simple animation...

[pete moss]

i am adding a bit of animation code to my yoda app.  i want his eyes to
blink :)

currently, i have the animation code taking place on a nilEvent. 
however, everytime i interact with the forms buttons, or hit the
applications button, it seems like a nilEvent is generated because the
eyes blink.  this action seriously disrupts the actions the buttons
produce.  any tips on how to make this smoother?  is there a better way
to do the animation?

i am including the entire source file below if you need to see my code

thanks in advance
pete


beware of line wrapping!!!

#include <Pilot.h>                              
#include "yoda.h"
#include "Callbacks.h"

static Err StartApplication(void)
{
        FrmGotoForm(YodaForm);
        SysRandom(TimGetTicks());
        return 0;
}

static void StopApplication(void)
{
        FrmCloseAllForms();
}

void DrawBitmap(Int x, Int y, Int id)
{
        VoidHand h;
        BitmapPtr p;

        h = DmGet1Resource('Tbmp', id);
        if (h != NULL)
                {
                p = (BitmapPtr) MemHandleLock(h);
                WinDrawBitmap(p, x, y);
                MemHandleUnlock(h);
                }
        DmReleaseResource(h);
}

static Int RandInt(Int MaxNo)
{
        // returns 0 <= int <= MaxNo-1
        return(SysRandom(0) % MaxNo);
}

static FieldPtr SetFieldTextFromStr(Word fieldID, CharPtr strP)
{
        VoidHand txtH, oldTxtH;
        FormPtr frm = FrmGetActiveForm();
        FieldPtr fldP;
        
        // get some space in which to stash the string
        txtH = MemHandleNew(StrLen(strP) + 1);
        if (!txtH) return NULL;
                
        // copy the string to the locked VoidHand.
        StrCopy(MemHandleLock(txtH), strP);
        
        // unlock the string VoidHand 
        MemHandleUnlock(txtH);
        
        // get the field and the field's current text VoidHand.
        fldP = FrmGetObjectPtr(frm, FrmGetObjectIndex(frm, fieldID));
        ErrNonFatalDisplayIf(!fldP, "missing field");
        oldTxtH = (VoidHand) FldGetTextHandle(fldP);
        
        // set the field's text to the new text
        FldSetTextHandle(fldP, (Handle) txtH);
        FldDrawField(fldP);
                
        // free the VoidHand AFTER we call FldSetTextHandle.
        if (oldTxtH) MemHandleFree(oldTxtH);
        
        return;
}

static Boolean MyFormHandleEvent(EventPtr event)
{
        static Int      oldrnd = 0;
        Boolean         handled;
        Int                     rnd;
        VoidHand        h;
        CharPtr         s;

        CALLBACK_PROLOGUE

        handled = false;

        switch (event->eType)
        {
        case ctlSelectEvent:  // A control button was pressed and released.
                if (event->data.ctlEnter.controlID==WisdomBtn)
                        {
                        rnd = 3000+RandInt(34);
                        while(rnd==oldrnd) rnd = 3000+RandInt(34);
                        oldrnd=rnd;
                        h = DmGetResource('tSTR', rnd);
                        s = MemHandleLock(h);
                        SetFieldTextFromStr(YodaField, s);
                        MemHandleUnlock(h);
                        DmReleaseResource(h);
                        handled = true;
                        }
                if (event->data.ctlEnter.controlID==QuestionBtn)
                        {
                        rnd = 4000+RandInt(11);
                        while(rnd==oldrnd) rnd = 4000+RandInt(11);
                        oldrnd=rnd;
                        h = DmGetResource('tSTR', rnd);
                        s = MemHandleLock(h);
                        SetFieldTextFromStr(YodaField, s);
                        MemHandleUnlock(h);
                        DmReleaseResource(h);
                        handled = true;
                        }
        break;
        
        case nilEvent:
                if (RandInt(2))
                        {
                        DrawBitmap(30, 56, 102+RandInt(2));
                        SysTaskDelay(SysTicksPerSecond() / 3);
                        DrawBitmap(30, 56, 101);
                        handled = true;
                        }
        break;
        
        case frmOpenEvent:      
                FrmDrawForm(FrmGetActiveForm());
                handled = true;
        break;
                
        case menuEvent:
                if (event->data.menu.itemID==5002)
                        {
                        FrmHelp(5000);
                        handled = true;
                        }
        break;
        }                       

        CALLBACK_EPILOGUE

        return(handled);
}


static Boolean ApplicationHandleEvent(EventPtr event)
{
        FormPtr frm;
        Int             formId;
        Boolean handled = false;

        if (event->eType == frmLoadEvent)
                {
                // Load the form resource specified in the event then activate the
form.
                formId = event->data.frmLoad.formID;
                frm = FrmInitForm(formId);
                FrmSetActiveForm(frm);

                // Set the event handler for the form.  The handler of the currently 
                // active form is called by FrmDispatchEvent each time it receives an
event.
                switch (formId)
                        {
                        case YodaForm:
                                FrmSetEventHandler(frm, MyFormHandleEvent);
                                break;
                        }
                handled = true;
                }
        
        return handled;
}


static void EventLoop(void)
{
        EventType       event;
        Word            error;
        
        do
                {
                EvtGetEvent(&event, 10*SysTicksPerSecond()); //evtWaitForever);
                
                if (! SysHandleEvent(&event))
                        if (! MenuHandleEvent(0, &event, &error))
                                if (! ApplicationHandleEvent(&event))
                                        FrmDispatchEvent(&event);
                }
        while (event.eType != appStopEvent);
}


DWord PilotMain(Word cmd, Ptr cmdPBP, Word launchFlags)
{
        Err err = 0;            
        
        if (cmd == sysAppLaunchCmdNormalLaunch)
                {
                if ((err = StartApplication()) == 0)
                {   
                EventLoop();
                StopApplication();
                        }
                }

        return err;
}