Create a scene with multiple lights

.gitignore

@@ -1,3 +1,4 @@
 .cache
 compile_commands.json
 main
+*.py

shaders/frag.glsl

@@ -1,13 +1,111 @@
 #version 330 core
 
-in vec2 tex_coords;
+#define POINT_LIGHT_COUNT 4
+
+struct Material {
+  sampler2D diffuse;
+  sampler2D specular;
+  float shininess;
+};
+
+struct DirLight {
+  vec3 direction;
+  vec3 ambient;
+  vec3 diffuse;
+  vec3 specular;
+};
+
+struct PointLight {
+  vec3 position;
+  vec3 ambient;
+  vec3 diffuse;
+  vec3 specular;
+  float constant;
+  float linear;
+  float quadratic;
+};
+
+struct SpotLight {
+  vec3 position;
+  vec3 direction;
+  vec3 ambient;
+  vec3 diffuse;
+  vec3 specular;
+  float cutoff;
+  float outer_cutoff;
+};
+
+in vec3 vert_normal;
+in vec3 frag_position;
+in vec2 uv_coords;
 
 out vec4 color;
 
-uniform float     mix_factor;
-uniform sampler2D texture0;
-uniform sampler2D texture1;
+uniform Material material;
+uniform DirLight directional_light;
+uniform PointLight point_lights[POINT_LIGHT_COUNT];
+uniform SpotLight spot_light;
+uniform vec3 camera_position;
+
+vec3 calc_dir_light(DirLight light, vec3 normal, vec3 view_direction);
+vec3 calc_point_light(PointLight light, vec3 normal, vec3 frag_position, vec3 view_direction);
+vec3 calc_spot_light(SpotLight light, vec3 normal, vec3 frag_position, vec3 view_direction);
 
 void main() {
-  color = mix(texture(texture0, tex_coords), texture(texture1, tex_coords), mix_factor);
+  vec3  normal         = normalize(vert_normal);
+  vec3  view_direction = normalize(camera_position - frag_position);
+
+  vec3 result = calc_dir_light(directional_light, normal, view_direction);
+
+  for (int i = 0; i < POINT_LIGHT_COUNT; ++i) {
+    result += calc_point_light(point_lights[i], normal, frag_position, view_direction);
+  }
+
+  result += calc_spot_light(spot_light, normal, frag_position, view_direction);
+
+  color = vec4(result, 1.0);
 };
+
+vec3 calc_dir_light(DirLight light, vec3 normal, vec3 view_direction) {
+  vec3 light_direction     = normalize(-light.direction);
+  vec3  reflect_direction  = reflect(-light_direction, normal);
+  float diff               = max(dot(normal, light_direction), 0.0);
+  vec3  diff_tex           = vec3(texture(material.diffuse, uv_coords));
+  float spec               = pow(max(dot(reflect_direction, view_direction), 0.0), material.shininess);
+  vec3  ambient            = light.ambient * diff_tex;
+  vec3  diffuse            = light.diffuse * (diff * diff_tex);
+  vec3  specular           = light.specular * (spec * vec3(texture(material.specular, uv_coords)));
+
+  return ambient + diffuse + specular;
+}
+
+vec3 calc_point_light(PointLight light, vec3 normal, vec3 frag_position, vec3 view_direction) {
+  vec3 light_direction     = normalize(light.position - frag_position);
+  vec3  reflect_direction  = reflect(-light_direction, normal);
+  float distance           = length(light.position - frag_position);
+  float attenuation        = 1.0 / (light.constant + light.linear * distance + light.quadratic * (distance * distance));
+  float diff               = max(dot(normal, light_direction), 0.0);
+  vec3  diff_tex           = vec3(texture(material.diffuse, uv_coords));
+  float spec               = pow(max(dot(reflect_direction, view_direction), 0.0), material.shininess);
+  vec3  ambient            = light.ambient * diff_tex * attenuation;
+  vec3  diffuse            = light.diffuse * (diff * diff_tex) * attenuation;
+  vec3  specular           = light.specular * (spec * vec3(texture(material.specular, uv_coords))) * attenuation;
+
+  return ambient + diffuse + specular;
+}
+
+vec3 calc_spot_light(SpotLight light, vec3 normal, vec3 frag_position, vec3 view_direction) {
+  vec3 light_direction     = normalize(light.position - frag_position);
+  vec3  reflect_direction  = reflect(-light_direction, normal);
+  float theta              = dot(light_direction, normalize(-light.direction));
+  float epsilon            = light.cutoff - light.outer_cutoff;
+  float intensity          = clamp((theta - light.outer_cutoff) / epsilon, 0.0, 1.0);
+  float diff               = max(dot(normal, light_direction), 0.0);
+  float spec               = pow(max(dot(reflect_direction, view_direction), 0.0), material.shininess);
+  vec3  diff_tex           = vec3(texture(material.diffuse, uv_coords));
+  vec3  ambient            = light.ambient * diff_tex;
+  vec3  diffuse            = light.diffuse * (diff * diff_tex) * intensity;
+  vec3  specular           = light.specular * (spec * vec3(texture(material.specular, uv_coords))) * intensity;
+
+  return ambient + diffuse + specular;
+}

