ShadowMap peter-panning和错误的方向

Question

我正在创建前向渲染的DX11引擎，我在阴影映射算法方面有一些问题，因为它不像想象的那样工作。

如你所见-影子是彼得-潘宁，看起来完全没有释放。基本上，正如我所测试的，PixelShader中的比较没有任何效果。如果语句不做任何操作，则只返回投影阴影贴图纹理。

MyVertexShader:

PixelInputType ColorVertexShader(VertexInputType input)
{
    PixelInputType output;
    float4 worldPosition;

    input.position.w = 1.0f;
    worldPosition = mul(input.position, worldMatrix);
    output.normal = input.normal;

    // Calculate the position of the vertex against the world, view, and projection matrices.
    output.position = mul(input.position, worldMatrix);
    output.position = mul(output.position, viewMatrix);
    output.position = mul(output.position, projectionMatrix);

    //Calculate object seen by light
    output.lightViewPosition = mul(input.position, worldMatrix);
    output.lightViewPosition = mul(output.lightViewPosition, g_lightViewMatrix);
    output.lightViewPosition = mul(output.lightViewPosition, g_lightProjectionMatrix);

    //Calculate light-object vector
    output.lightPos = g_lightPosition.xyz - worldPosition.xyz;
    output.lightPos = normalize(output.lightPos);

    return output;
}

MyPixelShader:

float4 ColorPixelShader(PixelInputType input) : SV_TARGET
{
    float4 color = float4(0.0, 0.0, 0.0, 1.0);
    float depthValue;
    float lightDepthValue;
    float bias = 0.001f;
    float4 textureColor = float4(1.0, 1.0, 1.0, 1.0);
    float4 ambientColor = float4(1.0, 0.0, 1.0, 1.0);
    float2 tex;
    float lightIntensity = 0.0f;

    input.lightViewPosition.xyz /= input.lightViewPosition.w;

    tex.x = input.lightViewPosition.x / 2.0f + 0.5f;
    tex.y = -input.lightViewPosition.y / 2.0f + 0.5f;

    return depthValue = shadowMap.Sample(SampleType, tex).r;
    color = float4(depthValue, depthValue, depthValue, 1.0f);

    lightDepthValue = input.lightViewPosition.z;// / input.lightViewPosition.w;
    lightDepthValue = lightDepthValue - bias;
    if(lightDepthValue < depthValue)
    {
        lightIntensity = saturate(dot(input.normal, input.lightPos));

        if(lightIntensity > 0.0f)
        {
            // Determine the final diffuse color based on the diffuse color and the amount of light intensity.
            color += (ambientColor * lightIntensity);

            // Saturate the final light color.
            color = saturate(color);
        }
    }
    return color;
}

Answer 1

我发现在将和弦转换为0，1时，只需去掉阴影中的负号就可以解决方向问题。但规模仍在缩小--以下是一个例子：

void LightClass::GenerateViewMatrix()
{
    XMVECTOR eyePos = { m_position.x, m_position.y, m_position.z };
    XMVECTOR focusPos = { m_lookAt.x, m_lookAt.y, m_lookAt.z };
    XMVECTOR upVec = { 0, 1, 0 };

    m_viewMatrix = XMMatrixLookAtLH(eyePos, focusPos, upVec);
}

void LightClass::GenerateProjectionMatrix(float screenDepth, float screenNear)
{
    float fieldOfView = (float)3.14f / 2.0f;
    float screenAspect = 16.0f / 9.0f;

    m_projectionMatrix = XMMatrixPerspectiveFovLH(fieldOfView, screenAspect, screenNear, screenDepth);
}

编辑实际解决方案-忽略以前的帖子:

我遵循了PaulHK解决方案(谢谢，这是您第二次帮助我)再次检查视图/投影矩阵。基本上我的计算是错的。我调试了从模型到光空间的转换，并将顶点着色器从：

output.lightViewPosition = mul(input.position, worldMatrix);
output.lightViewPosition = mul(output.lightViewPosition, g_lightViewMatrix);
output.lightViewPosition = mul(output.lightViewPosition, g_lightProjectionMatrix);

纠正：

matrix lightViewProj = mul(g_lightProjectionMatrix, g_lightViewMatrix);
output.lightViewPosition = mul(input.position, lightViewProj);

那个简单的改变了我的结果。下面使用简单的像素着色器代码，我得到了以下结果：

input.lightViewPosition.xyz /= input.lightViewPosition.w;

tex.x = input.lightViewPosition.x / 2.0f + 0.5f;
tex.y = -input.lightViewPosition.y / 2.0f + 0.5f;

depthValue = shadowMap.Sample(SampleType, tex).r;
return color = float4(depthValue, depthValue, depthValue, 1.0f);

然而，即使这似乎是正确的，我的怀疑是，我需要比较我的阴影地图与轻型Z-缓冲器，所以我修改了我的像素阴影，并增加了一点色彩：

input.lightViewPosition.xyz /= input.lightViewPosition.w;

tex.x = input.lightViewPosition.x / 2.0f + 0.5f;
tex.y = -input.lightViewPosition.y / 2.0f + 0.5f;

depthValue = shadowMap.Sample(SampleType, tex).r;
color = float4(depthValue, depthValue, depthValue, 1.0f);

lightDepthValue = input.lightViewPosition.z - bias;
if(lightDepthValue < depthValue)
{
    lightIntensity = saturate(dot(input.normal, input.lightPos));

    if(lightIntensity > 0.0f)
    {
        // Determine the final diffuse color based on the diffuse color and the amount of light intensity.
        color += (ambientColor * lightIntensity);

        // Saturate the final light color.
        color = saturate(color);
    }
}
return color;

我可能是不对的，但如果没有这个检查，你会得到错误与更复杂的阴影。因为我以前的PixelShader代码基本上只是在平面上投影阴影图，而没有任何实际的深度检查。因此，它会在所有它能做的事情上放置阴影地图，甚至不检查它是否正确。