Modify a IDirect3DSurface9* with shader - c++

Question

I got a IDirect3DSurface9 * from a DXVA2 video decoder. I'd like to modify that surface with a shader. I' m able to render the video frames without shader by "drawing" the surface in the back buffer.
I use the following code to render the frames without shader:
void Draw(Example* exps){
IDirect3DSurface9* backbuffer;
hwctx->d3d9device->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0, 0, 0), 1.0f, 0);
hwctx->d3d9device->BeginScene();
hwctx->swap_chain->GetBackBuffer(0, D3DBACKBUFFER_TYPE_MONO, &backbuffer);
hwctx->d3d9device->StretchRect(videoSurface, NULL, backbuffer, NULL, D3DTEXF_LINEAR);
hwctx->d3d9device->EndScene();
hwctx->swap_chain->Present(0, 0, 0, 0, 0);
backbuffer->Release();
}
Up until here, everithing works.
I would modify the Draw function to render video frames with the following shader:
uniform extern float4x4 gWVP;
uniform extern texture gTexRGB;
uniform extern texture gTexAlpha;
sampler TexRGB = sampler_state
{
Texture = <gTexRGB>;
AddressU = WRAP;
AddressV = WRAP;
};
sampler TexAlpha = sampler_state
{
Texture = <gTexAlpha>;
AddressU = WRAP;
AddressV = WRAP;
};
struct OutputVS
{
float4 posH : POSITION0;
float2 tex0 : TEXCOORD0;
};
OutputVS DirLightTexVS(float3 posL : POSITION0, float3 normalL : NORMAL0, float2 tex0: TEXCOORD0)
{
// Zero out our output.
OutputVS outVS = (OutputVS)0;
// Transform to homogeneous clip space.
outVS.posH = mul(float4(posL, 1.0f), gWVP);
// Pass on texture coordinates to be interpolated in rasterization.
outVS.tex0 = tex0;
// Done--return the output.
return outVS;
}
float4 DirLightTexPS(float4 c : COLOR0, float4 spec : COLOR1, float2 tex0 : TEXCOORD0) : COLOR
{
float3 rgb = tex2D(TexRGB, tex0).rgb;
float alpha = tex2D(TexAlpha, tex0).g;
return float4(rgb, alpha);
}
technique DirLightTexTech
{
pass P0
{
// Specify the vertex and pixel shader associated with this pass.
vertexShader = compile vs_2_0 DirLightTexVS();
pixelShader = compile ps_2_0 DirLightTexPS();
}
}
where TexRGB is the texture associated to the video frame, while TexAlpha is another texture that contains alpha values.
How can I pass the decoded surface to the shader? I never used Directx9 so an example is appreciated and could help me to solve the problem.
UPDATE 1:
I created the InitEffect function to load the effect from file
void InitEffect(Example* ctx) {
auto hwctx = ctx->decoder->stream->HWAccelCtx;
// Create the FX from a .fx file.
ID3DXBuffer* errors = 0;
D3DXCreateEffectFromFile(hwctx->d3d9device, "basicEffect.fx", 0, 0, D3DXSHADER_DEBUG, 0, &ctx->mFX, &errors);
if (errors)
MessageBox(0, (LPCSTR)errors->GetBufferPointer(), 0, 0);
// Obtain handles.
ctx->mhTech = ctx->mFX->GetTechniqueByName("DirLightTexTech");
ctx->mhWVP = ctx->mFX->GetParameterByName(0, "gWVP");
ctx->mhTexAlpha = ctx->mFX->GetParameterByName(0, "gTexAlpha");
ctx->mhTexRGB = ctx->mFX->GetParameterByName(0, "gTexRGB");
}
and changed the rendering fuction to:
void Draw(Example* ctx) {
InitMatrices(ctx);
IDirect3DSurface9* backbuffer;
hwctx->d3d9device->Clear(0, 0, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, 0xffeeeeee, 1.0f, 0);
hwctx->d3d9device->BeginScene();
ctx->mFX->SetTechnique(ctx->mhTech);
ctx->mFX->SetMatrix(ctx->mhWVP, &(ctx->mCrateWorld*ctx->mView*ctx->mProj));
ctx->texRGB->GetSurfaceLevel(0, &ctx->surfRGB);
hwctx->d3d9device->SetRenderTarget(0, ctx->surfRGB);
hwctx->d3d9device->StretchRect((IDirect3DSurface9*)s->frame->data[3], NULL, ctx->surfRGB, NULL, D3DTEXF_LINEAR);
ctx->mFX->SetTexture(ctx->mhTexAlpha, ctx->texAlpha);
ctx->mFX->SetTexture(ctx->mhTexRGB, ctx->texRGB);
// Enable alpha blending.
