prog8/examples/cube3d-float.p8
2020-11-22 18:35:43 +01:00

112 lines
3.1 KiB
Lua

%import floats
%import textio
%import test_stack
%zeropage basicsafe
; Note: this program is compatible with C64 and CX16.
main {
; 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
ubyte timer_jiffies
repeat {
rotate_vertices(time)
txt.clear_screenchars(' ')
draw_edges()
time+=0.1
txt.plot(0,0)
txt.print("3d cube! floats. ")
%asm {{
stx P8ZP_SCRATCH_REG
jsr c64.RDTIM ; A/X/Y
sta timer_jiffies
lda #0
jsr c64.SETTIM
ldx P8ZP_SCRATCH_REG
}}
txt.print_ub(timer_jiffies)
txt.print(" jiffies/fr = ")
txt.print_ub(60/timer_jiffies)
txt.print(" fps")
;test_stack.test()
}
}
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
ubyte @zp i
for 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)
ubyte @zp i
float rz
float persp
ubyte sx
ubyte sy
for i in 0 to len(xcoor)-1 {
rz = rotatedz[i]
if rz >= 0.1 {
persp = (5.0+rz)/(txt.DEFAULT_HEIGHT as float)
sx = rotatedx[i] / persp + txt.DEFAULT_WIDTH/2.0 as ubyte
sy = rotatedy[i] / persp + txt.DEFAULT_HEIGHT/2.0 as ubyte
txt.setcc(sx, sy, 46, 1)
}
}
for i in 0 to len(xcoor)-1 {
rz = rotatedz[i]
if rz < 0.1 {
persp = (5.0+rz)/(txt.DEFAULT_HEIGHT as float)
sx = rotatedx[i] / persp + txt.DEFAULT_WIDTH/2.0 as ubyte
sy = rotatedy[i] / persp + txt.DEFAULT_HEIGHT/2.0 as ubyte
txt.setcc(sx, sy, 81, 1)
}
}
}
}