examples/shaders: Add an example for deferred shading (#3496)

* add example for deferred rendering/shading

* adapt convention

---------

Co-authored-by: 27justin <me@justin.cx>

examples/shaders/resources/shaders/glsl330/gbuffer.vs

@@ -0,0 +1,24 @@
+#version 330 core
+layout (location = 0) in vec3 vertexPosition;
+layout (location = 1) in vec2 vertexTexCoord;
+layout (location = 2) in vec3 vertexNormal;
+
+out vec3 fragPosition;
+out vec2 fragTexCoord;
+out vec3 fragNormal;
+
+uniform mat4 matModel;
+uniform mat4 matView;
+uniform mat4 matProjection;
+
+void main()
+{
+    vec4 worldPos = matModel * vec4(vertexPosition, 1.0);
+    fragPosition = worldPos.xyz; 
+    fragTexCoord = vertexTexCoord;
+
+    mat3 normalMatrix = transpose(inverse(mat3(matModel)));
+    fragNormal = normalMatrix * vertexNormal;
+
+    gl_Position = matProjection * matView * worldPos;
+}