OpenGL de プログラミング

#include <iostream>
#include <gl/glut.h>


//-------- 各種外部変数 ---------//
float feedBuffer[1024];


//--------- 各種プロトタイプ宣言 ------------//
void display();
void reshape(int w , int h);
void DRAW_XYZ();
void outPutFeedBuffer(int size,float *Buffer);

//------------ OpenGLの初期設定 ----------------//
void GLUT_CALL_FUNCs()
{
	glutDisplayFunc(display);
	glutReshapeFunc(reshape);
}


void myOtherInit()
{
	glClearColor(1,1,1,1);
}

void GLUT_INITs(int *argcp,char **argv)
{
	glutInit(argcp,argv);
	glutInitDisplayMode(GLUT_RGBA| GLUT_DOUBLE | GLUT_DEPTH); //ダブルバッファ、Zバッファ
	glutInitWindowSize(640,480);
	glutCreateWindow("FeedBack Buffer");

	GLUT_CALL_FUNCs();
	
	myOtherInit();

}


//---------- メイン関数 --------------//
int main(int argc, char *argv[])
{
	GLUT_INITs(&argc,argv);
	glutMainLoop();
	return 0;
}

//---------- 各種コールバック ----------------//
void display()
{
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	
	//表示用に描画
	glPointSize(2);
	glColor3f(1,0.5,0.4);
	glBegin(GL_POINTS);
	glVertex3f(1,1,1);
	glEnd();
	glPointSize(1);


	int size;
	glFeedbackBuffer (1024, GL_3D_COLOR, feedBuffer);
	glRenderMode (GL_FEEDBACK);
	glPointSize(2);
	glColor3f(0.2,0.5,0.4);
	glBegin(GL_POINTS);
	glVertex3f(1,1,1);
	glEnd();
	glPointSize(1);
	
	size = glRenderMode (GL_RENDER);
	std::cout <<"size is "<< size << '\n';
	
	if( feedBuffer[0] == GL_POINT_TOKEN)
	{
		std::cout << "GL_POINT_TOKEN\n";
	}
	std::cout <<"x:"<< feedBuffer[1] << '\n';
	std::cout <<"y:"<< feedBuffer[2] << '\n';
	std::cout <<"z:"<< feedBuffer[3] << '\n';
	std::cout <<"R:"<< feedBuffer[4] << '\n';
	std::cout <<"G:"<< feedBuffer[5] << '\n';
	std::cout <<"B:"<< feedBuffer[6] << '\n';
	std::cout <<"A:"<< feedBuffer[7] << '\n';
	DRAW_XYZ();
	glutSwapBuffers();
	memset(feedBuffer,0,sizeof(float)*1024 );
}


void reshape(int w , int h)
{
	glViewport(0, 0, w, h);

	glMatrixMode(GL_PROJECTION); 
	glLoadIdentity();  
	gluPerspective(30.0, (double)w / (double)h, 1.0, 100.0);

	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	gluLookAt(3.0, 4.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);

}


//------------- 各種関数 --------------//
void DRAW_XYZ()
{
	glBegin(GL_LINES);

	glColor3f(0,1,0);//x
	glVertex2f(-100,0);
	glVertex2f(100, 0);

	glColor3f(1,0,0);//y
	glVertex2f(0,0);
	glVertex2f(0,100);

	glColor3f(0,0,1);//z
	glVertex3f(0,0,-100);
	glVertex3f(0,0, 100);
	glEnd();
}