The Fred Fish Collection 1.5/ffcollection-1-5-1992-11.iso/ff_progs/graphics/raydance.lzh/demo_scripts.lha/tutorial3.art

Text File | 1991-10-20 | 3.9 KB | 152 lines

!---------------------------------------------------------------
!
! TUTORIAL3 - RayDance tutorial script #3.
!
! This script demonstrates specular hilite control on a 4 x 5
! array of spheres.
!
! Concepts include :
!
!  o Declaring PHONG surfaces with different ks and n values.
!
!  o Declaring and calling procedures
!
!  o Using variables
!
!  o Using WHILE loops
!
!  o Using a PRINT statement to display the contents of
!    variables
!
!---------------------------------------------------------------

! Provide some informative text on the message window describing
! this script.

? "TUTORIAL3 - This script defines a scene with four rows of\n",
  "5 spheres.  Each sphere will be the same color but will\n",
  "have different specular reflection surface values (ks and\n",
  "n).  ks will increase toward the bottom rows.  n will\n",
  "increase toward the right side of the screen.  Higher\n",
  "values of ks increase the brightness of specular\n",
  "highlighting while higher values of n will make the\n",
  "highlight more focused.\n";

! The camera will be positioned along the negative y axis
! looking at the origin.

CAMERA'POS = [0,-3000,0];
CAMERA'TARGET = [0,0,0];


! Define the color of the sphere

SPHERE_COLOR : COLOR ( RGB, [0.8,0.4,0] );  ! Lt orange


! Declare our variables.

real   XPOS,ZPOS;

real   KS,N;


! Declare a procedure (subroutine).  This procedure will create
! a sphere at the specified location with the specified surface
! characteristics.
!
! NOTE: All variables declared inside a procedure (including
! surfaces) are local.  This means that each time you call the
! procedure a completely new and unique variable will be
! created.  We will exploit this feature to create a seperate
! surface for each sphere within this procedure.

proc MAKESPHERE( vector POS, real RADIUS,
                 real PHONG_KS, real PHONG_N )

!                  ka  kd  ks       n      km  kr  ir  kb  flags
  SPHERE_SURF :
    SURFACE(PHONG, 1.0,1.0,PHONG_KS,PHONG_N,0.0,0.0,0.0,0.0,0 );

! Create the actual sphere

  SPHERE( POS, RADIUS, SPHERE_COLOR, SPHERE_SURF );

! Print the position and surface parameters of each sphere

  ? "Creating sphere,", POS, RADIUS,
    "Ks & n", PHONG_KS, PHONG_N, "\n";

endproc


! Setup two loops to create the spheres.  The spheres will be
! placed in rows parallel to the x axis and columns parallel to
! the z axis.

XPOS = -800;
N = 1;

while (XPOS <= 800) {

  ZPOS = 600;
  KS = 0.1;

  while (ZPOS >= -600) {

! Call the procedure that will construct the sphere.  Since
! radius was declared as a REAL we MUST pass a real constant,
! 100.0.  Passing 100 (an integer constant) will cause syntax
! errors.

    MAKESPHERE( [XPOS,0,ZPOS], 100.0, KS, N );

    KS = KS + .2;
    ZPOS = ZPOS - 400;
  }

  XPOS = XPOS + 400;
  N = N * 3;
}


! Specify the ambient light.  This will provide illumination for
! the areas that are shadows from the star light source.
! Positioning of ambient lights is reserved for future
! expansion.  For now, set position to [0,0,0].  The intensity
! of ambient lights should range from [0,0,0] to [1,1,1].  We
! will use a muted white light. The ambient direction is UP, but
! since K1 and K2 are zero this light is non-directional making
! direction a place holder.  UP is toward the positive z-axis.

!        always 0's  color      direction k1(base) k2(range)

AMBIENT( [0,0,0], [0.6,0.6,0.6], [0,0,1],   0,     0 );


! Specify the STAR light.  Position it above, behind, and to the
! right of the camera.  Since the light of a star doesn't
! diminish with distance good light values range from [0,0,0] to
! [1,1,1].  Make a slightly yellowish star.

!       position          color   radius

STAR( [5000,-5000,4000], [1,1,.9], 300 );


! Set the background color to a dark, muddy red

!           type   rgb color value

BACKGROUND( PLAIN, [0.2,0.05,0.05] );


! The scene has now been constructed, render it!

RENDER;


! All scripts must terminate with an END

END