Studio/OpenGL/Teapot

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The easy way to draw a teapot in OpenGL is to call the teapot demo in the auxiliary library. More interesting, and not difficult, is to draw it yourself.

The teapot below consists of 4 parts. The lid and body are created as a surface of revolution, the handle and spout as a tube. For a surface of revolution, you can specify the outer edge; for a tube, the positions of opposite points along the tube. Once you have a reasonable definition, it becomes easy to experiment with different values.

The code is given at the end of this page.

Teapot1.jpg

This view leaves out the body, making the parts clear:

Teapotp1.jpg

This view shows the nurbs tessellation of a Russian teapot, with the lid offset for easy refilling.

Teapott1.png

Here is the code:

NB. teapot
NB.
NB. The construction has four parts - zero
NB. out elements of VIEW to remove parts.
NB.
NB. Try uncommenting the GS_DISPLAYMODE assignments.
NB. Try uncommenting GS_COLOR=: RED assignment in demo
NB.
NB. Experiment with part definitions,
NB. e.g. add 10 to LID

NB. GS_DISPLAYMODE=: GLU_OUTLINE_PATCH
NB. GS_DISPLAYMODE=: GLU_OUTLINE_POLYGON

VIEW=: 1 1 1 1

GS_CLEARCOLOR=: SKYBLUE
GS_COLOR=: SPRINGGREEN
GS_ROTXYZ=: 290 0 _10
GS_TRNXYZ=: _0.1 _0.7 0

paint=: 3 : 0
if. gsinit GS_LIGHT do.
  gsnewlist 1
  scale=. 0.03
  4 3 gsdrawsurface (0{VIEW) # BODY*scale
  4 3 gsdrawsurface (1{VIEW) # LID*scale
  4 3 gsdrawsurface (2{VIEW) # HANDLE*scale
  4 3 gsdrawsurface (3{VIEW) # SPOUT*scale
  gsendlist ''
end.
glCallList 1
gsfini''
)

NB. =========================================================
BODY=: gssurfacerev gstonum 0 : 0
27 45
28 48
29 48
31 45
34 35
39 24
39 15
38  6
30  2
30  0
15  0
0   0
)

NB. =========================================================
LID=: gssurfacerev gstonum 0 : 0
 0 59
12 58
 0 54
 4 51
 8 48
26 48
26 45
26 44
)

NB. =========================================================
HANDLE=: gsmaketube gstonum 0 : 0
_35  8 _35 18 6
_46 11 _44 22 6
_55 21 _45 26 6
_57 32 _48 32 6
_56 40 _47 34 6
_41 45 _41 35 6
_28 43 _28 35 6
)

NB. =========================================================
SPOUT=: gsmaketube gstonum 0 : 0
34 27 34 11 10
38 27 39 12 9
40 28 43 14 9
43 29 50 21 8
47 36 56 34 7
49 40 57 38 6
51 44 60 42 6
53 46 64 45 6
)