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#include "gldisc.h"
GLDisc::GLDisc(double radius, double height, int sides, GLColorRgba color,
QString textureFile)
: GLBody(sqrt(pow(radius, 2) + pow(0.5 * height, 2)), color, textureFile)
{
m_height = height;
m_sides = sides;
m_center = v_Z * 0.5 * m_height;
m_circleRadius = radius;
}
void GLDisc::makeSurface(QVector<GLPoint> *pointContainer,
QVector<GLshort> *indexContainer)
{
GLBody::makeSurface(pointContainer, indexContainer);
m_firstPoint = m_points->size();
m_points->append(GLPoint(v_Zero, -v_Z, QVector3D(0.5, 0.5, 0.0), m_color));
for (int side = 0; side < m_sides; side++)
{
QVector2D tmp = calculatePoint(side * 2 * M_PI / m_sides);
QVector2D tmpTextCoo = (0.5 * tmp) + QVector2D(0.5, 0.5);
m_points->append(GLPoint(m_circleRadius * tmp, -v_Z, tmpTextCoo, m_color));
m_points->append(GLPoint(m_circleRadius * tmp, tmp, tmpTextCoo, m_color));
m_points->append(GLPoint(QVector3D(m_circleRadius * tmp, m_height), tmp,
tmpTextCoo, m_color));
m_points->append(GLPoint(QVector3D(m_circleRadius * tmp, m_height), v_Z,
tmpTextCoo, m_color));
}
m_points->append(GLPoint(m_height * v_Z, v_Z, QVector3D(0.5, 0.5, 0.0),
m_color));
m_nextPoint = m_points->size();
m_firstIndex = m_indices->size();
for (int side = 0; side < m_sides - 1; side++)
{
m_indices->append(m_firstPoint);
m_indices->append(m_firstPoint + 1 + 4 * side);
m_indices->append(m_firstPoint + 5 + 4 * side);
m_indices->append(m_firstPoint + 2 + 4 * side);
m_indices->append(m_firstPoint + 6 + 4 * side);
m_indices->append(m_firstPoint + 3 + 4 * side);
m_indices->append(m_firstPoint + 3 + 4 * side);
m_indices->append(m_firstPoint + 7 + 4 * side);
m_indices->append(m_firstPoint + 6 + 4 * side);
m_indices->append(m_firstPoint + 4 + 4 * side);
m_indices->append(m_firstPoint + 8 + 4 * side);
m_indices->append(m_nextPoint - 1);
}
m_indices->append(m_firstPoint);
m_indices->append(m_firstPoint + 1 + 4 * (m_sides - 1));
m_indices->append(m_firstPoint + 1);
m_indices->append(m_firstPoint + 2 + 4 * (m_sides - 1));
m_indices->append(m_firstPoint + 2);
m_indices->append(m_firstPoint + 3 + 4 * (m_sides - 1));
m_indices->append(m_firstPoint + 3 + 4 * (m_sides - 1));
m_indices->append(m_firstPoint + 3);
m_indices->append(m_firstPoint + 2);
m_indices->append(m_firstPoint + 4 + 4 * (m_sides - 1));
m_indices->append(m_firstPoint + 4);
m_indices->append(m_nextPoint - 1);
m_nextIndex = m_indices->size();
}
bool GLDisc::isHit(QVector3D p1, QVector3D p2)
{
if (!GLBody::isHit(p1, p2))
{
return false;
}
QVector3D lineVector = p2 - p1;
// Calculate intersection point with the xy plane
QVector3D vecBottom = p1 + lineVector * (-p1.z() / lineVector.z());
if (vecBottom.length() < m_circleRadius)
{
return true;
}
// Calculate intersection point with the xy + m_heigth plane
// Then drop z so that we get a projection onto the xy plane
QVector3D vecTop = (p1 + lineVector * ((m_height - p1.z()) /
lineVector.z())).toVector2D();
if (vecTop.length() < m_circleRadius)
{
return true;
}
// Check if the mouse line is hitting the outer disc side
QVector2D vecXYProjection = lineVector.toVector2D();
QVector2D vecXYStart = p1.toVector2D();
// Solved via the "Mitternachtsformel"
float a = QVector2D::dotProduct(vecXYProjection, vecXYProjection);
float b = 2 * QVector2D::dotProduct(vecXYStart, vecXYProjection);
float c = QVector2D::dotProduct(vecXYStart,
vecXYStart) - m_circleRadius * m_circleRadius;
float discriminant = b * b - 4 * a * c;
if (discriminant >= 0)
{
discriminant = sqrt(discriminant);
float lambda1 = (-b - discriminant) / (2*a);
float z1 = (p1 + lambda1 * lineVector).z();
if(z1 >= 0 && z1 <= m_height)
{
return true;
}
float lambda2 = (-b + discriminant) / (2*a);
float z2 = (p1 + lambda2 * lineVector).z();
if(z2 >= 0 && z2 <= m_height)
{
return true;
}
}
return false;
}
QVector2D GLDisc::calculatePoint(double sideAngle)
{
double x = sin(sideAngle);
double y = cos(sideAngle);
return QVector2D(x, y);
}
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