Update texture from vector directx9 - directx

Question

I' m trying to render two textures one for RGB and another on for the alpha channel, I blend them together with a shader.
The alpha channel texture doesn't overlap properly to the RGB one. It seems to be stretched.
The alpha channel texture changes at every frame and I need to fill starting from an array of uint8_t by the following fuction:
D3DLOCKED_RECT locked_rect;
HRESULT hr = alpha_tex->LockRect(0, &locked_rect, nullptr, 0);
if (!FAILED(hr)) {
ret_code = 0;
BYTE *p_dst = (BYTE *)locked_rect.pBits;
for (uint y = 0; y < height; y++) {
memcpy(p_dst, alpha_array, width);
alpha_array += width;
p_dst += locked_rect.Pitch;
}
alpha_tex->UnlockRect(0);
}
where the alpha_array is a uint8_t array containing the alpha values.
To render the texture i use the following function:
hwctx->d3d9device->Clear(0, 0, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, 0xffeeeeee, 1.0f, 0);
hwctx->d3d9device->BeginScene();
ctx->mFX->SetTechnique(ctx->mhTech);
ctx->texRGB->GetSurfaceLevel(0, &ctx->surfRGB);
hwctx->d3d9device->StretchRect((IDirect3DSurface9*)s->vdrFrame->data[3], NULL, ctx->surfRGB, NULL, D3DTEXF_LINEAR);
ctx->mFX->SetTexture(ctx->mhTexRGB, ctx->texRGB);
ctx->mFX->SetTexture(ctx->mhTexAlpha, ctx->texAlpha);
// Enable alpha blending.
hwctx->d3d9device->SetRenderState(D3DRS_ALPHABLENDENABLE, true);
hwctx->d3d9device->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA);
hwctx->d3d9device->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA);
UINT numPasses = 0;
ctx->mFX->Begin(&numPasses, 0);
for (UINT i = 0; i < numPasses; ++i){
ctx->mFX->BeginPass(i);
hwctx->d3d9device->DrawPrimitive(D3DPT_TRIANGLEFAN, 0, 2);
ctx->mFX->EndPass();
}
ctx->mFX->End();
hwctx->d3d9device->EndScene();
hwctx->d3d9device->Present(0, 0, 0, 0);
// Disable alpha blending.
hwctx->d3d9device->SetRenderState(D3DRS_ALPHABLENDENABLE, false);
I combine the textures by vertex/pixel shader:
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 TextureBlendingVS(float2 tex0: TEXCOORD0){
// Zero out our output.
OutputVS outVS = (OutputVS)0;
// Pass on texture coordinates to be interpolated in rasterization.
outVS.tex0 = tex0;
// Done--return the output.
return outVS;
}
float4 TextureBlendingPS(float2 tex0 : TEXCOORD0) : COLOR{
float3 rgb = tex2D(TexRGB, tex0).rgb;
float alpha = tex2D(TexAlpha, tex0).a;
return float4(rgb, alpha);
}
technique DirLightTexTech{
pass P0 {
// Specify the vertex and pixel shader associated with this pass.
vertexShader = compile vs_2_0 TextureBlendingVS();
pixelShader = compile ps_2_0 TextureBlendingPS();
}
}
The size of the textures is the same but during the rendering something goes wrong.
Please help me. :)