Set uniform color to pixel shader - c++

Question

I am a newbie in DirectX11, so sorry for a dull question.
I have a pixel shader:
struct PixelShaderInput
{
float4 pos : SV_POSITION;
float2 texCoord : TEXCOORD0;
};
Texture2D s_texture : register(t0);
SamplerState s_sampleParams
{
Filter = MIN_MAG_MIP_LINEAR;
AddressU = CLAMP;
AddressV = CLAMP;
};
float4 main(PixelShaderInput input) : SV_TARGET
{
float4 t = s_texture.Sample(s_sampleParams, input.texCoord);
return t;
}
Now I want to add a color to my shader:
struct PixelShaderInput
{
float4 pos : SV_POSITION;
float2 texCoord : TEXCOORD0;
};
Texture2D s_texture : register(t0);
float4 s_color;
SamplerState s_sampleParams
{
Filter = MIN_MAG_MIP_LINEAR;
AddressU = CLAMP;
AddressV = CLAMP;
};
float4 main(PixelShaderInput input) : SV_TARGET
{
float4 t = s_texture.Sample(s_sampleParams, input.texCoord);
return t * s_color;
}
How do I set s_color from C++ code? Do I have to use m_d3dContext->PSSetConstantBuffers? In this case I should change
`float4 s_color;`
to
cbuffer ColorOnlyConstantBuffer : register(b0)
{
float4 m_color;
};
, right?
Or I can keep simple definition float4 s_color; and set it from C++ somehow else?

Answer 1

As far as I remember, you specify input items for vertex shader by using specific structure:
D3D11_INPUT_ELEMENT_DESC inputLayoutDesc[2] =
{
{ "Position",
0,
DXGI_FORMAT_R32G32B32_FLOAT,
0,
D3D11_APPEND_ALIGNED_ELEMENT,
D3D11_INPUT_PER_VERTEX_DATA,
0
},
{ "Color",
0,
DXGI_FORMAT_R32G32B32_FLOAT,
0,
D3D11_APPEND_ALIGNED_ELEMENT,
D3D11_INPUT_PER_VERTEX_DATA,
0
}
};
This structure is being used to create ID3D11InputLayout:
const UINT inputLayoutDescCount = 2;
hr = device->CreateInputLayout(
inputLayoutDesc,
inputLayoutDescCount,
compiledVsShader->GetBufferPointer(),
compiledVsShader->GetBufferSize(),
&inputLayout);
You can then use semantics to specify, which element represents which entry:
struct VS_INPUT
{
float4 Pos : POSITION;
float4 Col : COLOR;
};
Edit: in response to comments.
Sorry, didn't get that. You'll need a constant buffer. Relevant (sample) parts of code follows. Just modify them to your needs:
struct PixelConstantBuffer
{
XMFLOAT4 lightPos;
XMFLOAT4 observerPos;
};
// ***
D3D11_BUFFER_DESC pixelConstantBufferDesc;
pixelConstantBufferDesc.ByteWidth = sizeof(PixelConstantBuffer);
pixelConstantBufferDesc.Usage = D3D11_USAGE_DEFAULT;
pixelConstantBufferDesc.BindFlags = D3D11_BIND_CONSTANT_BUFFER;
pixelConstantBufferDesc.CPUAccessFlags = 0;
pixelConstantBufferDesc.MiscFlags = 0;
pixelConstantBufferDesc.StructureByteStride = 0;
hr = device->CreateBuffer(&pixelConstantBufferDesc, nullptr, &pixelConstantBuffer);
// ***
context->PSSetConstantBuffers(1, 1, &pixelConstantBuffer);
context->PSSetShader(pixelShader, nullptr, 0);
// ***
PixelConstantBuffer pcBuffer;
pcBuffer.lightPos = XMFLOAT4(lightPos.m128_f32[0], lightPos.m128_f32[1], lightPos.m128_f32[2], lightPos.m128_f32[3]);
pcBuffer.observerPos = XMFLOAT4(camPos.m128_f32[0], camPos.m128_f32[1], camPos.m128_f32[2], camPos.m128_f32[3]);
context->UpdateSubresource(pixelConstantBuffer, 0, nullptr, &pcBuffer, 0, 0);
// *** (hlsl)
cbuffer PixelConstantBuffer : register(b1)
{
float4 LightPos;
float4 ObserverPos;
}