Added Parallax Mapping code/resources

Added code samples and necessary texture resources for upcoming Parallax
Mapping tutorial

CMakeLists.txt

@@ -112,7 +112,7 @@ set(5.advanced_lighting
     3.2.point_shadows
     # 3.3.csm
     4.normal_mapping
-    # 5.parallax_mapping
+    5.parallax_mapping
     # 6.hdr
     # 7.bloom
     # 8.deferred_shading

includes/learnopengl/mesh.h

@@ -58,6 +58,7 @@ public:
         GLuint diffuseNr = 1;
         GLuint specularNr = 1;
         GLuint normalNr = 1;
+        GLuint heightNr = 1;
         for(GLuint i = 0; i < this->textures.size(); i++)
         {
             glActiveTexture(GL_TEXTURE0 + i); // Active proper texture unit before binding
@@ -71,6 +72,8 @@ public:
                 ss << specularNr++; // Transfer GLuint to stream
             else if(name == "texture_normal")
                 ss << normalNr++; // Transfer GLuint to stream
+             else if(name == "texture_height")
+                ss << heightNr++; // Transfer GLuint to stream
             number = ss.str(); 
             // Now set the sampler to the correct texture unit
             glUniform1i(glGetUniformLocation(shader.Program, (name + number).c_str()), i);

includes/learnopengl/model.h

@@ -157,6 +157,9 @@ private:
             // 3. Normal maps
             std::vector<Texture> normalMaps = this->loadMaterialTextures(material, aiTextureType_HEIGHT, "texture_normal");
             textures.insert(textures.end(), normalMaps.begin(), normalMaps.end());
+            // 4. Height maps
+            std::vector<Texture> heightMaps = this->loadMaterialTextures(material, aiTextureType_AMBIENT, "texture_height");
+            textures.insert(textures.end(), heightMaps.begin(), heightMaps.end());
         }
         
         // Return a mesh object created from the extracted mesh data

src/5.advanced_lighting/5.parallax_mapping/parallax_mapping.cpp

@@ -11,6 +11,7 @@
 // GL includes
 #include <learnopengl/shader.h>
 #include <learnopengl/camera.h>
+#include <learnopengl/model.h>
 
 // GLM Mathemtics
 #include <glm/glm.hpp>
@@ -21,7 +22,7 @@
 #include <SOIL.h>
 
 // Properties
-GLuint screenWidth = 800, screenHeight = 600;
+const GLuint SCR_WIDTH = 800, SCR_HEIGHT = 600;
 
 // Function prototypes
 void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode);
@@ -29,16 +30,17 @@ void scroll_callback(GLFWwindow* window, double xoffset, double yoffset);
 void mouse_callback(GLFWwindow* window, double xpos, double ypos);
 void Do_Movement();
 GLuint loadTexture(GLchar* path);
+void RenderQuad();
 
 // Camera
 Camera camera(glm::vec3(0.0f, 0.0f, 3.0f));
-bool keys[1024];
-GLfloat lastX = 400, lastY = 300;
-bool firstMouse = true;
 
 GLfloat deltaTime = 0.0f;
 GLfloat lastFrame = 0.0f;
 
+GLboolean parallax_mapping = true;
+GLfloat height_scale = 0.1;
+
 // The MAIN function, from here we start our application and run our Game loop
 int main()
 {
@@ -49,7 +51,7 @@ int main()
     glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
     glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
 
-    GLFWwindow* window = glfwCreateWindow(screenWidth, screenHeight, "LearnOpenGL", nullptr, nullptr); // Windowed
+    GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", nullptr, nullptr); // Windowed
     glfwMakeContextCurrent(window);
 
     // Set the required callback functions
@@ -65,100 +67,30 @@ int main()
     glewInit();
 
     // Define the viewport dimensions
-    glViewport(0, 0, screenWidth, screenHeight);
+    glViewport(0, 0, SCR_WIDTH, SCR_HEIGHT);
 
