Complete code re-work 'Getting Started' tutorials.

src/1.getting_started/4.5.textures_exercise4/4.5.texture.fs

@@ -0,0 +1,17 @@
+#version 330 core
+out vec4 fragColor;
+
+in vec3 ourColor;
+in vec2 texCoord;
+
+uniform float mixValue;
+
+// texture samplers
+uniform sampler2D texture1;
+uniform sampler2D texture2;
+
+void main()
+{
+	// linearly interpolate between both textures
+	fragColor = mix(texture(texture1, texCoord), texture(texture2, texCoord), mixValue);
+}

src/1.getting_started/4.5.textures_exercise4/4.5.texture.vs

@@ -0,0 +1,14 @@
+#version 330 core
+layout (location = 0) in vec3 aPos;
+layout (location = 1) in vec3 aColor;
+layout (location = 2) in vec2 aTexCoord;
+
+out vec3 ourColor;
+out vec2 texCoord;
+
+void main()
+{
+	gl_Position = vec4(aPos, 1.0f);
+	ourColor = aColor;
+	texCoord = vec2(aTexCoord.x, aTexCoord.y);
+}

src/1.getting_started/4.5.textures_exercise4/textures_exercise4.cpp

@@ -0,0 +1,222 @@
+#include <glad/glad.h>
+#include <GLFW/glfw3.h>
+#include <stb_image.h>
+
+#include <learnopengl/filesystem.h>
+#include <learnopengl/shader_s.h>
+
+#include <iostream>
+
+void framebuffer_size_callback(GLFWwindow* window, int width, int height);
+void processInput(GLFWwindow *window);
+
+// stores how much we're seeing of either texture
+float mixValue = 0.2f;
+
+int main()
+{
+    // glfw: initialize and configure
+    // ------------------------------
+    glfwInit();
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
+    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
+    //glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // uncomment this statement to fix compilation on OS X
+
+    // glfw window creation
+    // --------------------
+    GLFWwindow* window = glfwCreateWindow(800, 600, "LearnOpenGL", NULL, NULL);
+    glfwMakeContextCurrent(window);
+    if (window == NULL)
+    {
+        std::cout << "Failed to create GLFW window" << std::endl;
+        glfwTerminate();
+        return -1;
+    }
+    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
+
+    // glad: load all OpenGL function pointers
+    // ---------------------------------------
+    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
+    {
+        std::cout << "Failed to initialize GLAD" << std::endl;
+        return -1;
+    }
+
+
+    // build and compile our shader zprogram
+    // ------------------------------------
+    Shader ourShader("4.5.texture.vs", "4.5.texture.fs");
+
+    // set up vertex data (and buffer(s)) and configure vertex attributes
+    // ------------------------------------------------------------------
+    float vertices[] = {
+        // positions          // colors           // texture coords
+         0.5f,  0.5f, 0.0f,   1.0f, 0.0f, 0.0f,   1.0f, 1.0f, // top right
+         0.5f, -0.5f, 0.0f,   0.0f, 1.0f, 0.0f,   1.0f, 0.0f, // bottom right
+        -0.5f, -0.5f, 0.0f,   0.0f, 0.0f, 1.0f,   0.0f, 0.0f, // bottom left
+        -0.5f,  0.5f, 0.0f,   1.0f, 1.0f, 0.0f,   0.0f, 1.0f  // top left 
+    };
+    unsigned int indices[] = {
+        0, 1, 3, // first triangle
+        1, 2, 3  // second triangle
+    };
+    unsigned int VBO, VAO, EBO;
+    glGenVertexArrays(1, &VAO);
+    glGenBuffers(1, &VBO);
+    glGenBuffers(1, &EBO);
+
+    glBindVertexArray(VAO);
+
+    glBindBuffer(GL_ARRAY_BUFFER, VBO);
+    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
+    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
+
+    // position attribute
+    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
+    glEnableVertexAttribArray(0);
+    // color attribute
+    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
+    glEnableVertexAttribArray(1);
+    // texture coord attribute
+    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
+    glEnableVertexAttribArray(2);
+
+
+    // load and create a texture 
+    // -------------------------
+    unsigned int texture1, texture2;
+    // texture 1
+    // ---------
+    glGenTextures(1, &texture1);
+    glBindTexture(GL_TEXTURE_2D, texture1);
+    // set the texture wrapping parameters
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);	// set texture wrapping to GL_REPEAT (default wrapping method)
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+    // set texture filtering parameters
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+    // load image, create texture and generate mipmaps
+    int width, height, nrComponents;
+    stbi_set_flip_vertically_on_load(true); // tell stb_image.h to flip loaded texture's on the y-axis.
+    unsigned char *data = stbi_load(FileSystem::getPath("resources/textures/container.jpg").c_str(), &width, &height, &nrComponents, 0);
