bjorneek / 3d-graphics

simple 3d rasterizer made in sdl2

3D-graphics

---

A program that reads obj files and renders them in a window.

The goal with the project was to render a Utah-teapot in a window using only code written myself. I was mostly successful in doing this however i had to do some research and learn about projection matrices as well as freshen up on cross products.

---

The program is fairly limited in the files it can parse and it will not be able to render all .obj files. For a file to function it cannot contain normal data and the faces must be triangles. see the example below for a simple cube.

This file works:

o Cube
v 0.0 0.0 0.0
v 0.0 0.0 1.0
v 0.0 1.0 0.0
v 0.0 1.0 1.0
v 1.0 0.0 0.0
v 1.0 0.0 1.0
v 1.0 1.0 0.0
v 1.0 1.0 1.0
f 1 3 5
f 3 7 5
f 5 7 6
f 7 8 6
f 6 8 2
f 8 4 2
f 2 4 1
f 4 3 1
f 3 4 8
f 8 7 3
f 2 1 5
f 5 6 2

This file does not:

o Cube
v 0.0 0.0 0.0
v 0.0 0.0 1.0
v 0.0 1.0 0.0
v 0.0 1.0 1.0
v 1.0 0.0 0.0
v 1.0 0.0 1.0
v 1.0 1.0 0.0
v 1.0 1.0 1.0
f 1 3 5 7
f 5 7 6 8
f 6 8 2 4
f 2 4 1 3
f 3 4 8 7
f 2 1 5 6

The lines begining with a 'f' in a .obj file represents a face and they have to be in the format f P1 P2 P3 and not f P1 P2 P3 ... Pn or f P1/N1 P2/N2 P3/N3.

---

Usage

$ ./3D-graphics <filename.obj>
$ ./3D-graphics <filename.obj> rand (for random colors)
$ ./3D-graphics <filename.obj> <FOREGROUND_COLOR> (RED, GREEN, BLUE)
$ ./3D-graphics <filename.obj> <FOREGROUND_COLOR> <BACKGROUND_COLOR>
$ ./3D-graphics <filename.obj> <FOREGROUND_RGB> (1,0.7,0.3) values between 1 and 0
$ ./3D-graphics <filename.obj> <FOREGROUND_RGB> <BACKGROUND_RGB>

controlls

Key	Action, enable/dissable
H	wireframe
J	render with color
L	render with light
k	dissable triangle sorting
W/UP	move light source up
A/LEFT	move light source left
S/DOWN	move light source down
D/RIGHT	move light source right
left mouse	rotate object
SHIFT+ left mouse	move object
scroll wheel	move object in Z dir