week15_wendy

電腦圖學 學習日誌

week15

• 主題: 攝影機與運鏡
• 實作: gluPerspective(), glFrustum()
• 實作: gluLookAt()
• 複習: 上週的FILE讀檔、動作內插
• 提醒: 16,17週,期末作品

(一)攝影機、運鏡

開啟window資料夾中→Projection.exe

函式→gluPerspective(GLdouble fovy,GLdouble aspect,GLdouble zNear, GLdouble zFar);

參數介紹:

fov: field of view 視野

fovy: Y方向的視野

aspect radio: 長寬比例

zNear: z方向， 近的面

zFar: z方， 遠的面

函式→glFrustum(GLdouble left, GLdouble Right, GLdouble bottom, GLdouble top, GLdouble near, GLdouble far);






函式→glOrtho(GLdouble left, GLdouble right, GLdouble bottom, GLdouble top, GLdouble near, GLdouble far);

(二)實作練習

建立glut專案 → 執行原程式碼



修改程式碼:

glFrustum(-ar, ar, -1.0, 1.0, 2.0, 100.0);     ⇒    gluPerspective(60, 1, 0.001, 1000);




修改程式碼:

gluPerspective(60, 1, 0.001, 1000);   ⇒   glOrtho(-3.4, +3.4, -2.2, +2.2,-6.0, +16.0);

(三)實作練習2

#ifdef __APPLE__

#include <GLUT/glut.h>

#else

#include <GL/glut.h>

#endif

#include <stdlib.h>

static int slices = 16;

static int stacks = 16;

/* GLUT callback Handlers */

float eyeX=0, eyeY=0, eyeZ=1; ///TODO3 for gluLookAt()

float centerX=0, centerY=0, centerZ=0;///TODO3 for gluLookAt()

static void resize(int width, int height)

{

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

    glViewport(0, 0, width, height);

    glMatrixMode(GL_PROJECTION);

    glLoadIdentity();

    ///glFrustum(-ar, ar, -1.0, 1.0, 2.0, 100.0);

    gluPerspective( 60, ar, 0.001, 1000 );///TODO3

    ///glOrtho(-1,+1, -1,+1, -1,+1);///預設值,很限制

    ///glOrtho(-3.4, +3.4,  -2.2, +2.2, -6.0, +16.0);///TODO2

    glMatrixMode(GL_MODELVIEW);

    glLoadIdentity() ;///TODO3 for gluLookAt()

    gluLookAt(eyeX,eyeY,eyeZ, centerX,centerY,centerZ, 0,1,0);

}

static void display(void)

{

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glutSolidTeapot(0.3);///TODO3,只放我們的Teapot

    glutSwapBuffers();

}

///key全刪....

static void idle(void)

{

    ///TODO3: 等一下要在這裡做動作....

    glutPostRedisplay();

}

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);

    ///glutKeyboardFunc(key);

    glutIdleFunc(idle);

    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;

}

添加滑鼠移動 → 視角轉變

void motion(int x, int y)

{

    eyeX = (x-320)/320.0;

    eyeY = (y-240)/240.0;

    glMatrixMode(GL_MODELVIEW);

    glLoadIdentity();

    gluLookAt(eyeX,eyeY,eyeZ,centerX,centerY,centerZ,0,1,0);

}