prog8/examples/cube3d-float.p8

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%import floats
%import textio
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%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
repeat {
cbm.SETTIM(0,0,0)
rotate_vertices(time)
txt.clear_screenchars(' ')
draw_edges()
time+=0.1
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txt.plot(0,0)
txt.print("3d cube! floats. ")
ubyte jiffies = lsb(cbm.RDTIM16())
txt.print_ub(jiffies)
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txt.print(" jiffies/fr = ")
txt.print_ub(60/jiffies)
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txt.print(" fps")
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;test_stack.test()
}
}
sub rotate_vertices(float t) {
; rotate around origin (0,0,0)
; set up the 3d rotation matrix values
float cosa = floats.cos(t)
float sina = floats.sin(t)
float cosb = floats.cos(t*0.33)
float sinb = floats.sin(t*0.33)
float cosc = floats.cos(t*0.78)
float sinc = floats.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 {
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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
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ubyte sx
ubyte sy
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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)
}
}
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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)
}
}
}
}