prog8/examples/cube3d-float.p8
2019-07-29 23:11:13 +02:00

91 lines
2.7 KiB
Lua

%import c64lib
%import c64utils
%import c64flt
main {
const uword width = 40
const uword height = 25
; vertices
float[] xcoor = [ -1.0, -1.0, -1.0, -1.0, 1.0, 1.0, 1.0, 1.0 ]
float[] ycoor = [ -1.0, -1.0, 1.0, 1.0, -1.0, -1.0, 1.0, 1.0 ]
float[] zcoor = [ -1.0, 1.0, -1.0, 1.0, -1.0, 1.0, -1.0, 1.0 ]
; storage for rotated coordinates
float[len(xcoor)] rotatedx=0.0
float[len(ycoor)] rotatedy=0.0
float[len(zcoor)] rotatedz=-1.0
sub start() {
float time=0.0
while(true) {
rotate_vertices(time)
c64scr.clear_screenchars(32)
draw_edges()
time+=0.2
c64scr.plot(0,0)
c64scr.print("3d cube! (float) ")
c64scr.print_ub(c64.TIME_LO)
c64scr.print(" jiffies/frame")
c64.TIME_LO=0
}
}
sub rotate_vertices(float t) {
; rotate around origin (0,0,0)
; set up the 3d rotation matrix values
float cosa = cos(t)
float sina = sin(t)
float cosb = cos(t*0.33)
float sinb = sin(t*0.33)
float cosc = cos(t*0.78)
float sinc = sin(t*0.78)
float cosa_sinb = cosa*sinb
float sina_sinb = sina*sinb
float Axx = cosa*cosb
float Axy = cosa_sinb*sinc - sina*cosc
float Axz = cosa_sinb*cosc + sina*sinc
float Ayx = sina*cosb
float Ayy = sina_sinb*sinc + cosa*cosc
float Ayz = sina_sinb*cosc - cosa*sinc
float Azx = -sinb
float Azy = cosb*sinc
float Azz = cosb*cosc
for ubyte i in 0 to len(xcoor)-1 {
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 draw_edges() {
; plot the points of the 3d cube
; first the points on the back, then the points on the front (painter algorithm)
for ubyte i in 0 to len(xcoor)-1 {
float rz = rotatedz[i]
if rz >= 0.1 {
float persp = (5.0+rz)/height
ubyte sx = rotatedx[i] / persp + width/2.0 as ubyte
ubyte sy = rotatedy[i] / persp + height/2.0 as ubyte
c64scr.setcc(sx, sy, 46, i+2)
}
}
for ubyte i in 0 to len(xcoor)-1 {
float rz = rotatedz[i]
if rz < 0.1 {
float persp = (5.0+rz)/height
ubyte sx = rotatedx[i] / persp + width/2.0 as ubyte
ubyte sy = rotatedy[i] / persp + height/2.0 as ubyte
c64scr.setcc(sx, sy, 81, i+2)
}
}
}
}