CODEWITHSUNDEEP
3dgeometryraytracing
user1804036
user1804036

Reputation:

draw 3D sphere in c++ without OpenGL

I need to make a sphere ray-tracer in c/c++ without the use of OpenGL. I'm confused though at how to put a sphere or light in a scene without any gl functions. Can someone please explain how this can be done?

Upvotes: 0

Views: 1538

Answers (1)

Aki Suihkonen
Aki Suihkonen

Reputation: 20087

Raytracing has nothing to do with opengl. It can be done with a desktop calculator.

The point is that it's pure geometry done with vectors, that are essentially three floating point variables. (or even integers).

You "put" your camera at origin: ox=0, oy=0, oz=0.

You "put" your sphere at 5 "meters" or units towards z-axis: sx=0,sy=0,sz=5;

You start to cast rays at 90 degree Field of View towards z-axis:

for (i=-1;i<1; i+=0.01) {
   for (j=-1;j<1; j+=0.01) {
       dx=i; dy=j;dz=1;  // perhaps you then need to normalize the "vector" dx,dy,dz
       // check if the ray hits the sphere with radius 2.3 (located at 0,0,5)

       // if it does, calculate the angle of the normal of the hit point and
       // the light source at position lx=1,ly=-0.5;lz=-2.33;

       // if normal dot lightray is positive, calculate angle, apply Phong model

       // add lambertian model, distance attenuation, fog, texturemapping

  }
 }

In the end you have calculated pixel intensities or color values for ~200 x 200 image. This example uses 90 degree FoV.

Upvotes: 1

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