BALL.H

//==========================================================================; 
// 
//  THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY 
//  KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE 
//  IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR 
//  PURPOSE. 
// 
//  Copyright (c) 1992 - 1997  Microsoft Corporation.  All Rights Reserved. 
// 
//--------------------------------------------------------------------------; 
 
class CBall 
{ 
public: 
 
    CBall(int iImageWidth = 320, int iImageHeight = 240, int iBallSize = 10); 
 
    // Plots the square ball in the image buffer, at the current location. 
    // Use BallPixel[] as pixel value for the ball. 
    // Plots zero in all 'background' image locations. 
    // iPixelSize - the number of bytes in a pixel (size of BallPixel[]) 
    void PlotBall(BYTE pFrame[], BYTE BallPixel[], int iPixelSize); 
 
    // Moves the ball 1 pixel in each of the x and y directions 
    void MoveBall(CRefTime rt); 
 
private: 
 
    enum xdir { LEFT = -1, RIGHT = 1 }; 
    enum ydir { UP = 1, DOWN = -1 }; 
 
    // The dimensions we can plot in, allowing for the width of the ball 
    int m_iAvailableHeight, m_iAvailableWidth; 
 
    int m_iImageHeight;         // The image height 
    int m_iImageWidth;// The image width 
    int m_iBallSize;// The diameter of the ball 
    int m_iRandX, m_iRandY;     // For a bit of randomness 
    xdir m_xDir;        // Direction the ball 
    ydir m_yDir;        // Likewise vertically 
 
    // The x position, in pixels, of the ball in the frame 
    // (0 < x < m_iAvailableWidth) 
    int m_x; 
 
    // the y position, in pixels, of the ball in the frame 
    // (0 < y < m_iAvailableHeight) 
    int m_y; 
 
    // Return the 1-dimensional position of the ball at time t millisecs 
    int BallPosition(int iPixelTime, int iLength, int time, int iOffset); 
 
    /// tests a given pixel to see if it should be plotted 
    BOOL WithinCircle(int x, int y); 
 
}; // CBall