// 3D Angle Tool
//
// Use this tool to measure angles in 3D by selecting 3 points, 
// where the middle point is the vertex. Add it to StartupMacros.txt
// to have it automatically installed when ImageJ starts up.

var coords = newArray(9);
var angle_index = 0;

macro '3D Angle Tool - C037L0fb4L0fffLafacL9b9aD89L0011L1102L0213L1304L4233L3344L5054' {
    getCursorLoc(x, y, z, flags);
    getVoxelSize(vw, vh, vd, unit);
    x*=vw; y*=vh; z*=vd;
    coords[angle_index++] = x;
    coords[angle_index++] = y;
    coords[angle_index++] = z;
    if (angle_index == 3) {
        showStatus("selected first end point: " + x + ", " + y + ", " + z);
        showResults(NaN);
    } else if (angle_index == 6) {
        showStatus("selected vertex: " + x + ", " + y + ", " + z);
        showResults(NaN);
    } else {
        coords[0] -= coords[3]; 
        coords[1] -= coords[4]; 
        coords[2] -= coords[5]; 
        coords[6] -= coords[3]; 
        coords[7] -= coords[4]; 
        coords[8] -= coords[5]; 
		// scalar product 
        product = coords[0] * coords[6] 
            + coords[1] * coords[7] 
            + coords[2] * coords[8]; 
        length1 = sqrt(coords[0] * coords[0]
            + coords[1] * coords[1] 
            + coords[2] * coords[2]); 
        length2 = sqrt(coords[6] * coords[6] 
            + coords[7] * coords[7] 
            + coords[8] * coords[8]); 
        degrees = acos(product / length1 / length2) * 45 / atan(1); 
        showStatus("3d angle is " + degrees + " degrees"); 
        showResults(degrees);
        angle_index = 0; 
    }
}

function showResults(angle) {
    row = nResults - 1;
    if (angle_index==3) {
        row++;
        setResult("Label", row, "First point defined");
    } else if (angle_index==6)
        setResult("Label", row, "Vertex defined");
    else
        setResult("Label", row, "Last point defined");
    setResult("Angle", row, angle);
    updateResults();
}
