Continuing with Square.cpp

• A note on some OpenGL commands
  • glfoocount[v][u][bsifd]
  • man glColor
• The redisplay function is drawScene
  • This gets called
    • When there is an expose event
    • When the window is created
    • When the window is resized
    • When glutPostRedisplay is called.
  • In our case, this just draws the square.
    • glBegin() .. glEnd()
      • These begin and end the definition of an object.
      • glBegin takes a single argument.
        • GL_POLYGON : a polygon
        • GL_POINTS : draw individual points
        • GL_LINES: Draw a series of lines
        • GL_LINE_STRIP:
        • GL_LINE_LOOP:
        • GL_TRIANGLES:
        • GL_TRIANGLE_STRIP
        • GL_TRIANGLE_FAN
        • GL_QUADS
        • GL_QUAD_STRIP
  • Let's look at myCircle.C
    • p will decrease the number of points
    • P will increase the number of points
    • s will change the mode in glBegin()
    • r will reset
    • x,X will change the x coordinate by -/+ 10
    • y,Y will change the y coordinate by -/+ 10
    • l/L will change the lower coordinates of the window
    • u/U will change the upper coordinates of the window.
  • Play with x/X, y/Y a bit
    • How does the coordinate system seem to work in OpenGL?
    • Is this different from mouse coordinates?