Ray Trace example: Pyramid

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§ 16.90.6.10 - Ray Trace example: Pyramid

Not much has been done with triangles up to this point. Triangles can come together to form something as simple as this pyramid to anything you can imagine. Most professional computer animation is constructed of triangles.

The image on the left is a brick texture we can use for an imagemap of the triangles. But image mapping on a triangle assumes a right triangle when it scales the image. This can be corrected for our pyramid, which uses equilateral triangles, by shearing the image 45°, as has been done with the image on the right. Now the imagemapping will un-shear the mapped image back to its original upright position.

Library:
     <libpath "c:\w3\"> 
     <lib "textures.w3d"> 

Random Numbers:
     <seed 35> 

The following keys act as variables for the easy manipulation of the pyramid. At any time, the corner points (A,B,C,D) or the apex (E) can be moved just by altering these keys. No other searching or altering is necessary in the script. Each key starts in frame 1 and sets the following value for all succeeding frames; basically that means a constant value during timeline generation:
     <keys "Ax" 1 -3> 
     <keys "Ay" 1 0> 
     <keys "Az" 1 3> 
     <keys "Bx" 1 3> 
     <keys "By" 1 0> 
     <keys "Bz" 1 3> 
     <keys "Cx" 1 3> 
     <keys "Cy" 1 0> 
     <keys "Cz" 1 -3> 
     <keys "Dx" 1 -3> 
     <keys "Dy" 1 0> 
     <keys "Dz" 1 -3> 
     <keys "Ex" 1 0> 
     <keys "Ey" 1 5> 
     <keys "Ez" 1 0> 
     <keys "av" 1 .5> 

Each of the following four triangles will be bound to two corner points and the apex defined by the keys above. This allows for complete control over the shape of the pyramid. Here is the pyramid object:
 <normalize> 
 <structure> 
     <apply "matte"> 
     <ambient av> 
     <vtx0 Ax Ay Az> 
     <vtx1 Bx By Bz> 
     <vtx2 Ex Ey Ez> 
     <color0 0 0 1> 
     <color1 0 0 1> 
     <color2 0 0 1> 
     <imagemap "c:\imagemaps\brick1.jpg"> 
     <object tri "tri_1"> 
 </structure> 

 <structure> 
     <apply "matte"> 
     <ambient av> 
     <vtx0 Bx By Bz> 
     <vtx1 Cx Cy Cz> 
     <vtx2 Ex Ey Ez> 
     <color0 0 0 1> 
     <color1 0 0 1> 
     <color2 0 0 1> 
     <imagemap "c:\imagemaps\brick1.jpg"> 
     <object tri "tri_2"> 
 </structure> 

 <structure> 
     <apply "matte"> 
     <ambient av> 
     <vtx0 Cx Cy Cz> 
     <vtx1 Dx Dy Dz> 
     <vtx2 Ex Ey Ez> 
     <color0 0 0 1> 
     <color1 0 0 1> 
     <color2 0 0 1> 
     <imagemap "c:\imagemaps\brick1.jpg"> 
     <object tri "tri_3"> 
 </structure> 

 <structure> 
     <apply "matte"> 
     <ambient av> 
     <vtx0 Dx Dy Dz> 
     <vtx1 Ax Ay Az> 
     <vtx2 Ex Ey Ez> 
     <color0 0 0 1> 
     <color1 0 0 1> 
     <color2 0 0 1> 
     <imagemap "c:\imagemaps\brick1.jpg"> 
     <object tri "tri_4"> 
 </structure> 

Ground:
 <normalize> 
 <structure> 
     <apply "brightmatte"> 
     <vtx0 10000 0 10000> 
     <vtx1 10000 0 -10000> 
     <vtx2 -10000 0 10000> 
     <color 1 0.9 0.8> 
     <color0 1 .8 .2> 
     <uvtexture "dunes" 2 .01 0> 
     <object rect "sand"> 
 </structure> 
 <object bound> 

Light:
     <normalize> 
     <position 5000 500 2500> 
     <color 1 1 1> 
     <object light "light_1"> 

Camera moves in a circle on the x-z plane:
     <viewlocation !cos(loopv(cframe(0))*6.281835)*14 6 !sin(loopv(cframe(0))*6.281835)*14> 

 <viewtarget 0 0 0> 