     // Setup some OpenGL options
     glEnable(GL_DEPTH_TEST);
-    // glDepthFunc(GL_ALWAYS); // Set to always pass the depth test (same effect as glDisable(GL_DEPTH_TEST))
 
     // Setup and compile our shaders
-    Shader shader("depth_testing.vs", "depth_testing.frag");
+    Shader shader("parallax_mapping.vs", "parallax_mapping.frag");
-
-    #pragma region "object_initialization"
-    // Set the object data (buffers, vertex attributes)
-    GLfloat cubeVertices[] = {
-        // Positions          // Texture Coords
-        -0.5f, -0.5f, -0.5f,  0.0f, 0.0f,
-         0.5f, -0.5f, -0.5f,  1.0f, 0.0f,
-         0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
-         0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
-        -0.5f,  0.5f, -0.5f,  0.0f, 1.0f,
-        -0.5f, -0.5f, -0.5f,  0.0f, 0.0f,
-
-        -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
-         0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
-         0.5f,  0.5f,  0.5f,  1.0f, 1.0f,
-         0.5f,  0.5f,  0.5f,  1.0f, 1.0f,
-        -0.5f,  0.5f,  0.5f,  0.0f, 1.0f,
-        -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
-
-        -0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
-        -0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
-        -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
-        -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
-        -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
-        -0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
-
-         0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
-         0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
-         0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
-         0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
-         0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
-         0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
-
-        -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
-         0.5f, -0.5f, -0.5f,  1.0f, 1.0f,
-         0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
-         0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
-        -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
-        -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
-
-        -0.5f,  0.5f, -0.5f,  0.0f, 1.0f,
-         0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
-         0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
-         0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
-        -0.5f,  0.5f,  0.5f,  0.0f, 0.0f,
-        -0.5f,  0.5f, -0.5f,  0.0f, 1.0f
-    };
-    GLfloat planeVertices[] = {
-        // Positions            // Texture Coords (note we set these higher than 1 that together with GL_REPEAT as texture wrapping mode will cause the floor texture to repeat)
-        5.0f,  -0.5f,  5.0f,  2.0f, 0.0f,
-        -5.0f, -0.5f,  5.0f,  0.0f, 0.0f,
-        -5.0f, -0.5f, -5.0f,  0.0f, 2.0f,
-
-        5.0f,  -0.5f,  5.0f,  2.0f, 0.0f,
-        -5.0f, -0.5f, -5.0f,  0.0f, 2.0f,
-        5.0f,  -0.5f, -5.0f,  2.0f, 2.0f								
-    };
-    // Setup cube VAO
-    GLuint cubeVAO, cubeVBO;
-    glGenVertexArrays(1, &cubeVAO);
-    glGenBuffers(1, &cubeVBO);
-    glBindVertexArray(cubeVAO);
-    glBindBuffer(GL_ARRAY_BUFFER, cubeVBO);
-    glBufferData(GL_ARRAY_BUFFER, sizeof(cubeVertices), &cubeVertices, GL_STATIC_DRAW);
-    glEnableVertexAttribArray(0);
-    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), (GLvoid*)0);
-    glEnableVertexAttribArray(1);
-    glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
-    glBindVertexArray(0);
-    // Setup plane VAO
-    GLuint planeVAO, planeVBO;
-    glGenVertexArrays(1, &planeVAO);
-    glGenBuffers(1, &planeVBO);
-    glBindVertexArray(planeVAO);
-    glBindBuffer(GL_ARRAY_BUFFER, planeVBO);
-    glBufferData(GL_ARRAY_BUFFER, sizeof(planeVertices), &planeVertices, GL_STATIC_DRAW);
-    glEnableVertexAttribArray(0);
-    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), (GLvoid*)0);
-    glEnableVertexAttribArray(1);
-    glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
-    glBindVertexArray(0);
 
