asteroids-cs165/uiInteract.cpp

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2020-06-30 22:04:55 -04:00
/***********************************************************************
* Source File:
* UI INTERACT
* Author:
* Br. Helfrich
* Description:
* Implement the interfaces specified in uiInterface.h. This handles
* all the interfaces and events necessary to work with OpenGL. Your
* program will interface with this thorough the callback function
* pointer towards the bottom of the file.
************************************************************************/
#include <string> // need you ask?
#include <sstream> // convert an integer into text
#include <cassert> // I feel the need... the need for asserts
#include <time.h> // for clock
#include <cstdlib> // for rand()
#ifdef __APPLE__
#include <openGL/gl.h> // Main OpenGL library
#include <GLUT/glut.h> // Second OpenGL library
#endif // __APPLE__
#ifdef __linux__
#include <GL/gl.h> // Main OpenGL library
#include <GL/glut.h> // Second OpenGL library
#endif // __linux__
#ifdef _WIN32
#include <stdio.h>
#include <stdlib.h>
#include <Gl/glut.h> // OpenGL library we copied
#include <ctime> // for ::Sleep();
#include <Windows.h>
#define _USE_MATH_DEFINES
#include <math.h>
#endif // _WIN32
#include "uiInteract.h"
#include "point.h"
using namespace std;
/*********************************************************************
* SLEEP
* Pause for a while. We want to put the program to sleep until it
* is time to draw again. Note that this requires us to tell the OS
* that we are idle. the nanosleep function performs this task for us
* INPUT: msSleep: sleep time in milliseconds
*********************************************************************/
void sleep(unsigned long msSleep)
{
// Windows handles sleep one way
#ifdef _WIN32
::Sleep(msSleep + 35);
// Unix-based operating systems (OS-X, Linux) do it another
#else // LINUX, XCODE
timespec req = {};
time_t sec = (int)(msSleep / 1000);
msSleep -= (sec * 1000);
req.tv_sec = sec;
req.tv_nsec = msSleep * 1000000L;
while (nanosleep(&req, &req) == -1)
;
#endif // LINUX, XCODE
return;
}
/************************************************************************
* DRAW CALLBACK
* This is the main callback from OpenGL. It gets called constantly by
* the graphics engine to refresh and draw the window. Here we will
* clear the background buffer, draw on it, and send it to the forefront
* when the appropriate time period has passsed.
*
* Note: This and all other callbacks can't be member functions, they must
* have global scope for OpenGL to see them.
*************************************************************************/
void drawCallback()
{
// even though this is a local variable, all the members are static
Interface ui;
// Prepare the background buffer for drawing
glClear(GL_COLOR_BUFFER_BIT); //clear the screen
glColor3f(1,1,1);
//calls the client's display function
assert(ui.callBack != NULL);
ui.callBack(&ui, ui.p);
//loop until the timer runs out
if (!ui.isTimeToDraw())
sleep((unsigned long)((ui.getNextTick() - clock()) / 1000));
// from this point, set the next draw time
ui.setNextDrawTime();
// bring forth the background buffer
glutSwapBuffers();
// clear the space at the end
ui.keyEvent();
}
/************************************************************************
* KEY DOWN CALLBACK
* When a key on the keyboard has been pressed, we need to pass that
* on to the client. Currently, we are only registering the arrow keys
* INPUT key: the key we pressed according to the GLUT_KEY_ prefix
* x y: the position in the window, which we ignore
*************************************************************************/
void keyDownCallback(int key, int x, int y)
{
// Even though this is a local variable, all the members are static
// so we are actually getting the same version as in the constructor.
Interface ui;
ui.keyEvent(key, true /*fDown*/);
}
/************************************************************************
* KEY UP CALLBACK
* When the user has released the key, we need to reset the pressed flag
* INPUT key: the key we pressed according to the GLUT_KEY_ prefix
* x y: the position in the window, which we ignore
*************************************************************************/
void keyUpCallback(int key, int x, int y)
{
// Even though this is a local variable, all the members are static
// so we are actually getting the same version as in the constructor.
Interface ui;
ui.keyEvent(key, false /*fDown*/);
}
/***************************************************************
* KEYBOARD CALLBACK
* Generic callback to a regular ascii keyboard event, such as
* the space bar or the letter 'q'
***************************************************************/
void keyboardCallback(unsigned char key, int x, int y)
{
// Even though this is a local variable, all the members are static
// so we are actually getting the same version as in the constructor.
