DirectX9 Surfaces Transparency
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DirectX9Surface support alpha-channel and can be loaded from.pngfile. How can I make them draw with transparency ?"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.
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"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.
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 laterID3DDevice::StretchRect()to draw on the bacbuffer surface. It seems to me like theSetRenderState()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. -
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 laterID3DDevice::StretchRect()to draw on the bacbuffer surface. It seems to me like theSetRenderState()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.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.
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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.
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(). -
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().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
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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
Thanks again for your help.
Rajkumar R wrote:
i was thinking on IDirectDrawSurface:Blt which supports that
I don't think
DirectDrawSurfacesupport any alpha-blending. It support color-keying - setting a specific color not to be shown. Also, AFAIKDirectDrawSurfacecannot be loaded from.PNGfile. 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. -
Thanks again for your help.
Rajkumar R wrote:
i was thinking on IDirectDrawSurface:Blt which supports that
I don't think
DirectDrawSurfacesupport any alpha-blending. It support color-keying - setting a specific color not to be shown. Also, AFAIKDirectDrawSurfacecannot be loaded from.PNGfile. 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.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.
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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.
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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.
Hanan888 wrote:
Are you sure this applies to the latest SDK?
yep, but not in Direct3D 9(though 9 is not latest) since directdraw interfaces are outdated in direct3d9. It is used latest directshow sdk, where VMR7 is supported by this IDirectDrawSurface interfaces while VMR9 is supported by IDirect3DSurface9 interfaces. Haven't you seen this "The IDirectDrawSurface interface is exposed on DirectDrawSurface objects that are used in the DirectShow multimedia streaming APIs" in that link. you can also refer some samples in DirectShow how custom allocator are implemented to mix various video streams much similar like your requirement.