public static bool IsTheretAEncounterAtTheRange(LinearFunc first, LinearFunc second)
{
double x = 0.0d;
double y = 0.0d;
if (!first.isXFixed && !first.isYFixed && !second.isXFixed && !second.isYFixed)
{
//if enter here, means the no slope are zeros, and we can solve using normal equation solution
//check if both lines are the same line and the range touch of one touch the another
if (first.slope == second.slope && first.bias == second.bias && ((first.xMax <= second.xMax && first.xMax >= second.xMin) || (first.xMin <= second.xMax && first.xMin >= second.xMin)))
{
return true;
}
//check if both line are the same line
else if (second.slope == first.slope && first.bias == second.bias)
{
return false;
}
//check if both lines are parallel
else if (second.slope == first.slope)
{
return false;
}
// finally solve the equation system
// first.slope*x + first.bias = y
// second.slope*x + second.bias = y
// by the magic of high school math it can be transforme in
// first.slope*x + first.bias = second.slope*x + second.bias
// and
// first.slope*x = second.slope*x + second.bias - first.bias
// and
// first.slope*x - second.slope*x = second.bias - first.bias
// and
// x * (first.slope - second.slope) = second.bias - first.bias
// and FINALLY
// x = (second.bias - first.bias)/(first.slope-second.slope)
// after solve the "x" unknown, just put x in any of the equations
// like
// y = x*first.slope + first.bias
// and we have x and y
else
{
x = (second.bias - first.bias) / (first.slope - second.slope);
y = x * first.slope + first.bias;
}
}
//Test if both linear func are points
else if (first.isXFixed && first.isYFixed && second.isXFixed && second.isYFixed)
{
//if they are the same points, they are visible one to other and no one is
//blocking the vision
if (first.xMax == second.xMax && first.yMax == second.yMax)
{
x = first.xMax;
y = first.yMax;
return false;
}
else
//otherwise they have no solution, but still dont block the vision
return false;
}
//if first is a point, check is that point is part of the line of the second
else if (first.isXFixed && first.isYFixed)
{
y = first.xMax * second.slope + second.bias;
x = first.xMax;
//if it's not, it will return that it's not blocking the vision, if it is, will
//load y and x to later check if they are in the range.
if (y != first.yMax)
return false;
}
//the same check but now with second
else if (second.isXFixed && second.isYFixed)
{
y = second.xMax * first.slope + first.bias;
x = second.xMax;
if (y != second.yMax)
return false;
}
// if first and second are perpendicular it's easy to calc the encounter point
else if (first.isXFixed && second.isYFixed)
{
x = first.xMax;
y = second.yMax;
}
// if first and second are perpendicular it's easy to calc the encounter point( again, hehe)
else if (first.isYFixed && second.isXFixed)
{
x = second.xMax;
y = first.yMax;
}
//if first and second are parallel horizontaly
else if (first.isXFixed && second.isXFixed)
{
//check if they are the same line, and also check if the range of the two lines crosses one another
//if yes, they are blocking the vision
if (first.xMax == second.xMax && ((first.yMax < second.yMax && first.yMax > second.yMin) || (first.yMin < second.yMax && first.yMin > second.yMin) || (second.yMin < first.yMax && second.yMin > first.yMin)))
return true;
//otherwise still check if they are the same line, but they are not blocking the vision and systems have many solutions
else if (first.xMax == second.xMax)
return false;
else
// if they are not the same line, there is no solution
return false;
}
//if first and second are parallel vertically, do the same check before
else if (first.isYFixed && second.isYFixed)
{
if (first.yMax == second.yMax && ((first.xMax < second.xMax && first.xMax > second.xMin) || (first.xMin < second.xMax && first.xMin > second.xMin) || (second.xMin < first.xMax && second.xMin > first.xMin)))
return true;
else if (first.yMax == second.yMax)
return false;
else
return false;
}
//if it is here, the two lines are not fixed, so check
//if one is fixed, if it is, keep the variable who is fixed, fixed
// and run the linear func to calc the y point
