圖學筆記-14

1.攝影機

• fovy=field of view，視野

• aspect=長寬比

• zNear=近面

• zfar=背景遠近

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2.resize

 會將視窗鎖定，並且依據高度大小來縮放畫面

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3.gluPerspective()

ar=aspect ratio

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4.glOrtho()

預設為 glOrtho(-1,+1,-1,+1,-1,+1)

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5.gluLookAt

各個值的數值變換結果

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6.旋轉立體茶壺

///留下resize()
{
    const float ar = (float) width / (float) height;

    glViewport(0, 0, width, height);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(60, ar, 0.01, 1000);///我們改了它!!!

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity() ;///原本只有2行, 沒有運鏡
    ///需要運鏡時, 要加上第3行 gluLookAt()
}

static void display(void)
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glutSolidTeapot(0.3);
    glutSwapBuffers();
}
#include <math.h>
float eyeX=0, eyeY=0, eyeZ=1;///TODO
float angle=0;
static void idle(void)
{
    eyeX=sin(angle);
    eyeZ=cos(angle);
    angle+=0.01;

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity() ;///原本只有2行, 沒有運鏡
    gluLookAt(eyeX, eyeY, eyeZ, 0,0,0, 0,1,0); ///需要運鏡時, 要加上第3行 gluLookAt()

    glutPostRedisplay();
}
void motion(int x, int y)
{
    eyeY = (y-240)/240.0;
}

const GLfloat light_ambient[]  = { 0.0f, 0.0f, 0.0f, 1.0f };
const GLfloat light_diffuse[]  = { 1.0f, 1.0f, 1.0f, 1.0f };
const GLfloat light_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };
const GLfloat light_position[] = { 2.0f, 5.0f, 5.0f, 0.0f };

const GLfloat mat_ambient[]    = { 0.7f, 0.7f, 0.7f, 1.0f };
const GLfloat mat_diffuse[]    = { 0.8f, 0.8f, 0.8f, 1.0f };
const GLfloat mat_specular[]   = { 1.0f, 1.0f, 1.0f, 1.0f };
const GLfloat high_shininess[] = { 100.0f };

/* Program entry point */

int main(int argc, char *argv[])
{
    glutInit(&argc, argv);
    glutInitWindowSize(640,480);
    glutInitWindowPosition(10,10);
    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);

    glutCreateWindow("GLUT Shapes");

    glutReshapeFunc(resize);
    glutDisplayFunc(display);
    glutIdleFunc(idle);
    glutMotionFunc(motion);///TODO 控制 eyeY

    glClearColor(1,1,1,1);

    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LESS);

    glEnable(GL_LIGHT0);
    glEnable(GL_NORMALIZE);
    glEnable(GL_COLOR_MATERIAL);
    glEnable(GL_LIGHTING);

    glLightfv(GL_LIGHT0, GL_AMBIENT,  light_ambient);
    glLightfv(GL_LIGHT0, GL_DIFFUSE,  light_diffuse);
    glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);
    glLightfv(GL_LIGHT0, GL_POSITION, light_position);

    glMaterialfv(GL_FRONT, GL_AMBIENT,   mat_ambient);
    glMaterialfv(GL_FRONT, GL_DIFFUSE,   mat_diffuse);
    glMaterialfv(GL_FRONT, GL_SPECULAR,  mat_specular);
    glMaterialfv(GL_FRONT, GL_SHININESS, high_shininess);

    glutMainLoop();

    return EXIT_SUCCESS;
}