Cubemap texturing issue D3D11 (C++)

Question

I have a texture problem with the cubemap I'm rendering and can't seem to figure it out. I've generated a cube map with direct x's texture tools and then read it using

D3DX11CreateShaderResourceViewFromFile(device, L"cubemap.dds", 0, 0, &fullcubemap, 0);

The cubemap texture is not high quality at all and it looks really stretched/distorted. I can definitely tell that the images used for the cubemap match correctly, but it's not great at all at the moment

I'm not sure why this is happening. Is it because my textures are too large/small or is it something else? If it's due to the size of the textures, what is a recommended texture size? I am using a sphere for the cubemap not a cube.

Edit:

Shader:

cbuffer SkyboxConstantBuffer {
    float4x4 world;
    float4x4 view;
    float4x4 projection;
};

TextureCube gCubeMap;

SamplerState samTriLinearSam {
    Filter = MIN_MAG_MIP_LINEAR;
    AddressU = Wrap;
    AddressV = Wrap;
};

struct VertexIn {
    float4 position : POSITION;
};

struct VertexOut {
    float4 position : SV_POSITION;
    float4 spherePosition : POSITION;
};

VertexOut VS(VertexIn vin) {
    VertexOut vout = (VertexOut)0;

    vin.position.w = 1.0f;

    vout.position = mul(vin.position, world);
    vout.position = mul(vout.position, view);
    vout.position = mul(vout.position, projection);

    vout.spherePosition = vin.position;

    return vout;
}

float4 PS(VertexOut pin) : SV_Target {
    return gCubeMap.Sample(samTriLinearSam, pin.spherePosition);//float4(1.0, 0.5, 0.5, 1.0);
}

RasterizerState NoCull {
    CullMode = None;
};

DepthStencilState LessEqualDSS {
    DepthFunc = LESS_EQUAL;
};

technique11 SkyTech {
    pass p0 {
        SetVertexShader(CompileShader(vs_4_0, VS()));
        SetGeometryShader(NULL);
        SetPixelShader(CompileShader(ps_4_0, PS()));

        SetRasterizerState(NoCull);
        SetDepthStencilState(LessEqualDSS, 0);
    }
}

Draw:

immediateContext->OMSetRenderTargets(1, &renderTarget, nullptr);

XMMATRIX sworld, sview, sprojection;
SkyboxConstantBuffer scb;
sview = XMLoadFloat4x4(&_view);
sprojection = XMLoadFloat4x4(&_projection);
sworld = XMLoadFloat4x4(&_world);

scb.world = sworld;
scb.view = sview;
scb.projection = sprojection;

immediateContext->IASetIndexBuffer(cubeMapSphere->getIndexBuffer(), DXGI_FORMAT_R32_UINT, 0);
ID3D11Buffer*  vertexBuffer = cubeMapSphere->getVertexBuffer();
//ID3DX11EffectShaderResourceVariable * cMap;
////cMap = skyboxShader->GetVariableByName("gCubeMap")->AsShaderResource();
immediateContext->PSSetShaderResources(0, 1, &fullcubemap);//textures
//cMap->SetResource(fullcubemap);
immediateContext->IASetVertexBuffers(0, 1, &vertexBuffer, &stride, &offset);
immediateContext->VSSetShader(skyboxVertexShader, nullptr, 0);
immediateContext->VSSetConstantBuffers(0, 1, &skyboxConstantBuffer);
immediateContext->PSSetConstantBuffers(0, 1, &skyboxConstantBuffer);
immediateContext->PSSetShader(skyboxPixelShader, nullptr, 0);

immediateContext->UpdateSubresource(skyboxConstantBuffer, 0, nullptr, &scb, 0, 0);
immediateContext->DrawIndexed(cubeMapSphere->getIndexBufferSize(), 0, 0);

Initially I was planning to use this snippet to update the TextureCube variable in the shader

ID3DX11EffectShaderResourceVariable * cMap;
cMap = skyboxShader->GetVariableByName("gCubeMap")->AsShaderResource();
cMap->SetResource(fullcubemap);

But it seems that has no effect, and in fact, without the following line, the sphere I'm using for the cubemap textures with a texture used with another object in the scene, so perhaps there's something going on here? I'm not sure what though.

immediateContext->PSSetShaderResources(0, 1, &fullcubemap);//textures

Edit: Probably not the above, realised that if this wasn't updated, the old texture would be applied as it's never wiped after each draw.

Edit: Tried the cubemap with both a sphere and a cube, still the same texture issue.

Edit: Tried loading the shader resource view differently

D3DX11_IMAGE_LOAD_INFO loadSMInfo;
loadSMInfo.MiscFlags = D3D11_RESOURCE_MISC_TEXTURECUBE;

ID3D11Texture2D* SMTexture = 0;
hr = D3DX11CreateTextureFromFile(device, L"cubemap.dds",
    &loadSMInfo, 0, (ID3D11Resource**)&SMTexture, 0);

D3D11_TEXTURE2D_DESC SMTextureDesc;
SMTexture->GetDesc(&SMTextureDesc);

D3D11_SHADER_RESOURCE_VIEW_DESC SMViewDesc;
SMViewDesc.Format = SMTextureDesc.Format;
SMViewDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURECUBE;
SMViewDesc.TextureCube.MipLevels = SMTextureDesc.MipLevels;
SMViewDesc.TextureCube.MostDetailedMip = 0;

hr = device->CreateShaderResourceView(SMTexture, &SMViewDesc, &fullcubemap);

Still produces the same output, any ideas?

Edit: Tried increasing the zfar distance and the texture remains the exact same no matter what value I put.

Example with second texture with increased view distance.

This texture is used on another object in my scene and comes out fine.

Answer 1

It turned out to be that I needed to use XMMatrixTranspose