主題一 動作內插
1.利用Excel學習內插，在Excel上輸入time、alpha、angle等格子
*alpha是一個參數 angle裡輸入公式 「alpha*新的+(1-alpha)*舊的」
```c
| ///week15_angles_TRT_again | |
| #include <GL/glut.h> | |
| #include <stdio.h> ///為了 printf, fprintf, fopen, fclose .. | |
| float angle[20], oldX=0; | |
| int angleID=0;///0:第0個關節, 1:第1個關節, 2:第2個關節 | |
| FILE * fout = NULL, * fin = NULL; | |
| void myWrite(){ | |
| if(fin!=NULL){ | |
| fclose(fin); | |
| fin=NULL; | |
| ///最好這裡再做個警告, 因為整個file.txt將被清空!! | |
| } | |
| if(fout==NULL) fout = fopen("file.txt", "w+"); | |
| for(int i=0; i<20; i++){ | |
| printf( "%.2f ", angle[i] ); | |
| fprintf(fout, "%.2f ", angle[i] ); | |
| } | |
| printf("\n"); | |
| fprintf(fout, "\n");///少了fclose,因為不想要才印一行,就結束。想寫多行一些 | |
| } | |
| void myRead(){ | |
| if(fout!=NULL) { fclose(fout); fout=NULL; }///還在讀的檔案要關掉 | |
| if(fin==NULL) fin = fopen("file.txt", "r"); | |
| for(int i=0; i<20; i++){ | |
| fscanf(fin, "%f", &angle[i] ); | |
| } | |
| glutPostRedisplay();///重畫畫面!! | |
| } | |
| void keyboard( unsigned char key, int x, int y){ | |
| if( key=='r' ) myRead(); | |
| if( key=='s' ) myWrite();///save | |
| if( key=='0' ) angleID=0;///預設是這一個 | |
| if( key=='1' ) angleID=1; | |
| if( key=='2' ) angleID=2; | |
| if( key=='3' ) angleID=3; | |
| }///用keyboard的按鍵,來決定等一下 motion()裡要改的 angle[i] 是哪一個 | |
| void mouse(int button, int state, int x, int y){///mouse按下去 | |
| oldX = x; | |
| } | |
| void motion(int x, int y){ | |
| angle[angleID] += (x-oldX); | |
| ///myWrite();///沒有必要一直寫檔啦 | |
| oldX = x; | |
| glutPostRedisplay(); | |
| } | |
| #include <math.h> | |
| void myCircle(float x, float y) | |
| { | |
| glBegin(GL_POLYGON); | |
| for(float a=0; a<3.1415*2; a+=0.1){ | |
| glVertex2f( x + 0.1*cos(a), y + 0.1*sin(a) ); | |
| } | |
| glEnd(); | |
| } | |
| void display() | |
| { | |
| glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); | |
| glColor3f(1,1,1);///白色的 | |
| glRectf(0.3, 0.5, -0.3, -0.2);///身體,瘦身 | |
| glPushMatrix(); ///右半邊 | |
| glTranslatef( 0.3, 0.5, 0);///(3) 等下要掛在0.5,0.5 | |
| glRotatef( angle[0], 0, 0, 1);///(2) 旋轉 | |
| glTranslatef( -0.3, -0.4, 0);///(1)先把旋轉中心放正中心 | |
| glColor3f(1,0,0);///紅色的 | |
| glRectf(0.3, 0.5, 0.8, 0.3);///右上手臂 | |
| myCircle(0.3, 0.4); ///圓心在 0.3, 0.4 | |
| glPushMatrix(); | |
| glTranslatef(0.8, 0.4, 0); ///(3) 把下手肘掛在關節上 | |
| glRotatef( angle[1], 0, 0, 1); ///(2) 旋轉 | |
| glTranslatef(-0.8, -0.4, 0 );///(1) 把下手肘的旋轉中心,放正中心 | |
| glColor3f(0,1,0);///綠色的 | |
| glRectf(0.8, 0.5, 1.1, 0.3);///再畫右下手肘 | |
| myCircle(0.8, 0.4); ///圓心 0.8 0.4 | |
| glPopMatrix(); | |
| glPopMatrix(); | |
| glPushMatrix(); ///左半邊 | |
| glTranslatef( -0.3, 0.5, 0);///(3) 等下要掛在0.5,0.5 | |
| glRotatef( angle[2], 0, 0, 1);///(2) 旋轉 | |
| glTranslatef( +0.3, -0.4, 0);///(1)先把旋轉中心放正中心 | |
| glColor3f(1,0,0);///紅色的 | |
| glRectf(-0.3, 0.5, -0.8, 0.3);///左上手臂 | |
