mirror of
https://github.com/irmen/prog8.git
synced 2024-11-01 15:07:10 +00:00
106 lines
3.0 KiB
Lua
106 lines
3.0 KiB
Lua
%import c64lib
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%import c64utils
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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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byte[] xcoor = [ -40, -40, -40, -40, 40, 40, 40, 40 ]
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byte[] ycoor = [ -40, -40, 40, 40, -40, -40, 40, 40 ]
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byte[] zcoor = [ -40, 40, -40, 40, -40, 40, -40, 40 ]
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; storage for rotated coordinates
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word[len(xcoor)] rotatedx
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word[len(ycoor)] rotatedy
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word[len(zcoor)] rotatedz
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sub start() {
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uword anglex
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uword angley
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uword anglez
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forever {
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rotate_vertices(msb(anglex), msb(angley), msb(anglez))
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c64scr.clear_screenchars(32)
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draw_edges()
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anglex+=1000
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angley+=433
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anglez+=907
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c64scr.plot(0,0)
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c64scr.print("3d cube! ")
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c64scr.print_ub(c64.TIME_LO)
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c64scr.print(" jiffies/fr = ")
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c64scr.print_ub(60/c64.TIME_LO)
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c64scr.print(" fps")
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c64.TIME_LO=0
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}
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}
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sub rotate_vertices(ubyte ax, ubyte ay, ubyte az) {
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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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word wcosa = cos8(ax)
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word wsina = sin8(ax)
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word wcosb = cos8(ay)
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word wsinb = sin8(ay)
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word wcosc = cos8(az)
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word wsinc = sin8(az)
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word wcosa_sinb = wcosa*wsinb / 128
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word wsina_sinb = wsina*wsinb / 128
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word Axx = wcosa*wcosb / 128
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word Axy = (wcosa_sinb*wsinc - wsina*wcosc) / 128
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word Axz = (wcosa_sinb*wcosc + wsina*wsinc) / 128
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word Ayx = wsina*wcosb / 128
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word Ayy = (wsina_sinb*wsinc + wcosa*wcosc) / 128
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word Ayz = (wsina_sinb*wcosc - wcosa*wsinc) / 128
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word Azx = -wsinb
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word Azy = wcosb*wsinc / 128
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word Azz = wcosb*wcosc / 128
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ubyte i
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for i in 0 to len(xcoor)-1 {
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; don't normalize by dividing by 128, instead keep some precision for perspective calc later
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rotatedx[i] = Axx*xcoor[i] + Axy*ycoor[i] + Axz*zcoor[i]
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rotatedy[i] = Ayx*xcoor[i] + Ayy*ycoor[i] + Ayz*zcoor[i]
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rotatedz[i] = Azx*xcoor[i] + Azy*ycoor[i] + Azz*zcoor[i]
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}
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}
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sub draw_edges() {
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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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ubyte i
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word rz
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word persp
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byte sx
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byte sy
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for i in 0 to len(xcoor)-1 {
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rz = rotatedz[i]
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if rz >= 10 {
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persp = 900 + rz/32
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sx = rotatedx[i] / persp as byte + width/2
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sy = rotatedy[i] / persp as byte + height/2
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c64scr.setcc(sx as ubyte, sy as ubyte, 46, 7)
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}
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}
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for i in 0 to len(xcoor)-1 {
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rz = rotatedz[i]
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if rz < 10 {
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persp = 900 + rz/32
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sx = rotatedx[i] / persp as byte + width/2
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sy = rotatedy[i] / persp as byte + height/2
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c64scr.setcc(sx as ubyte, sy as ubyte, 81, 7)
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}
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}
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}
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}
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