Alpha channel is acting and outputting green in directx11 and c++ - c++

Question

I am new to Directx11 .I wanted to create point Light behaviour to my program.So I defined a struct like so
struct PointLights
{
XMFLOAT3 Pos; //Light Position in (X,Y,Z)
float Range; //the range after which objects will not be affected by this light
XMFLOAT4 Color; //Light Color
XMFLOAT3 att; // Attenuation Parameters
float Intensity;
};
And Added it to constant buffer like
struct ConstantBuffer
{
XMMATRIX World;
XMMATRIX WorldInv;
XMMATRIX View;
XMMATRIX Project;
XMFLOAT3 LighDirs[2];
XMFLOAT4 LightColor[2];
float SpecualrIntensity;
XMFLOAT3 CameraPos;
PointLights pointLight;
};
This function is used to create buffer
void InitConstantBuffer(void)
{
D3D11_BUFFER_DESC desc;
SecureZeroMemory(&desc,sizeof(desc));
desc.BindFlags= D3D11_BIND_CONSTANT_BUFFER;
desc.ByteWidth = sizeof(ConstantBuffer);
desc.CPUAccessFlags = 0;
desc.Usage = D3D11_USAGE_DEFAULT;
SecureZeroMemory(&g_ConstantBuffer,sizeof(ID3D11Buffer));
HRESULT HR= dev->CreateBuffer(&desc,0,&g_ConstantBuffer);
if(FAILED(HR))
MessageBox(_hwnd,L"Couldnt Create constant buffer",L"ERROR",0);
}
Now When i update the point lights color to black but set its alpha to 1 (0,0,0,1)
the out put is green and output is black if alpha is 0 (0,0,0,0)
PointLights pointLight;
SecureZeroMemory(&pointLight,sizeof(PointLights));
pointLight.att = XMFLOAT3(0,0,1);
pointLight.Intensity = 5;
pointLight.Pos = XMFLOAT3(Lppos[0],Lppos[1],Lppos[2]);
pointLight.Range = 200;
pointLight.Color = XMFLOAT4(0,0,0,1); // black
ConstantBuffer cb;
cb.World = XMMatrixTranspose(g_World);
cb.View = XMMatrixTranspose(g_View);
cb.Project = XMMatrixTranspose(g_Projection);
cb.WorldInv = InverseTranspose(g_World);
cb.LighDirs[1] = lights[1].Dir;
cb.LightColor[1] = lights[1].Color;
cb.LightColor[0] = lights[0].Color;cb.LighDirs[0] = lights[0].Dir;
cb.LightColor[0] = lights[0].Color;
cb.SpecualrIntensity = 10;
cb.CameraPos = XMFLOAT3(0,0,-10);
cb.pointLight = pointLight;
devcon->UpdateSubresource(g_ConstantBuffer,0,0,&cb,0,0);
![output is green][1]
Cant upload image as stackoverflow wont let me...I hate it
Here is hte pixel shader
struct PointLights{
float3 Position;
float Range;
float4 Color;
float3 Atten;
float Intensity;
};
cbuffer ConstantBuffer:register(b0)
{
matrix world;
matrix worldInv;
matrix view;
matrix project;
float3 LightDir[2];
float4 LightColor[2];
float SpecualrIntensity;
float3 CameraPos;
PointLights pointLight;
};
float4 Ps(Vout vo):SV_TARGET
{
float4 col = (float4)0;
col = pointLight.Color;
return col;}
Please do help me out.. I tried rearranging the members of struct but still in vain
Thanks ....

Answer 1

It's quite likely that the data alignment between the C++ constant buffer structures and HLSL cbuffer declarations do not quite match. Try using XMFLOAT4 instead of XMFLOAT3 to ensure they line up the same way in both.
You are using XMMATRIX in struct ConstantBuffer. This might work, it might not, depending on exactly how you are using it. It makes ConstantBuffer require 16-byte alignement in memory. If you are making this assumption, use XMVECTOR rather then XMFLOAT3 or XMFLOAT4. Otherwise, change XMMATRIX to XMMFLOAT4X4.
If you find the DirectXMath alignment thing confusing, consider using the SimpleMath wrapper from DirectX Tool Kit.