像素着色器问题中的 c++ DirectX 照明

Question

我有一个我无法解决的问题。我刚刚在我的项目中添加了一个点光源，它使纹理完全变黑。我不知道为什么。

我认为这可能是法线没有正确更新，也可能是 s.x、s.y 和 s.z 的计算。

如果有人有时间看一下并帮助我，我会很高兴。谢谢。

所以。这是我的像素着色器:

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);

};

几何着色器:

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();
}

初始化点光源的代码:

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);

然后在 render() 中运行

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

Answer 1

如果 s.x, s.y, s.z 为零，纹理将为黑色。

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);

尝试用非零常量更改diff 和amb，这样您就可以确定您是否正确设置了contant buffer。如果在您更改它们之后，它仍然是黑色，则它必须是 nDotL 和/或采样纹理为零。然后尝试使用非零常数作为纹理样本。如果它们仍然导致纹理看起来变黑，那么您的光 vector 计算就是罪魁祸首。