OPENGL 简单图形绘制

直接上代码：

#include <stdio.h>
#include <GL/glut.h>
#include <math.h>

void myDisplay()
{
	glClear(GL_COLOR_BUFFER_BIT);
	glRectf(-0.5f, -0.5f, 0.5f, 0.5f);
	glFlush();
}

// 画圆
const int n = 50;
const GLfloat R = 0.5f;
const GLfloat Pi = 3.1415926536f;

void DrawArc()
{
	int i;
	glClear(GL_COLOR_BUFFER_BIT);
	glBegin(GL_POLYGON);// 面
	for (i = 0; i < n; ++i)
	{
		glVertex2f(R*cos(2 * Pi / n*i), R*sin(2 * Pi / n*i));
	}
	glEnd();
	glFlush();
}

// 绘制五角星
void DrawFiveStarts()
{
	GLfloat a = 1 / (2 - 2 * cos(72 * Pi / 180));
	GLfloat bx = a*cos(18 * Pi / 180);
	GLfloat by = a*sin(18 * Pi / 180);
	GLfloat cy = -a*cos(18 * Pi / 180);

	GLfloat PointA[2] = { 0, a };
	GLfloat PointB[2] = { bx, by };
	GLfloat PointC[2] = { 0.5, cy };
	GLfloat PointD[2] = { -0.5, cy };
	GLfloat PointE[2] = { -bx, by };

	glClear(GL_COLOR_BUFFER_BIT);
	glBegin(GL_LINE_LOOP);
	glVertex2fv(PointA);
	glVertex2fv(PointC);
	glVertex2fv(PointE);
	glVertex2fv(PointB);
	glVertex2fv(PointD);
	glEnd();
	glFlush();
}

// 正弦函数绘制
const GLfloat factor = 0.1f;
void DrawSinFunc()
{
	GLfloat x;
	glClear(GL_COLOR_BUFFER_BIT);
	glBegin(GL_LINES);
	// X轴
	glVertex2f(-1.0f, 0.0f);
	glVertex2f(1.0f, 0.0f);
	// Y轴
	glVertex2f(0.0f, -1.0f);
	glVertex2f(0.0f, 1.0f);
	glEnd();

	glBegin(GL_LINE_STRIP);

	for (x = -1.0f / factor; x < 1.0f / factor; x += 0.1f)
	{
		glVertex2f(x*factor, sin(x)*factor);
	}
	glEnd();
	glFlush();
}

// 绘制点
void DrawPoint()
{
	glClear(GL_COLOR_BUFFER_BIT);
	glPointSize(10.0f);
	glBegin(GL_POINT);
	glVertex2f(0.0f, 0.0f);
	glVertex2f(0.5f, 0.5f);
	glEnd();
	glFlush();
}

// 绘制直线
void DrawLine()
{
	glClear(GL_COLOR_BUFFER_BIT);
	glEnable(GL_LINE_STIPPLE);// 启动画线模式（虚线）
	glLineStipple(2, 0x0f0f);
	glLineWidth(10.0f);
	glBegin(GL_LINES);
	glVertex2f(0.0f, 0.0f);
	glVertex2f(0.5f, 0.5f);
	glEnd();
	glFlush();
}


// RGBA颜色
void DrawRGBA()
{
	glClear(GL_COLOR_BUFFER_BIT);
	glColor3f(0.0f, 1.0f, 1.0f);
	glRectf(-0.5f, -0.5f, 0.5f, 0.5f);
	glFlush();
}

int main(int argc, char* argv[])
{
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
	glutInitWindowPosition(100, 100);
	glutInitWindowSize(400, 400);
	
	glutCreateWindow("hello World");
	glutDisplayFunc(&DrawRGBA);// 设置显示方式
	glutMainLoop();// 消息循环
	return 0;
}