shaders/light_frag.glsl

@@ -0,0 +1,9 @@
+#version 330 core
+
+out vec4 color;
+
+uniform vec3 light_diffuse;
+
+void main() {
+  color = vec4(light_diffuse, 1.0);
+}

shaders/vert.glsl

@@ -1,15 +1,21 @@
 #version 330 core
 
 layout(location=0) in vec3 position;
-layout(location=1) in vec2 uv;
+layout(location=1) in vec3 normal;
+layout(location=2) in vec2 uv;
 
+out vec3 vert_normal;
+out vec3 frag_position;
+out vec2 uv_coords;
+
+uniform mat3 normal_mat;
 uniform mat4 model;
 uniform mat4 view;
 uniform mat4 projection;
 
-out vec2 tex_coords;
-
 void main() {
-  tex_coords  = uv;
-  gl_Position = projection * view * model * vec4(position, 1.0);
+  vert_normal   = normal_mat * normal;
+  frag_position = vec3(model * vec4(position, 1.0));
+  uv_coords     = uv;
+  gl_Position   = projection * view * model * vec4(position, 1.0);
 };

src/main.cc

@@ -1,6 +1,10 @@
 // GLAD
 #include "glad/glad.h"
 
+// STB Image
+#define STB_IMAGE_IMPLEMENTATION
+#include "stb_image.h"
+
 // GLM
 #define GLM_ENABLE_EXPERIMENTAL
 #include "glm/ext/matrix_transform.hpp"
@@ -10,10 +14,6 @@
 #include "glm/gtx/rotate_vector.hpp"
 #include "glm/gtx/string_cast.hpp"
 
-// STB Image
-#define STB_IMAGE_IMPLEMENTATION
-#include "stb_image.h"
-
 // SDL
 #include <SDL2/SDL.h>
 #include <SDL2/SDL_timer.h>
@@ -31,11 +31,15 @@
 #include <string>
 #include <vector>
 
-#define WINDOW_WIDTH       1280
-#define WINDOW_HEIGHT      720
-#define WINDOW_HALF_WIDTH  640
+#define WINDOW_WIDTH 1280
+#define WINDOW_HEIGHT 720
+#define WINDOW_HALF_WIDTH 640
 #define WINDOW_HALF_HEIGHT 360
 
