真正的等距投影与opengl

本文介绍了真正的等距投影与opengl的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我是使用C ++的OpenGL编程的新手，而不是很好的数学。有一个简单的方法来等距投影吗？

我的意思是真正的等距投影

（等距投影仅在单位X，Y和Z向量的投影长度相等且它们之间的角度为

解决方案

尝试使用 gluLookAt

glClearColor（0.0，0.0，0.0，1.0）; glClear（GL_COLOR_BUFFER_BIT）; glMatrixMode（GL_PROJECTION）; glLoadIdentity（）; / *使用这个长度，以便摄像机离原点1个单位* / double dist = sqrt（1 / 3.0）; gluLookAt（dist，dist，dist，/ * camera的相对位置* / 0.0，0.0，0.0，/ *相机指向* / 0.0，1.0， 0.0）; / *哪个方向向上* / glMatrixMode（GL_MODELVIEW）; glBegin（GL_LINES）; glColor3d（1.0，0.0，0.0）; glVertex3d（0.0，0.0，0.0）; glVertex3d（1.0，0.0，0.0）; glColor3d（0.0，1.0，0.0）; glVertex3d（0.0，0.0，0.0）; glVertex3d（0.0，1.0，0.0）; glColor3d（0.0，0.0，1.0）; glVertex3d（0.0，0.0，0.0）; glVertex3d（0.0，0.0，1.0）; glEnd（）; glFlush（）;

结果

我们可以绘制一个立方体来检查并行线确实是并行

glPushMatrix glTranslated（0.5，0.5，0.5）; glColor3d（0.5，0.5，0.5）; glutWireCube（1）; glPopMatrix（）; 202.pngalt =alt text>

I am a newbie in OpenGL programming with C++ and not very good at mathematics. Is there a simple way to have isometric projection?

I mean the true isometric projection, not the general orthogonal projection.

(Isometric projection happens only when projections of unit X, Y and Z vectors are equally long and angles between them are exactly 120 degrees.)

Code snippets are highly appreciated..

解决方案

Try using gluLookAt

glClearColor(0.0, 0.0, 0.0, 1.0); glClear(GL_COLOR_BUFFER_BIT); glMatrixMode(GL_PROJECTION); glLoadIdentity(); /* use this length so that camera is 1 unit away from origin */ double dist = sqrt(1 / 3.0); gluLookAt(dist, dist, dist, /* position of camera */ 0.0, 0.0, 0.0, /* where camera is pointing at */ 0.0, 1.0, 0.0); /* which direction is up */ glMatrixMode(GL_MODELVIEW); glBegin(GL_LINES); glColor3d(1.0, 0.0, 0.0); glVertex3d(0.0, 0.0, 0.0); glVertex3d(1.0, 0.0, 0.0); glColor3d(0.0, 1.0, 0.0); glVertex3d(0.0, 0.0, 0.0); glVertex3d(0.0, 1.0, 0.0); glColor3d(0.0, 0.0, 1.0); glVertex3d(0.0, 0.0, 0.0); glVertex3d(0.0, 0.0, 1.0); glEnd(); glFlush();

Results in

We can draw a cube to check that parallel lines are indeed parallel

glPushMatrix(); glTranslated(0.5, 0.5, 0.5); glColor3d(0.5, 0.5, 0.5); glutWireCube(1); glPopMatrix();