Move some heap code to using the stack.

src/main.cc

@@ -3,7 +3,6 @@
 
 #include <iostream>
 #include <format>
-#include <memory>
 
 #include "shader.hh"
 #include "utilities.hh"
@@ -21,11 +20,7 @@ struct GlRenderObjects {
 	unsigned int vertexBufferObject;
 	unsigned int vertexArrayObject;
 	unsigned int elementBufferObject;
-	GlRenderObjects(unsigned int vbo, unsigned int vao, unsigned int ebo) {
+
-		vertexBufferObject = vbo;
-		vertexArrayObject = vao;
-		elementBufferObject = ebo;
-	}
 	~GlRenderObjects() {
 		glDeleteBuffers(1, &vertexBufferObject);
 		glDeleteVertexArrays(1, &vertexArrayObject);
@@ -33,7 +28,7 @@ struct GlRenderObjects {
 	}
 };
 
-GlRenderObjects* triangle() {
+GlRenderObjects triangle() {
 	// An array of verticies containing data for a triangle.
 	float vertices[] = {
 		// positions		// colors		// texture coords
@@ -75,10 +70,10 @@ GlRenderObjects* triangle() {
 	glBindBuffer(GL_ARRAY_BUFFER, 0);
 	glBindVertexArray(0);
 
-	return new GlRenderObjects(vertexBufferObject, vertexArrayObject, 0);
+	return {vertexArrayObject, vertexArrayObject, 0};
 }
 
-GlRenderObjects* rectangle() {
+GlRenderObjects rectangle() {
 	float vertices[] = {
 		// positions		// colors		// texture coords
 		0.5f,  0.5f, 0.0f,	1.0f, 0.0f, 0.0f,	1.0f, 1.0f,
@@ -129,12 +124,38 @@ GlRenderObjects* rectangle() {
 	glBindVertexArray(0);
 	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
 
-	return new GlRenderObjects(vertexBufferObject, vertexArrayObject, elementBufferObject);
+	return {vertexBufferObject, vertexArrayObject, elementBufferObject};
+}
+
+void createTexture(uint* textureInt, const char* path, GLenum imageType, GLenum minFilter, GLenum magFilter) {
+	// Create a texture ID and assign it to the textureInt pointer.
+	glGenTextures(1, textureInt);
+	// Bind that texture to the GL_TEXTURE_2D state.
+	glBindTexture(GL_TEXTURE_2D, *textureInt);
+
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, minFilter);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, magFilter);
+
+	Image texture(utilities::getCurrentPath(path));
+	if (texture.data) {
+		// Read the texture data and assign it to the GL texture.
+		glTexImage2D(GL_TEXTURE_2D, 0, imageType, texture.width, texture.height, 0, imageType, GL_UNSIGNED_BYTE, texture.data);
+		// Generate a mipmap of the texture data.
+		glGenerateMipmap(GL_TEXTURE_2D);
+	} else {
+		std::cout << "Failed to load texture." << std::endl;
+	}
 }
 
 int main() {
 	glfwInit();
 
+// These brackets are a RAII (Resource Acquisition Is Initialization) pattern,
+// which means these brackets are its own "scope" which means stack allocated memory
+// and heap allocated memory wrapped in a smart pointer like unique_ptr will be cleaned
+// up after you go out of scope.
 {
 	// Set OpenGL version to 3.3.
 	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
@@ -166,48 +187,14 @@ int main() {
 	// Create a shader class.
 	Shader shader(std::format("{}/vertex.glsl", currentPath).c_str(), std::format("{}/fragment.glsl", currentPath).c_str());
 
-	std::unique_ptr<GlRenderObjects> triangleRenderObjs(triangle());
+	GlRenderObjects triangleRenderObjs = triangle();
-	std::unique_ptr<GlRenderObjects> rectangleRenderObjs(rectangle());
+	GlRenderObjects rectangleRenderObjs = rectangle();
 
 	unsigned int texture1, texture2;
+
+	createTexture(&texture1, "container.jpg", GL_RGB, GL_LINEAR_MIPMAP_LINEAR, GL_LINEAR);
+	createTexture(&texture2, "awesomeface.png", GL_RGBA, GL_LINEAR, GL_LINEAR);
 	
-{
-	glGenTextures(1, &texture1);
-	glBindTexture(GL_TEXTURE_2D, texture1);
-
-	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
-	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
-	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
-	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-
-	Image texture(utilities::getCurrentPath("container.jpg"));
-	if (texture.data) {
-		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, texture.width, texture.height, 0, GL_RGB, GL_UNSIGNED_BYTE, texture.data);
-		glGenerateMipmap(GL_TEXTURE_2D);
-	} else {
-		std::cout << "Failed to load texture." << std::endl;
-	}
-}
-
-{
-	glGenTextures(1, &texture2);
-	glBindTexture(GL_TEXTURE_2D, texture2);
-
-	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
-	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
-	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
-	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-
-	Image texture(utilities::getCurrentPath("awesomeface.png"));
-
-	if (texture.data) {
-		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texture.width, texture.height, 0, GL_RGBA, GL_UNSIGNED_BYTE, texture.data);
-		glGenerateMipmap(GL_TEXTURE_2D);
-	} else {
-		std::cout << "Failed to load texture." << std::endl;
-	}
-}
-
 	// activate the shader
 	shader.activate();
 
@@ -227,8 +214,11 @@ int main() {
 		// Clear the screen and use the color from the state.
 		glClear(GL_COLOR_BUFFER_BIT);
 
+		// assign texture1 to the GL_TEXTURE0 texture unit.
 		glActiveTexture(GL_TEXTURE0);
 		glBindTexture(GL_TEXTURE_2D, texture1);
+
+		// assign texture1 to the GL_TEXTURE1 texture unit.
 		glActiveTexture(GL_TEXTURE1);
 		glBindTexture(GL_TEXTURE_2D, texture2);
 
@@ -236,12 +226,12 @@ int main() {
 
 		if (!rectangleToggled) {
 			// Bind the state to use the vertexArrayObject object so OpenGL knows what to do with the verticies.
-			glBindVertexArray(triangleRenderObjs->vertexArrayObject);
+			glBindVertexArray(triangleRenderObjs.vertexArrayObject);
 			// Draw the verticies with the first index being 0 and the size of the vertex being 3 floats.
 			glDrawArrays(GL_TRIANGLES, 0, 3);
 			glBindVertexArray(0);
 		} else {
-			glBindVertexArray(rectangleRenderObjs->vertexArrayObject);
+			glBindVertexArray(rectangleRenderObjs.vertexArrayObject);
 			// Draw 6 elements (indices) that are unsigned ints.
 			glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
 			glBindVertexArray(0);

src/utilities.cc

@@ -3,7 +3,7 @@
 #include <string>
 #include <sstream>
 #include <unistd.h>
-#include <linux/limits.h>
+#include <limits.h>
 #include <format>
 
 std::string utilities::getCurrentPath() {