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rename math.atan() to math.atan2()

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Irmen de Jong 2023-06-18 13:05:36 +02:00
parent f56c12ee4e
commit 0aac9350d5
4 changed files with 14 additions and 8 deletions
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2
compiler/res/prog8lib/math.p8
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@ -254,7 +254,7 @@ _quadrant_region_to_direction:
}}
}
asmsub atan(ubyte x1 @R0, ubyte y1 @R1, ubyte x2 @R2, ubyte y2 @R3) -> ubyte @A {
asmsub atan2(ubyte x1 @R0, ubyte y1 @R1, ubyte x2 @R2, ubyte y2 @R3) -> ubyte @A {
;; Calculate the angle, in a 256-degree circle, between two points into A.
;; The points (x1, y1) and (x2, y2) have to use *unsigned coordinates only* from the positive quadrant in the carthesian plane!
;; https://www.codebase64.org/doku.php?id=base:8bit_atan2_8-bit_angle

12
compiler/res/prog8lib/virtual/math.p8
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@ -187,7 +187,7 @@ math {
sub direction(ubyte x1, ubyte y1, ubyte x2, ubyte y2) -> ubyte {
; From a pair of positive coordinates, calculate discrete direction between 0 and 23 into A.
; This adjusts the atan() result so that the direction N is centered on the angle=N instead of having it as a boundary
ubyte angle = atan(x1, y1, x2, y2) - 256/48
ubyte angle = atan2(x1, y1, x2, y2) - 256/48
return 23-lsb(mkword(angle,0) / 2730)
}
@ -226,14 +226,14 @@ sub direction_qd(ubyte quadrant, ubyte xdelta, ubyte ydelta) -> ubyte {
}
}
sub atan(ubyte x1, ubyte y1, ubyte x2, ubyte y2) -> ubyte {
sub atan2(ubyte x1, ubyte y1, ubyte x2, ubyte y2) -> ubyte {
;; Calculate the angle, in a 256-degree circle, between two points into A.
;; The points (x1, y1) and (x2, y2) have to use *unsigned coordinates only* from the positive quadrant in the carthesian plane!
%ir {{
loadm.b r65532,math.atan.x1
loadm.b r65533,math.atan.y1
loadm.b r65534,math.atan.x2
loadm.b r65535,math.atan.y2
loadm.b r65532,math.atan2.x1
loadm.b r65533,math.atan2.y1
loadm.b r65534,math.atan2.x2
loadm.b r65535,math.atan2.y2
syscall 44 (r65532.b, r65533.b, r65534.b, r65535.b): r0.b
returnr.b r0
}}

2
docs/source/libraries.rst
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@ -384,7 +384,7 @@ but perhaps the provided ones can be of service too.
Fast 8-bit byte cosine of angle 0..179 (each is a 2 degree step), result is in range -127..127
Angles 180..255 will yield a garbage result!
``atan (ubyte x1, ubyte y1, ubyte x2, ubyte y2)``
``atan2 (ubyte x1, ubyte y1, ubyte x2, ubyte y2)``
Fast arctan routine that uses more memory because of large lookup tables.
Calculate the angle, in a 256-degree circle, between two points in the positive quadrant.

6
examples/cx16/spotlight.p8
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@ -1,6 +1,12 @@
%import math
%import palette
; use the mouse to move the cursor around the screen
; it uses the fast direction routine to spotlight your mouse position.
; you can use the atan2() routine as well for more precision laser beams,
; but it will use a lot more memory due to the required lookup tables.
main {
sub start() {
const uword WIDTH=320