mgs/quickhull
2
0
Fork 0
Code Issues Pull Requests Projects Releases 1 Wiki Activity

calculate perpendicular distance to find furthest point from line

Browse Source
This commit is contained in:
incredibleLeitman 2020-11-27 03:48:34 +01:00
parent 880d6252fa
commit c64b2b01e5
2 changed files with 72 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
Display.cpp
View File

@ -137,6 +137,7 @@ void Display::update ()
sf::Vector2f pos = pt.getPosition();
float x = pos.x;
float y = pos.y;
// TODO: only check explicit x and y seperate!
if (x < topLeft.x && y < topLeft.y) topLeft = pos;
if (x > topRight.x && y < topLeft.y) topRight = pos;
if (x < botLeft.x && y > botLeft.y) botLeft = pos;
@ -186,17 +187,48 @@ void Display::update ()
for (auto& pt : m_points)
{
sf::Vector2f pos = pt.getPosition();
float x = pos.x;
float y = pos.y;
pt.setFillColor(sign(x, y, m_hull[0].position.x, m_hull[0].position.y, m_hull[1].position.x, m_hull[1].position.y) > 0 ? sf::Color::Red : sf::Color::Green);
pt.setFillColor(sign(
pt.getPosition().x, pt.getPosition().y,
m_hull[0].position.x, m_hull[0].position.y,
m_hull[1].position.x, m_hull[1].position.y) > 0 ? sf::Color::Red : sf::Color::Green);
}
}
else if (curStep == 3)
{
// third step: draw triangle, remove inner points
m_textStatus.setString(text + "find furthest point and draw triangle...");
sf::Vector2f pos = m_points[0].getPosition();
float maxDistance = 0;
for (auto& pt : m_points)
{
float distance = pDistance(
pt.getPosition().x, pt.getPosition().y,
m_hull[0].position.x, m_hull[0].position.y,
m_hull[1].position.x, m_hull[1].position.y);
if (pt.getFillColor() == sf::Color::Green)
{
std::cout << "distance to green point " << pt.getPosition().x << ", " << pt.getPosition().y << ": " << distance << std::endl;
}
else if (pt.getFillColor() == sf::Color::Red)
{
std::cout << "distance to red point " << pt.getPosition().x << ", " << pt.getPosition().y << ": " << distance << std::endl;
}
if (distance > maxDistance)
{
pos = pt.getPosition();
maxDistance = distance;
}
}
if (maxDistance > 0)
{
// TODO: not append but insert between last line points
m_hull.append(sf::Vertex(pos, sf::Color::Blue));
}
}
else if (curStep == 4)
{

37
Utility.h
View File

@ -1,9 +1,9 @@
#pragma once
#ifndef UTILITY_H
static float sign(float x1, float y1, float x2, float y2, float x3, float y3)
static float sign(float x, float y, float x1, float y1, float x2, float y2)
{
return (x1 - x3) * (y2 - y3) - (x2 - x3) * (y1 - y3);
return (x - x2) * (y1 - y2) - (x1 - x2) * (y - y2);
}
static float sign (Point &p1, Point &p2, Point &p3)
@ -23,6 +23,39 @@ static bool IsPointInTriangle(Point &pt, Point &p1, Point &p2, Point &p3)
return !(has_neg && has_pos);
}
static float pDistance(float x, float y, float x1, float y1, float x2, float y2) {
float A = x - x1;
float B = y - y1;
float C = x2 - x1;
float D = y2 - y1;
float dot = A * C + B * D;
float len_sq = C * C + D * D;
float param = -1;
if (len_sq != 0) // in case of 0 length line
param = dot / len_sq;
float xx, yy;
if (param < 0) {
xx = x1;
yy = y1;
}
else if (param > 1) {
xx = x2;
yy = y2;
}
else {
xx = x1 + param * C;
yy = y1 + param * D;
}
float dx = x - xx;
float dy = y - yy;
return dx * dx + dy * dy;
//return sqrt(dx * dx + dy * dy);
}
static bool SortForMinXMaxY (const Point& a, const Point& b)
{
if (a.x() != b.x())