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Aaron JJ's questions

Martin Hope
Aaron JJ
Asked: 2025-01-05 23:48:25 +0000 UTC
  • 6

看起来一切都配置正确：6 个视图矩阵、1 个投影矩阵、一个将图元转换为光源空间并将 6 个纹理写入深度缓冲区立方体贴图的几何着色器。仅当视图矩阵中的近平面和 lightPerspectiveValues 来源的矩阵不同（分别为 0.1f 和 1.0f）时，它才起作用。但结果并不相同 - 远处的物体不会被遮挡，只有那些距离点光源很近的物体才会被遮挡。我在 HLSL 开发书籍和这篇文章中看到了该技术： https: //habr.com/ru/articles/259679/

结果

void TestApplication::PrepareLightViewMatrixes(glm::vec3 lightPos)
{
    glm::vec3 vectors[] =
    {
        glm::vec3(0.f, 0.f, 0.f), glm::vec3(1.0f,  0.0f,  0.0f), glm::vec3(0.0f, 1.0f,  0.0f),
        glm::vec3(0.f, 0.f, 0.f), glm::vec3(-1.0f,  0.0f,  0.0f), glm::vec3(0.0f, 1.0f,  0.0f),
        glm::vec3(0.f, 0.f, 0.f), glm::vec3(0.0f,  1.0f,  0.0f), glm::vec3(0.0f,  0.0f,  -1.0f),
        glm::vec3(0.f, 0.f, 0.f), glm::vec3(0.0f, -1.0f,  0.0f), glm::vec3(0.0f,  0.0f, 1.0f),
        glm::vec3(0.f, 0.f, 0.f), glm::vec3(0.0f,  0.0f,  1.0f), glm::vec3(0.0f, 1.0f,  0.0f),
        glm::vec3(0.f, 0.f, 0.f), glm::vec3(0.0f,  0.0f, -1.0f), glm::vec3(0.0f, 1.0f,  0.0f)
    };

    m_DepthCaptureViews =
    {
        glm::lookAtLH(lightPos, lightPos + vectors[1], vectors[2]),
        glm::lookAtLH(lightPos, lightPos + vectors[4], vectors[5]),
        glm::lookAtLH(lightPos, lightPos + vectors[7], vectors[8]),
        glm::lookAtLH(lightPos, lightPos + vectors[10], vectors[11]),
        glm::lookAtLH(lightPos, lightPos + vectors[13], vectors[14]),
        glm::lookAtLH(lightPos, lightPos + vectors[16], vectors[17])
    };
}

glm::mat4 lightProjMat = glm::perspectiveLH(XM_PIDIV2, 1.f, 0.1f, 100.f);

///// Передаю lightPerspectiveValues и матрицы через константный буфер /////

XMMATRIX matPointProj = XMMatrixPerspectiveFovLH(XM_PIDIV2, 1.0, 1.f, 100.f);
XMFLOAT4X4 matPointProjFloat;
XMStoreFloat4x4(&matPointProjFloat, matPointProj);
lightCb.lightPerspectiveValues = glm::vec2(matPointProjFloat.m[2][2], matPointProjFloat.m[3][2]);
lightCb.cubeView[0] = glm::transpose(m_DepthCaptureViews[0]);
lightCb.cubeView[1] = glm::transpose(m_DepthCaptureViews[1]);
lightCb.cubeView[2] = glm::transpose(m_DepthCaptureViews[2]);
lightCb.cubeView[3] = glm::transpose(m_DepthCaptureViews[3]);
lightCb.cubeView[4] = glm::transpose(m_DepthCaptureViews[4]);
lightCb.cubeView[5] = glm::transpose(m_DepthCaptureViews[5]);
lightCb.cubeProj = glm::transpose(lightProjMat);

///// Геометрический шейдер /////

struct GS_OUTPUT
{
    float4 Pos : SV_POSITION;
    uint RTIndex : SV_RenderTargetArrayIndex;
};

[maxvertexcount(18)]
void GSMain(triangle float4 InPos[3] : SV_Position, inout TriangleStream<GS_OUTPUT> OutStream)
{
    for (int iFace = 0; iFace < 6; iFace++)
    {
        GS_OUTPUT output;

        output.RTIndex = iFace;

        for (int v = 0; v < 3; v++)
        {
            output.Pos = mul(InPos[v], CubeView[iFace]);
            output.Pos = mul(output.Pos, CubeProj);
            OutStream.Append(output);
        }
        OutStream.RestartStrip();
    }
}

///// Пиксельный шейдер, который берет из Depth Cubemap значения глубины и рассчитывает тени /////

float SpotShadowPCF(float3 ToPixel)
{
    float3 ToPixelAbs = abs(ToPixel);
    float Z = max(ToPixelAbs.x, max(ToPixelAbs.y, ToPixelAbs.z));
    float Depth = (lightPerspectiveValues.x * Z + lightPerspectiveValues.y) / Z; 
    return depthMap.SampleCmpLevelZero(comparisonSampler, ToPixel, Depth);
}

float3 CalcLight(float3 position, float4 lightSpacePosition, float3 normal, float4 diffuseColor)
{
    float3 ToLight = normalize(lightPos.xyz - position.xyz);

    float NDotL = saturate(dot(ToLight, normal));
    float3 finalColor = diffuseColor.rgb * NDotL;
    
    float shadowAtt = SpotShadowPCF(position.xyz - lightPos.xyz);
    
    finalColor *= shadowAtt;
    
    return finalColor;
}

float4 PSMain(Input input) : SV_Target
{
    float4 diffuseColor = albedoMap.Sample(textureSampler, input.uv);
    
    if (diffuseColor.a < 0.1f)
        discard;
    
    float3 ambient = diffuseColor.xyz * 0.1;
    
    float3 color = CalcLight(input.fragPos, input.lightViewPosition, input.normal, diffuseColor);
    return float4(ambient + color, 1.f);
}
разработка-игр