week16
1. 利用Excel學習內插
t：0.0 ...... 1.0
alpha ：0.0 .... 1.0
angle =13 ... 90
內插公式 alpha*新的 + (1-alpha)*舊的
2. 更改week15程式碼
- 按 r 後按住 p 後可顯示動作緩慢移動
```c
#include <GL/glut.h>
#include <stdio.h> ///為了 printf, fprintf, fopen, fclose
float angle[20], oldX=0;
int angleID=0;
FILE * fout = NULL, * fin = NULL;
void myWrite(){
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");
}
float NewAngle[20], OldAngle[20];
void myRead(){
if(fout!=NULL) {
fclose(fout);///還在讀的檔案要關掉
fout=NULL;
}
if(fin==NULL) fin = fopen("file.txt", "r");
for(int i=0; i<20; i++){
OldAngle[i] = NewAngle[i];
fscanf(fin, "%f", &NewAngle[i]);
///fscanf(fin, "%f", &angle[i]);
}
glutPostRedisplay();///重畫畫面
}
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();
}
float alpha =0;
void keyboard( unsigned char key, int x, int y){
if( key=='p' ) {
myInterpolate(alpha);
alpha = (alpha+0.01);
if(alpha>1) alpha = alpha-1;
}
if( key=='r' ) myRead();
if( key=='s' ) myWrite();///save
if( key=='0' ) angleID=0;
if( key=='1' ) angleID=1;
if( key=='2' ) angleID=2;
if( key=='3' ) angleID=3;
}///用keyboard的按鍵來決定
void mouse(int button, int state, int x, int y){
oldX = x;
}
void motion(int x, int y){
angle[angleID] += (x-oldX);
///myWrite();///沒有必要一直寫檔
oldX = x;
glutPostRedisplay();
}
void display()
{
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
glColor3f(1, 1, 1);///白色
glRectf(0.3, 0.5, -0.3, -0.2);///身體，瘦身
glPushMatrix();///掛的位置改變了
glTranslatef(0.3, 0.5, 0);
glRotatef(angle[0], 0, 0, 1);
glTranslatef(-0.3, -0.4, 0);
glColor3f(1, 0, 0);
glRectf(0.3, 0.5, 0.8, 0.3);///上手臂
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);/// 再畫下手肘
glPopMatrix();
glPopMatrix();
glPushMatrix();///左半邊
glTranslatef(-0.3, 0.5, 0);
glRotatef(angle[2], 0, 0, 1);
glTranslatef(+0.3, -0.4, 0);
glColor3f(1, 0, 0);
glRectf(-0.3, 0.5, -0.8, 0.3);///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 TRT angles again");
glutMouseFunc(mouse);
glutMotionFunc(motion);
glutKeyboardFunc(keyboard);
glutDisplayFunc( display );
glutMainLoop();
return 0;
}
```
3. 將程式碼修改完成
- 加入timer函式自動做內插
- 先執行第一次在擺好動作後按s
- 關閉視窗
- 再次執行後按下p
- 得到動畫
```c
#include <GL/glut.h>
#include <stdio.h> ///為了 printf, fprintf, fopen, fclose
float angle[20], oldX=0;
int angleID=0;
FILE * fout = NULL, * fin = NULL;
void myWrite(){
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");
}
float NewAngle[20], OldAngle[20];
void myRead(){
if(fout!=NULL) {
fclose(fout);///還在讀的檔案要關掉
fout=NULL;
}
if(fin==NULL) fin = fopen("file.txt", "r");
for(int i=0; i<20; i++){
OldAngle[i] = NewAngle[i];
fscanf(fin, "%f", &NewAngle[i]);
///fscanf(fin, "%f", &angle[i]);
}
glutPostRedisplay();///重畫畫面
}
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();
}
///float alpha =0;
void timer(int t){
float alpha = (t%30)/30.0;
if(t%30==0) myRead();
myInterpolate(alpha);
glutTimerFunc(33, timer, t+1);
}
void keyboard( unsigned char key, int x, int y){
if( key=='p' ) {
myRead();///先讀一行
glutTimerFunc(0, timer, 0);
///myInterpolate(alpha);
///alpha = (alpha+0.01);
///if(alpha>1) alpha = alpha-1;
}
if( key=='r' ) myRead();
if( key=='s' ) myWrite();///save
if( key=='0' ) angleID=0;
if( key=='1' ) angleID=1;
if( key=='2' ) angleID=2;
if( key=='3' ) angleID=3;
}///用keyboard的按鍵來決定
void mouse(int button, int state, int x, int y){
oldX = x;
}
void motion(int x, int y){
angle[angleID] += (x-oldX);
///myWrite();///沒有必要一直寫檔
oldX = x;
glutPostRedisplay();
}
void display()
{
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
glColor3f(1, 1, 1);///白色
glRectf(0.3, 0.5, -0.3, -0.2);///身體，瘦身
glPushMatrix();///掛的位置改變了
glTranslatef(0.3, 0.5, 0);
glRotatef(angle[0], 0, 0, 1);
glTranslatef(-0.3, -0.4, 0);
glColor3f(1, 0, 0);
glRectf(0.3, 0.5, 0.8, 0.3);///上手臂
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);/// 再畫下手肘
glPopMatrix();
glPopMatrix();
glPushMatrix();///左半邊
glTranslatef(-0.3, 0.5, 0);
glRotatef(angle[2], 0, 0, 1);
glTranslatef(+0.3, -0.4, 0);
glColor3f(1, 0, 0);
glRectf(-0.3, 0.5, -0.8, 0.3);///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 TRT angles again");
glutMouseFunc(mouse);
glutMotionFunc(motion);
glutKeyboardFunc(keyboard);
glutDisplayFunc( display );
glutMainLoop();
return 0;
}
```
4. 投影（簡易）
- 到 https://jsyeh.org/3dcg10/
- 下載windows跟data解壓縮後將data丟進window
- 開啟windows裡面的projection
- gluLookAt固定在一個焦點上
5. 以白色茶壺當範例做投影
```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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