c++ DirectX lighting in pixel shader issue

Question

I have a problem that I cant manage to figure out. I just added a point light to my project and it makes the textures go completely black. I have no idea why.

I think that it might be either the normal that is not updating correctly or it might be calculation of s.x, s.y and s.z.

I would be very happy if someone had time to take a look at it and help me. Thanks.

So. Here is my pixel shader :

Texture2D txDiffuse : register(t0);
SamplerState sampState;
cbuffer PointLight : register(b0)
{
    float3 Pos;
    float diff;
    float amb;
    float spec;
    float range;
    float intensity;
};
struct VS_IN
{
    float4 Pos : SV_POSITION;
    float2 Tex : TEXCOORD;
    float4 Norm : NORMAL;
    float4 Pos2 : POSITION;
};
float4 PS_main(VS_IN input) : SV_Target
{
    float3 s = txDiffuse.Sample(sampState, input.Tex).xyz;

    float3 lightPos = Pos;

    float3 lightVector = lightPos - input.Pos2;
    lightVector = normalize(lightVector);
    float nDotL = dot(lightVector, input.Norm);

    float diff1 = 0.8;
    float amb1 = 0.1;

    s.x = (s.x * diff * nDotL + s.x * amb);
    s.y = (s.y * diff * nDotL + s.y * amb);
    s.z = (s.z * diff * nDotL + s.z * amb);



    return float4(s, 0.0);

};

Geometry shader :

cbuffer worldMatrix : register(b0)
{
    matrix world;
}
cbuffer viewMatrix : register(b1)
{
    matrix view;
}
cbuffer projectionMatrix : register(b2)
{
    matrix projection;
}
struct VS_IN
{
    float4 Pos : SV_POSITION;
    float2 Tex : TEXCOORD;
};
struct VS_OUT
{
    float4 Pos : SV_POSITION;
    float2 Tex : TEXCOORD;
    float4 Norm : NORMAL;
    float4 Pos2 : POSITION;
};

[maxvertexcount(6)]
void main(triangle VS_IN input[3] : SV_POSITION, inout TriangleStream< VS_OUT > output2)
{

    matrix wvp = mul(projection, mul(world, view));
    matrix worldView = mul(world, view);


    float4 normal = float4(cross(input[1].Pos - input[0].Pos, input[2].Pos - input[0].Pos), 0.0f);
    normal = normalize(normal);

    float4 rotNorm = mul(worldView, normal);
    rotNorm = normalize(rotNorm);

    VS_OUT output[3];
    for (uint i = 0; i < 3; i++)
    {
        output[i].Pos = input[i].Pos;
        output[i].Pos = mul(wvp, input[i].Pos);
        output[i].Tex = input[i].Tex;
        output[i].Norm = rotNorm;
        output[i].Pos2 = mul(worldView, output[i].Pos);
        output2.Append(output[i]);
    }
    output2.RestartStrip();

    VS_OUT outputcopy[3];
    for (uint i = 0; i < 3; i++)
    {
        outputcopy[i].Pos = input[i].Pos + (normal);
        outputcopy[i].Pos = mul(wvp, outputcopy[i].Pos);
        outputcopy[i].Tex = input[i].Tex;
        outputcopy[i].Norm = rotNorm;
        outputcopy[i].Pos2 = mul(worldView, outputcopy[i].Pos);
        output2.Append(outputcopy[i]);
    }

    output2.RestartStrip();
}

Code to initializing the point light:

struct PointLight
{
    Vector3 Pos;
    float diff;
    float   amb;
    float   spec;
    float   range;
    float   intensity;

};
PointLight* pointLight = nullptr;
PointLight PL =
    {
    Vector3(0.0f, 0.0f, -3.0f),
    0.8f,
    0.2f,
    0.0f,
    100.0f,
    1.0f
    };

    pointLight = &PL;

    D3D11_BUFFER_DESC lightBufferDesc;
    memset(&lightBufferDesc, 0, sizeof(lightBufferDesc));
    lightBufferDesc.BindFlags = D3D11_BIND_CONSTANT_BUFFER;
    lightBufferDesc.Usage = D3D11_USAGE_DEFAULT;
    lightBufferDesc.StructureByteStride = 0;
    lightBufferDesc.MiscFlags = 0;
    lightBufferDesc.ByteWidth = sizeof(PointLight);

    D3D11_SUBRESOURCE_DATA pointLightData;
    memset(&pointLightData, 0, sizeof(pointLightData));
    pointLightData.pSysMem = &PL;

    gDevice->CreateBuffer(&lightBufferDesc, &pointLightData, &lightBuffer);

and in render() i run

gDeviceContext->PSSetConstantBuffers(0, 1, &lightBuffer);

Could there be alignment / padding issues on your pointlight buffer? I'm not sure the rules are the same in c++ and the shader language. — jcoder, Feb 29 '16 at 17:12

score 0 · Answer 1 · answered Mar 01 '16 at 04:29

Texture will be black if s.x, s.y, s.z equal to zero.

s.x = (s.x * diff * nDotL + s.x * amb);
s.y = (s.y * diff * nDotL + s.y * amb);
s.z = (s.z * diff * nDotL + s.z * amb);

Try to change diff and amb with a non-zero constant so that you can be sure that you set contant buffer correctly or not. If after you change them, it's still black then it must be nDotL and/or sampled texture that is zero. Then try with non-zero constant for texture sample. If they're still causing texture to look black then your light vector calculation is the culprit.

c++ DirectX lighting in pixel shader issue

1 Answers1