From 3956459af8a12f8ef56de6be81c467619d4e018b Mon Sep 17 00:00:00 2001
From: LiuZengqiang <74355935+LiuZengqiang@users.noreply.github.com>
Date: Sat, 8 Mar 2025 12:01:22 +0800
Subject: [PATCH] Fix error in 07-PBR-IBL-Diffuse irradiance.md (#332)
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* Update 06 HDR.md

typo

* Update 06 HDR.md

Delete wrong figure insertion.

* Fix error in 07-PBR-IBL-Diffuse irradiance.md

离散积分 kd*c/pi*... -> kd*c*pi...;
方向向量normalize；
---
 docs/07 PBR/03 IBL/01 Diffuse irradiance.md | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/docs/07 PBR/03 IBL/01 Diffuse irradiance.md b/docs/07 PBR/03 IBL/01 Diffuse irradiance.md
index cc2e903..53d4f2f 100644
--- a/docs/07 PBR/03 IBL/01 Diffuse irradiance.md	
+++ b/docs/07 PBR/03 IBL/01 Diffuse irradiance.md	
@@ -375,7 +375,7 @@ $$
 
 $$
 L_o(p,\phi_o, \theta_o) = 
-        k_d\frac{c}{\pi} \frac{1}{n1 n2} \sum_{\phi = 0}^{n1} \sum_{\theta = 0}^{n2} L_i(p,\phi_i, \theta_i) \cos(\theta) \sin(\theta)  d\phi d\theta
+        k_d \frac{c\pi}{n1 n2} \sum_{\phi = 0}^{n1} \sum_{\theta = 0}^{n2} L_i(p,\phi_i, \theta_i) \cos(\theta) \sin(\theta)  d\phi d\theta
 $$
 
 当我们离散地对两个球坐标轴进行采样时，每个采样近似代表了半球上的一小块区域，如上图所示。注意，由于球的一般性质，当采样区域朝向中心顶部会聚时，天顶角 \(\theta\) 变高，半球的离散采样区域变小。为了平衡较小的区域贡献度，我们使用 \(sin\theta\) 来权衡区域贡献度，这就是多出来的 \(sin\) 的作用。
@@ -386,8 +386,8 @@ $$
 vec3 irradiance = vec3(0.0);  
 
 vec3 up    = vec3(0.0, 1.0, 0.0);
-vec3 right = cross(up, normal);
-up         = cross(normal, right);
+vec3 right = normalize(cross(up, normal));
+up         = normalize(cross(normal, right));
 
 float sampleDelta = 0.025;
 float nrSamples = 0.0;