CODEWITHSUNDEEP
directx-11
suzz
suzz

Reputation: 31

DirectX11 Loaded texture colour becomes more saturated

I'm loading an image to the screen using DirectX11, but the image becomes more saturated. Left is the loaded image and right is the original image.

enter image description here

Strange thing is that this happens only when I'm loading large images. The resolution of the image I'm trying to print is 1080 x 675 and my window size is 1280 x 800. Also, although the original image has a high resolution the image becomes a little pixelated. This is solved if I use LINEAR filter but I'm curious why this is happening. I'm fairly new to DirectX and I'm struggling..

Vertex data:

_vertices[0].p = { -1.0f, 1.0f, 0.0f };
//_vertices[0].c = { 1.0f, 1.0f, 1.0f, 1.0f };
_vertices[0].t = { 0.0f, 0.0f };

_vertices[1].p = { 1.0f, 1.0f, 0.0f };
//_vertices[1].c = { 1.0f, 1.0f, 1.0f, 1.0f };
_vertices[1].t = { 1.0f, 0.0f };

_vertices[2].p = { -1.0f, -1.0f, 0.0f };
//_vertices[2].c = { 1.0f, 1.0f, 1.0f, 1.0f };
_vertices[2].t = { 0.0f, 1.0f };

_vertices[3].p = { 1.0f, -1.0f, 0.0f };
//_vertices[3].c = { 1.0f, 1.0f, 1.0f, 1.0f };
_vertices[3].t = { 1.0f, 1.0f };

Vertex layout:

D3D11_INPUT_ELEMENT_DESC elementDesc[] = {
        { "POSITION", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0, D3D11_INPUT_PER_VERTEX_DATA, 0},
        //{ "COLOR", 0, DXGI_FORMAT_R32G32B32A32_FLOAT, 0, 12, D3D11_INPUT_PER_VERTEX_DATA, 0},
        { "TEXTURE", 0, DXGI_FORMAT_R32G32_FLOAT, 0, 28, D3D11_INPUT_PER_VERTEX_DATA, 0},
    };

Sampler state:

 D3D11_SAMPLER_DESC samplerDesc;
    ZeroMemory(&samplerDesc, sizeof(samplerDesc));
    samplerDesc.Filter = D3D11_FILTER_MIN_MAG_MIP_POINT;
    samplerDesc.AddressU = D3D11_TEXTURE_ADDRESS_WRAP;
    samplerDesc.AddressV = D3D11_TEXTURE_ADDRESS_WRAP;
    samplerDesc.AddressW = D3D11_TEXTURE_ADDRESS_WRAP;
    device->CreateSamplerState(&samplerDesc, &g_defaultSS);

Vertex shader:

struct VS_IN
{
    float3 p : POSITION; 
    //float4 c : COLOR;
    float2 t : TEXTURE;
};

struct VS_OUT
{
    float4 p : SV_POSITION;
    //float4 c : COLOR0;
    float2 t : TEXCOORD0;
};

VS_OUT VSMain(VS_IN input) 
{
    VS_OUT output = (VS_OUT)0;
    output.p = float4(input.p, 1.0f);
    //output.c = input.c;
    output.t = input.t;
    return output;
}

Pixel shader:

Texture2D     g_texture         : register(t0);
SamplerState  g_sampleWrap      : register(s0);
float4 PSMain(VS_OUT input) : SV_Target
    {
        float4 vColor = g_texture.Sample(g_sampleWrap, input.t);    
        return vColor; //* input.c;
    }

Upvotes: 0

Views: 354

Answers (1)

Chuck Walbourn
Chuck Walbourn

Reputation: 41047

This is most likely an issue of colorspace. If rendering using 'linear colors' (which is recommended), then likely your image is in sRGB colorspace. You can let the texture hardware deal with the gamma by using DXGI_FORMAT_*_SRGB formats for your texture, or you can do it directly in the shader.

See these resources:

Linear-Space Lighting (i.e. Gamma)

Chapter 24. The Importance of Being Linear, GPU Gems 3

Gamma-correct rendering

In the DirectX Tool Kit, you can do various load-time tricks as well. See DDSTextureLoader and WICTextureLoader.

Upvotes: 2

Related Questions