Tricks of the Mac Game Programming Gurus/TricksOfTheMacGameProgrammingGurus.iso/Book Chapters/03 - Advanced Graphics/Example 2/sprite.c

Text File | 1995-06-02 | 5KB | 202 lines

//
//    File: sprite.c
//
//    This file contains the routines to draw the sprites
//
//    2/19/95 -- Created by Mick
//

// include files

#include "global.h"

#include "sprite.h"

#include "main.h"

// defines for this file

// global function declarations

tSpriteInfo *loadSprite( signed short inSpriteResID, signed short inMaskResID );
void disposeSprite( tSpriteInfo *inSpriteInfo );
void startSpriteDraw( Rect *inClipRect, PixMapHandle inDestPixMap );
void endSpriteDraw( void );
void drawSprite( tSpriteInfo *inSpriteInfo, Point inWhere );

// global data owned by this file

// local function declarations

// static data

RgnHandle sOldClipRgn;                                // storage space for the clip region before the startSpriteDraw call
PixMapHandle sDestPixMap;                // where we are going to draw this data

// functions


//
//    loadSprite -
//
//    Loads/allocates all the data for a sprite.
//

tSpriteInfo *loadSprite( signed short inSpriteResID, signed short inMaskResID )
{
    tSpriteInfo *newSprite;            // the new sprite data
    PicHandle spritePict;                        // the sprite/mask picture
    CGrafPtr oldCPort;                    // the graf port that is in place when we are called
    GrafPtr oldPort;                // the b&w port that we are saving
    GDHandle oldDevice;            // the gdevice that is in place when we are called

    // create the sprite info record
    newSprite = ( tSpriteInfo * )NewPtr( sizeof( tSpriteInfo ) );

    // load the pict
    spritePict = GetPicture( inSpriteResID );
    if ( spritePict == ( PicHandle )kNil )
        {
            // if it did not load, drop into the debugger -- real programs would have error checking
            Debugger();
        }

    // copy its bounds rect
    newSprite->fSpriteRect = ( *spritePict )->picFrame;

    // create a gworld for it
    NewGWorld( &newSprite->fSpriteWorld, 8, &( newSprite->fSpriteRect ),
            gAppColorTable, ( GDHandle )kNil, keepLocal );

    // extract the pixmap handle
    newSprite->fSpritePix = GetGWorldPixMap( newSprite->fSpriteWorld );

    // save the current port and gdevice
    GetGWorld( &oldCPort, &oldDevice );

    // set the offscreen buffer as current ( and lock the pixel map )
    SetGWorld( newSprite->fSpriteWorld, ( GDHandle )kNil );
    LockPixels( newSprite->fSpritePix );

    // draw the picture
    EraseRect( &( newSprite->fSpriteRect ) );
    DrawPicture( spritePict, &( newSprite->fSpriteRect ) );

    // restore the current port and gdevice
    UnlockPixels( newSprite->fSpritePix );
    SetGWorld( oldCPort, oldDevice );

    // dump this pict
    ReleaseResource( ( Handle )spritePict );

    // load the mask pict
    spritePict = GetPicture( inMaskResID );

    // allocate a new port
    newSprite->fMaskPort = ( GrafPtr )NewPtr( sizeof( GrafPort ) );
    OpenPort( newSprite->fMaskPort );

    // fiddle with its port bits
    newSprite->fMaskPort->portBits.bounds = newSprite->fSpriteRect;
    newSprite->fMaskPort->portBits.rowBytes = ( ( newSprite->fSpriteRect.right - newSprite->fSpriteRect.left ) + 15 ) / 8;
    newSprite->fMaskPort->portBits.baseAddr =
            NewPtr( newSprite->fMaskPort->portBits.rowBytes * ( newSprite->fSpriteRect.bottom - newSprite->fSpriteRect.top ) );

    // save the port
    GetPort( &oldPort );

    // set the new port
    SetPort( newSprite->fMaskPort );

    // draw the picture
    EraseRect( &( newSprite->fSpriteRect ) );
    DrawPicture( spritePict, &( newSprite->fSpriteRect ) );

    // restore the old port
    SetPort( oldPort );

    // dump this pict
    ReleaseResource( ( Handle )spritePict );

    // return the new sprite!
    return newSprite;
}


//
//    disposeSprite -
//
//    Disposes/releases all the memory used in a sprite
//

void disposeSprite( tSpriteInfo *inSpriteInfo )
{
    // dump the gworld
    DisposeGWorld( inSpriteInfo->fSpriteWorld );

    // dump the memory from the bitmap
    DisposePtr( ( Ptr )( inSpriteInfo->fMaskPort->portBits.baseAddr ) );

    // dump the port
    DisposePtr( ( Ptr )( inSpriteInfo->fMaskPort ) );

    // free the structure
    DisposePtr( ( Ptr )inSpriteInfo );
}


//
//    startSpriteDraw -
//
//    Prepare the sprite draw. Assumes that the port is set to the destination port.
//

void startSpriteDraw( Rect *inClipRect, PixMapHandle inDestPixMap )
{
    // save the current port's clip region
    sOldClipRgn = NewRgn();
    GetClip( sOldClipRgn );

    // set the clip region to be the passed in rect
    ClipRect( inClipRect );

    // save the pix map info (so we can use it)
    sDestPixMap = inDestPixMap;
}


//
//    endSpriteDraw -
//
//    End the sprite draw sequence.
//

void endSpriteDraw( void )
{
    // restore the old clip region
    SetClip( sOldClipRgn );

    // dump the region
    DisposeRgn( sOldClipRgn );
}


//
//    drawSprite -
//
//    Draw the sprite in the port.
//

void drawSprite( tSpriteInfo *inSpriteInfo, Point inWhere )
{
    Rect destRect;        // where we want to draw the sprite

    // calculate the destination rect
    destRect = inSpriteInfo->fSpriteRect;
    OffsetRect( &destRect, inWhere.h, inWhere.v );

    // draw the sprite
    CopyMask( ( BitMap * )( *( inSpriteInfo->fSpritePix ) ), &( inSpriteInfo->fMaskPort->portBits ),
            ( BitMap * )( *sDestPixMap ), &( inSpriteInfo->fSpriteRect ), &( inSpriteInfo->fSpriteRect ), &destRect );
}