Added circle circle intersection area #139
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| double circleCircleArea(P c, double cr, P d, double dr) { | ||
| if (cr < dr) swap(c, d), swap(cr, dr); | ||
| auto A = [&](double r, double h) { | ||
| return r*r*acos(h/r)-h*sqrt(r*r-h*h); |
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The removal of the epsilons now means that r < h can happen due to numerical precision, I suspect (though I haven't tested). h = min(h, r); may be reasonable? h < 0 can likely also happen but doesn't seem like a problem.
| auto l = (c - d).dist(), a = (l*l + cr*cr - dr*dr)/(2*l); | ||
| if (l - cr - dr >= 0) return 0; // far away | ||
| if (l - cr + dr <= 0) return M_PI*dr*dr; | ||
| if (l - cr >= 0) return A(cr, a) + A(dr, l-a); |
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these inequalities can be simplified now without the epsilons
| auto A = [&](double r, double h) { | ||
| return r*r*acos(h/r)-h*sqrt(r*r-h*h); | ||
| }; | ||
| auto l = (c - d).dist(), a = (l*l + cr*cr - dr*dr)/(2*l); |
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double is clearer than auto
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No tests - sanity checked it.