firstly, I use dx9.
when using alpha blend, I set the src alpha factor to D3DSRCALPHA,
dest alpha factor to D3DINVSRCALPHA,
the blend operator to D3DBLEND_ADD.
I use a bright pass to set the alpha value of the texture where is black , to 0.
I first draw the scene, then blend the texture to the scene .
but the black part of the texture are still black , it can't become transparent.
[attachment=32183:360??20160608213853386.jpg]
I use a bright pass to set the alpha value of the texture where is black , to 0.
Are you doing this on the CPU and updating the texture? Are you doing it in some pre-processing step in your import pipeline? Are you rendering your texture to a render target and then drawing that render target instead of the texture?
I use a bright pass to set the alpha value of the texture where is black , to 0.
Are you doing this on the CPU and updating the texture? Are you doing it in some pre-processing step in your import pipeline? Are you rendering your texture to a render target and then drawing that render target instead of the texture?
first use a bright-pass shader render a texture to a rendertarget, making the above picture , and sample the rendertarget in second pass,
and find that the alpha is always be 1.0.....
If you're using shaders you don't even need to do a separate brightpass stage. Instead you could do something like:
float4 color = tex2D (mySampler, ps_in.TexCoord);
color.a = step (0.00392f, color.r + color.g + color.b);
That will work in a single pass - read the texture, set alpha to 0 if it's black, 1 otherwise.
If you're using shaders you don't even need to do a separate brightpass stage. Instead you could do something like:
float4 color = tex2D (mySampler, ps_in.TexCoord);
color.a = step (0.00392f, color.r + color.g + color.b);
That will work in a single pass - read the texture, set alpha to 0 if it's black, 1 otherwise.
I do the brightpass like you, and set the alpha to 0 when it's black. the problem is after I draw the result to rendertarget, the alpha of the rendertarget is always be 1.0......
and the texture format has been a8r8g8b8...
- Show the code where you create the render target to which your brightpass draws.
Otherwise, people can only guess at what your problem might be.
