Week04

加分作業

畫圓

#include <GL/glut.h>

#include <math.h>

void display()

{

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glColor3f(0,1,1);///水藍色

    ///畫圓: cos() sin()

    glBegin(GL_POLYGON);

    for(float angle=0; angle<3.14159*2; angle+=0.1){

        glVertex2f( cos(angle), sin(angle) );

    }

    glEnd();

    glutSwapBuffers();

}

int main( int argc, char**argv )

{

    glutInit( &argc, argv);

    glutInitDisplayMode( GLUT_DOUBLE | GLUT_DEPTH );

    glutCreateWindow("HW2 bonus");

    glutDisplayFunc(display);

    glutMainLoop();

}

Translate 移動

1.glPushMatrix() 備份矩陣, glPopMatrix() 還原矩陣

#include <GL/glut.h>

void myTeapot(float x, float y)///自訂的函式

{

    glPushMatrix();///push備份矩陣

        glTranslatef( x, y, 0);

        glutSolidTeapot(0.3);

    glPopMatrix();///pop還原矩陣

}

void display()

{

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glColor3f(1,0,0);///red

    myTeapot(+0.5, +0.5);

    myTeapot(+0.5, -0.5);

    myTeapot(-0.5, -0.5);

    myTeapot(-0.5, +0.5);

    glutSwapBuffers();

}

int main( int argc, char**argv )

{

    glutInit( &argc, argv);

    glutInitDisplayMode( GLUT_DOUBLE | GLUT_DEPTH );

    glutCreateWindow("week04 translate");

    glutDisplayFunc(display);

    glutMainLoop();

}

2. Mouse滑鼠事件0是左鍵，1是中鍵，2是右鍵

#include <GL/glut.h>

#include <stdio.h>///printf()

void display()

{

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glutSwapBuffers();

}

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

{

    printf("%d %d %d %d\n", button, state, x, y);

}

int main( int argc, char**argv )

{

    glutInit( &argc, argv);

    glutInitDisplayMode( GLUT_DOUBLE | GLUT_DEPTH );

    glutCreateWindow("week04 mouse");

    glutDisplayFunc(display);///Display顯示

    glutMouseFunc(mouse);///Mouse滑鼠

    glutMainLoop();

}

3. 座標轉換

視窗左上角座標為(0, 0)，右下角為(300, 300)

#include <GL/glut.h>

#include <stdio.h>

int mouseX=0, mouseY=0;

void display()

{

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glColor3f(1,1,0);///黃色的

    glPushMatrix(); ///口訣:減一半、除一半, y還倒過來

        glTranslatef( (mouseX-150)/150.0 , -(mouseY-150)/150.0 , 0);

        glutSolidTeapot(0.3);///茶壼

    glPopMatrix();

    glutSwapBuffers();

}

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

{   //printf("%d %d %d %d\n", button, state, x, y);

    mouseX=x; mouseY=y;

}

int main( int argc, char**argv )

{

    glutInit( &argc, argv);

    glutInitDisplayMode( GLUT_DOUBLE | GLUT_DEPTH );

    glutCreateWindow("week04 mouse");

    glutDisplayFunc(display);///Display顯示

    glutMouseFunc(mouse);///Mouse滑鼠

    glutMainLoop();

}

原始位置在(0, 0)

茶壺隨著滑鼠點擊移動位置

4. 利用滑鼠點擊繪製圖型

#include <GL/glut.h>

#include <stdio.h>

int mouseX=0, mouseY=0, N=0;///N個點!!!

int mx[100], my[100];///用來記錄,等一下要畫出來哦!!!

void display()

{

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glColor3f(1,1,0);///黃色的

    glBegin(GL_LINE_LOOP);

        for(int i=0; i<N; i++){

            glVertex2f( (mx[i]-150)/150.0, -(my[i]-150)/150.0 );

        }

    glEnd();

    glutSwapBuffers();

}

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

{

    mouseX=x; mouseY=y;

    if(state==GLUT_DOWN){///按下去的 (放開的那個不算數)

        printf("    glVertex2f( (%d-150)/150.0, -(%d-150)/150.0 );\n", x,y);

        N++;

        mx[N-1]=x; my[N-1]=y;

    }

}

int main( int argc, char**argv )

{

    glutInit( &argc, argv);

    glutInitDisplayMode( GLUT_DOUBLE | GLUT_DEPTH );

    glutCreateWindow("week04 mouse");

    glutDisplayFunc(display);///Display顯示

    glutMouseFunc(mouse);///Mouse滑鼠

    glutMainLoop();

}