30 lines
1.7 KiB
C
30 lines
1.7 KiB
C
#include "structs.h"
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#include "math.h"
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vec3 collisionPointSphere(ray *lightray, sphere *object)
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{
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vec3 collisionPoint;
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collisionPoint.x = -1;
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collisionPoint.y = -1;
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collisionPoint.z = -1;
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double a = lightray->direction.x * lightray->direction.x + lightray->direction.y * lightray->direction.y + lightray->direction.z * lightray->direction.z;
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double b = 2 * ((lightray->direction.x * (lightray->origin.x - object->origin.x)) + (lightray->direction.y * (lightray->origin.y - object->origin.y)) + (lightray->direction.z * (lightray->origin.z - object->origin.z)));
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double c = (lightray->origin.x * lightray->origin.x + object->origin.x * object->origin.x - 2 * lightray->origin.x * object->origin.x)
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+ (lightray->origin.y * lightray->origin.y + object->origin.y * object->origin.y - 2 * lightray->origin.y * object->origin.y)
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+ (lightray->origin.z * lightray->origin.z + object->origin.z * object->origin.z - 2 * lightray->origin.z * object->origin.z)
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- object->radius * object->radius;
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double discriminant = b * b - 4 * a * c;
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if (discriminant < 0) return collisionPoint;
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if (discriminant > 0) {
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double S = (-b - sqrt(discriminant)) / (2 * a);
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collisionPoint.x = S * lightray->direction.x + lightray->origin.x;
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collisionPoint.y = S * lightray->direction.y + lightray->origin.y;
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collisionPoint.z = S * lightray->direction.z + lightray->origin.z;
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return collisionPoint;
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}
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double S = (-b)/(2*a);
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collisionPoint.x = S * lightray->direction.x + lightray->origin.x;
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collisionPoint.y = S * lightray->direction.y + lightray->origin.y;
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collisionPoint.z = S * lightray->direction.z + lightray->origin.z;
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return collisionPoint;
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} |