prog8/examples/cube3d-sprites.p8

173 lines
6.4 KiB
Lua

%target c64
%import syslib
%import textio
spritedata $2000 {
; this memory block contains the sprite data
; it must start on an address aligned to 64 bytes.
%option force_output ; make sure the data in this block appears in the resulting program
ubyte[] sprites = [
%00000000,%00000000,%00000000,
%00000000,%00111100,%00000000,
%00000000,%11111111,%00000000,
%00000001,%11111101,%10000000,
%00000001,%11111111,%10000000,
%00000011,%11111111,%11000000,
%00000011,%11111111,%11000000,
%00000011,%11111111,%11000000,
%00000001,%11111111,%10000000,
%00000001,%11111111,%10000000,
%00000000,%11111111,%00000000,
%00000000,%00111100,%00000000,
%00000000,%00000000,%00000000,
%00000000,%00000000,%00000000,
%00000000,%00000000,%00000000,
%00000000,%00000000,%00000000,
%00000000,%00000000,%00000000,
%00000000,%00000000,%00000000,
%00000000,%00000000,%00000000,
%00000000,%00000000,%00000000,
%00000000,%00000000,%00000000,
0,
%00000000,%00111110,%00000000,
%00000000,%11111111,%10000000,
%00000001,%11111110,%11000000,
%00000011,%11111111,%01100000,
%00000011,%11111111,%11100000,
%00000111,%11111111,%11110000,
%00000111,%11111111,%11110000,
%00000111,%11111111,%11110000,
%00000111,%11111111,%11110000,
%00000011,%11111111,%11100000,
%00000011,%11111111,%11100000,
%00000001,%11111111,%11000000,
%00000000,%11111111,%10000000,
%00000000,%00111110,%00000000,
%00000000,%00000000,%00000000,
%00000000,%00000000,%00000000,
%00000000,%00000000,%00000000,
%00000000,%00000000,%00000000,
%00000000,%00000000,%00000000,
%00000000,%00000000,%00000000,
%00000000,%00000000,%00000000,
0
]
}
main {
const uword width = 255
const uword height = 200
; vertices
word[] xcoor = [ -100, -100, -100, -100, 100, 100, 100, 100 ]
word[] ycoor = [ -100, -100, 100, 100, -100, -100, 100, 100 ]
word[] zcoor = [ -100, 100, -100, 100, -100, 100, -100, 100 ]
; storage for rotated coordinates
word[len(xcoor)] rotatedx
word[len(ycoor)] rotatedy
word[len(zcoor)] rotatedz
sub start() {
c64.SPENA = 255 ; enable all sprites
uword anglex
uword angley
uword anglez
repeat {
c64.TIME_LO=0
rotate_vertices(msb(anglex), msb(angley), msb(anglez))
position_sprites()
anglex-=500
angley+=217
anglez+=452
txt.plot(0,0)
txt.print("3d cube! (sprites) ")
txt.print_ub(c64.TIME_LO)
txt.print(" jiffies/fr = ")
txt.print_ub(60/c64.TIME_LO)
txt.print(" fps")
}
}
sub rotate_vertices(ubyte ax, ubyte ay, ubyte az) {
; rotate around origin (0,0,0)
; set up the 3d rotation matrix values
word wcosa = cos8(ax)
word wsina = sin8(ax)
word wcosb = cos8(ay)
word wsinb = sin8(ay)
word wcosc = cos8(az)
word wsinc = sin8(az)
word wcosa_sinb = wcosa*wsinb / 128
word wsina_sinb = wsina*wsinb / 128
word Axx = wcosa*wcosb / 128
word Axy = (wcosa_sinb*wsinc - wsina*wcosc) / 128
word Axz = (wcosa_sinb*wcosc + wsina*wsinc) / 128
word Ayx = wsina*wcosb / 128
word Ayy = (wsina_sinb*wsinc + wcosa*wcosc) / 128
word Ayz = (wsina_sinb*wcosc - wcosa*wsinc) / 128
word Azx = -wsinb
word Azy = wcosb*wsinc / 128
word Azz = wcosb*wcosc / 128
ubyte @zp i
for i in 0 to len(xcoor)-1 {
; don't normalize by dividing by 128, instead keep some precision for perspective calc later
rotatedx[i] = (Axx*xcoor[i] + Axy*ycoor[i] + Axz*zcoor[i])
rotatedy[i] = (Ayx*xcoor[i] + Ayy*ycoor[i] + Ayz*zcoor[i])
rotatedz[i] = (Azx*xcoor[i] + Azy*ycoor[i] + Azz*zcoor[i])
}
}
sub position_sprites() {
; set each of the 8 sprites to the correct vertex of the cube
; first sort vertices to sprite order so the back/front order is correct as well
; (simple bubble sort as it's only 8 items to sort)
ubyte @zp i
ubyte @zp i1
for i in 6 downto 0 {
for i1 in 0 to i {
ubyte i2 = i1+1
if(rotatedz[i1] > rotatedz[i2]) {
swap(rotatedx[i1], rotatedx[i2])
swap(rotatedy[i1], rotatedy[i2])
swap(rotatedz[i1], rotatedz[i2])
}
}
}
ubyte[] spritecolors = [1,1,7,15,12,11,9,9]
for i in 0 to 7 {
word @zp zc = rotatedz[i]
word persp = 300+zc/256
ubyte sx = rotatedx[i] / persp + width/2 as ubyte + 20
ubyte sy = rotatedy[i] / persp + height/2 as ubyte + 40
c64.SPXYW[i] = mkword(sy, sx)
if(zc < 30*128)
c64.SPRPTR[i] = $2000/64 +1 ; large ball
else
c64.SPRPTR[i] = $2000/64 ; small ball
c64.SPCOL[i] = spritecolors[(zc>>13) as byte + 4] ; further away=darker color
}
}
}