mirror of
https://github.com/irmen/prog8.git
synced 2024-11-23 07:32:10 +00:00
99 lines
2.9 KiB
Lua
99 lines
2.9 KiB
Lua
%import textio
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%import math
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main {
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; vertices
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word[] @split xcoor = [ -40, -40, -40, -40, 40, 40, 40, 40 ]
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word[] @split ycoor = [ -40, -40, 40, 40, -40, -40, 40, 40 ]
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word[] @split zcoor = [ -40, 40, -40, 40, -40, 40, -40, 40 ]
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; storage for rotated coordinates
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word[len(xcoor)] @split rotatedx
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word[len(ycoor)] @split rotatedy
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word[len(zcoor)] @split 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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repeat {
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rotate_vertices(msb(anglex), msb(angley), msb(anglez))
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txt.clear_screenchars(' ')
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draw_edges()
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anglex+=500
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angley+=215
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anglez+=453
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sys.waitvsync()
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sys.waitvsync()
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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 = math.cos8(ax)
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word wsina = math.sin8(ax)
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word wcosb = math.cos8(ay)
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word wsinb = math.sin8(ay)
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word wcosc = math.cos8(az)
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word wsinc = math.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 @zp 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 @zp i
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word @zp rz
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word @zp 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 = 400 + rz/64
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sx = rotatedx[i] / persp as byte + txt.DEFAULT_WIDTH/2
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sy = rotatedy[i] / persp as byte + txt.DEFAULT_HEIGHT/2
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txt.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 = 400 + rz/64
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sx = rotatedx[i] / persp as byte + txt.DEFAULT_WIDTH/2
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sy = rotatedy[i] / persp as byte + txt.DEFAULT_HEIGHT/2
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txt.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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