How would one go about retrieving scan lines for all the lines in a 2D triangle?
I’m attempting to implement the most basic feature of a 2D software renderer, that of texture mapping triangles. I’ve done this more times than i can count using OpenGL, but i find myself limping when trying to do it myself.
I see a number of articles saying that in order to fill a triangle (whose three vertices each have texture coordinates clamped to [0, 1]), i need to linearly interpolate between the three points. What? I thought interpolation was between two n-dimensional values.
NOTE; This is not for 3D, it’s strictly 2D, all the triangles are arbitrary (not axis-aligned in any way). I just need to fill the screen with their textures the way OpenGL would. I cannot use OpenGL as a solution.
An excellent answer and description can be found here: http://sol.gfxile.net/tri/index.html
You can use the Bresenham algorithm to draw/find the sides.