+    if (data)
+    {
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
+        glGenerateMipmap(GL_TEXTURE_2D);
+    }
+    else
+    {
+        std::cout << "Failed to load texture" << std::endl;
+    }
+    stbi_image_free(data);
+    // texture 2
+    // ---------
+    glGenTextures(1, &texture2);
+    glBindTexture(GL_TEXTURE_2D, texture2);
+    // set the texture wrapping parameters
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);	// set texture wrapping to GL_REPEAT (default wrapping method)
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+    // set texture filtering parameters
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+    // load image, create texture and generate mipmaps
+    data = stbi_load(FileSystem::getPath("resources/textures/awesomeface.png").c_str(), &width, &height, &nrComponents, 0);
+    if (data)
+    {
+        // note that the awesomeface.png has transparency and thus an alpha channel, so make sure to tell OpenGL the data type is of GL_RGBA
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
+        glGenerateMipmap(GL_TEXTURE_2D);
+    }
+    else
+    {
+        std::cout << "Failed to load texture" << std::endl;
+    }
+    stbi_image_free(data);
+
+    // tell opengl for each sampler to which texture unit it belongs to (only has to be done once)
+    // -------------------------------------------------------------------------------------------
+    ourShader.use(); // don't forget to activate/use the shader before setting uniforms!
+    // either set it manually like so:
+    glUniform1i(glGetUniformLocation(ourShader.ID, "texture1"), 0);
+    // or set it via the texture class
+    ourShader.setInt("texture2", 1);
+
+
+
+    // render loop
+    // -----------
+    while (!glfwWindowShouldClose(window))
+    {
+        // input
+        // -----
+        processInput(window);
+
+        // render
+        // ------
+        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
+        glClear(GL_COLOR_BUFFER_BIT);
+
+        // bind textures on corresponding texture units
+        glActiveTexture(GL_TEXTURE0);
+        glBindTexture(GL_TEXTURE_2D, texture1);
+        glActiveTexture(GL_TEXTURE1);
+        glBindTexture(GL_TEXTURE_2D, texture2);
+
+        // set the texture mix value in the shader
+        ourShader.setFloat("mixValue", mixValue);
+
+        // render container
+        ourShader.use();
+        glBindVertexArray(VAO);
+        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
+
+        // glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
+        // -------------------------------------------------------------------------------
+        glfwSwapBuffers(window);
+        glfwPollEvents();
+    }
+
+    // optional: de-allocate all resources once they've outlived their purpose:
+    // ------------------------------------------------------------------------
+    glDeleteVertexArrays(1, &VAO);
+    glDeleteBuffers(1, &VBO);
+    glDeleteBuffers(1, &EBO);
+
+    // glfw: terminate, clearing all previously allocated GLFW resources.
+    // ------------------------------------------------------------------
+    glfwTerminate();
+    return 0;
+}
+
+// process all input: query GLFW whether relevant keys are pressed/released this frame and react accordingly
+// ---------------------------------------------------------------------------------------------------------
+void processInput(GLFWwindow *window)
+{
+    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
+        glfwSetWindowShouldClose(window, true);
+
+    if (glfwGetKey(window, GLFW_KEY_UP) == GLFW_PRESS)
+    {
+        mixValue += 0.001f; // change this value accordingly (might be too slow or too fast based on system hardware)
+        if(mixValue >= 1.0f)
+            mixValue = 1.0f;
+    }
+    if (glfwGetKey(window, GLFW_KEY_DOWN) == GLFW_PRESS)
+    {
+        mixValue -= 0.001f; // change this value accordingly (might be too slow or too fast based on system hardware)
+        if (mixValue <= 0.0f)
+            mixValue = 0.0f;
+    }
+}
+
+// glfw: whenever the window size changed (by OS or user resize) this callback function executes
+// ---------------------------------------------------------------------------------------------
+void framebuffer_size_callback(GLFWwindow* window, int width, int height)
+{
+    // make sure the viewport matches the new window dimensions; note that width and 
+    // height will be significantly larger than specified on retina displays.
+    glViewport(0, 0, width, height);
+}