Stuff I learned while building Rasterizer in c
Note the following is my understanding of the listed topics, which may or may not be correct (:
TGA
Resources
Tga is a image file format.
The TGA has metadata within the header varying from image/color map specifications to the actual image data. The bytes in TGA’s are stored in little-endian ordering and image data has the option to be compressed with RLE compresssion.
OBJ
Resources
OBJ files are a geometry definition by wavefront. They first start with the declerations of verticies in 3d space in the format of “v <vertex 1> <vertex 2> <vertex 3>” and then two other specifications for the vertex the texture and normal vectors, but the last is what is the most important, the faces. The faces hold multiple set of numbers but the ones I am using right now to just draw the triangles are the set of three vectors specified by the index into the set of verticies which starts at 1.
Bresenhams Ling Algorithm
Resources
It is what it sounds like, a line algorithm used for guessing the pixels to fill along a line formed by two points. From what I could read and understand the algorithm iterates through the x cordinates of the line and calculates the best fit y position for each x position. It does this through the use of finding the the middle of two points y + 1 and y for each x cordinate and
Barycentric coordinate system
Resources
- https://users.csc.calpoly.edu/~zwood/teaching/csc471/2017F/barycentric.pdf
- https://www.youtube.com/watch?v=HYAgJN3x4GA
I used the barycentric coordinate system to determine if a point P is inside a triangle formed by three points A, B, and C when filling a triangle. The system uses two weight values lets say u and v to scale the line segments of two sides of a triangle(AB and AC) based on the cordinate of P. With the values of u(AB) and v(AC) we can add these new scaled vectors so that they result in the position of P. Using this system we now know if P is inside the triangle if u >= 0 and v >= 0 and (u + v) <= 1.