omni::visual::Circle Class Reference

Visualizer for drawing a circle with VBO. More...

#include <Circle.h>

Collaboration diagram for omni::visual::Circle:

Public Member Functions
	Circle ()
void	drawLine (QPointF const &_pos, float _rX, float _rY) const
	Draw lined circle. More...
void	drawFill (QPointF const &_pos, float _rX, float _rY) const
	Draw filled circle with triangle fan. More...
void	update ()
	Update circle mesh. More...

Static Public Attributes
static constexpr std::size_t	numberSegments = 32
	Standard number of segments. More...

Private Attributes
VBO	vertexVbo_
std::array< QVector2D, numberSegments+2 >	vertices_

Detailed Description

Visualizer for drawing a circle with VBO.

Constructor & Destructor Documentation

omni::visual::Circle::Circle

(

)

    {
      update();
    }

Member Function Documentation

void omni::visual::Circle::drawFill	(	QPointF const &	_pos,
		float	_rX,
		float	_rY
	)		const

Draw filled circle with triangle fan.

    {
      withCurrentContext([&](QOpenGLFunctions& _) {
        glPushMatrix();
        glLoadIdentity();
        glScalef(_rX, _rY, 1.0);
        glTranslatef(_pos.x() / _rX, _pos.y() / _rY, 0.0);
        glEnableClientState(GL_VERTEX_ARRAY);
        _.glBindBuffer(GL_ARRAY_BUFFER, vertexVbo_.id());

        glVertexPointer(2, GL_FLOAT, 0, nullptr);
        _.glDrawArrays(GL_TRIANGLE_FAN, 0, numberSegments + 2);

        _.glBindBuffer(GL_ARRAY_BUFFER,         0);
        glDisableClientState(GL_VERTEX_ARRAY);
        glPopMatrix();
      });
    }

void omni::visual::Circle::drawLine	(	QPointF const &	_pos,
		float	_rX,
		float	_rY
	)		const

Draw lined circle.

    {
      withCurrentContext([&](QOpenGLFunctions& _) {
        glPushMatrix();
        glScalef(_rX, _rY, 1.0);
        glTranslatef(_pos.x() / _rX, _pos.y() / _rY, 0.0);
        glEnableClientState(GL_VERTEX_ARRAY);
        _.glBindBuffer(GL_ARRAY_BUFFER, vertexVbo_.id());

        glVertexPointer(2, GL_FLOAT, 0, nullptr);
        _.glDrawArrays(GL_LINE_LOOP, 1, numberSegments);

        _.glBindBuffer(GL_ARRAY_BUFFER,         0);
        glDisableClientState(GL_VERTEX_ARRAY);
        glPopMatrix();
      });
    }

void omni::visual::Circle::update

(

)

Update circle mesh.

                        {
      vertexVbo_.gen();
      glEnableClientState(GL_VERTEX_ARRAY);

      vertices_[0] = QVector2D(0.0, 0.0);
      util::for_each_circle_point(numberSegments, 1.0,
                                  [&](size_t i, const QPointF& _p)
      {
        vertices_[i + 1] = QVector2D(_p);
      });
      vertices_[numberSegments + 1] = vertices_[1];

      vertexVbo_.bufferStaticArray(vertices_);
    }

Field Documentation

constexpr std::size_t omni::visual::Circle::numberSegments = 32

static

Standard number of segments.

VBO omni::visual::Circle::vertexVbo_

private

std::array<QVector2D, numberSegments + 2> omni::visual::Circle::vertices_

private

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The documentation for this class was generated from the following files:

• include/omni/visual/Circle.h
• src/lib/visual/Circle.cpp