openGL（四）

最新推荐文章于 2025-03-24 17:47:16 发布

原创最新推荐文章于 2025-03-24 17:47:16 发布 · 1k 阅读

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#callback #include #buffer

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本文介绍了一个使用OpenGL进行二维图形绘制的实例程序。该程序通过不同的变换（如平移、缩放、旋转）展示了如何在窗口中绘制不同形状的图形，并详细展示了初始化、绘制及窗口调整等关键函数的实现。

#include <windows.h>
#include <gl/gl.h>
#include <gl/glaux.h>
#include <gl/glu.h>

#pragma  comment (lib,"openGL32.lib")
#pragma  comment (lib,"glu32.lib")
#pragma  comment (lib,"glaux.lib")
/************************************************************************/
/* 声明初始化函数，显示函数（包括视点变换和模型变换）
reshape函数(包括投影变换和视口变换)
drawobject函数(画图函数)                                                                   */
/************************************************************************/
GLvoid myinit(GLvoid);
GLvoid CALLBACK display(GLvoid);
GLvoid CALLBACK myReshape(GLsizei w,GLsizei h);
GLvoid drawobject(GLvoid);

/*初始化函数*/
GLvoid myinit(GLvoid)
{
	glClearColor(0.0,0.0,0.0,0.0);//清屏幕为黑色
	glClear(GL_COLOR_BUFFER_BIT);//缓冲区也清为黑色
	glShadeModel(GL_FLAT);
}

/*画图函数*/
GLvoid drawobject(GLvoid)
{
	glBegin(GL_LINE_LOOP);
	glVertex2f(0.0,25.0);
	glVertex2f(-25.0,25.0);
	glVertex2f(-25.0,-25.0);
	glEnd();
}




/*显示函数*/
GLvoid CALLBACK display(GLvoid)
{
	glLoadIdentity();
	glColor3f(1.0,1.0,1.0);
	drawobject();
	
	glLoadIdentity();
	glTranslatef(-25.0,0.0,0.0);
	glColor3f(1.0,0.0,0.0);
	drawobject();

	glLoadIdentity();
	glScalef(1.5,0.5,1.0);
	glColor3f(0.0,1.0,0.0);
	drawobject();

	glLoadIdentity();
	glRotatef(90.0,0.0,0.0,1.0);
	glColor3f(0.0,0.0,1.0);
	drawobject();

	glLoadIdentity();
	glScalef(1.0,-0.5,1.0);
	glColor3f(1.0,1.0,0.0);
	drawobject();

	glFlush();
}

GLvoid CALLBACK myReshape(GLsizei w,GLsizei h)
{
	glViewport(0,0,w,h);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	if (w<=h)
	{

		glOrtho(-50.0,50.0,-50.0*(GLfloat)h/(GLfloat)w,50.0*(GLfloat)h/(GLfloat)w,-1.0,1.0);
	}
	else
	{
		glOrtho(-50.0*(GLfloat)w/(GLfloat)h,50.0*(GLfloat)w/(GLfloat)h,-50.0,50.0,-1.0,1.0);
	}
	glMatrixMode(GL_MODELVIEW);

}

void main()
{
	auxInitDisplayMode(AUX_SINGLE|AUX_RGBA);
	auxInitPosition(0,0,500,500);
	auxInitWindow("test3");
	myinit();
	auxReshapeFunc(myReshape);
	auxMainLoop(display);
}

运行结果：