3D projection

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DFrostCreated: ~5 years ago

DFrost #1

could someone make a DEF block for perspective projection, please

~5 years ago

spaceturtles #2

DEF DRAW_WIRE_RECTPRISM
 GLINE 200-8,120-8,200+8,120-8,#RED
 GLINE 200-8,120+8,200+8,120+8,#RED
 GLINE 200-8,120-8,200-8,120+8,#RED
 GLINE 200+8,120-8,200+8,120+8,#RED
 
 GLINE 200-4,120-4,200+4,120-4,RGB(90,0,0)
 GLINE 200-4,120+4,200+4,120+4,RGB(90,0,0)
 GLINE 200-4,120-4,200-4,120+4,RGB(90,0,0)
 GLINE 200+4,120-4,200+4,120+4,RGB(90,0,0)
 
 GLINE 200-8,120-8,200-4,120-4,RGB(175,0,0)
 GLINE 200+8,120-8,200+4,120-4,RGB(175,0,0)
 GLINE 200-8,120+8,200-4,120+4,RGB(175,0,0)
 GLINE 200+8,120+8,200+4,120+4,RGB(175,0,0)
 END

Draws a tiny red "cube" shape. You can see the lines get darker making it look like it has depth

~5 years agoEdited ~5 years ago by spaceturtles

DFrost #3

i want a function:

DEF PERSPECTIVE X,Y,Z OUT X2,Y2
'code
END

~5 years ago

Nathaniel #4

DEF PERSPECTIVE X,Y,Z,VP OUT X2,Y2
 X2=X/(Z-VP)
 Y2=Y/(Z-VP)
END

VP is the vanishing point distance. No "z" value should be bigger than this number and this number should be consistent for all calculations.

~5 years agoEdited ~5 years ago by Nathaniel

DFrost #5

what about rotation?

~5 years ago

Nathaniel #6

This is the function I usually use for two-axis rotation.

DEF ROT_3D X,Y,Z,A1,A2 OUT X3,Y3,Z3
 VAR W=SIN(RAD(A1)),W2=SIN(RAD(A2))
 VAR H=COS(RAD(A1)),H2=COS(RAD(A2))
 VAR Z2=Z*H-X*W
 X3=Z*W+X*H
 Y3=Y*H2-Z2*W2
 Z3=Y*W2+Z2*H2
END

It's also faster if you calculate all the sin/cos calculation before you calculate all the point's locations.

~5 years ago

rando #7

Cool.

~5 years ago

DFrost #8

So I could pass XYZ into ROT_3D and use the output in PERSPECTIVE?

~5 years ago