else if (first.isXFixed)
{
x = first.xMax;
y = first.xMax * second.slope + second.bias;
}
// the same thing as before
else if (first.isYFixed)
{
x = first.yMax * second.slopeInv + second.biasInv;
y = first.yMax;
}
// the same thing as before ( again)
else if (second.isXFixed)
{
x = second.xMax;
y = second.xMax * first.slope + first.bias;
}
// the same thing as before ( again II)
else if (second.isYFixed)
{
x = second.yMax * first.slopeInv + first.biasInv;
y = second.yMax;
}
else
{
return false;
//warn("if falls here, it will create a black hole and destroy all humankind")
}
// if it's here, means the both lines are not parallel, neither the same line
// so checks if the only solution to the system are inside of the range of both lines
// if it is, it means that the lines are blocking the vision one from another
if (x <= first.xMax && x >= first.xMin && y <= first.yMax && y >= first.yMin && x <= second.xMax && x >= second.xMin && y <= second.yMax && y >= second.yMin)
{
//the only exception is if the encounter point is exactly the start or the end of any of the lines
// it could consider that as blocking the vision, but the way it's now, it's easier to check if
// two obstacles are crossing one another and also the visibility problem, so I solve two problems with one algorithm
if ((x == first.x1 && y == first.y1) || (x == first.x2 && y == first.y2) || (x == second.x1 && y == second.y1) || (x == second.x2 && y == second.y2))
return false;
else
return true;
}
// otherwise the system has one solution and line intersection are out of the range
else
{
return false;
}
}
public void TestConditionConstantYConstantXTrue()
{
LinearFunc l1 = new LinearFunc(-50, 1, 50, 1);
LinearFunc l2 = new LinearFunc(1, -50, 1, 50);
Assert.IsTrue(LinearFunc.IsTheretAEncounterAtTheRange(l1, l2));
}
public static Point? getEncounterPoint(LinearFunc first, LinearFunc second)
{
double x;
double y;
if (!first.isXFixed && !first.isYFixed && !second.isXFixed && !second.isYFixed)
{
//if enter here, means the no slope are zeros, and we can solve using normal equation solution
//check if both lines are the same line and the range touch of one touch the another
if (first.slope == second.slope && first.bias == second.bias && ((first.xMax <= second.xMax && first.xMax >= second.xMin) || (first.xMin <= second.xMax && first.xMin >= second.xMin)))
{
return null;
}
//check if both line are the same line
else if (second.slope == first.slope && first.bias == second.bias)
{
return null;
}
//check if both lines are parallel
else if (second.slope == first.slope)
{
return null;
}
// finally solve the equation system
// first.slope*x + first.bias = y
// second.slope*x + second.bias = y
// by the magic of high school math it can be transforme in
// first.slope*x + first.bias = second.slope*x + second.bias
// and
// first.slope*x = second.slope*x + second.bias - first.bias
// and
// first.slope*x - second.slope*x = second.bias - first.bias
// and
// x * (first.slope - second.slope) = second.bias - first.bias
// and FINALLY
// x = (second.bias - first.bias)/(first.slope-second.slope)
// after solve the "x" unknown, just put x in any of the equations
// like
// y = x*first.slope + first.bias
// and we have x and y
else
{
x = (second.bias - first.bias) / (first.slope - second.slope);
y = x * first.slope + first.bias;
}
}
//Test if both linear func are points
else if (first.isXFixed && first.isYFixed && second.isXFixed && second.isYFixed)
{
//if they are the same points, they are visible one to other and no one is
//blocking the vision
if (first.xMax == second.xMax && first.yMax == second.yMax)
{
x = first.xMax;
y = first.yMax;
return new Point(x,y);
}
else
//otherwise they have no solution, but still dont block the vision
return null;
}
//if first is a point, check is that point is part of the line of the second
else if (first.isXFixed && first.isYFixed)
{
y = first.xMax * second.slope + second.bias;
x = first.xMax;
//if it's not, it will return that it's not blocking the vision, if it is, will
//load y and x to later check if they are in the range.
