2D Addon to Irrlicht

[Listing]

I would recommend you to add this code to the next
irrlicht release

It comes with the methods draw2DTriangle and draw2DCircle, that should be in every common 2d engine.

To fill the circle just change the width to the max


Irrlichtprimitives.h

Code: Select all

#include <irrlicht.h>

using namespace irr;
using namespace core;
using namespace scene;
using namespace video;
using namespace io;
using namespace gui;

class CIrrlichtPrimitives
{
public: //Public functions
	CIrrlichtPrimitives(IVideoDriver*Driver) : pVideoDriver(Driver)	{}
	~CIrrlichtPrimitives()	{}
	void draw2dCircle(const core::position2d<s32>& center, unsigned int radius, irr::video::SColor &color);
	void draw2dCircle(const core::position2d<s32>& center, unsigned int radius, irr::video::SColor &color, unsigned int width);
	void draw2dTriangle(const core::position2d<s32>& a,const core::position2d<s32>& b,const core::position2d<s32>& c, irr::video::SColor &color);

private: //Private functions
	unsigned int GenerateCirclePointY (bool upperLimit, int x, int a, int b, int radius)
	{ //Point P(a|b) is the center of the circle... x is the relative pos to the radius
		if(upperLimit)
			return(unsigned int)(0.5+(b + sqrt((double) (-x * x + 2 * x * a - a * a + radius * radius))));
		else
			return(unsigned int)(0.5+(b - sqrt((double) (-x * x + 2 * x * a - a * a + radius * radius))));
	}

	unsigned int GenerateCirclePointX  (bool upperLimit, int y, int a, int b, int radius)
	{ //Point P(a|b) is the center of the circle... x is the relative pos to the radius
		if(upperLimit)
			return(unsigned int)(0.5+(a + sqrt((double) (2 * y * b - b * b - y * y + radius * radius))));
		else
			return(unsigned int)(0.5+(a - sqrt((double) (2 * y * b - b * b - y * y + radius * radius))));
	}




private: //Attributes
	IVideoDriver * pVideoDriver;
};

Irrlichtprimitives.cpp

Code: Select all

#include "IrrlichtPrimitives.h"

void CIrrlichtPrimitives::draw2dCircle(const core::position2d<s32>& center, unsigned int radius, irr::video::SColor &color)
{
	for(int vertical = 0; vertical < 2; ++vertical)
	{
		if(vertical)
		{
			for(unsigned int p = 1; p < 2*radius; ++p)
			{
				this->pVideoDriver->drawPixel(center.X-radius+p,this->GenerateCirclePointY(false,center.X-radius+p,center.X,center.Y,radius),color);
				this->pVideoDriver->drawPixel(center.X-radius+p,this->GenerateCirclePointY(true ,center.X-radius+p,center.X,center.Y,radius),color);
			}
		}
		else //horizontal
		{
			for(unsigned int p = 1; p < 2*radius; ++p)
			{
				this->pVideoDriver->drawPixel(this->GenerateCirclePointX(false,center.Y-radius+p,center.X,center.Y,radius),center.Y-radius+p,color);
				this->pVideoDriver->drawPixel(this->GenerateCirclePointX(true ,center.Y-radius+p,center.X,center.Y,radius),center.Y-radius+p,color);
			}
		}		
	}

}

void CIrrlichtPrimitives::draw2dCircle(const core::position2d<s32>& center, unsigned int radius, irr::video::SColor &color, unsigned int width)
{
	for(unsigned int i = 0; i < width; ++i)
	{
		this->draw2dCircle(center,radius-i,color);
	}
}

void CIrrlichtPrimitives::draw2dTriangle(const core::position2d<s32>& a,const core::position2d<s32>& b,const core::position2d<s32>& c, irr::video::SColor &color)
{
	this->pVideoDriver->draw2DLine(a,b,color);
	this->pVideoDriver->draw2DLine(b,c,color);
	this->pVideoDriver->draw2DLine(c,a,color);
}

Recognize it as a present done because of the nice support for irrlicht

Greetings
Listing

[Sylence]

Drawing circles this way is very inefficient. Believe me I tried. I draw 2 circles and my fps drop below 50 (without anything on screen) on a quadcore and geforce 8800

[vitek]

Filled circles can be efficiently rendered with a triangle fan, and a circle edge with a line loop.

Travis

[Listing]

Yes, you can if you want, post an optimized version.

Didn't know that it is that inefficient

Greetings

[FuzzYspo0N]

i dont think drawing a circle is efficient at all,cos an image is a quad that makes the image of a circle fastest.but i dont actually see any reason to have a draw 2d circle? Maybe im just biased

[FuzzYspo0N]

-
.