     // Load textures
-    GLuint cubeTexture = loadTexture("../../../resources/textures/marble.jpg");
+    GLuint diffuseMap = loadTexture("../../../resources/textures/bricks2.jpg");
-    GLuint floorTexture = loadTexture("../../../resources/textures/metal.png");
+	GLuint normalMap = loadTexture("../../../resources/textures/bricks2_normal.jpg");
-    #pragma endregion
+	GLuint heightMap = loadTexture("../../../resources/textures/bricks2_disp.jpg");
+    //GLuint diffuseMap = loadTexture("../../../resources/textures/wood.png");
+    //GLuint normalMap = loadTexture("../../../resources/textures/toy_box_normal.png");
+    //GLuint heightMap = loadTexture("../../../resources/textures/toy_box_disp.png");
+
+    // Set texture units 
+    shader.Use();
+    glUniform1i(glGetUniformLocation(shader.Program, "diffuseMap"), 0);
+	glUniform1i(glGetUniformLocation(shader.Program, "normalMap"), 1);
+	glUniform1i(glGetUniformLocation(shader.Program, "depthMap"), 2);
+
+    // Light position
+    glm::vec3 lightPos(0.5f, 1.0f, 0.3f);
 
     // Game loop
     while (!glfwWindowShouldClose(window))
@@ -176,31 +108,34 @@ int main()
         glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
-        // Draw objects
+        // Configure view/projection matrices
         shader.Use();
-        glm::mat4 model;
         glm::mat4 view = camera.GetViewMatrix();
-        glm::mat4 projection = glm::perspective(camera.Zoom, (float)screenWidth/(float)screenHeight, 0.1f, 100.0f);
+        glm::mat4 projection = glm::perspective(camera.Zoom, (GLfloat)SCR_WIDTH / (GLfloat)SCR_HEIGHT, 0.1f, 100.0f);
         glUniformMatrix4fv(glGetUniformLocation(shader.Program, "view"), 1, GL_FALSE, glm::value_ptr(view));
         glUniformMatrix4fv(glGetUniformLocation(shader.Program, "projection"), 1, GL_FALSE, glm::value_ptr(projection));
-        // Cubes
+        // Render normal-mapped quad
-        glBindVertexArray(cubeVAO);
+        glm::mat4 model;
-        glBindTexture(GL_TEXTURE_2D, cubeTexture);  // We omit the glActiveTexture part since TEXTURE0 is already the default active texture unit. (sampler used in fragment is set to 0 as well as default)		
+        model = glm::rotate(model, (GLfloat)glfwGetTime() * -10, glm::normalize(glm::vec3(1.0, 0.0, 1.0))); // Rotates the quad to show parallax mapping works in all directions
-        model = glm::translate(model, glm::vec3(-1.0f, 0.0f, -1.0f));
         glUniformMatrix4fv(glGetUniformLocation(shader.Program, "model"), 1, GL_FALSE, glm::value_ptr(model));
-        glDrawArrays(GL_TRIANGLES, 0, 36);
+        glUniform3fv(glGetUniformLocation(shader.Program, "lightPos"), 1, &lightPos[0]);
-        model = glm::mat4();
+		glUniform3fv(glGetUniformLocation(shader.Program, "viewPos"), 1, &camera.Position[0]);
-        model = glm::translate(model, glm::vec3(2.0f, 0.0f, 0.0f));
+		glUniform1f(glGetUniformLocation(shader.Program, "height_scale"), height_scale);
-        glUniformMatrix4fv(glGetUniformLocation(shader.Program, "model"), 1, GL_FALSE, glm::value_ptr(model));
+		glUniform1i(glGetUniformLocation(shader.Program, "parallax"), parallax_mapping);
-        glDrawArrays(GL_TRIANGLES, 0, 36);
+        glActiveTexture(GL_TEXTURE0);
-        // Floor
+        glBindTexture(GL_TEXTURE_2D, diffuseMap);
-        glBindVertexArray(planeVAO);
+        glActiveTexture(GL_TEXTURE1);
-        glBindTexture(GL_TEXTURE_2D, floorTexture);
+        glBindTexture(GL_TEXTURE_2D, normalMap);
-        model = glm::mat4();
+		glActiveTexture(GL_TEXTURE2);
-        glUniformMatrix4fv(glGetUniformLocation(shader.Program, "model"), 1, GL_FALSE, glm::value_ptr(model));
+		glBindTexture(GL_TEXTURE_2D, heightMap);
-        glDrawArrays(GL_TRIANGLES, 0, 6);
+        RenderQuad();
-        glBindVertexArray(0);				
 