hwctx->d3d9device->SetRenderState(D3DRS_ALPHABLENDENABLE, true);
hwctx->d3d9device->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA);
hwctx->d3d9device->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA);
hwctx->d3d9device->SetVertexDeclaration(VertexPNT::Decl);
hwctx->d3d9device->SetStreamSource(0, ctx->mBoxVB, 0, sizeof(VertexPNT));
hwctx->d3d9device->SetIndices(ctx->mBoxIB);
UINT numPasses = 0;
ctx->mFX->Begin(&numPasses, 0);
for (UINT i = 0; i < numPasses; ++i){
ctx->mFX->BeginPass(i);
hwctx->d3d9device->DrawIndexedPrimitive(D3DPT_TRIANGLELIST, 0, 0, 24, 0, 12);
ctx->mFX->EndPass();
}
ctx->mFX->End();
hwctx->d3d9device->EndScene();
hwctx->swap_chain->Present(0, 0, 0, 0, 0);
backbuffer->Release();
// Disable alpha blending.
hwctx->d3d9device->SetRenderState(D3DRS_ALPHABLENDENABLE, false);
}
but it still doesn't work.
UPDATE 2
I modified the code by following the code Asesh shared. In the InitEffect function I added the following lines to create a render target surface:
ctx->texRGB->GetSurfaceLevel(0, &ctx->surfRGB);
// store orginal rendertarget
hwctx->d3d9device->GetRenderTarget(0, &ctx->origTarget_);
D3DSURFACE_DESC desc;
ctx->origTarget_->GetDesc(&desc);
// create our surface as render target
hwctx->d3d9device->CreateRenderTarget(1920, 1080, D3DFMT_X8R8G8B8,
desc.MultiSampleType, desc.MultiSampleQuality,
false, &ctx->surfRGB, NULL);
the draw function is:
void drawScene(Example* ctx) {
InitMatrices(ctx);
auto hwctx = ctx->decoder->stream->HWAccelCtx;
auto s = (VdrStreamContext*)ctx->decoder->stream->vdrCodecCtx->opaque;
IDirect3DSurface9* backbuffer;
hwctx->d3d9device->SetRenderTarget(0, ctx->surfRGB);
hwctx->d3d9device->Clear(0, 0, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, 0xffeeeeee, 1.0f, 0);
hwctx->d3d9device->BeginScene();
hwctx->d3d9device->StretchRect((IDirect3DSurface9*)s->vdrFrame->data[3], NULL, ctx->surfRGB, NULL, D3DTEXF_NONE);
hwctx->d3d9device->SetRenderTarget(0, ctx->origTarget_);
if (!hwctx->d3d9device->GetBackBuffer(0, 0, D3DBACKBUFFER_TYPE_MONO, &backbuffer)) {
hwctx->d3d9device->StretchRect(ctx->surfRGB, NULL, backbuffer, NULL, D3DTEXF_NONE);
}
ctx->mFX->SetTechnique(ctx->mhTech);
ctx->mFX->SetMatrix(ctx->mhWVP, &(ctx->mCrateWorld*ctx->mView*ctx->mProj));
ctx->mFX->SetTexture(ctx->mhTexAlpha, ctx->texAlpha);
ctx->mFX->SetTexture(ctx->mhTexRGB, ctx->texRGB);
// Enable alpha blending.
hwctx->d3d9device->SetRenderState(D3DRS_ALPHABLENDENABLE, true);
hwctx->d3d9device->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA);
hwctx->d3d9device->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA);
hwctx->d3d9device->SetVertexDeclaration(VertexPNT::Decl);
hwctx->d3d9device->SetStreamSource(0, ctx->mBoxVB, 0, sizeof(VertexPNT));
hwctx->d3d9device->SetIndices(ctx->mBoxIB);
UINT numPasses = 0;
ctx->mFX->Begin(&numPasses, 0);
for (UINT i = 0; i < numPasses; ++i){
ctx->mFX->BeginPass(i);
hwctx->d3d9device->DrawIndexedPrimitive(D3DPT_TRIANGLELIST, 0, 0, 24, 0, 12);
ctx->mFX->EndPass();
}
ctx->mFX->End();
hwctx->d3d9device->EndScene();
hwctx->d3d9device->Present(0, 0, 0, 0);
backbuffer->Release();
// Disable alpha blending.
hwctx->d3d9device->SetRenderState(D3DRS_ALPHABLENDENABLE, false);
}
by drawing in the backbuffer by hwctx->d3d9device->StretchRect(ctx->surfRGB, NULL, backbuffer, NULL, D3DTEXF_NONE); even if the ctx->surfRGB is associated to the texture passed to the shader, the video frame is showed on the screen but alpha blending is not applied. If I remove hwctx->d3d9device->StretchRect(ctx->surfRGB, NULL, backbuffer, NULL, D3DTEXF_NONE); video frame is not showed even if the ctx->surfRGB is not empty.