OpenGL画简单图形

#include <GL/glut.h>

#pragma comment(linker,"/subsystem:\"windows\" /entry:\"mainCRTStartup\"") 


/*
三角形
GL_TRIANGLES(三个点成一个三角形)
GL_TRIANGLE_STRIP(相邻三点成一个三角形)
GL_TRIANGLE_FAN(同第二个，后2个和第一个成三角形)

四边形
GL_QUADS(四点一个)
GL_QUAD_STRIP(相邻四点一个)

多边形
GL_POLYGON

glPolygonMode(GL_FRONT_AND_BACK,GL_LINE);
*/
void drawPoint(void)
{
	int i;
	
	glColor3f (0.0, 0.0, 1.0);
	glPointSize(5);
	glBegin(GL_POINTS);
	for (i = 0; i < 7; i++)
		glVertex2f (0.2 + ((GLfloat) i * 0.1), 0.6);
	glEnd ();
}

void drawLines(void)
{
	glColor3f(0.0,0.0,1.0);
	glLineWidth(5);
	glBegin(GL_LINES);
		glVertex2f(0.0, 0.0);
		glVertex2f(0.25,0.25);
		glVertex2f(0.75,0.25);
		glVertex2f(0.0,0.0);
	glEnd();
}

void drawOneLine(GLfloat a,GLfloat b,GLfloat c,GLfloat d)
{
	glBegin(GL_LINES);
		glVertex2f(a,b);
		glVertex2f(c,d);
	glEnd();
}

void drawLineStripple(void)
{
	glEnable (GL_LINE_STIPPLE);
	glColor3f (0.0, 0.0, 1.0);
	glLineStipple (1, 0x0101);  /*  dotted  */
	drawOneLine (-0.25, 0.8, -0.75, 0.8);
	glLineStipple (1, 0x00FF);  /*  dashed  */
	drawOneLine (-0.25, 0.6, -0.75, 0.6);
	glLineStipple (1, 0x1C47);  /*  dash/dot/dash  */
	drawOneLine (-0.25, 0.4, -0.75, 0.4);
	
	///* in 2nd row, 3 wide lines, each with different stipple */
	glLineWidth (5.0);
	glLineStipple (1, 0x0101);  /*  dotted  */
	drawOneLine (-0.25, 0.2, -0.75, 0.2);
	glLineStipple (1, 0x00FF);  /*  dashed  */
	drawOneLine (-0.25, 0.0, -0.75, 0.0);
	glLineStipple (1, 0x1C47);  /*  dash/dot/dash  */
	drawOneLine (-0.25, -0.2, -0.75, -0.2);
	glLineWidth (1.0);
	///* in 4th row, 6 independent lines with same stipple  */
	int i;
	for (i = 0; i < 6; i++) {
		drawOneLine (0.05 + ((GLfloat) i * 0.01), 0.5,
			0.05 + ((GLfloat)(i+1) * 0.01), 0.5);
	}
	//
	///* in 5th row, 1 line, with dash/dot/dash stipple    */
	///* and a stipple repeat factor of 5                  */
	glLineStipple (5, 0x1C47);  /*  dash/dot/dash  */
	drawOneLine (50.0, 25.0, 350.0, 25.0);
	
	glDisable (GL_LINE_STIPPLE);
	
}

void drawLineStrip()
{
       glColor3f (0.0, 0.0, 1.0);
       glPointSize(5);
      // glBegin(GL_LINE_STRIP);
	   glBegin(GL_LINE_LOOP);
       glVertex2f(0.0,0.0);
       glVertex2f(-0.3,-0.5);
       glVertex2f(0.3,-0.5);
       glEnd ();
}

void myDisplay(void)
{
	glClear(GL_COLOR_BUFFER_BIT);
	// glRectf(-0.5f, -0.5f, 0.5f, 0.5f);
    
	//设置颜色
    glColor3f(1.0,1.0,0.0);
    
	//画出矩形
    glBegin(GL_POLYGON);
		glVertex3f(0.25,0.25,0.25);
		glVertex3f(0.75,0.25,0.0);
		glVertex3f(0.75,0.75,0.0);
		glVertex3f(0.25,0.75,0.0);
	//glVertex3f(0.0,0.5,0.0);
    glEnd();
    drawPoint();
	drawLines();
	drawLineStripple();
	drawLineStrip();
	glFlush();
}

void reshape (int w, int h)
{
	// glViewport (0, 0, (GLsizei) w, (GLsizei) h);
	glMatrixMode (GL_PROJECTION);
	glLoadIdentity ();
	//gluOrtho2D (0.0, (GLdouble) w, 0.0, (GLdouble) h);
	// glOrtho(0.0, 1.0, 0.0, 1.0, -1.0, 1.0);
	//glOrtho(left, right, bottom, top, near, far)
}

int main(int argc, char *argv[])
{
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
	glutInitWindowPosition(100, 100);
	glutInitWindowSize(400, 400);
	glutCreateWindow("第一个OpenGL程序");
	//glClearColor (0.0, 1.0, 1.0, 0.0);
	glutDisplayFunc(myDisplay);
	glutReshapeFunc(reshape);
	glutMainLoop();
	return 0;
}

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