Deverra//Week04旋轉

WEEK04----旋轉

在老師的網頁中找到課本範例>> https://jsyeh.org/3dcg10/

找到data win32的檔案>>下載>>把data檔丟進windows的解壓檔裡做解壓

打開Transformation.exe檔👇

第二行中看到glRotate (旋轉)

Z軸的存在??

打開右手,平行掃到垂直,大姆指的指向就是Z軸

把Z軸調成1.00,可以觀察是怎麼轉

(想像成從車子射出一條座標軸到臉上)

如果把座標調整到(1.00 1.00 0.00)

想像成車子的右肩向左下壓

我們的視角是車的左照後鏡向右下壓

            **可以利用右手做想像，姆指比的方向其餘手指頭向著的方向就是物體的方向**

▦來試試讓茶壼轉起來吧

======================================================================

#include <GL/glut.h>
float angle=0;  //給角度初始值=0
void display()
{
    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glPushMatrix();
        glRotatef(angle,0 ,1 ,0);
        glutSolidTeapot( 0.3 );
    glPopMatrix();
    glutSwapBuffers();
    angle++;  //角度加加(轉起來)
}
int main(int argc, char *argv[])
{
  glutInit(&argc, argv);
  glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
  glutCreateWindow("GLUT Shapes");
  glutDisplayFunc(display);
  glutIdleFunc(display);
  glutMainLoop();
}

▦為茶壼打光!

-----------------------------------------------------------------------------------------------------------------

#include <GL/glut.h> ///把有light的利用cirl+f找出
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 };

void myLight() //打光
{
    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);
}

float angle=0;
void display()
{
    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glPushMatrix();
        glRotatef(angle,0 ,1 ,0);
        glutSolidTeapot( 0.3 );
    glPopMatrix();
    glutSwapBuffers();
    angle++;
}

int main(int argc, char *argv[])
{
  glutInit(&argc, argv);
  glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
  glutCreateWindow("GLUT Shapes");
  glutDisplayFunc(display);
  glutIdleFunc(display);
  myLight();
  glutMainLoop(); //結尾
}

▦為茶壼加上顏色吧

-----------------------------------------------------------------------------------------------------------------

利用上面的程式碼在display函式中加入
float angle=0;
void display()
{
    glClearColor(1,1,1,1); //清除背景顏色
    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glPushMatrix();
        glRotatef(angle,0 ,1 ,0);

        glColor3f(0,0.2,1); //給茶壼上色
        glutSolidTeapot( 0.3 );
    glPopMatrix();
    glutSwapBuffers();
    angle++;
}

=========================================================================

▦回去看一下課本範例~~

交換"移動"跟"旋轉"

發現更改後的模型是怎麼移動的

Rotate translate兩者的差異

rotate是繞著物件轉

translate是自己移動旋轉

▦寫出程式利用兩個茶壼來理解兩者的差別

#include <GL/glut.h>
float angle=0;
void display()
{
    glEnable(GL_DEPTH_TEST);
    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glPushMatrix();
        glTranslatef(0.6,0,0);
        glRotatef(angle,0 ,1 ,0);
        glColor3f(1,1,0);
        glutSolidTeapot( 0.3 );
    glPopMatrix();
    glPushMatrix();
        glRotatef(angle,0 ,1 ,0);
        glTranslatef(0.6,0,0);
        glColor3f(1,0,0);
        glutSolidTeapot( 0.3 );
    glPopMatrix();
    glutSwapBuffers();
    angle++;
}

-----------------------------------------------------------------------------------------------------------------------