Simple sphere with normals
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@ -4,9 +4,27 @@
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#include <iostream>
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double hit_sphere (const point3& center, double radius, const ray& r) {
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vec3 oc = r.origin() - center;
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auto a = dot(r.direction(), r.direction());
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auto b = 2.0 * dot(oc, r.direction());
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auto c = dot(oc, oc) - radius*radius;
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auto discriminant = b*b - 4*a*c;
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if ( discriminant < 0) {
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return -1.0;
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}else{
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return (-b - sqrt(discriminant) ) / (2.0*a);
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}
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}
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color ray_color(const ray& r){
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auto t = hit_sphere(point3(0,0,-1), 0.5, r);
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if(t > 0.0){
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vec3 N = unit_vector(r.at(t) - vec3(0,0,-1));
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return 0.5*color(N.x()+1, N.y()+1, N.z()+1);
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}
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vec3 unit_direction = unit_vector(r.direction());
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auto t = 0.5*(unit_direction.y() + 1.0);
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t = 0.5*(unit_direction.y() + 1.0);
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return (1.0-t)*color(1.0, 1.0, 1.0) + t*color(0.5,0.7,1.0);
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}
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