+        // render light source (simply renders a smaller plane at the light's position for debugging/visualization)
+        model = glm::mat4();
+        model = glm::translate(model, lightPos);
+        model = glm::scale(model, glm::vec3(0.1f));
+        glUniformMatrix4fv(glGetUniformLocation(shader.Program, "model"), 1, GL_FALSE, glm::value_ptr(model));
+        //RenderQuad();
 
         // Swap the buffers
         glfwSwapBuffers(window);
@@ -210,6 +145,99 @@ int main()
     return 0;
 }
 
+// RenderQuad() Renders a 1x1 quad in NDC
+GLuint quadVAO = 0;
+GLuint quadVBO;
+void RenderQuad()
+{
+    if (quadVAO == 0)
+    {
+        // positions
+        glm::vec3 pos1(-1.0, 1.0, 0.0);
+        glm::vec3 pos2(-1.0, -1.0, 0.0);
+        glm::vec3 pos3(1.0, -1.0, 0.0);
+        glm::vec3 pos4(1.0, 1.0, 0.0);
+        // texture coordinates
+        glm::vec2 uv1(0.0, 1.0);
+        glm::vec2 uv2(0.0, 0.0);
+        glm::vec2 uv3(1.0, 0.0);
+        glm::vec2 uv4(1.0, 1.0);
+        // normal vector
+        glm::vec3 nm(0.0, 0.0, 1.0);
+
+        // calculate tangent/bitangent vectors of both triangles
+        glm::vec3 tangent1, bitangent1;
+        glm::vec3 tangent2, bitangent2;
+        // - triangle 1
+        glm::vec3 edge1 = pos2 - pos1;
+        glm::vec3 edge2 = pos3 - pos1;
+        glm::vec2 deltaUV1 = uv2 - uv1;
+        glm::vec2 deltaUV2 = uv3 - uv1;
+
+        GLfloat f = 1.0f / (deltaUV1.x * deltaUV2.y - deltaUV2.x * deltaUV1.y);
+
+        tangent1.x = f * (deltaUV2.y * edge1.x - deltaUV1.y * edge2.x);
+        tangent1.y = f * (deltaUV2.y * edge1.y - deltaUV1.y * edge2.y);
+        tangent1.z = f * (deltaUV2.y * edge1.z - deltaUV1.y * edge2.z);
+        tangent1 = glm::normalize(tangent1);
+
+        bitangent1.x = f * (-deltaUV2.x * edge1.x + deltaUV1.x * edge2.x);
+        bitangent1.y = f * (-deltaUV2.x * edge1.y + deltaUV1.x * edge2.y);
+        bitangent1.z = f * (-deltaUV2.x * edge1.z + deltaUV1.x * edge2.z);
+        bitangent1 = glm::normalize(bitangent1);
+
+        // - triangle 2
+        edge1 = pos3 - pos1;
+        edge2 = pos4 - pos1;
+        deltaUV1 = uv3 - uv1;
+        deltaUV2 = uv4 - uv1;
+
+        f = 1.0f / (deltaUV1.x * deltaUV2.y - deltaUV2.x * deltaUV1.y);
+
+        tangent2.x = f * (deltaUV2.y * edge1.x - deltaUV1.y * edge2.x);
+        tangent2.y = f * (deltaUV2.y * edge1.y - deltaUV1.y * edge2.y);
+        tangent2.z = f * (deltaUV2.y * edge1.z - deltaUV1.y * edge2.z);
+        tangent2 = glm::normalize(tangent2);
+
+
+        bitangent2.x = f * (-deltaUV2.x * edge1.x + deltaUV1.x * edge2.x);
+        bitangent2.y = f * (-deltaUV2.x * edge1.y + deltaUV1.x * edge2.y);
+        bitangent2.z = f * (-deltaUV2.x * edge1.z + deltaUV1.x * edge2.z);