| glPushMatrix(); | |
| glTranslatef(-0.8, 0.4, 0); ///(3) 把下手肘掛在關節上 | |
| glRotatef( angle[3], 0, 0, 1); ///(2) 旋轉 | |
| glTranslatef(+0.8, -0.4, 0 );///(1) 把下手肘的旋轉中心,放正中心 | |
| glColor3f(0,1,0);///綠色的 | |
| glRectf(-0.8, 0.5, -1.1, 0.3);///再畫左下手肘 | |
| glPopMatrix(); | |
| glPopMatrix(); | |
| glutSwapBuffers(); | |
| } | |
| int main(int argc, char**argv) | |
| { | |
| glutInit(&argc, argv); | |
| glutInitDisplayMode(GLUT_DOUBLE | GLUT_DEPTH); | |
| ///glutInitWindowSize(600,600); | |
| glutCreateWindow("week15 angles TRT again"); | |
| glutKeyboardFunc(keyboard); | |
| glutMouseFunc(mouse); | |
| glutMotionFunc(motion); | |
| glutDisplayFunc(display);///不放Idle | |
| glutMainLoop(); | |
| } |
```
3.錯誤版(印出來的數值都是0)
3-1 myRead()函式前面加
float NewAngle[20],OldAngle[20];
myRead()函式裡面把fscanf(fin,"%f",&angle[i]);給註解掉
3-2 在for迴圈加入
OldAngle[i]=NewAngle[i];
fscanf(fin, "%f",&NewAngle[i]);
3-3 新增myInterpolate()函式
void myInterpolate(float alpha)
{
for(int i=0;i<20;i++)
{
angle[i]=alpha*NewAngle[i]+(1-alpha)*OldAngle[i];
printf("%.2f",angle[i]);
}
printf("\n");
glutPostRedisplay();
alpha=(alpha+0.1);
if(alpha>1)alpha=alpha-1;
}
3-4 keyboard()函式前面加入
float alpha=0;
3-5 keyboard()函式內加入
if(key=='p')myInterpolate(alpha);
4.修正版
4-1 將myInterpolate(float alpha)內glutPostRedisplay();下面兩行
alpha=(alpha+0.01);
if(alpha>1)alpha=alpha-1;
4-2 移到keyboard()函式內的if(key='p')內
if(key=='p'){
myInterpolate(alpha);
alpha=(alpha+0.01);
if(alpha>1)alpha=alpha-1;
}
5.寫一個timer函式自動做內插，先按S存4個動作，接著重開後按Ｐ
```c
void timer(int t)
{
float alpha = (t%100)/100.0;
if(t%100==0)myRead();
myInterpolate(alpha);
glutTimerFunc(33,timer,t+1);
}
```
將if(key='p'){內改成
myRead(); ///先讀一行
glutTimerFunc(0,timer,0); ///馬上開始播動畫
}
主題二 攝影機、運鏡
1.下載ｄａｔａ、ｗｉｎｄｏｗｓ等壓縮檔，解壓縮後打開Projection.exe
＊ａｓｐｅｃｔ ｒａｔｉｏ是長寬比：寬度除以高度
＊ｇｌＭａｔｒｉｘＭｏｄｅ（ＧＬ＿ＰＲＯＪＥＣＴＩＯＮ）； 投影，把３Ｄ投射到２Ｄ畫面
２．透視投影:利用不同的攝影機角度來看茶壺
gluPerspective、glutReshapeFunc()、glutLookAt()
‵‵‵ｃ
#include <GL/glut.h>
void display()
{
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glutSolidTeapot(2);///大茶壼
glutSwapBuffers();
}
void motion(int x, int y)
{
glMatrixMode(GL_MODELVIEW);///3D經過轉換到你最後的攝影機
glLoadIdentity();
gluLookAt( (x-150)/15.0, (y-150)/15.0, 3, ///eye
0, 0, 0, ///center
0, 1, 0);///up
glutPostRedisplay();
}
void reshape(int w, int h)
{ const float ar = (float) w / (float) h;
glViewport(0, 0, w, h);
glMatrixMode(GL_PROJECTION);///投影,把3D投射到2D畫面
glLoadIdentity();
gluPerspective(60, ar, 0.1, 100);
glMatrixMode(GL_MODELVIEW);///3D經過轉換到你最後的攝影機
glLoadIdentity() ;
gluLookAt( 0, 0, 3, 0, 0, 0, 0, 1, 0);
}
int main(int argc, char**argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_DEPTH);
glutCreateWindow("week16 camera lookat");
glutReshapeFunc(reshape);
glutDisplayFunc(display);
glutMotionFunc(motion);
glutMainLoop();
}
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