OpenGL gluLookAt
OpenGL gluLookAt
我试图画一个茶壶并在 3D 中查看它，但是当我 运行 程序时，没有任何显示。 window 中没有任何内容。我知道它与我的 gluLookAt() 函数有关，但我不确定如何修复它。
// helloteapot.cc
//#include <GLUT/gl.h>
#include <GLUT/glut.h>
#include "GL/glui.h"
void display () {
/* clear window */
glClear(GL_COLOR_BUFFER_BIT);
/* draw scene */
glColor3f(1.0, 0.0, 0.0);
glTranslatef(0.0, 0.5, 0.0);
glutSolidTeapot(0.15);
/* flush drawing routines to the window */
glFlush();
}
int main ( int argc, char * argv[] ) {
glutInit(&argc,argv);
/* setup the size, position, and display mode for new windows */
glutInitWindowSize(800,600);
glutInitWindowPosition(0,0);
glutInitDisplayMode(GLUT_RGB);
/* create and set up a window */
glutCreateWindow("hello, teapot!");
glutDisplayFunc(display);
/*GLfloat width = 800;
GLfloat height = 600;
GLfloat aspect = (GLfloat)width / (GLfloat)height;
// Set the viewport to cover the new window
glViewport(0, 0, width, height);*/
// Set the aspect ratio of the clipping volume to match the
viewport
glMatrixMode(GL_PROJECTION); // To operate on the Projection
matrix
glLoadIdentity(); // Reset
// Enable perspective projection with fovy, aspect, zNear and zFar
//luPerspective(45.0f, aspect, -100.0f, 100.0f);
gluLookAt(0, 0, 0, 0, 0.5, 0, 0, -1, 0);
/* tell GLUT to wait for events */
glutMainLoop();
}
您要求 GL 将相机定位在原点，将相机向上对准点 (0, 0.5, 0)，并且还指定（错误地）向上矢量为 0, -1, 0问题是相机的前向是(0, 1, 0) [由你的眼睛和瞄准位置指定]，这个方向与向上矢量或(0, -1, 0)冲突。尝试使用与前进方向成直角的矢量来代替！ （例如 [1, 0, 0], [0, 0, 1]）
gluLookAt(
0, 0, 0, //< camera location
0, 0.5, 0, //< looking towards point
1, 0, 0); //< which direction is up?
我试图画一个茶壶并在 3D 中查看它，但是当我 运行 程序时，没有任何显示。 window 中没有任何内容。我知道它与我的 gluLookAt() 函数有关，但我不确定如何修复它。
// helloteapot.cc
//#include <GLUT/gl.h>
#include <GLUT/glut.h>
#include "GL/glui.h"
void display () {
/* clear window */
glClear(GL_COLOR_BUFFER_BIT);
/* draw scene */
glColor3f(1.0, 0.0, 0.0);
glTranslatef(0.0, 0.5, 0.0);
glutSolidTeapot(0.15);
/* flush drawing routines to the window */
glFlush();
}
int main ( int argc, char * argv[] ) {
glutInit(&argc,argv);
/* setup the size, position, and display mode for new windows */
glutInitWindowSize(800,600);
glutInitWindowPosition(0,0);
glutInitDisplayMode(GLUT_RGB);
/* create and set up a window */
glutCreateWindow("hello, teapot!");
glutDisplayFunc(display);
/*GLfloat width = 800;
GLfloat height = 600;
GLfloat aspect = (GLfloat)width / (GLfloat)height;
// Set the viewport to cover the new window
glViewport(0, 0, width, height);*/
// Set the aspect ratio of the clipping volume to match the
viewport
glMatrixMode(GL_PROJECTION); // To operate on the Projection
matrix
glLoadIdentity(); // Reset
// Enable perspective projection with fovy, aspect, zNear and zFar
//luPerspective(45.0f, aspect, -100.0f, 100.0f);
gluLookAt(0, 0, 0, 0, 0.5, 0, 0, -1, 0);
/* tell GLUT to wait for events */
glutMainLoop();
}
您要求 GL 将相机定位在原点，将相机向上对准点 (0, 0.5, 0)，并且还指定（错误地）向上矢量为 0, -1, 0问题是相机的前向是(0, 1, 0) [由你的眼睛和瞄准位置指定]，这个方向与向上矢量或(0, -1, 0)冲突。尝试使用与前进方向成直角的矢量来代替！ （例如 [1, 0, 0], [0, 0, 1]）
gluLookAt(
0, 0, 0, //< camera location
0, 0.5, 0, //< looking towards point
1, 0, 0); //< which direction is up?