From 1d5f5a1ad8bdbbcdd80f3c622f007e0e1e3eace5 Mon Sep 17 00:00:00 2001
From: Riyyi <riyyi3@gmail.com>
Date: Fri, 9 Aug 2024 23:10:39 +0200
Subject: [PATCH] Shader: Cache uniform location lookup

---
 src/inferno/asset/shader.cpp | 41 +++++++++++++++++++++---------------
 src/inferno/asset/shader.h   | 18 +++++++++-------
 2 files changed, 34 insertions(+), 25 deletions(-)

diff --git a/src/inferno/asset/shader.cpp b/src/inferno/asset/shader.cpp
index d327e9e..65e7f72 100644
--- a/src/inferno/asset/shader.cpp
+++ b/src/inferno/asset/shader.cpp
@@ -50,65 +50,72 @@ Shader::~Shader()
 	}
 }
 
-int32_t Shader::findUniform(std::string_view name) const
+int32_t Shader::findUniformLocation(std::string_view name)
 {
+	// Cache uniform locations, prevent going to the GPU every call
+	if (m_uniformLocation.find(name) != m_uniformLocation.end()) {
+		return m_uniformLocation[name];
+	}
+
 	int32_t location = glGetUniformLocation(m_id, name.data());
 	VERIFY(location != -1, "Shader could not find uniform '{}'", name);
+	m_uniformLocation[name] = location;
+
 	return location;
 }
 
 void Shader::setInt(std::string_view name, int value)
 {
 	// Set uniform int
-	glUniform1i(findUniform(name), value);
+	glUniform1i(findUniformLocation(name), value);
 }
 
 void Shader::setInt(std::string_view name, int* values, uint32_t count)
 {
 	// Set uniform int array
-	glUniform1iv(findUniform(name), count, values);
+	glUniform1iv(findUniformLocation(name), count, values);
 }
 
-void Shader::setFloat(std::string_view name, float value) const
+void Shader::setFloat(std::string_view name, float value)
 {
 	// Set uniform float
-	glUniform1f(findUniform(name), value);
+	glUniform1f(findUniformLocation(name), value);
 }
 
-void Shader::setFloat(std::string_view name, float v1, float v2, float v3, float v4) const
+void Shader::setFloat(std::string_view name, float v1, float v2, float v3, float v4)
 {
 	// Set uniform vec4 data
-	glUniform4f(findUniform(name), v1, v2, v3, v4);
+	glUniform4f(findUniformLocation(name), v1, v2, v3, v4);
 }
 
-void Shader::setFloat(std::string_view name, glm::vec2 value) const
+void Shader::setFloat(std::string_view name, glm::vec2 value)
 {
 	// Set uniform vec2 data
-	glUniform2f(findUniform(name), value.x, value.y);
+	glUniform2f(findUniformLocation(name), value.x, value.y);
 }
 
-void Shader::setFloat(std::string_view name, glm::vec3 value) const
+void Shader::setFloat(std::string_view name, glm::vec3 value)
 {
 	// Set uniform vec3 data
-	glUniform3f(findUniform(name), value.x, value.y, value.z);
+	glUniform3f(findUniformLocation(name), value.x, value.y, value.z);
 }
 
-void Shader::setFloat(std::string_view name, glm::vec4 value) const
+void Shader::setFloat(std::string_view name, glm::vec4 value)
 {
 	// Set uniform vec4 data
-	glUniform4f(findUniform(name), value.x, value.y, value.z, value.w);
+	glUniform4f(findUniformLocation(name), value.x, value.y, value.z, value.w);
 }
 
-void Shader::setFloat(std::string_view name, glm::mat3 matrix) const
+void Shader::setFloat(std::string_view name, glm::mat3 matrix)
 {
 	// Set uniform mat3 data
-	glUniformMatrix3fv(findUniform(name), 1, GL_FALSE, glm::value_ptr(matrix));
+	glUniformMatrix3fv(findUniformLocation(name), 1, GL_FALSE, glm::value_ptr(matrix));
 }
 
-void Shader::setFloat(std::string_view name, glm::mat4 matrix) const
+void Shader::setFloat(std::string_view name, glm::mat4 matrix)
 {
 	// Set uniform mat4 data
-	glUniformMatrix4fv(findUniform(name), 1, GL_FALSE, glm::value_ptr(matrix));
+	glUniformMatrix4fv(findUniformLocation(name), 1, GL_FALSE, glm::value_ptr(matrix));
 }
 
 void Shader::bind() const
diff --git a/src/inferno/asset/shader.h b/src/inferno/asset/shader.h
index f4458f0..d0aada6 100644
--- a/src/inferno/asset/shader.h
+++ b/src/inferno/asset/shader.h
@@ -6,6 +6,7 @@
 
 #include <cstdint> // int32_t, uint32_t
 #include <string_view>
+#include <unordered_map>
 
 #include "glm/fwd.hpp" // glm::mat3, glm::mat4, glm::vec2, glm::vec3
 
@@ -20,17 +21,17 @@ public:
 	// Factory function
 	static std::shared_ptr<Shader> create(std::string_view path);
 
-	int32_t findUniform(std::string_view name) const;
+	int32_t findUniformLocation(std::string_view name);
 
 	void setInt(std::string_view name, int value);
 	void setInt(std::string_view name, int* values, uint32_t count);
-	void setFloat(std::string_view name, float value) const;
-	void setFloat(std::string_view name, float v1, float v2, float v3, float v4) const;
-	void setFloat(std::string_view name, glm::vec2 value) const;
-	void setFloat(std::string_view name, glm::vec3 value) const;
-	void setFloat(std::string_view name, glm::vec4 value) const;
-	void setFloat(std::string_view name, glm::mat3 matrix) const;
-	void setFloat(std::string_view name, glm::mat4 matrix) const;
+	void setFloat(std::string_view name, float value);
+	void setFloat(std::string_view name, float v1, float v2, float v3, float v4);
+	void setFloat(std::string_view name, glm::vec2 value);
+	void setFloat(std::string_view name, glm::vec3 value);
+	void setFloat(std::string_view name, glm::vec4 value);
+	void setFloat(std::string_view name, glm::mat3 matrix);
+	void setFloat(std::string_view name, glm::mat4 matrix);
 
 	void bind() const;
 	void unbind() const;
@@ -52,6 +53,7 @@ private:
 
 private:
 	uint32_t m_id { 0 };
+	std::unordered_map<std::string_view, int32_t> m_uniformLocation;
 };
 
 // -----------------------------------------