wk15

gluPerspective

fov = Field of View 視野

fovy = fov 在y方向

aspect = 展寬比例，

當顯示範圍不是正方形時，

可以調整這來保持正常比例

glFrustum

glFrustum是gl系列

gluPerspective是glu系列

glFrustum和gluPerspective都屬於Perspective Projection

改用gluPerprtive

static void resize(int width, int height)

{

    const float ar = (float) width / (float) height;

    glViewport(0, 0, width, height);

    glMatrixMode(GL_PROJECTION);

    glLoadIdentity();

    gluPerspective(60,ar,2,100);

    glMatrixMode(GL_MODELVIEW);

    glLoadIdentity() ;

}

glOrtho

glOrtho是顯示出所圍的立方體中的物件

Orthogonal Matrix = 正交矩陣

改用glOrtho

無法把所有東西放進去

static void resize(int width, int height)

{

    const float ar = (float) width / (float) height;

    glViewport(0, 0, width, height);

    glMatrixMode(GL_PROJECTION);

    glLoadIdentity();

    glOrtho(-2.4,2.4,-1.2,1.2,-6,6);

    glMatrixMode(GL_MODELVIEW);

    glLoadIdentity() ;

}

 調整

全部都放進來了

static void resize(int width, int height)

{

    const float ar = (float) width / (float) height;

    glViewport(0, 0, width, height);

    glMatrixMode(GL_PROJECTION);

    glLoadIdentity();

    glOrtho(-2.4*2,2.4*2,-1.2*2,1.2*2,-6,6*2);///乘上2讓全部都可以放進

    glMatrixMode(GL_MODELVIEW);

    glLoadIdentity() ;

}

運鏡

物體本身是不會旋轉，是利用運鏡的方式來達到的

#include <GL/glut.h>

static void resize(int width, int height)///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 };

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;

}