if (y != first.yMax)
return null;
}
//the same check but now with second
else if (second.isXFixed && second.isYFixed)
{
y = second.xMax * first.slope + first.bias;
x = second.xMax;
if (y != second.yMax)
return null;
}
// if first and second are perpendicular it's easy to calc the encounter point
else if (first.isXFixed && second.isYFixed)
{
x = first.xMax;
y = second.yMax;
}
// if first and second are perpendicular it's easy to calc the encounter point( again, hehe)
else if (first.isYFixed && second.isXFixed)
{
x = second.xMax;
y = first.yMax;
}
//if first and second are parallel horizontaly
else if (first.isXFixed && second.isXFixed)
{
//check if they are the same line, and also check if the range of the two lines crosses one another
//if yes, they are blocking the vision
if (first.xMax == second.xMax && ((first.yMax < second.yMax && first.yMax > second.yMin) || (first.yMin < second.yMax && first.yMin > second.yMin) || (second.yMin < first.yMax && second.yMin > first.yMin)))
return null;
//otherwise still check if they are the same line, but they are not blocking the vision and systems have many solutions
else if (first.xMax == second.xMax)
return null;
else
// if they are not the same line, there is no solution
return null;
}
//if first and second are parallel vertically, do the same check before
else if (first.isYFixed && second.isYFixed)
{
if (first.yMax == second.yMax && ((first.xMax < second.xMax && first.xMax > second.xMin) || (first.xMin < second.xMax && first.xMin > second.xMin) || (second.xMin < first.xMax && second.xMin > first.xMin)))
return null;
else if (first.yMax == second.yMax)
return null;
else
return null;
}
//if it is here, the two lines are not fixed, so check
//if one is fixed, if it is, keep the variable who is fixed, fixed
// and run the linear func to calc the y point
else if (first.isXFixed)
{
x = first.xMax;
y = first.xMax * second.slope + second.bias;
}
// the same thing as before
else if (first.isYFixed)
{
x = first.yMax * second.slopeInv + second.biasInv;
y = first.yMax;
}
// the same thing as before ( again)
else if (second.isXFixed)
{
x = second.xMax;
y = second.xMax * first.slope + first.bias;
}
// the same thing as before ( again II)
else if (second.isYFixed)
{
x = second.yMax * first.slopeInv + first.biasInv;
y = second.yMax;
}
else
{
return null;
//warn("if falls here, it will create a black hole and destroy all humankind")
}
return new Point(x, y);
}
public void TestConditionConstantXSameLineTrue()
{
LinearFunc l1 = new LinearFunc(1, 2, 1, 50);
LinearFunc l2 = new LinearFunc(1, 49, 1, 100);
Assert.IsTrue(LinearFunc.IsTheretAEncounterAtTheRange(l1, l2));
}
public void TestConditionConstantYAndMovingTrue()
{
LinearFunc l1 = new LinearFunc(100, 1, 150, 1);
LinearFunc l2 = new LinearFunc(100, -10, 150, 50);
Assert.IsTrue(LinearFunc.IsTheretAEncounterAtTheRange(l1, l2));
}
public void TestConditionConstantXParallelFalse()
{
LinearFunc l1 = new LinearFunc(1, 10, 1, 100);
LinearFunc l2 = new LinearFunc(2, 10, 2, 100);
Assert.IsFalse(LinearFunc.IsTheretAEncounterAtTheRange(l1, l2));
}
public void TestConditionConstantXAndMovingTrue()
{
LinearFunc l1 = new LinearFunc(-100, -10, -100, 10);
LinearFunc l2 = new LinearFunc(-101, -9, -99, 11);
Assert.IsTrue(LinearFunc.IsTheretAEncounterAtTheRange(l1, l2));
}
public void TestConditionConstantXAndMovingFalse()
{
LinearFunc l1 = new LinearFunc(-100, -10, -100, 10);
LinearFunc l2 = new LinearFunc(-150, -110, -101, 50);
Assert.IsFalse(LinearFunc.IsTheretAEncounterAtTheRange(l1, l2));
}
public void TestConditionBothMovingTrue()
{
LinearFunc l1 = new LinearFunc(45, 45, -45, -45);
LinearFunc l2 = new LinearFunc(45, -45, -45, 45);
Assert.IsTrue(LinearFunc.IsTheretAEncounterAtTheRange(l1, l2));
}
public void TestConditionConstantYSameLineFalse()
{
LinearFunc l1 = new LinearFunc(10, 1, 50, 1);
LinearFunc l2 = new LinearFunc(52, 1, 100, 1);
Assert.IsFalse(LinearFunc.IsTheretAEncounterAtTheRange(l1, l2));
}