C / C++ / MFC

Re: Save CBitmap object to disk

1-Jun-08 0:15

capint wrote:
Bitmap.CreateCompatibleBitmap(pDC,screenMaxX, screenMaxY);
Image.Attach(Bitmap);

this creates only the bitmap object, allocates resources for the bitmap and the color format is compatible with the Device context, but the image it initially contains is blank, you need to fill the image in to the allocated bitmap resource.
I assume you want the image in the Device context then you need to copy the bitmap from dc to this bitmap,

CBitmap Bitmap;
Bitmap.CreateCompatibleBitmap(pDC,screenMaxX, screenMaxY);
CDC dcMemory;
dcMemory.CreateCompatibleDC(pDC);

// Select the bitmap into the in-memory DC
CBitmap* pOldBitmap = dcMemory.SelectObject(&Bitmap);
  
// Copy the bits from the on-screen DC into the 
// in-memory DC 
dcMemory.BitBlt(0, 0, screenMaxX, screenMaxY, pDC, 
         0, 0, SRCCOPY);

dcMemory.SelectObject(pOldBitmap);

capint1-Jun-08 0:29

capint

1-Jun-08 0:29

Thanks so much Big Grin | :-D

Re: Save CBitmap object to disk

Hamid_RT1-Jun-08 6:34

Hamid_RT

1-Jun-08 6:34

Saving a Drawing to a Bitmap File[^].

DirectX9 Surfaces Transparency

Hanan88831-May-08 23:20

31-May-08 23:20

DirectX9 Surface support alpha-channel and can be loaded from .png file. How can I make them draw with transparency ?

Rajkumar R31-May-08 23:58

31-May-08 23:58

"A Microsoft® Direct3D® device is a state computer", you need to enable/set the render states for Transparency. see [Alpha Blending State ^] you need to use the D3DRS_ALPHABLENDABLE render state to enable alpha transparency blending and set the blending type.

Hanan8881-Jun-08 2:20

1-Jun-08 2:20

from the above link:
The alpha value of a color controls its transparency. Enabling alpha blending allows colors, materials, and textures on a surface to be blended with transparency onto another surface.

In my game, I just need to draw .png images with alpha, the same size they are. I've got a lot of those for drawing a complicated animation. I've got about 650 images.

I find the textures interface unsuitable, because of their creation cost, and the fact they don't natively looked exactly as the images.

So, I'm using D3DxCreateSurfaceFromFile() and later ID3DDevice::StretchRect() to draw on the bacbuffer surface.

It seems to me like the SetRenderState() capabilities do not apply to DirectX9 surfaces. But I do guess there is some way to alpha-blend surfaces because they contain alpha-channel color.

Rajkumar R1-Jun-08 2:40

1-Jun-08 2:40

Hanan888 wrote:
The alpha value of a color controls its transparency. Enabling alpha blending allows colors, materials, and textures on a surface to be blended with transparency onto another surface.

have you seen "on a surface" to another surface. without enabling alpha blending state, you are not going to get transparency from Direct 3D, which doesnot do/skips any alpha blending calculation on the device.

Hanan888 wrote:
It seems to me like the SetRenderState() capabilities do not apply to DirectX9 surfaces

have you tried?

Hanan888 wrote:
So, I'm using D3DxCreateSurfaceFromFile()

AFAIK, D3DxCreateSurfaceFromFile is not dx9 API, may be you are using some wrapper which creates a surface and uses D3DXLoadSurfaceFromFile API.

Hanan8881-Jun-08 3:10

1-Jun-08 3:10

Thank you.

Rajkumar R wrote:
have you seen "on a surface" to another surface. without enabling alpha blending state, you are not going to get transparency from Direct 3D, which doesnot do/skips any alpha blending calculation on the device.

I think perhaps StretchRect() doesn't go through that processing.

this is what I tried:

pd3dDevice->SetRenderState(D3DRS_ALPHABLENDENABLE,TRUE);
pd3dDevice->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCCOLOR);
pd3dDevice->SetRenderState(D3DRS_DESTBLEND,D3DBLEND_INVSRCCOLOR);
pd3dDevice->GetBackBuffer(0,0,D3DBACKBUFFER_TYPE_MONO,&pBackBuf);
pd3dDevice->StretchRect(sourceSurface, pSourceRect, pBackBuf, 
			pRectOnBackbuffer,D3DTEXF_NONE);

I use surfaces in the A8R8G8B8 format, load from PNG images with alpha-channels.

saw no effect.

This is how I create the source surfaces:

device->CreateOffscreenPlainSurface(width,height, D3DFMT_A8R8G8B8, D3DPOOL_DEFAULT,
		&surface, NULL);

Rajkumar R wrote:
AFAIK, D3DxCreateSurfaceFromFile is not dx9 API, may be you are using some wrapper which creates a surface and uses D3DXLoadSurfaceFromFile API.

Sorry for the typo, it's D3DXLoadSurfaceFromFile().

Rajkumar R1-Jun-08 23:25

1-Jun-08 23:25

I think so, StretchRect replaces the surface color values without doing alpha blending, i was thinking on IDirectDrawSurface:Blt which supports that.

I think you need to go to texture only (collection of surface), consider using [ID3DXSprite Interface^] which made ease displaying the 2d textures. to reduce the cost of texture creation, i think you create a single texture with only one level and load surface of that level each time using D3DXLoadSurfaceFromFile, while you can get the surface of the texture level with IDirect3DTexture9::GetSurfaceLevel

Hanan8882-Jun-08 1:30

2-Jun-08 1:30

Thanks again for your help.

Rajkumar R wrote:
i was thinking on IDirectDrawSurface:Blt which supports that

I don't think DirectDrawSurface support any alpha-blending. It support color-keying - setting a specific color not to be shown. Also, AFAIK DirectDrawSurface cannot be loaded from .PNG file.

It seems I'm gonna use the sprite interface with textures.

AFAIK, all textures must be power of 2 in size which will force me to alter the resource files.
Also, with the many images I have, it's kinda slow and I'm looking for anything that speeds up the loading.

Rajkumar R2-Jun-08 2:15

2-Jun-08 2:15

Hanan888 wrote:
I don't think DirectDrawSurface support any alpha-blending

see, [IDirectDrawSurface::Blt^] and see the DDBLT_ALPHASRC flag.

Hanan888 wrote:
Also, with the many images I have, it's kinda slow and I'm looking for anything that speeds up the loading.

i think you can use *.dds, which stores exactly in surface format.

Hanan8882-Jun-08 2:28

2-Jun-08 2:28

Rajkumar R wrote:
see, [IDirectDrawSurface::Blt^] and see the DDBLT_ALPHASRC flag.

Are you sure this applies to the latest SDK? couldn't find it in any branch of the MSDN documentation tree.

Rajkumar R2-Jun-08 2:58