One More Drawing Program

• Drawing an off file.
  • I decided to break it down into a single indexed array object.
  • Instead of the many different polygons
  • When I encountered a polygon with more than 3 points
    • I added p₁, p₂ and p₃ to the index list
    • Then p₁, p₃, p₄
    • ...
    • Until p₁, p_n-1, p_n
  • Thus I could draw everything with glDrawElements
• I made extensive use of the vec3 class
  • I built a vertex object (vertexT) out of vec3
  • And a vector of these (vertices)
  • Which I used for drawing.
• I made a routine to compute normals (DoNormal)
  • Which used the built in normalize and cross routines for the vec3 class.
• In MinMax I treated the vec3 as an indexable array, this is nice
• In LoadOff I used
  • overloaded stream extraction operator
  • And overloaded stream insertion operator (for debugging)
  • And many of the overloaded math operators
  • And a constructor (vec3(1,1,1))
  • Oh, and I scaled translated the data so it was inside the clipping cube centered at 0.
• Nothing huge in setup except
  • vecotor.data() returns a pointer to contiguous data store in a vector.
  • indices are stored in a GL_ELEMENT_ARRAY_BUFFER buffer.
  • And I am using two VBOs for my VAO
• There are more buffer manipulation routines, but this will do for now.
• The code
• The vertex shader