그래픽스 실습 4.27

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#include<iostream> #include <gl glut.h="">     void draw_axes(); void init(); void draw_drag(); void display(void); void mouse(int button,int status,int x, int y); void motion(int,int);   int last_x,last_y;          //last (x,y) position , where the left button pressed. int current_x, current_y;   // current (x,y) position bool b_draw_dragbox = false;   int main() {     glutCreateWindow("TransFormation");     glutDisplayFunc(display);     glutMouseFunc(mouse);     glutMotionFunc(motion);     init();           glutMainLoop();       return 0; }   void init() {       glClearColor(1.0f,1.0f,1.0f,1.0f);   }   void display() {     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);     // set the current camera     // f) extrinsic camera property, which can be specified by GL_MODELVIEW matirix     // s) intrinsic camera property, which can be specified by GL_PROJECTION matrix       glMatrixMode(GL_PROJECTION);     glLoadIdentity();     glOrtho(-1,1,- 1,1 ,-1, 1);       glMatrixMode(GL_MODELVIEW);     glLoadIdentity();                                                       // M = I     gluLookAt(0, 0, 1, 0, 0, 0, 0, 1 , 0);           draw_axes();     // Object를 조작함.     //glRotatef(75.0f,0,0,1);                                           // R 메트릭스    M *=R   => M=R     //glScalef(2.0f,2.0f,2.0f);                                     // S 메트릭스       M *=S   => M=RS     glTranslatef(0.3f,0.3f,0.0f);                                       // T 메트릭스       M *=T   => M=RST                                                                                 // T ( S ( Rx))     // Model Matrix Continue....                                                                        M'  = RSTx    => T먼저 적용됨.       // Draw DragBox     if(b_draw_dragbox)         draw_drag();               //Drawing an object (a red box)     // Object는 절대 건들이지 않는다. 메트릭스만 곱해서 조절 ->그리는건 조형대 애들이.     glColor3f(1.0f,0.0f,0.0f);     glBegin(GL_QUADS);     // -------------------------------     glVertex2f(0.5f,0.5f);     glVertex2f(-0.5f,0.5f);                                         // x메트릭스     glVertex2f(-0.5f,-0.5f);     glVertex2f(0.5f,-0.5f);     // -------------------------------     glEnd();                                                                                 //  = > Tx     glFlush();     }   void draw_drag() {     glColor3f(0.0f,1.0f,0.0f);     glBegin(GL_LINE_LOOP);     glVertex2f(last_x,last_y);     glVertex2f(last_x,current_y);     glVertex2f(current_x,current_y);     glVertex2f(current_x,last_y);     glEnd();     printf("adfasd");   } void draw_axes() {     glMatrixMode(GL_MODELVIEW);     glBegin(GL_LINES);       glColor3f(1.0f,0.0f,0.0f);     glVertex2d(-5,0);     glVertex2d(5,0);         glColor3f(1.0f,1.0f,0.0f);     glVertex2d(0,-5);     glVertex2d(0,5);     glEnd();     glFlush();   }   void mouse(int button,int state,int x, int y) {     if( button == GLUT_LEFT_BUTTON&& state == GLUT_DOWN)     {         printf("left mouse button is pressed!\n");         last_x = x;         last_y = y;         b_draw_dragbox=true;         // 네모 그리고     } else if( button == GLUT_LEFT_BUTTON && state == GLUT_UP)     {         printf("left mouse button is Releassed!\n");         b_draw_dragbox=false;         // 네모지우고     } }     void motion(int x,int y) {     current_x =x;     current_y = y;     printf("mouse is dragging : x : %d   y: %d \n",x,y);   }   </gl></iostream>