/*------------------------------------------------------------------------------ // Name: // // Date: // // Description: // // Assumptions: // // Input: // // Outputs: // // //--------------------------------------------------------------------------------*/ #include #include #include #include /* OpenGL include */ #define DEBUG /* Coment to remove diagnostic messages */ /*------------------------------------------------------------------------------- // Program Constants //-------------------------------------------------------------------------------*/ /* initial window size constants (in pixels) */ #define INIT_WINDOW_SIZE_WIDTH 400 #define INIT_WINDOW_SIZE_HEIGHT 400 /* initial window postion in screen coordinates (pixels) // i.e. w.r.t upper left corner of the screen, and positive y pointing downwards */ #define INIT_WINDOW_POS_X 200 #define INIT_WINDOW_POS_Y 150 /*---------------------------------- // Object and Color IDs (Menu IDs) //----------------------------------*/ #define RED 1 #define GREEN 2 #define BLUE 3 #define WHITE 4 #define LINE 5 #define SQUARE 6 #define PENTAGON 7 #define CIRCLE 8 #define TRIANGLE 9 #define ERASE 10 #define QUIT 11 /*---------------------------------- // Object Properties //----------------------------------*/ #define MAX_OBJECTS 20 #define RADIUS 50 #define PI 3.14159265358979 /* title of the drawing window */ const char *WINDOWTITLE = { "OpenGL Sample -- Bart Simpson" }; /* window background color definitions */ #define BLACK 0.0f,0.0f,0.0f /* Background color */ typedef struct { int type; float red; float green; float blue; int x0, y0; float ang; } PRIMATIVE_TYPE ; /*------------------------------------------------------------------------------- // Global variables //-------------------------------------------------------------------------------*/ PRIMATIVE_TYPE gObjects[MAX_OBJECTS]; /* holds objects to draw */ int gNumObjects; /* num objects to draw */ int gCurrentObject; float gCurrentRed, gCurrentBlue, gCurrentGreen; int gPosX, gPosY; int gCur_Win_Width, gCur_Win_Height; /*------------------------------------------------------------------------------- // Function Prototypes //-------------------------------------------------------------------------------*/ void InitGraphics(void); void myDisplay(void); void myChangeSize( int width, int height ); void myMouseFunc( int button, int state, int mouseX, int mouseY); void InitMenu(void); void MenuHandler(int id); /*------------------------------------------------------------------------------ // Main Funtion //------------------------------------------------------------------------------*/ int main( int argc, char **argv ) { /* Initalize OpenGL Toolkit */ glutInit( &argc, argv); /* Function to initalize graphics */ InitGraphics(); /*------------------------------------------------------------- // Regisister event callback with glut //-----------------------------------------------------------*/ glutMouseFunc(myMouseFunc); /* handles mouse clicks */ glutDisplayFunc( myDisplay ); /* handles drawing */ glutReshapeFunc( myChangeSize ); /* handles window resize */ //------------------------------------------------------------------ // Call OpenGL main loop. This function does not return until // the graphics window is closed or destroyed. //------------------------------------------------------------------ glutMainLoop(); return 0; } /*===================================================================================== // OpenGL calls this function only once to initalize drawing properties. //=====================================================================================*/ void InitGraphics(void) { #ifdef DEBUG fprintf( stderr, "InitGraphics\n" ); #endif /* setup the display mode: // ( *must* be done before call to glutCreateWindow() ) // ask for color, single-buffering: */ glutInitDisplayMode( GLUT_RGB | GLUT_SINGLE ); /* set the initial window configuration: */ glutInitWindowSize( INIT_WINDOW_SIZE_WIDTH, INIT_WINDOW_SIZE_HEIGHT ); /* set windows initial postion in screen coordinates w.r.t upper left corner of screen */ glutInitWindowPosition(INIT_WINDOW_POS_X, INIT_WINDOW_POS_Y); /* create the window and set its title: */ glutCreateWindow( WINDOWTITLE ); glutSetWindowTitle( WINDOWTITLE ); /* set the drawing window background color to black */ glClearColor(BLACK, 0.0f); /* reset projection matrix */ glMatrixMode(GL_PROJECTION); glLoadIdentity(); /* set default settings */ glOrtho(0, INIT_WINDOW_SIZE_WIDTH, 0, INIT_WINDOW_SIZE_HEIGHT, 1.0, -1.0); InitMenu(); /* Initalize Objects Array */ for (int i= 0; i< MAX_OBJECTS; i++) { gObjects[i].type = 0; gObjects[i].red = 0.0; gObjects[i].green = 0.0; gObjects[i].blue = 0.0; gObjects[i].x0 = gObjects[i].y0 = -1; gObjects[i].ang = 0.0; } gNumObjects = 0; gCurrentObject = LINE; gCurrentRed = 1.0; gCurrentGreen = 0; gCurrentBlue = 0.0; } /*---------------------------------------------------------------------- // Call