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Back to Math and Physics

Rotate object in world space - Raytracing

ellenature · 2020-08-27T12:29:54

I’m programming a C raytracing project. I’ve been wanting to implement object rotations (square, cylinder) for several days but I can’t do it. For each object, I have its position (x, y, z) in the world space and its 3d normalized orientation vector. For the moment, I do nothing more than applying once of the three following functions on the 3d normalized orientation vector. I don’t know if I’m doing it right. Rotation doesn't work well. For example, I want to rotate my object left with the j key and right with the l key (x_rotation), up with the i key and down with the k key (y_rotation). I'm not sure how to use the z axis. I'm starting to despair, can you please help me? I will be very grateful for your help :) t_vec x_rotation(t_vec vec, float alpha) { t_vec res; res.x = vec.x; res.y = vec.y * cos(alpha) - vec.z * sin(alpha); res.z = vec.y * sin(alpha) + vec.z * cos(alpha); return (res); } t_vec y_rotation(t_vec vec, float alpha) { t_vec res; res.x = vec.z * sin(alpha) + vec.x * cos(alpha); res.y = vec.y; res.z = vec.z * cos(alpha) - vec.x * sin(alpha); return (res); } t_vec z_rotation(t_vec vec, float alpha) { t_vec res; res.x = vec.x * cos(alpha) - vec.y * sin(alpha); res.y = vec.x * sin(alpha) + vec.y + cos(alpha); res.z = vec.z; return (res); }