OpenGL织梦之旅【第四章】第1节.设置视点函数gluLookAt

最新推荐文章于 2022-02-18 14:22:16 发布

原创

最新推荐文章于 2022-02-18 14:22:16 发布 · 4.4k 阅读

12 ·

CC 4.0 BY-SA版权

本文介绍了在3D环境中如何使用OpenGL进行绘图，特别是讲解了gluLookAt函数的使用，用于设置视点。文章通过绘制正方体并添加3D效果，详细阐述了gluLookAt的九个参数及其作用，并提醒在使用前需调用glLoadIdentity。此外，还分享了如何通过键盘事件调整视点，以实现摄像机在轨道上的移动，增强3D体验。作者强调了掌握三维坐标和空间想象力在OpenGL 3D编程中的重要性，并提供了本节全部代码。

在做所有的事情之前，我们必须要了解怎么在3D的世界中绘图。这也是为了帮助我们调整视点，不然调来调去都是黑框...

3D世界中的坐标系也是笛卡尔坐标系，y轴就像是现实世界中的“高低”，而x和z像是地面的坐标。

我们写一个DrawBox函数，这函数负责绘制一个正方体。

void DrawBox()
{
	
	glBegin(GL_POLYGON);
			

			glColor3f(1.0,0.0,0.0);
		    glVertex3f(0.0f, 0.0f, 0.0f);	 
			glVertex3f(0.0f, 0.0f, 1.0f);
			glVertex3f(1.0f, 0.0f, 1.0f);
			glVertex3f(1.0f, 0.0f, 0.0f);
	glEnd();
	glBegin(GL_POLYGON);		
    
			glColor3f(0.0,1.0,0.0);
			glVertex3f(0.0f, 0.0f, 0.0f);	 
			glVertex3f(1.0f, 0.0f, 0.0f);
			glVertex3f(1.0f, 1.0f, 0.0f);
			glVertex3f(0.0f, 1.0f, 0.0f);
	glEnd();
	glBegin(GL_POLYGON);		
		
			glColor3f(0.0,0.0,1.0);
			glVertex3f(0.0f, 0.0f, 0.0f);	
			glVertex3f(0.0f, 1.0f, 0.0f);
			glVertex3f(0.0f, 1.0f, 1.0f);
			glVertex3f(0.0f, 0.0f, 1.0f);
	glEnd();
	glBegin(GL_POLYGON);		
		
			glColor3f(1.0,0.0,1.0);
			glVertex3f(1.0f, 0.0f, 0.0f);	
			glVertex3f(1.0f, 0.0f, 1.0f);
			glVertex3f(1.0f, 1.0f, 1.0f);
			glVertex3f(1.0f, 1.0f, 0.0f);
		glEnd();
	glBegin(GL_POLYGON);		
		
			glColor3f(1.0,1.0,0.0);
			glVertex3f(0.0f, 1.0f, 0.0f);	
			glVertex3f(0.0f, 1.0f, 1.0f);
			glVertex3f(1.0f, 1.0f, 1.0f);
			glVertex3f(1.0f, 1.0f, 0.0f);
	glEnd();			
	glBegin(GL_POLYGON);		
		
			glColor3f(0.0,1.0,1.0);
			glVertex3f(0.0f, 0.0f, 1.0f);
			glVertex3f(1.0f, 0.0f, 1.0f);
			glVertex3f(1.0f, 1.0f, 1.0f);
			glVertex3f(0.0f, 1.0f, 1.0f);
		glEnd();
}