PC Format (South-Africa) 2001 June/PCFJune.iso/Xenon/XenonSource.exe/demo1/demo1.cpp

C/C++ Source or Header | 2000-09-12 | 4.7 KB | 238 lines

//-------------------------------------------------------------
//
// Program:    Demo 1
//
// Author:    John M Phillips
//
// Started:    20/08/00
//
// Remarks:    This is a simple demo program using the GameSystem library
//            which opens a full-screen window and draws some moving sprites.
//
//-------------------------------------------------------------

#include "demo1.h"

//-------------------------------------------------------------
// Constants

const char *GRAPHICS_DIRECTORY = "..\\..\\Demo1\\Graphics\\";

const char *SPRITE_IMAGE = "ship.bmp";

const int NUMBER_OF_SPRITES = 10;

//-------------------------------------------------------------
// Create an instance of the application class
// GameSystem will run this automatically

CDemo1 myApp("Demo 1");

//-------------------------------------------------------------
// Initialize the demo
//
// Return: true if successful

bool CDemo1::initialize()
{
    // initialize the GameSystem framework

    if (!gsCApplication::initialize())
        return false;

    // create the keyboard handler and screen window

    if (!m_keyboard.create())
        return false;

    if (!m_screen.createWindowed(getWindow()))
        return false;

    // load images and create some sprites

    if (!createSprites())
        return false;

    // create a 16 layer starfield

    m_stars.initialize(16);

    return true;
}

//-------------------------------------------------------------
// Main loop : draws sprites to the screen and test the keyboard
//
// Return: true if successful
//           false if error or ESCAPE pressed

bool CDemo1::mainloop()
{
    // clear the screen to black

    m_screen.clear(gsCColour(gsBLACK));

    // draw starfield and animate it

    m_stars.draw();
    m_stars.move(4);

    // draw our sprites

    drawSprites();

    // flip the screen to view

    m_screen.flip();

    // move sprites for next frame

    moveSprites();

    // test for ESCAPE pressed and exit demo if so

    gsKeyCode key = m_keyboard.getKey();

    if (key == gsKEY_ESCAPE)
        return false;

    return true;
}

//-------------------------------------------------------------
// Shutdown demo

bool CDemo1::shutdown()
{
    // destroy out sprites and images

    destroySprites();

    // destroy the screen and keyboard handler

    m_screen.destroy();
    m_keyboard.destroy();

    // exit

    return gsCApplication::shutdown();
}

//-------------------------------------------------------------
// Create our images and sprites
//
// Return: true if success
//           false if error

bool CDemo1::createSprites()
{
    // set the directory path for our images

    gsCFile::setDirectory(GRAPHICS_DIRECTORY);

    // load image

    if (!m_image.load(SPRITE_IMAGE))
        return false;

    // treat magenta colour as being transparent

    m_image.enableColourKey(gsCColour(gsMAGENTA));

    // random number generator for sprite positions

    gsCRandom rnd;

    // now we create the sprites

    for (int i = 0; i < NUMBER_OF_SPRITES; i++) {

        // create a new sprite

        gsCSprite *spr = new gsCSprite;

        // add it to our list of sprites

        m_sprite.addItem(spr);

        // use the image we loaded earlier

        spr->setImage(&m_image);

        // set the centre of the sprite

        spr->setHotspot(m_image.getSize() / 2);

        // give it a random starting position on screen

        gsCPoint pos;

        pos.setX(rnd.getInt(0,m_screen.getSize().getX()));
        pos.setY(rnd.getInt(0,m_screen.getSize().getY()));

        spr->setPosition(pos);

        // activate it

        spr->setActive(true);
        }

    return true;
}

//-------------------------------------------------------------
// Destroy our images and sprites

bool CDemo1::destroySprites()
{
    // delete each sprite

    for (int i = 0; i < m_sprite.getSize(); i++)
        delete m_sprite[i];

    // clear the sprite list

    m_sprite.clear();

    // destroy our image

    m_image.destroy();

    return true;
}

//-------------------------------------------------------------
// Draw all the sprites on screen

void CDemo1::drawSprites()
{
    for (int i = 0; i < m_sprite.getSize(); i++)
        m_sprite[i]->draw();
}

//-------------------------------------------------------------
// Move all sprites

void CDemo1::moveSprites()
{
    gsCRect screen_rect = m_screen.getRect();

    // this basically moves each sprite up the screen

    // if the sprite goes off the screen it's wrapped
    // around to the bottom

    for (int i = 0; i < m_sprite.getSize(); i++) {

        m_sprite[i]->move(gsCPoint(0,-((i & 3) + 1)));

        gsCRect sprite_rect = m_sprite[i]->getRect();

        if (!(sprite_rect.overlaps(screen_rect)))
            m_sprite[i]->move(gsCPoint(0,m_screen.getSize().getY() + m_image.getSize().getY()));
        }
}

//-------------------------------------------------------------