+        bitangent2 = glm::normalize(bitangent2);
+
+
+        GLfloat quadVertices[] = {
+            // Positions            // normal         // TexCoords  // Tangent                          // Bitangent
+            pos1.x, pos1.y, pos1.z, nm.x, nm.y, nm.z, uv1.x, uv1.y, tangent1.x, tangent1.y, tangent1.z, bitangent1.x, bitangent1.y, bitangent1.z,
+            pos2.x, pos2.y, pos2.z, nm.x, nm.y, nm.z, uv2.x, uv2.y, tangent1.x, tangent1.y, tangent1.z, bitangent1.x, bitangent1.y, bitangent1.z,
+            pos3.x, pos3.y, pos3.z, nm.x, nm.y, nm.z, uv3.x, uv3.y, tangent1.x, tangent1.y, tangent1.z, bitangent1.x, bitangent1.y, bitangent1.z,
+
+            pos1.x, pos1.y, pos1.z, nm.x, nm.y, nm.z, uv1.x, uv1.y, tangent2.x, tangent2.y, tangent2.z, bitangent2.x, bitangent2.y, bitangent2.z,
+            pos3.x, pos3.y, pos3.z, nm.x, nm.y, nm.z, uv3.x, uv3.y, tangent2.x, tangent2.y, tangent2.z, bitangent2.x, bitangent2.y, bitangent2.z,
+            pos4.x, pos4.y, pos4.z, nm.x, nm.y, nm.z, uv4.x, uv4.y, tangent2.x, tangent2.y, tangent2.z, bitangent2.x, bitangent2.y, bitangent2.z
+        };
+        // Setup plane VAO
+        glGenVertexArrays(1, &quadVAO);
+        glGenBuffers(1, &quadVBO);
+        glBindVertexArray(quadVAO);
+        glBindBuffer(GL_ARRAY_BUFFER, quadVBO);
+        glBufferData(GL_ARRAY_BUFFER, sizeof(quadVertices), &quadVertices, GL_STATIC_DRAW);
+        glEnableVertexAttribArray(0);
+        glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 14 * sizeof(GLfloat), (GLvoid*)0);
+        glEnableVertexAttribArray(1);
+        glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 14 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
+        glEnableVertexAttribArray(2);
+        glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 14 * sizeof(GLfloat), (GLvoid*)(6 * sizeof(GLfloat)));
+        glEnableVertexAttribArray(3);
+        glVertexAttribPointer(3, 3, GL_FLOAT, GL_FALSE, 14 * sizeof(GLfloat), (GLvoid*)(8 * sizeof(GLfloat)));
+        glEnableVertexAttribArray(4);
+        glVertexAttribPointer(4, 3, GL_FLOAT, GL_FALSE, 14 * sizeof(GLfloat), (GLvoid*)(11 * sizeof(GLfloat)));
+    }
+    glBindVertexArray(quadVAO);
+    glDrawArrays(GL_TRIANGLES, 0, 6);
+    glBindVertexArray(0);
+}
+
 // This function loads a texture from file. Note: texture loading functions like these are usually 
 // managed by a 'Resource Manager' that manages all resources (like textures, models, audio). 
 // For learning purposes we'll just define it as a utility function.
@@ -233,11 +261,12 @@ GLuint loadTexture(GLchar* path)
     glBindTexture(GL_TEXTURE_2D, 0);
     SOIL_free_image_data(image);
     return textureID;
-
 }
 
 #pragma region "User input"
 
