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thu0x31/innerTangents.vfl

Created May 21, 2022 17:04
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  1. thu0x31 created this gist May 21, 2022.
    35 changes: 35 additions & 0 deletions innerTangents.vfl
    View file
    Original file line number Diff line number Diff line change
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    function vector[] innerTangents(vector circle1Pos, circle2Pos;
    float circle1Radius, circle2Radius) {

    float hypotenuse = distance(circle1Pos, circle2Pos);
    float shortEdgeLen = circle1Radius + circle2Radius;
    float rad = atan2(circle2Pos.z - circle1Pos.z, circle2Pos.x - circle1Pos.x)
    + asin(shortEdgeLen/hypotenuse) - PI/2;
    vector circle1InnerTangent1 = set(
    circle1Pos.x + circle1Radius * cos(rad),
    circle1Pos.y,
    circle1Pos.z + circle1Radius * sin(rad)
    );

    vector circle2InnerTangent1 = set(
    circle2Pos.x + circle2Radius * cos(rad + PI),
    circle2Pos.y,
    circle2Pos.z + circle2Radius * sin(rad + PI)
    );

    float oppositeRad = atan2(circle2Pos.z - circle1Pos.z, circle2Pos.x - circle1Pos.x)
    - asin(shortEdgeLen/hypotenuse) + PI/2;
    vector circle1InnerTangent2 = set(
    circle1Pos.x + circle1Radius * cos(oppositeRad),
    circle1Pos.y,
    circle1Pos.z + circle1Radius * sin(oppositeRad)
    );

    vector circle2InnerTangent2 = set(
    circle2Pos.x + circle2Radius * cos(oppositeRad + PI),
    circle2Pos.y,
    circle2Pos.z + circle2Radius * sin(oppositeRad + PI)
    );

    return array(circle1InnerTangent1, circle1InnerTangent2, circle2InnerTangent1, circle2InnerTangent2);
    }