RFOC (version 3.4-10)

phong3D: Phong shading for a 3D body

Description

Create phong shading for faces showing on the 3D block

Usage

phong3D(aglyph, M = diag(1, nrow = 4), M2 = diag(1, nrow = 4),
          Light = c(45, 45), anorms = list(), zee = c(0, 0, 1),
         col = "white", border = "black")

Value

Graphical Side effect

Arguments

aglyph

3-D body list of faces and normals

M

Rotation Matrix

M2

Viewing Matrix

Light

light source direction

anorms

normals to faces

zee

Up vector for Body

col

color for faces

border

border color for sides

Author

Jonathan M. Lees<[e-mail]>

Details

Uses a standard phong shading model based ont eh dot product of the face normal vector and direction of incoming light.

References

Watt, Alan. Fundamentals of Three-dimensional Computer Graphics, Addison-Wesley, 1989, 430p.

See Also

makeblock3D, BOXarrows3D, PROJ3D, Z3Darrow, pglyph3D

Examples

###########  create a block and rotation matrix, then color it
ANG=(45)
DEGRAD = pi/180

y1 = 1.5

  y2 = y1 - 1/tan((ANG)*DEGRAD)


  z1 = 1
  x1 = 1


Ablock1 = matrix(c(0,0,0,
    1,0,0,
    1,y1,0,
    0,y1,0,
    0,0,-1,
    1,0,-1,
    1,y2,-1,
    0,y2,-1), byrow=TRUE, ncol=3)


Nblock1 = makeblock3D(Ablock1)
Light=c(45,45)
angz = -45
angx = -45

R1 = ROTZ(angz)
R2 = ROTX(angx)

   M =    R1 

Z2 = PROJ3D(Nblock1$aglyph, M=M,  anorms=Nblock1$anorm ,  zee=c(0,0,1))
RangesX = range(attr(Z2, "RangesX"))

  RangesY = range(attr(Z2, "RangesY"))


plot( RangesX, RangesY, type='n', asp=1, ann=FALSE, axes=FALSE)

phong3D(Nblock1$aglyph, M=M,  anorms=Nblock1$anorm , Light = Light,
zee=c(0,0,1), col=rgb(.7,.5, .5)  , border="black")