Interface ui;
ui.keyEvent(key, true /*fDown*/);
}
/***************************************************************
* INTERFACE : KEY EVENT
* Either set the up or down event for a given key
* INPUT key which key is pressed
* fDown down or brown
****************************************************************/
void Interface::keyEvent(int key, bool fDown)
{
switch(key)
{
case GLUT_KEY_DOWN:
isDownPress = fDown;
break;
case GLUT_KEY_UP:
isUpPress = fDown;
break;
case GLUT_KEY_RIGHT:
isRightPress = fDown;
break;
case GLUT_KEY_LEFT:
isLeftPress = fDown;
break;
case GLUT_KEY_HOME:
case ' ':
isSpacePress = fDown;
break;
}
}
/***************************************************************
* INTERFACE : KEY EVENT
* Either set the up or down event for a given key
* INPUT key which key is pressed
* fDown down or brown
****************************************************************/
void Interface::keyEvent()
{
if (isDownPress)
isDownPress++;
if (isUpPress)
isUpPress++;
if (isLeftPress)
isLeftPress++;
if (isRightPress)
isRightPress++;
isSpacePress = false;
}
/************************************************************************
* INTEFACE : IS TIME TO DRAW
* Have we waited long enough to draw swap the background buffer with
* the foreground buffer?
*************************************************************************/
bool Interface::isTimeToDraw()
{
return ((unsigned int)clock() >= nextTick);
}
/************************************************************************
* INTERFACE : SET NEXT DRAW TIME
* What time should we draw the buffer again? This is a function of
* the current time and the frames per second.
*************************************************************************/
void Interface::setNextDrawTime()
{
nextTick = clock() + static_cast<int> (timePeriod * CLOCKS_PER_SEC);
}
/************************************************************************
* INTERFACE : SET FRAMES PER SECOND
* The frames per second dictates the speed of the game. The more frames
* per second, the quicker the game will appear to the user. We will default
* to 30 frames/second but the client can set this at will.
* INPUT value The number of frames per second. 30 is default
*************************************************************************/
void Interface::setFramesPerSecond(double value)
{
timePeriod = (1 / value);
}
/***************************************************
* STATICS
* All the static member variables need to be initialized
* Somewhere globally. This is a good spot
**************************************************/
int Interface::isDownPress = 0;
int Interface::isUpPress = 0;
int Interface::isLeftPress = 0;
int Interface::isRightPress = 0;
bool Interface::isSpacePress = false;
bool Interface::initialized = false;
double Interface::timePeriod = 1.0 / 30; // default to 30 frames/second
unsigned int Interface::nextTick = 0; // redraw now please
void * Interface::p = NULL;
void (*Interface::callBack)(const Interface *, void *) = NULL;
/************************************************************************
* INTERFACE : DESTRUCTOR
* Nothing here!
***********************************************************************/
Interface::~Interface()
{
}
/************************************************************************
* INTEFACE : INITIALIZE
* Initialize our drawing window. This will set the size and position,
* get ready for drawing, set up the colors, and everything else ready to
* draw the window. All these are part of initializing Open GL.
* INPUT argc: Count of command-line arguments from main
* argv: The actual command-line parameters
* title: The text for the titlebar of the window
*************************************************************************/
void Interface::initialize(int argc, char ** argv, const char * title, Point topLeft, Point bottomRight)
{
if (initialized)
return;
// set up the random number generator
srand((unsigned int)time(NULL));
// create the window
glutInit(&argc, argv);
Point point;
glutInitWindowSize( // size of the window
(int)(bottomRight.getX() - topLeft.getX()),
(int)(topLeft.getY() - bottomRight.getY()));
glutInitWindowPosition( 10, 10); // initial position
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB); // double buffering
glutCreateWindow(title); // text on titlebar
glutIgnoreKeyRepeat(true);
// set up the drawing style: B/W and 2D
glClearColor(0, 0, 0, 0); // Black is the background color
gluOrtho2D((int)topLeft.getX(), (int)bottomRight.getX(),
(int)bottomRight.getY(), (int)topLeft.getY()); // 2D environment
// register the callbacks so OpenGL knows how to call us
glutDisplayFunc( drawCallback );
glutIdleFunc( drawCallback );
glutKeyboardFunc( keyboardCallback);
glutSpecialFunc( keyDownCallback );
glutSpecialUpFunc( keyUpCallback );
initialized = true;
// done
return;
}
/************************************************************************
* INTERFACE : RUN
* Start the main graphics loop and play the game
* INPUT callBack: Callback function. Every time we are beginning
* to draw a new frame, we first callback to the client
* to see if he wants to do anything, such as move
* the game pieces or respond to input
* p: Void point to whatever the caller wants. You
* will need to cast this back to your own data
* type before using it.
*************************************************************************/
void Interface::run(void (*callBack)(const Interface *, void *), void *p)
{
// setup the callbacks
this->p = p;
this->callBack = callBack;
glutMainLoop();
return;
}