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這是我的代碼,它設置了一個透視視圖體積。矩形顯示正確。爲什麼茶壺不顯示? OpenGL
我想現在添加一個茶壺到我的場景中,所以我在繪製矩形後添加一條繪製茶壺的線條。但沒有顯示茶壺。
我設置了哪些參數?我的看法和茶壺有什麼問題?
GLint winWidth = 600, winHeight = 600; // Initial display-window size.
GLfloat x0 = 50.0, y0 = 50.0, z0 = 50.0; // Viewing-coordinate origin.
GLfloat xref = 50.0, yref = 50.0, zref = 0.0; // Look-at point.
GLfloat Vx = 0.0, Vy = 1.0, Vz = 0.0; // View-up vector.
/* Set coordinate limits for the clipping window: */
//GLfloat xwMin = -40.0, ywMin = -60.0, xwMax = 40.0, ywMax = 60.0;
GLfloat xwMin = -100.0, ywMin = -100.0, xwMax = 100.0, ywMax = 100.0;
/* Set positions for near and far clipping planes: */
GLfloat dnear = 25.0, dfar = 125.0;
void init (void)
{
glClearColor (1.0, 1.0, 1.0, 0.0);
glMatrixMode (GL_MODELVIEW);
glLoadIdentity();
gluLookAt (x0, y0, z0, xref, yref, zref, Vx, Vy, Vz);
printf("look at orign:%.0f %.0f %.0f, pref: %.0f %.0f %.0f\n",x0, y0, z0, xref, yref, zref);
glMatrixMode (GL_PROJECTION);
glLoadIdentity();
glFrustum (xwMin, xwMax, ywMin, ywMax, dnear, dfar);
}
void displayFcn (void)
{
init ();
glClear (GL_COLOR_BUFFER_BIT);
/* Set parameters for a square fill area. */
glColor3f (0.0, 1.0, 0.0); // Set fill color to green.
//glPolygonMode (GL_FRONT, GL_FILL);
glPolygonMode(GL_FRONT, GL_LINE);
glPolygonMode (GL_BACK, GL_LINE); // Wire-frame back face.
glBegin (GL_QUADS);
glVertex3f (0.0, 0.0, 0.0);
glVertex3f (100.0, 0.0, 0.0);
glVertex3f (100.0, 100.0, 0.0);
glVertex3f (0.0, 100.0, 0.0);
glEnd ();
glutSolidTeapot(50.9);
glFlush ();
}
void reshapeFcn (GLint newWidth, GLint newHeight)
{
glViewport (0, 0, newWidth, newHeight);
winWidth = newWidth;
winHeight = newHeight;
}
void keyboard(unsigned char key, int x, int y);
int main (int argc, char** argv)
{
glutInit (&argc, argv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
glutInitWindowPosition (50, 50);
glutInitWindowSize (winWidth, winHeight);
glutCreateWindow ("Perspective View of A Square");
glutKeyboardFunc(keyboard);
glutDisplayFunc (displayFcn);
glutReshapeFunc (reshapeFcn);
glutMainLoop ();
}
感謝您的耐心解答。 「視場角非常高」解釋了爲什麼我的茶壺看起來非常透視...在我目前的視錐體中,theta差不多是110度。我的計算是否正確? – HRLTY
在我的計算中,frstum在距離25的近平面上從-100到+100,使得半角的截面積爲100/25 = 4,所以總的來說,如果視場達到〜152度,從水平到垂直。 – derhass