fantasy earth zero

課程要了解攝影機的運鏡

開啟projection檔案 了解視角的變化

fovy : Y方向的視野
aspect ratio : 長寬比例
zNear : z方向, 近的面
zFar : z方向, 遠的面

按下滑鼠右鍵 點glFrustum 就可以變換了

開啟GLUT專案 開始實作

一開始先把glFrustum反斜線掉

再加上gluPerspective來調整視窗的大小

結果如下



在修改一下 把36行程式碼裡面的 1 改成 ar
ar 就是 aspect ratio : 長寬比例



結果就能改變視窗大小 但不改變圖形的長寬比





在反斜線掉剛剛的程式碼 加上glOrtho



因為範圍太小 所以只顯示到空白的地方




所以我們要改變它的範圍



結果就成功跑出來了


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程式碼：
/*
 * GLUT Shapes Demo
 *
 * Written by Nigel Stewart November 2003
 *
 * This program is test harness for the sphere, cone
 * and torus shapes in GLUT.
 *
 * Spinning wireframe and smooth shaded shapes are
 * displayed until the ESC or q key is pressed.  The
 * number of geometry stacks and slices can be adjusted
 * using the + and - keys.
 */

#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;
}

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再來讓茶壺可以自由轉動

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/*
 * GLUT Shapes Demo
 *
 * Written by Nigel Stewart November 2003
 *
 * This program is test harness for the sphere, cone
 * and torus shapes in GLUT.
 *
 * Spinning wireframe and smooth shaded shapes are
 * displayed until the ESC or q key is pressed.  The
 * number of geometry stacks and slices can be adjusted
 * using the + and - keys.
 */

#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 */
void motion(int x, int y)///TODO5
{
    ///我們的window:640x480
    eyeX = (x-320)/320.0;///TODO5
    eyeY = (y-240)/240.0;///TODO5;
    glMatrixMode(GL_MODELVIEW); ///TODO5
    glLoadIdentity() ;///TODO5
    gluLookAt(eyeX,eyeY,eyeZ, centerX,centerY,centerZ, 0,1,0);///TODO5

}
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);
    glutMotionFunc(motion);///TODO5: 用motion來控制camera

    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;
}

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