mirror of
https://github.com/irmen/prog8.git
synced 2024-11-02 22:04:40 +00:00
94 lines
2.7 KiB
Lua
94 lines
2.7 KiB
Lua
%import c64utils
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%option enable_floats
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~ main {
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const uword width = 40
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const uword height = 25
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; vertices
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float[8] xcoor = [ -1.0, -1.0, -1.0, -1.0, 1.0, 1.0, 1.0, 1.0 ]
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float[8] ycoor = [ -1.0, -1.0, 1.0, 1.0, -1.0, -1.0, 1.0, 1.0 ]
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float[8] zcoor = [ -1.0, 1.0, -1.0, 1.0, -1.0, 1.0, -1.0, 1.0 ]
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; storage for rotated coordinates
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float[len(xcoor)] rotatedx=0.0
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float[len(ycoor)] rotatedy=0.0
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float[len(zcoor)] rotatedz=-1.0
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sub start() {
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float time=0.0
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while(true) {
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rotate_vertices(time)
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c64.CLEARSCR()
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draw_edges()
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time+=0.2
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}
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}
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sub rotate_vertices(float t) {
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; rotate around origin (0,0,0)
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; set up the 3d rotation matrix values
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float cosa = cos(t)
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float sina = sin(t)
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float cosb = cos(t*0.33)
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float sinb = sin(t*0.33)
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float cosc = cos(t*0.78)
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float sinc = sin(t*0.78)
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float cosa_sinb = cosa*sinb
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float sina_sinb = sina*sinb
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float Axx = cosa*cosb
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float Axy = cosa_sinb*sinc - sina*cosc
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float Axz = cosa_sinb*cosc + sina*sinc
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float Ayx = sina*cosb
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float Ayy = sina_sinb*sinc + cosa*cosc
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float Ayz = sina_sinb*cosc - cosa*sinc
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float Azx = -sinb
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float Azy = cosb*sinc
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float Azz = cosb*cosc
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for ubyte i in 0 to len(xcoor)-1 {
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float xc = xcoor[i]
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float yc = ycoor[i]
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float zc = zcoor[i]
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rotatedx[i] = Axx*xc + Axy*yc + Axz*zc
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rotatedy[i] = Ayx*xc + Ayy*yc + Ayz*zc
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rotatedz[i] = Azx*xc + Azy*yc + Azz*zc
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}
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}
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sub draw_edges() {
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sub toscreenx(float x, float z) -> byte {
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return x/(5.0+z) * (height as float) as byte + width // 2
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}
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sub toscreeny(float y, float z) -> byte {
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return y/(5.0+z) * (height as float) as byte + height // 2
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}
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; plot the points of the 3d cube
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; first the points on the back, then the points on the front (painter algorithm)
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for ubyte i in 0 to len(xcoor)-1 {
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float rz = rotatedz[i]
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if rz >= 0.1 {
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ubyte sx = toscreenx(rotatedx[i], rz) as ubyte
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ubyte sy = toscreeny(rotatedy[i], rz) as ubyte
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c64scr.setchrclr(sx, sy, 46, i+2)
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}
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}
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for ubyte i in 0 to len(xcoor)-1 {
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float rz = rotatedz[i]
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if rz < 0.1 {
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ubyte sx = toscreenx(rotatedx[i], rz) as ubyte
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ubyte sy = toscreeny(rotatedy[i], rz) as ubyte
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c64scr.setchrclr(sx, sy, 81, i+2)
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}
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}
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}
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}
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