• the only objects in the scene are generic spheres, generic planes, generic cubes, generic squares, and generic tapered cylinders, which may have been
  • scaled
  • translated
  • rotated with respected to an axis
    
    
• in addition to color, the attributes of the generic primitives may include material values for diffuse, specular, ambient color
  
• in addition to material attributes, the plane, the square, and (*15) the sphere may be textured with a 2D image.
  
  • the image is defined in a ppm formatted file
  
  
• a positional light may be placed in the scene by specifying its position
  
• the light has a diffuse, specular, and ambient component
  
• a value for global ambient light may be assigned
  
• the intensity of lights may be attenuated by including values for
  • constant attenuation factor
  • linear attenuation factor
  • quadratic attenuation factor
    
• a spotlight may be placed in the scene by specifying its
  • position
  • spot direction
  • cutoff angle
  • spot exponent
  
  
• shadows are correctly rendered, including on textured surface
  
• speedup: extents are used around each generic primitive (generic cube around the generic primitive is test first; if hit, then primitive is tested)
  
• the camera is set up
  • at position (eye_x, eye_y, eye_z),
    
  • looking at point (look_at_x, look_at_y, look_at_z), with
    
  • the original up-direction for the camera being <up_x, up_y, up_z>.
    
    
• speed-up has been accomplished by more wisely computing the ray's direction, for each ray.
  
• descriptions of the objects, lights, and camera, as well as the names of the image files, are read in from a file, using SDL
  
• value for backgroundColor is now read in from the scene description file, using SDL