From 862ef6d34b428cc05bd6545b1ed977c2ea9b9177 Mon Sep 17 00:00:00 2001
From: Robert <robert.trololo@gmail.com>
Date: Tue, 26 Jan 2021 15:36:57 +0100
Subject: [PATCH] Added normal matrices to transformable

---
 examples/movement/main.cpp | 2 +-
 include/transformable.hpp  | 9 +++++++++
 src/transformable.cpp      | 5 +++++
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/examples/movement/main.cpp b/examples/movement/main.cpp
index 314ba7b..84ce3d0 100644
--- a/examples/movement/main.cpp
+++ b/examples/movement/main.cpp
@@ -274,7 +274,7 @@ int main(int argc, char** argv)
 		for (oglu::Object& cube : cubes)
 		{
 			shader->SetUniform("model", cube);
-			shader->SetUniformMatrix3fv("normal", 1, GL_FALSE, glm::value_ptr(glm::mat3(glm::transpose(glm::inverse(cube.GetMatrix())))));
+			shader->SetUniformMatrix3fv("normal", 1, GL_FALSE, glm::value_ptr(cube.GetNormalMatrix()));
 			cube.Render();
 		}
 
diff --git a/include/transformable.hpp b/include/transformable.hpp
index 57f85e8..74c6179 100644
--- a/include/transformable.hpp
+++ b/include/transformable.hpp
@@ -351,6 +351,15 @@ namespace oglu
 		 */
 		virtual const glm::mat4& GetMatrix();
 
+		/**
+		 * @brief Returns a normal matrix.
+		 * 
+		 * For use in shaders to compute normals of surfaces.
+		 * 
+		 * @return A 3x3 normal matrix
+		 */
+		glm::mat3 GetNormalMatrix();
+
 		/**
 		 * @brief Get position as a 3D vector.
 		 * 
diff --git a/src/transformable.cpp b/src/transformable.cpp
index 3f51968..5502638 100644
--- a/src/transformable.cpp
+++ b/src/transformable.cpp
@@ -197,6 +197,11 @@ namespace oglu
 		return transformation;
 	}
 
+	glm::mat3 Transformable::GetNormalMatrix()
+	{
+		return glm::mat3(glm::transpose(glm::inverse(GetMatrix())));
+	}
+
 	const glm::vec3& Transformable::GetPosition() const
 	{
 		return translation;