Add source code for the cascaded shadow mapping guest article.

src/8.guest/2021/2.csm/10.shadow_mapping.vs

@@ -0,0 +1,24 @@
+#version 460 core
+layout (location = 0) in vec3 aPos;
+layout (location = 1) in vec3 aNormal;
+layout (location = 2) in vec2 aTexCoords;
+
+out vec2 TexCoords;
+
+out VS_OUT {
+    vec3 FragPos;
+    vec3 Normal;
+    vec2 TexCoords;
+} vs_out;
+
+uniform mat4 projection;
+uniform mat4 view;
+uniform mat4 model;
+
+void main()
+{
+    vs_out.FragPos = vec3(model * vec4(aPos, 1.0));
+    vs_out.Normal = transpose(inverse(mat3(model))) * aNormal;
+    vs_out.TexCoords = aTexCoords;
+    gl_Position = projection * view * model * vec4(aPos, 1.0);
+}