+bool keys[1024];
+bool keysPressed[1024];
 // Moves/alters the camera positions based on user input
 void Do_Movement()
 {
@@ -250,6 +279,19 @@ void Do_Movement()
         camera.ProcessKeyboard(LEFT, deltaTime);
     if (keys[GLFW_KEY_D])
         camera.ProcessKeyboard(RIGHT, deltaTime);
+
+    // Change parallax height scale
+    if (keys[GLFW_KEY_Q])
+        height_scale -= 0.001;
+    else if (keys[GLFW_KEY_E])
+        height_scale += 0.001;
+
+	// Enable/disable parallax mapping
+	if (keys[GLFW_KEY_SPACE] && !keysPressed[GLFW_KEY_SPACE])
+	{
+		parallax_mapping = !parallax_mapping;
+		keysPressed[GLFW_KEY_SPACE] = true;
+	}
 }
 
 // Is called whenever a key is pressed/released via GLFW
@@ -258,12 +300,21 @@ void key_callback(GLFWwindow* window, int key, int scancode, int action, int mod
     if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
         glfwSetWindowShouldClose(window, GL_TRUE);
 
+    if (key >= 0 && key <= 1024)
+    {
         if (action == GLFW_PRESS)
             keys[key] = true;
         else if (action == GLFW_RELEASE)
+        {
             keys[key] = false;
+            keysPressed[key] = false;
+        }
+    }
 }
 
+GLfloat lastX = 400, lastY = 300;
+bool firstMouse = true;
+// Moves/alters the camera positions based on user input
 void mouse_callback(GLFWwindow* window, double xpos, double ypos)
 {
     if (firstMouse)

src/5.advanced_lighting/5.parallax_mapping/parallax_mapping.frag

@@ -1,16 +1,96 @@
 #version 330 core
-out vec4 color;
+out vec4 FragColor;
 
-float LinearizeDepth(float depth) // Note that this ranges from [0,1] instead of up to 'far plane distance' since we divide by 'far'
+in VS_OUT {
+    vec3 FragPos;
+    vec2 TexCoords;
+    vec3 TangentLightPos;
+    vec3 TangentViewPos;
+    vec3 TangentFragPos;
+} fs_in;
+
+uniform sampler2D diffuseMap;
+uniform sampler2D normalMap;
+uniform sampler2D depthMap;
+
+uniform bool parallax;
+uniform float height_scale;
+
+vec2 ParallaxMapping(vec2 texCoords, vec3 viewDir)
 { 
-    float near = 0.1; 
+    // float height =  texture(depthMap, texCoords).r;     
-    float far = 100.0; 
+    // return texCoords - viewDir.xy * (height * height_scale);        
-    float z = depth * 2.0 - 1.0; // Back to NDC 
+    
-    return (2.0 * near) / (far + near - z * (far - near));	
+    // number of depth layers
+    const float minLayers = 10;
+    const float maxLayers = 20;
+    float numLayers = mix(maxLayers, minLayers, abs(dot(vec3(0.0, 0.0, 1.0), viewDir)));  
+    // calculate the size of each layer
+    float layerDepth = 1.0 / numLayers;
+    // depth of current layer
+    float currentLayerDepth = 0.0;
+    // the amount to shift the texture coordinates per layer (from vector P)
+    vec2 P = viewDir.xy / viewDir.z * height_scale; 
+    vec2 deltaTexCoords = P / numLayers;
+  
+    // get initial values
+    vec2  currentTexCoords     = texCoords;
+    float currentDepthMapValue = texture(depthMap, currentTexCoords).r;
+      
+    while(currentLayerDepth < currentDepthMapValue)
+    {
+        // shift texture coordinates along direction of P
+        currentTexCoords -= deltaTexCoords;
+        // get depthmap value at current texture coordinates
+        currentDepthMapValue = texture(depthMap, currentTexCoords).r;  
+        // get depth of next layer
+        currentLayerDepth += layerDepth;  
+    }
+    
+    // -- parallax occlusion mapping interpolation from here on
+    // get texture coordinates before collision (reverse operations)
+    vec2 prevTexCoords = currentTexCoords + deltaTexCoords;
+
+    // get depth after and before collision for linear interpolation
+    float afterDepth  = currentDepthMapValue - currentLayerDepth;
+    float beforeDepth = texture(depthMap, prevTexCoords).r - currentLayerDepth + layerDepth;
+ 
+    // interpolation of texture coordinates
+    float weight = afterDepth / (afterDepth - beforeDepth);
+    vec2 finalTexCoords = prevTexCoords * weight + currentTexCoords * (1.0 - weight);
+
+    return finalTexCoords;
+    // return currentTexCoords;
 }
 
