There are several problems in your UpdateMover function.

First, you copy your Mover''s velocity values into local
variables and then when you change those values you
don''t change them in the Mover struct.

Second, if your rectangle moves off the edge of the screen,
your flip the velocity but you don''t adjust the rectangle
so it fits on the screen again.

Third, you don''t pass appropriate rectangles to the
BLT call.

Try changing it like this:


int UpdateMover(LPDIRECTDRAWSURFACE4 surface,Mover update)
{
velx = update.velocityx;
vely = update.velocityy;

update.mover.top += vely;
update.mover.left += velx;
update.mover.bottom += vely;
update.mover.right += velx;

if( update.mover.right >= 640 )
{
update.mover.left -= (update.mover.right - 640);
update.mover.right = 640;
update.velocityx = -velx;
}
else if( update.mover.left <= 0 )
{
update.mover.right -= update.mover.left;
update.mover.left = 0;
update.velocityx = -velx;
}

if( update.mover.bottom >= 480 )
{
update.mover.top -= (update.mover.bottom - 480);
update.mover.bottom = 480;
update.velocityy = -vely;
}
else if( update.mover.top <= 0 )
{
update.mover.bottom -= update.mover.top;
update.mover.top = 0;
update.velocityy = -vely;
}

RECT image_rect = { 0, 0, 32, 32 };
//Blit the mover''s new location
if(FAILED(surface->Blt(&update.mover,Bitmap,
ℑ_rect,DDBLT_WAIT,NULL)))
return 0;

return 1;
}

PsYcHoPrOg: Will you PLEASE stop posting these huge source code listings here? If you can''t narrow it down to a small section of code, then you aren''t spending enough time trying to figure things out on your own.

Ok. After a brief (ok, I spent some time here ) look at that code I can see some problems.

1) CreateMover(Mover & create)
Otherwise create is just a copy and is destroyed when the function returns.

2) Same deal in UpdateMover(... , Mover & update)

3) In UpdateMover(...) you don't set the new velocity on the edge hit. Need

update.velocityx = velx;
update.velocityy = vely;

before you leave the function to keep track of any changes.

4) In UpdateMove(...) when you BLT the image I think that you are getting the source and destination rects mixed up.

update.mover is where to draw the bitmap.
testRect is where to look on the surface for the bitmap.


RECT testRect;
testRect.top = 0;
testRect.left = 0;
testRect.bottom = 64; //My test image 64,64
testRect.right = 64;

if(FAILED(surface->Blt(&update.mover, Bitmap,&testRect, DDBLT_WAIT, NULL)))


5) You don't clean out the back buffer so all the crap from the last frame and stuff in memory is shown. Try


DDBLTFX ddBltFx;
ddBltFx.dwSize = sizeof(DDBLTFX); ddBltFx.dwFillColor = 0; // 0 = black;
bbuff->Blt(NULL, NULL, NULL,DDBLT_WAIT / DDBLT_COLORFILL, &ddBltFx);


as soon as you enter the GameMain().


Ok. I think I spent more time on this then I should have but what the hey it's good training.


If you want I can mail you the code and .exe that I have got working on my machine. You could also look at CDX since it is all open source and very well organized.

Andrew
acraig@engr.mun.ca


Edited by - acraig on 3/1/00 6:31:35 PM