電腦圖學week14課堂筆記

 課堂內容 : fprintf()、fscanf() 寫檔和讀檔；fprintf()、fscanf() + project

1.寫檔
#include <stdio.h>
int main()
{
    FILE * fout = fopen("file.txt", "w+");
    printf("Hello World\n");
    fprintf(fout,"Hello World\n");
    fclose(fout);
}

2.讀檔

#include <stdio.h>

int main()

{

    FILE * fout = fopen("file.txt", "w+");

    fprintf(fout,"3.1415926\n");

    fclose(fout);

    float angle=0;

    FILE * fin = fopen("file.txt", "r");

    fscanf(fin, "%f", &angle );

    printf("角度:%f", angle);

    fclose(fin);

}

3.加入上週的程式

#include <GL/glut.h>

#include <stdio.h>

float angle[20],oldx=0;

int angleID=0;

FILE*fout=NULL;

void mywrite()

{

    if(fout == NULL) fout=fopen("file.txt", "w+");

    for(int i=0 ; i<20 ; i++)

    {

        printf("%.1f\n", angle[i]);

        fprintf(fout, "%.1f", angle[i]);

    }

}

void keyboard(unsigned char key,int x,int y)

{

    if(key=='0')angleID=0;

    if(key=='1')angleID=1;

    if(key=='2')angleID=2;

    if(key=='3')angleID=3;

}

void mouse(int button,int state,int x,int y)

{

    oldx=x;

}

void motion(int x,int y)

{

    angle[angleID]+=(x-oldx);

    mywrite();

    oldx=x;

    glutPostRedisplay();

}

void display()

{

    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);

    glColor3f(1,1,1);

    glRectf(0.3,0.5,-0.3,-0.5);

    glPushMatrix();

        glTranslatef(0.3,0.4,0);

        glRotatef(angle[0],0,0,1);

        glTranslatef(-0.3,-0.4,0);

        glColor3f(1,0,0);

        glRectf(0.3,0.5,0.7,0.3);

        glPushMatrix();

            glTranslatef(0.7,0.4,0);

            glRotatef(angle[1],0,0,1);

            glTranslatef(-0.7,-0.4,0);

            glColor3f(0,1,0);

            glRectf(0.7,0.5,1.0,0.3);

        glPopMatrix();

    glPopMatrix();

    glPushMatrix();

        glTranslatef(-0.3,0.4,0);

        glRotatef(-angle[2],0,0,1);

        glTranslatef(0.3,0.4,0);

        glColor3f(1,0,0);

        glRectf(-0.3,-0.5,-0.7,-0.3);

        glPushMatrix();

            glTranslatef(-0.7,-0.4,0);

            glRotatef(-angle[3],0,0,1);

            glTranslatef(0.7,0.4,0);

            glColor3f(0,1,0);

            glRectf(-0.7,-0.5,-1.0,-0.3);

        glPopMatrix();

    glPopMatrix();

    glutSwapBuffers();

}

int main(int argc,char**argv)

{

    glutInit(&argc,argv);

    glutInitDisplayMode(GLUT_DOUBLE|GLUT_DEPTH);

    glutCreateWindow("week14");

    glutMouseFunc(mouse);

    glutMotionFunc(motion);

    glutKeyboardFunc(keyboard);

    glutDisplayFunc(display);

    glutMainLoop();

}

最後可以做成動畫 : 

#include <GL/glut.h>

#include <stdio.h>

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("%.1f ", angle[i] );

        fprintf(fout, "%.1f ", angle[i] );

    }

    printf("\n");

    fprintf(fout,"\n");

}

void myRead()

{

    if( fout != NULL )  fclose(fout); fout=NULL;

    if( fin == NULL ) fin = fopen("file.txt", "r");

    for(int i=0; i<20; i++)

    {

        fscanf(fin, "%f",&angle[i] );

    }

    glutPostRedisplay();

}

void keyboard(unsigned char key , int x  , int y)

{

    if (key=='r') myRead();

    if (key=='0') angleID=0;

    if (key=='1') angleID=1;

    if (key=='2') angleID=2;

    if (key=='3') angleID=3;

}

void mouse(int button , int state , int x ,int y)

{

    oldx=x;

}

void motion (int x, int y)

{

    angle[angleID]+=(x-oldx);

    myWrite();

    oldx=x;

    glutPostRedisplay();

}

void display()

{

    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glColor3f(1,1,1);

    glRectf(0.3,0.5,-0.3,-0.5);

    glPushMatrix();

        glTranslatef(0.3,0.4,0);

        glRotatef(angle[0],0,0,1);

        glTranslatef(-0.3,-0.4,0);

        glColor3f(1,0,0);

        glRectf(0.3,0.5,0.7,0.3);

        glPushMatrix();

            glTranslatef(0.7,0.4,0);

            glRotatef(angle[1],0,0,1);

            glTranslatef(-0.7,-0.4,0);

            glColor3f(0,1,0);

            glRectf(0.7,0.5,1.0,0.3);

        glPopMatrix();

    glPopMatrix();

    glPushMatrix();

        glTranslatef(-0.3,0.4,0);

        glRotatef(angle[2],0,0,1);

        glTranslatef(0.3,-0.4,0);

        glColor3f(1,0,0);

        glRectf(-0.3,0.5,-0.7,0.3);

        glPushMatrix();

            glTranslatef(-0.7,0.4,0);

            glRotatef(angle[3],0,0,1);

            glTranslatef(0.7,-0.4,0);

            glColor3f(0,1,0);

            glRectf(-0.7,0.5,-1.0,0.3);

        glPopMatrix();

    glPopMatrix();

    glutSwapBuffers();

}

int main(int argc, char** argv)

{

    glutInit( &argc, argv);

    glutInitDisplayMode( GLUT_DOUBLE | GLUT_DEPTH );

    glutCreateWindow("week14");

    glutKeyboardFunc(keyboard);

    glutMouseFunc(mouse);

    glutMotionFunc(motion);

    glutDisplayFunc(display);

    glutMainLoop();

}

按 r 可以重複剛剛的動作