Now can view blocks instead of just walls. Angle of view and distance from block supported. Doesn't yet handle both sides of a block. (ie field of vision is always in the forward direction - no looking back) Height of viewer is not going to be alterable, so you'll never see the top surface of blocks. (a crude technique but it means you only ever draw 2 faces out of 6 for any cube) Ceiling and floor may need to be drawn with the pen. TO DO: alter the luminosity according to the angle of incidence with the light source... (depends if this is a moving block or a moving viewer of course...)
Ultimately for use with vanishing-point-based perspective engine. The images were created as 360x360 with transparent pixels for the background. The centers are all 180px in from the left margin. Then the width of the visible pixels in the images was counted by the code. Note the shading cue on one side. :-)