Graphics PBR-不正确的直接照明

基于许多internet资源，我为DirectX 11游戏引擎编写了定向照明的PBR实现，但它工作不正确

下面，你们可以看到一个截图，我强制金属度为0.0f，粗糙度为1.0f。正如你所看到的，有太多的反射。例如，草反射性很强，但粗糙度设置为0，因此看起来不应该是这样

贝娄，我想象了环境照明，它看起来是正确的

不幸的是，directLighting似乎完全关闭了，我不知道为什么。反思太多了。这可能是因为我对定向光源应用了错误的PBR公式，但我不知道如何使其正确

这是我的PBR源代码。我希望你能帮我解决这个问题，或者至少给我一个提示，问题可能在哪里，因为老实说，我现在不知道如何解决它

static const float PI = 3.14159265359f;
static const float3 DIELECTRIC_FACTOR = float3(0.04f, 0.04f, 0.04f);
static const float EPSILON = 0.00001f;

float DistributionGGX(float3 normal, float3 halfway, float roughness)
{
    float alpha = roughness * roughness;
    float alphaSquare = alpha * alpha;
    float cosHalfway = max(dot(normal, halfway), 0.0f);
    float cosHalfwaySquare = cosHalfway * cosHalfway;

    float denominator = (cosHalfwaySquare * (alphaSquare - 1.0f)) + 1.0f;
    denominator = PI * denominator * denominator;

    return alphaSquare / denominator;
}

float GeometrySchlickGGX(float cosinus, float roughness)
{
    float r = (roughness + 1.0);
    float k = (r * r) / 8.0;

    float denominator = cosinus * (1.0 - k) + k;

    return cosinus / denominator;
}

float GeometrySmith(float3 normal, float roughness, float cosView, float cosLight)
{
    return GeometrySchlickGGX(cosView, roughness) * GeometrySchlickGGX(cosLight, roughness);
}

float3 FresnelSchlick(float cosTheta, float3 F0)
{
    return F0 + (1.0f - F0) * pow(1.0f - cosTheta, 5.0f);
}

float3 FresnelSchlickRoughness(float cosTheta, float3 F0, float roughness)
{
    return F0 + (max(float(1.0f - roughness).xxx, F0) - F0) * pow(1.0f - cosTheta, 5.0f);
}

int GetTextureMipMapLevels(TextureCube input)
{
    int width, heigth, levels;
    input.GetDimensions(0, width, heigth, levels);
    return levels;
}

float3 Pbr(float3 albedo, float3 normal, float metallic, float roughness, float occlusion,
          TextureCube irradianceTexture, TextureCube radianceTexture, Texture2D brdfLut, 
          SamplerState defaultSampler, SamplerState brdfSampler, float3 lightDirection, 
          float3 lightColor, float3 cameraPosition, float3 pixelPosition, float shadowMultiplier)
{
    lightDirection *= -1;

    float3 viewDirection = normalize(cameraPosition - pixelPosition);
    float3 halfwayDirection = normalize(viewDirection + lightDirection);
    float3 reflectionDirection = reflect(-viewDirection, normal);

    float3 F0 = lerp(DIELECTRIC_FACTOR, albedo, metallic);

    float cosView = max(dot(normal, viewDirection), 0.0f);
    float cosLight = max(dot(normal, lightDirection), 0.0f);

    float NDF = DistributionGGX(normal, halfwayDirection, roughness);
    float G = GeometrySmith(normal, roughness, cosView, cosLight);
    float3 F = FresnelSchlick(max(dot(halfwayDirection, viewDirection), 0.0f), F0);

    float3 nominator = NDF * G * F;
    float denominator = 4 * cosView * cosLight + EPSILON;
    float3 specular = nominator / denominator;

    float3 kD = lerp(float3(1.0f, 1.0f, 1.0f) - F, float3(0.0f, 0.0f, 0.0f), metallic);

    float3 directLighting = (kD * albedo / PI + specular) * lightColor * cosLight;

    F = FresnelSchlickRoughness(cosView, F0, roughness);
    kD = lerp(float3(1.0f, 1.0f, 1.0f) - F, float3(0.0f, 0.0f, 0.0f), metallic);

    float3 irradiance = irradianceTexture.Sample(defaultSampler, normal).rgb;
    float3 diffuse = irradiance * albedo;

    int radianceLevels = GetTextureMipMapLevels(radianceTexture);
    float3 radiance = radianceTexture.SampleLevel(defaultSampler, reflectionDirection, roughness * radianceLevels).rgb;
    float2 brdf = brdfLut.Sample(brdfSampler, float2(cosView, roughness)).xy;
    float3 specularColor = radiance * (F0 * brdf.x + brdf.y);

    float3 ambientLighting = (kD * diffuse + specularColor) * occlusion;

    return ambientLighting + (directLighting * shadowMultiplier);
}

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你解决了这个问题吗？你能分别测试反照率和镜面反射成分吗？是的，看起来我对地形的法线计算不正确。