Overlay a transparent meme over the crate texture.

src/fragment.glsl

@@ -5,8 +5,9 @@ out vec4 FragColor;
 in vec3 ourColor;
 in vec2 TexCoord;
 
-uniform sampler2D ourTexture;
+uniform sampler2D texture1;
+uniform sampler2D texture2;
 
 void main() {
-	FragColor = texture(ourTexture, TexCoord);
+	FragColor = mix(texture(texture1, TexCoord), texture(texture2, TexCoord), 0.2);
 }

src/image.cc

@@ -1,8 +1,9 @@
 #include "image.hh"
 #include <stb/stb_image.h>
 
-Image::Image(const char* path) {
-	data = stbi_load(path, &width, &height, &nrChannels, 0);
+Image::Image(std::string path) {
+	stbi_set_flip_vertically_on_load(true);
+	data = stbi_load(path.c_str(), &width, &height, &nrChannels, 0);
 }
 
 Image::~Image() {

src/image.hh

@@ -1,11 +1,12 @@
 #ifndef IMAGE_HH
 #define IMAGE_HH
+#include <string>
 #define STB_IMAGE_IMPLEMENTATION
 class Image {
 	public:
 		int width, height, nrChannels;
 		unsigned char* data;
-		Image(const char* path);
+		Image(std::string path);
 		~Image();
 };
 #endif

src/main.cc

@@ -3,6 +3,7 @@
 
 #include <iostream>
 #include <format>
+#include <memory>
 
 #include "shader.hh"
 #include "utilities.hh"
@@ -134,6 +135,7 @@ GlRenderObjects* rectangle() {
 int main() {
 	glfwInit();
 
+{
 	// Set OpenGL version to 3.3.
 	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
 	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
@@ -162,29 +164,56 @@ int main() {
 	std::string currentPath = utilities::getCurrentPath();
 
 	// Create a shader class.
-	Shader* shader = new Shader(std::format("{}/vertex.glsl", currentPath).c_str(), std::format("{}/fragment.glsl", currentPath).c_str());
+	Shader shader(std::format("{}/vertex.glsl", currentPath).c_str(), std::format("{}/fragment.glsl", currentPath).c_str());
 
-	GlRenderObjects* triangleRenderObjs = triangle();
-	GlRenderObjects* rectangleRenderObjs = rectangle();
+	std::unique_ptr<GlRenderObjects> triangleRenderObjs(triangle());
+	std::unique_ptr<GlRenderObjects> rectangleRenderObjs(rectangle());
 
-	unsigned int texture;
-	glGenTextures(1, &texture);
-	glBindTexture(GL_TEXTURE_2D, texture);
+	unsigned int texture1, texture2;
+	
+{
+	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(std::format("{}/container.jpg", utilities::getCurrentPath()).c_str());
-		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;
-		}
+	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();
+
+	// tell the shader what texture unit the textures are on
+	shader.setInt("texture1", 0);
+	shader.setInt("texture2", 1);
 
 	// Create a render loop, which keeps the program open until glfw tells the loop that the window should close.
 	while (!glfwWindowShouldClose(window)) {
@@ -198,8 +227,12 @@ int main() {
 		// Clear the screen and use the color from the state.
 		glClear(GL_COLOR_BUFFER_BIT);
 
-		// activate the shader
-		shader->activate();
+		glActiveTexture(GL_TEXTURE0);
+		glBindTexture(GL_TEXTURE_2D, texture1);
+		glActiveTexture(GL_TEXTURE1);
+		glBindTexture(GL_TEXTURE_2D, texture2);
+
+		shader.activate();
 
 		if (!rectangleToggled) {
 			// Bind the state to use the vertexArrayObject object so OpenGL knows what to do with the verticies.
@@ -219,11 +252,7 @@ int main() {
 		// Check if any events are triggered.
 		glfwPollEvents();
 	}
-
-	// Clean up objects from memory.
-	delete triangleRenderObjs;
-	delete rectangleRenderObjs;
-	delete shader;
+}
 
 	glfwTerminate();
 	return 0;

src/meson.build

@@ -10,6 +10,7 @@ copy = find_program('cp')
 fragment = custom_target('fragment', output: 'fragment.glsl', input: 'fragment.glsl', command: [copy, '@INPUT@', '@OUTPUT@'])
 vertex = custom_target('vertex', output: 'vertex.glsl', input: 'vertex.glsl', command: [copy, '@INPUT@', '@OUTPUT@'])
 container = custom_target('container', output: 'container.jpg', input: 'container.jpg', command: [copy, '@INPUT@', '@OUTPUT@'])
+awesomeface = custom_target('awesomeface', output: 'awesomeface.png', input: 'awesomeface.png', command: [copy, '@INPUT@', '@OUTPUT@'])
 
-executable('main', [sources] + [fragment, vertex, container], dependencies: [glfw, libepoxy])
+executable('main', [sources, fragment, vertex, container, awesomeface], dependencies: [glfw, libepoxy])
 executable('fixedfunction', ['fixedfunction.cc'], dependencies: [glfw, libepoxy])

src/shader.cc

@@ -94,12 +94,12 @@ void Shader::activate() {
 	glUseProgram(id);
 }
 
-void Shader::setBool(const std::string &name, bool value) const {
-	glUniform1f(glGetUniformLocation(id, name.c_str()), (int)value);
+void Shader::setBool(const char* name, bool value) const {
+	glUniform1i(glGetUniformLocation(id, name), (int)value);
 }
-void Shader::setInt(const std::string &name, int value) const {
-	glUniform1f(glGetUniformLocation(id, name.c_str()), value);
+void Shader::setInt(const char* name, int value)  {
+	glUniform1i(glGetUniformLocation(id, name), value);
 }
-void Shader::setFloat(const std::string &name, float value) const {
-	glUniform1f(glGetUniformLocation(id, name.c_str()), value);
+void Shader::setFloat(const char* name, float value) const {
+	glUniform1f(glGetUniformLocation(id, name), value);
 }

src/shader.hh

@@ -14,9 +14,9 @@ class Shader {
 	// activate the shader.
 	void activate();
     // utility uniform functions
-	void setBool(const std::string &name, bool value) const;  
-	void setInt(const std::string &name, int value) const;   
-	void setFloat(const std::string &name, float value) const;
+	void setBool(const char* name, bool value) const;  
+	void setInt(const char* name, int value) ;   
+	void setFloat(const char* name, float value) const;
 	private:
 	uint compileShader(std::string code, GLenum type, std::string shaderTypeName);
 	uint compileVertexShader(std::string code);

src/utilities.cc

@@ -4,6 +4,7 @@
 #include <sstream>
 #include <unistd.h>
 #include <linux/limits.h>
+#include <format>
 
 std::string utilities::getCurrentPath() {
 	char result[PATH_MAX];
@@ -14,6 +15,10 @@ std::string utilities::getCurrentPath() {
 	return utilities::combineString(stringVector, '/');
 }
 
+std::string utilities::getCurrentPath(std::string file) {
+	return std::format("{}/{}", getCurrentPath(), file);
+}
+
 std::vector<std::string> utilities::splitString(std::string string, char delimiter) {
 	size_t last = 0;
 	size_t next = 0;

src/utilities.hh

@@ -5,6 +5,7 @@
 
 namespace utilities {
 	std::string getCurrentPath();
+	std::string getCurrentPath(std::string file);
 	std::vector<std::string> splitString(std::string string, char delimiter);
 	std::string combineString(std::vector<std::string> stringVector, char delimiter);
 }