0, 5 5
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var p1-storage: point
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var p1/edx: (addr point) <- address p1-storage
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initialize-point p1, 0x80 0x100
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var p2-storage: point
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var p2/ebx: (addr point) <- address p2-storage
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initialize-point p2, 0x200 0x140
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render screen, p0, p1, p2
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}
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type point {
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x: int
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y: int
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}
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fn initialize-point _p: (addr point), x: int, y: int {
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var p/esi: (addr point) <- copy _p
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var dest/eax: (addr int) <- get p, x
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var src/ecx: int <- copy x
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copy-to *dest, src
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dest <- get p, y
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src <- copy y
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copy-to *dest, src
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}
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fn render screen: (addr screen), p0: (addr point), p1: (addr point), p2: (addr point) {
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# control lines
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line screen, p0, p1, 7/color
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line screen, p1, p2, 7/color
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# curve above control lines
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bezier screen, p0, p1, p2, 0xc/color
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# points above curve
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disc screen, p0, 3/radius, 7/color 0xf/border
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disc screen, p1, 3/radius, 7/color 0xf/border
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disc screen, p2, 3/radius, 7/color 0xf/border
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}
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fn bezier screen: (addr screen), _p0: (addr point), _p1: (addr point), _p2: (addr point), color: int {
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var p0/esi: (addr point) <- copy _p0
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var x0/ecx: (addr int) <- get p0, x
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var y0/edx: (addr int) <- get p0, y
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var p1/esi: (addr point) <- copy _p1
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var x1/ebx: (addr int) <- get p1, x
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var y1/eax: (addr int) <- get p1, y
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var p2/esi: (addr point) <- copy _p2
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var x2/edi: (addr int) <- get p2, x
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var y2/esi: (addr int) <- get p2, y
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draw-monotonic-bezier screen, *x0 *y0, *x1 *y1, *x2 *y2, color
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}
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fn line screen: (addr screen), _p0: (addr point), _p1: (addr point), color: int {
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var p0/esi: (addr point) <- copy _p0
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var x0/ecx: (addr int) <- get p0, x
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var y0/edx: (addr int) <- get p0, y
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var p1/esi: (addr point) <- copy _p1
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var x1/ebx: (addr int) <- get p1, x
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var y1/eax: (addr int) <- get p1, y
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draw-line screen, *x0 *y0, *x1 *y1, color
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}
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fn disc screen: (addr screen), _p: (addr point), radius: int, color: int, border-color: int {
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var p/esi: (addr point) <- copy _p
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var x/ecx: (addr int) <- get p, x
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var y/edx: (addr int) <- get p, y
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draw-disc screen, *x *y, radius, color, border-color
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}
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