Opengl视点转换如何gluLookAt

Question

我想用极坐标通过键盘操作上下左右相机点。

#include <stdlib.h>
#include <glut.h>

GLint TopLeftX, TopLeftY, BottomRightX, BottomRightY ;

static int HourOfDay = 0;
static int DayOfYear = 10;

void init(void) {
    glClearColor(0.0, 0.0, 0.0, 0.0);
}


void myDisplay(void) {
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glPushMatrix(); // Origin

    glClear(GL_DEPTH_BUFFER_BIT);

    /* Sun */
    glColor3f(1.0, 1.0, 0.0);
    glutSolidSphere(1.0, 20, 10);


    /* Mercury */
    glPushMatrix();
    glRotatef((GLfloat)DayOfYear, 0.0, 0.0, 1.0);
    glTranslatef(3.0, 0.0, 0.0);
    glRotatef((GLfloat)HourOfDay, 0.0, 0.0, 1.0);
    glColor3f(0.87, 0.53, 0.25);
    glutSolidSphere(0.3, 10, 2);
    glPopMatrix();

    /* Venus */
    glPushMatrix();
    glRotatef((GLfloat)DayOfYear + 195, 0.0, 0.0, 1.0);
    glTranslatef(5.0, 0.0, 0.0);
    glRotatef((GLfloat)HourOfDay, 0.0, 0.0, 1.0);
    glColor3f(0.99, 0.91, 0.66);
    glutSolidSphere(0.5, 10, 2);
    glPopMatrix();

    /* Earth */
    glPushMatrix();
    glRotatef((GLfloat)DayOfYear + 80, 0.0, 0.0, 1.0);
    glTranslatef(7.0, 0.0, 0.0);
    glRotatef((GLfloat)HourOfDay, 0.0, 0.0, 1.0);
    glColor3f(0.47, 0.82, 0.98);
    glutSolidSphere(0.5, 10, 2);

    /* Earth's Moon 1*/
    glPushMatrix();
    glRotatef((GLfloat)DayOfYear, 0.0, 0.0, 1.0);
    glTranslatef(0.7, 0.0, 0.0);
    glColor3f(0.89, 0.93, 0.95);
    glutSolidSphere(0.1, 5, 5);
    glPopMatrix();

    glPopMatrix();

    /* Mars */
    glPushMatrix();
    glRotatef((GLfloat)DayOfYear + 275, 0.0, 0.0, 1.0);
    glTranslatef(9.0, 0.0, 0.0);
    glRotatef((GLfloat)HourOfDay, 0.0, 0.0, 1.0);
    glColor3f(0.84, 0.16, 0.15);
    glutSolidSphere(0.35, 10, 2);
    glPopMatrix();

    /* Jupiter */
    glPushMatrix();
    glRotatef((GLfloat)DayOfYear + 33, 0.0, 0.0, 1.0);
    glTranslatef(11.0, 0.0, 0.0);
    glRotatef((GLfloat)HourOfDay, 0.0, 0.0, 1.0);
    glColor3f(0.93, 0.64, 0.27);
    glutSolidSphere(1.0, 10, 2);
    glPopMatrix();

    /* Saturn */
    glPushMatrix();
    glRotatef((GLfloat)DayOfYear + 180, 0.0, 0.0, 1.0);
    glTranslatef(15.0, 0.0, 0.0);
    glRotatef((GLfloat)HourOfDay, 0.0, 0.0, 1.0);
    glColor3f(0.92, 0.82, 0.45);
    glutSolidSphere(0.9, 10, 2);
    glPopMatrix();

    /* Uranus */
    glPushMatrix();
    glRotatef((GLfloat)DayOfYear + 90, 0.0, 0.0, 1.0);
    glTranslatef(17.0, 0.0, 0.0);
    glRotatef((GLfloat)HourOfDay, 0.0, 0.0, 1.0);
    glColor3f(0.64, 0.84, 0.78);
    glutSolidSphere(0.8, 10, 2);
    glPopMatrix();

    /* Neptune */
    glPushMatrix();
    glRotatef((GLfloat)DayOfYear + 150, 0.0, 0.0, 1.0);
    glTranslatef(20.0, 0.0, 0.0);
    glRotatef((GLfloat)HourOfDay, 0.0, 0.0, 1.0);
    glColor3f(0.29, 0.74, 0.95);
    glutSolidSphere(0.25, 10, 2);
    glPopMatrix();

    glutSwapBuffers();

    // Animation State
    DayOfYear = (DayOfYear + 1) % 360;
    HourOfDay = (HourOfDay + 5) % 360;
}

void Timer(int iUnused) {
    glutPostRedisplay();
    glutTimerFunc(30, Timer, 0);
}

static float cam_axis_x = 0.0;
static float cam_axis_y = 0.0;
static float cam_axis_z = -50.0;

void reshape(int w, int h) {
    glViewport(0, 0, (GLsizei)w, (GLsizei)h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(45.0, (GLfloat)w / (GLfloat)h, 1.0, 90.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glTranslatef(cam_axis_x, cam_axis_y, cam_axis_z);
}

/*void reshape(int w, int h) {
    glViewport(0, 0, (GLsizei)w, (GLsizei)h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(45.0, (GLsizei)w / (GLsizei)h, 0.0, 90.0);
}*/

void keyboard(unsigned char key, int x, int y) {
    switch (key) {
    case 'q': // Esc
        exit(0);
        break;
    case '75': // left
        break;
    case '77': // right
        break;
    case '72': // up
        break;
    case '80': // down
        break;
    }
}

void MyMouseClick(GLint Button, GLint State, GLint X, GLint Y) {
    if (Button == GLUT_LEFT_BUTTON && State == GLUT_DOWN) {
        TopLeftX = X;
        TopLeftY = Y;
    }
}

void MyMouseMove(GLint X, GLint Y) {
    BottomRightX = X;
    BottomRightY = Y;
    glutPostRedisplay();
}

int main(int argc, char** argv) {
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
    glutInitWindowSize(500, 500);
    glutInitWindowPosition(100, 100);
    glutCreateWindow(argv[0]);
    init();
    glutDisplayFunc(myDisplay);
    glutReshapeFunc(reshape);
    Timer(0);
    glutKeyboardFunc(keyboard);
    glutMouseFunc(MyMouseClick);
    glutMotionFunc(MyMouseMove);

    glutMainLoop();
    return 0;
}

我想在阳光下移动相机

您能告诉我有关gluLookAt吗？

Answer 1

我不知道您所说的极坐标是什么意思，通常是二维的。也许你的意思是球坐标。