this function to draw a line //---------------------------------------------------------------------*/ void DrawLine(int index){ #ifdef DEBUG fprintf(stderr, "DrawLine: %d \n", gObjects[index].type); #endif } /*---------------------------------------------------------------------- // Call this function to draw an N-gon //---------------------------------------------------------------------*/ void DrawNGon(int index) { #ifdef DEBUG fprintf(stderr, "DrawNGon: %d \n", gObjects[index].type); #endif } /*---------------------------------------------------------------------- // Call this function to draw all objects in object array //---------------------------------------------------------------------*/ void DrawObjects(void) { } /*===================================================================================== // OpenGL calls this function any time the drawing window needs to be redrawn. //=====================================================================================*/ void myDisplay(void) { #ifdef DEBUG fprintf( stderr, "Display\n" ); #endif // Clear Screen glClear(GL_COLOR_BUFFER_BIT); if (gNumObjects > 0) DrawObjects(); // Flush Drawing Commands glFlush(); } /*===================================================================================== // OpenGL calls this function just after the window is created and before its visible, // and any time the window is resized by the user. //=====================================================================================*/ void myChangeSize( int width, int height ) { #ifdef DEBUG fprintf( stderr, "ChangeSize: w = %d, h = %d\n", width, height ); #endif /* store new dimensions for later */ gCur_Win_Width = width; gCur_Win_Height = height; /* set viewport to the same size as the newly resized window (in pixel units) */ glViewport(0, 0, width, height); /* reset projection matrix */ glMatrixMode(GL_PROJECTION); glLoadIdentity(); /* set drawing coordinates within viewport in physical units */ glOrtho(0, width, 0, height, 1.0, -1.0); /* reset modelview matrix */ glMatrixMode(GL_MODELVIEW); glLoadIdentity(); } /*----------------------------------------------------------------------------------- // OpenGl calls this function in response to a mouse event (mouse clicks). // // button = {GLUT_RIGHT_BUTTON, GLUT_MIDDLE_BUTTON, GLUT_LEFT_BUTTON} // // state = {GLUT_UP, GLUT_DOWN} //-----------------------------------------------------------------------------------*/ void myMouseFunc( int button, int state, int mouseX, int mouseY) { /* We are only interested in left clicks */ if (button != GLUT_LEFT_BUTTON || state != GLUT_DOWN) return; /* Translate mouse values contained in mouseX and mouse Y // so they are relative to the bottom left corner of drawing window */ gPosX = mouseX; gPosY = gCur_Win_Height - mouseY; #ifdef DEBUG fprintf( stderr, "myMouseFunc: w = %d, h = %d %d\n", gPosX, gPosY, gNumObjects ); #endif } /*---------------------------------------------------------------------------------- // This function is called to initalize a context menu //----------------------------------------------------------------------------------*/ void InitMenu(void){ #ifdef DEBUG fprintf( stderr, "InitMenu: \n"); #endif int menu, sub_menu; /* Create color submenu */ sub_menu = glutCreateMenu(MenuHandler); glutAddMenuEntry("Red", RED); glutAddMenuEntry("Green", GREEN); glutAddMenuEntry("Blue", BLUE); glutAddMenuEntry("White", WHITE); /* create main context menu */ menu = glutCreateMenu(MenuHandler); // attach submenu */ glutAddSubMenu("Color", sub_menu); /* create object menu items */ glutAddMenuEntry("Line", LINE); glutAddMenuEntry("Triangle", TRIANGLE); glutAddMenuEntry("Square", SQUARE); glutAddMenuEntry("Pentagon", PENTAGON); glutAddMenuEntry("Circle", CIRCLE); glutAddMenuEntry("Erase", ERASE); /* create a blank entry */ glutAddMenuEntry("", -1); glutAddMenuEntry("Quit", QUIT); glutAttachMenu(GLUT_RIGHT_BUTTON); } /*---------------------------------------------------------------------------------- // This function is called by OpenGL in response to a context menu selection //----------------------------------------------------------------------------------*/ void MenuHandler( int id) { switch (id) { case LINE: gCurrentObject = LINE; break; case TRIANGLE: gCurrentObject = TRIANGLE; break; case SQUARE: gCurrentObject = SQUARE; break; case PENTAGON: gCurrentObject = PENTAGON; break; case CIRCLE: gCurrentObject = CIRCLE; break; case RED: gCurrentRed = 1.0; gCurrentGreen = 0.0; gCurrentBlue = 0.0; break; case GREEN: gCurrentRed = 0.0; gCurrentGreen = 1.0; gCurrentBlue = 0.0; break; case BLUE: gCurrentRed = 0.0; gCurrentGreen = 0.0; gCurrentBlue = 1.0; break; case WHITE: gCurrentRed = 1.0; gCurrentGreen = 1.0; gCurrentBlue = 1.0; break; case ERASE: break; case QUIT: exit(0); break; } #ifdef DEBUG fprintf( stderr, "MenuHandler: %d\n", id); #endif }