Clipping
Author
Could anyone point me to a tutorial about how to set up the DirectDraw clipper? I have some code, but it doesn't work. At all. What so ever. :) When I try it, the first image blt works, but from then on, the blts fail, so I assume that my clipper set up is whacked.
Cheers
SIgma
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posted in the wrong form:
[edit] whoops: Posted this in Game programming, not DX. Damn. Ok, I'll post over there, but don't freak for a double post ok! :)
LPDIRECTDRAWCLIPPER lpClipper=NULL;//DirectDrawClipper result = lpDD->SetDisplayMode( SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_DEPTH, 0, 0); result = lpDD->CreateSurface( &ddsd, &lpFront, NULL ); result = lpDD->CreateSurface(&ddsd, &lpBack, NULL); // Create a clipper (used in IDirectDrawSurface::Blt call) result = lpDD->CreateClipper(0, &lpClipper, NULL); if( result!=DD_OK ) { return false; } result = lpClipper->SetHWnd(0, g_hWindow); //Client area of the window if( result!=DD_OK ) { return false; } result = lpBack->SetClipper(lpClipper); if( result!=DD_OK ) { return false; }NOTE: Don't try BltFast() with clipper - only Blt() or Flip()
PS: That's quick cut out of the working app - hope it helps
Author
Well, i got my code to work. I was attaching the clipper BEFORE I initialized the surface! Oopps...
You seem to be doing the attaching in WAY less code than me tho....I'll try your method. thx man
You seem to be doing the attaching in WAY less code than me tho....I'll try your method. thx man
Author
Actually it doesn't work 100% If I move off the screen at a diagonal angle, it crashes. Any idea what could cause this?
first question: is it fullscreen app or windowed?
second question: do you attach clipper to front surface or to the back one?
second question: do you attach clipper to front surface or to the back one?
You'd better post some code of yours, where are
- Clipper creation and attachment
- Blitting/Flipping Back to Front surfaces
- Viewport movement
- Clipper creation and attachment
- Blitting/Flipping Back to Front surfaces
- Viewport movement
Author
clipping creation
Attach then Blt source
LPDIRECTDRAWCLIPPER MercuryEngine::DDCrClipper(LPDIRECTDRAWSURFACE7 lpdds, int num_rects, LPRECT clip_list){ int index; //loop var LPDIRECTDRAWCLIPPER DDclipper; // our clipper LPRGNDATA region_data; //contains clip list if(FAILED(lpdd->CreateClipper(0,&DDclipper,NULL))) return(NULL); //creat clip list from data sent region_data = (LPRGNDATA)malloc((sizeof(RGNDATAHEADER) + num_rects * sizeof(RECT))); //copy rects into region data memcpy(region_data->Buffer, clip_list , sizeof(RECT)*num_rects); //set up fields region_data->rdh.dwSize = sizeof(RGNDATAHEADER); region_data->rdh.iType = RDH_RECTANGLES; region_data->rdh.nCount = num_rects; region_data->rdh.nRgnSize = num_rects * sizeof(RECT); region_data->rdh.rcBound.left = 64000; region_data->rdh.rcBound.top = 64000; region_data->rdh.rcBound.right = -64000; region_data->rdh.rcBound.bottom = -64000; //find bounds for clipping for(index = 0; index < num_rects; ++index) { //test if the next rectangle union with the current bound is alrger if (clip_list[index].left < region_data->rdh.rcBound.left) region_data->rdh.rcBound.left = clip_list[index].left; if (clip_list[index].right < region_data->rdh.rcBound.right) region_data->rdh.rcBound.right = clip_list[index].right; if (clip_list[index].top < region_data->rdh.rcBound.top) region_data->rdh.rcBound.top = clip_list[index].top; if (clip_list[index].bottom < region_data->rdh.rcBound.bottom) region_data->rdh.rcBound.bottom = clip_list[index].bottom; } //now we have computedthe bounding rectangle region and set up the data //now we deal with the clipping list if(FAILED(DDclipper->SetClipList(region_data,0))); { delete(region_data); //return(NULL); } if(FAILED(lpdds->SetClipper(DDclipper))); { delete(region_data); //return(NULL); } //and now we are done delete(region_data); return(DDclipper);}Attach then Blt source
RECT clipper_rect[1] = {0,0,799,599}; //fullscreen clipping area...//attach a clipper to the backsurface DDclipper = GameEngine.DDCrClipper(DDback,1,clipper_rect);BLT HERE//draw the back ground image if(FAILED(DDback->Blt(&dest_rect,DDback_sprite,&src_rect,DDBLT_WAIT, NULL))) { Application->MessageBoxA("Error","Boom",MB_OK); Application->Terminate(); } //draw the BOB sprite if(FAILED(DDback->Blt(&bob.dest_rect,bob.DDBOB,&bob.src_rect ,(DDBLT_WAIT | DDBLT_KEYSRC),NULL))) { //nail any errors that get through hr = DDback->Blt(&bob.dest_rect,bob.DDBOB,&bob.src_rect ,DDBLT_WAIT,NULL); //display said error Application->MessageBoxA(buf,"Boom",MB_OK); Application->Terminate(); } //flip while(FAILED(DDprimary->Flip(NULL,DDFLIP_WAIT)));
I had once tried to use windows regions with clipper, but that failed, too (strange, perhaps it's a windows bug), so I've clipped to hWnd and Back surface and
works fine for me in fullscreen and windowed modes
EDIT: Damn that tags!
lpClipper->SetHWnd(0, g_hWindow);lpBack->SetClipper(lpClipper);works fine for me in fullscreen and windowed modes
EDIT: Damn that tags!
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