 void main()
 {           
-    float depth = LinearizeDepth(gl_FragCoord.z);
+    // Offset texture coordinates with Parallax Mapping
-    color = vec4(vec3(depth), 1.0f);
+    vec3 viewDir = normalize(fs_in.TangentViewPos - fs_in.TangentFragPos);
+    vec2 texCoords = fs_in.TexCoords;
+    if(parallax)
+        texCoords = ParallaxMapping(fs_in.TexCoords,  viewDir);
+        
+    if(texCoords.x > 1.0 || texCoords.y > 1.0 || texCoords.x < 0.0 || texCoords.y < 0.0)
+        discard;
+
+    // Obtain normal from normal map
+    vec3 normal = texture(normalMap, texCoords).rgb;
+    normal = normalize(normal * 2.0 - 1.0);   
+   
+    // Get diffuse color
+    vec3 color = texture(diffuseMap, texCoords).rgb;
+    // Ambient
+    vec3 ambient = 0.1 * color;
+    // Diffuse
+    vec3 lightDir = normalize(fs_in.TangentLightPos - fs_in.TangentFragPos);
+    float diff = max(dot(lightDir, normal), 0.0);
+    vec3 diffuse = diff * color;
+    // Specular    
+    vec3 reflectDir = reflect(-lightDir, normal);
+    vec3 halfwayDir = normalize(lightDir + viewDir);  
+    float spec = pow(max(dot(normal, halfwayDir), 0.0), 32.0);
+
+    vec3 specular = vec3(0.2) * spec;
+    FragColor = vec4(ambient + diffuse + specular, 1.0f);
 }

src/5.advanced_lighting/5.parallax_mapping/parallax_mapping.vs

@@ -1,15 +1,38 @@
 #version 330 core
 layout (location = 0) in vec3 position;
-layout (location = 1) in vec2 texCoords;
+layout (location = 1) in vec3 normal;
+layout (location = 2) in vec2 texCoords;
+layout (location = 3) in vec3 tangent;
+layout (location = 4) in vec3 bitangent;
 
-out vec2 TexCoords;
+out VS_OUT {
+    vec3 FragPos;
+    vec2 TexCoords;
+    vec3 TangentLightPos;
+    vec3 TangentViewPos;
+    vec3 TangentFragPos;
+} vs_out;
 
-uniform mat4 model;
-uniform mat4 view;
 uniform mat4 projection;
+uniform mat4 view;
+uniform mat4 model;
+
+uniform vec3 lightPos;
+uniform vec3 viewPos;
 
 void main()
 {
     gl_Position = projection * view * model * vec4(position, 1.0f);
-    TexCoords = texCoords;
+    vs_out.FragPos = vec3(model * vec4(position, 1.0));   
+    vs_out.TexCoords = texCoords;
+    
+    
+    vec3 T = normalize(mat3(model) * tangent);
+    vec3 B = normalize(mat3(model) * bitangent);
+    vec3 N = normalize(mat3(model) * normal);
+    mat3 TBN = transpose(mat3(T, B, N));
+
+    vs_out.TangentLightPos = TBN * lightPos;
+    vs_out.TangentViewPos  = TBN * viewPos;
+    vs_out.TangentFragPos  = TBN * vs_out.FragPos;
 }