+#define min(a, b) (a < b ? a : b)
+#define max(a, b) (a > b ? a : b)
+#define clamp(v, a, b) (min(max(v, a), b))
+
 enum exit_codes : int {
   EXIT_CODE_SUCCESS,
   EXIT_CODE_SDL_INIT_FAILED,
@@ -49,6 +53,12 @@ class Shader {
     Shader(const std::string &vert_file, const std::string &frag_file);
     ~Shader();
     void activate();
+    void set_int(const char *name, int value);
+    void set_float(const char *name, float value);
+    void set_vec3(const char *name, glm::vec3 vector);
+    void set_vec4(const char *name, glm::vec4 vector);
+    void set_mat3(const char *name, glm::mat3 matrix);
+    void set_mat4(const char *name, glm::mat4 matrix);
     GLuint program;
   private:
     void link_program(GLuint vert, GLuint frag);
@@ -57,6 +67,20 @@ class Shader {
     static const char *get_shader_type_string(GLenum shader_type);
 };
 
+class Texture2D {
+  public:
+    Texture2D(const char *filename, GLint texture_unit);
+    ~Texture2D();
+    void activate();
+    int width;
+    int height;
+    int channels;
+  private:
+    GLuint texture;
+    GLint texture_unit;
+    GLint format;
+};
+
 int main() {
   if (SDL_Init(SDL_INIT_EVERYTHING) != 0) {
     return EXIT_CODE_SDL_INIT_FAILED;
@@ -86,49 +110,53 @@ int main() {
   SDL_SetRelativeMouseMode(SDL_TRUE);
   SDL_WarpMouseInWindow(window, WINDOW_HALF_WIDTH, WINDOW_HALF_HEIGHT);
 
-  // Set texture options
-  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);
+  stbi_set_flip_vertically_on_load(true);
 
   glViewport(0, 0, WINDOW_WIDTH, WINDOW_HEIGHT);
 
   glEnable(GL_DEPTH_TEST);
 
   std::vector<GLfloat> vertices = {
-     0.5f, -0.5f,  0.5f,  0.0f, 0.0f, // position, uv
-    -0.5f,  0.5f,  0.5f,  1.0f, 0.0f, // position, uv
-     0.5f,  0.5f,  0.5f,  1.0f, 0.0f, // position, uv
-     0.5f, -0.5f,  0.5f,  1.0f, 0.0f, // position, uv
-    -0.5f, -0.5f,  0.5f,  0.0f, 0.0f, // position, uv
-     0.5f, -0.5f, -0.5f,  1.0f, 0.0f, // position, uv
-    -0.5f,  0.5f, -0.5f,  1.0f, 1.0f, // position, uv
-    -0.5f,  0.5f, -0.5f,  0.0f, 1.0f, // position, uv
-    -0.5f,  0.5f,  0.5f,  0.0f, 1.0f, // position, uv
-     0.5f,  0.5f, -0.5f,  1.0f, 1.0f, // position, uv
-     0.5f, -0.5f, -0.5f,  1.0f, 1.0f, // position, uv
-    -0.5f,  0.5f,  0.5f,  0.0f, 0.0f, // position, uv
-     0.5f,  0.5f,  0.5f,  1.0f, 1.0f, // position, uv
-    -0.5f, -0.5f, -0.5f,  0.0f, 1.0f, // position, uv
-    -0.5f, -0.5f, -0.5f,  0.0f, 0.0f, // position, uv
-     0.5f, -0.5f, -0.5f,  0.0f, 1.0f, // position, uv
-    -0.5f,  0.5f, -0.5f,  0.0f, 1.0f  // position, uv
+    // positions         // normals           // texture coords
+   -0.5f, -0.5f, -0.5f, -1.0f,  0.0f,  0.0f,  0.0f, 1.0f,
+    0.5f,  0.5f,  0.5f,  1.0f,  0.0f,  0.0f,  1.0f, 0.0f,
+    0.5f,  0.5f, -0.5f,  1.0f,  0.0f,  0.0f,  1.0f, 1.0f,
+   -0.5f,  0.5f,  0.5f,  0.0f,  0.0f, 1.0f,   0.0f, 1.0f,
+    0.5f, -0.5f,  0.5f,  1.0f,  0.0f,  0.0f,  0.0f, 0.0f,
+    0.5f, -0.5f, -0.5f,  0.0f, -1.0f,  0.0f,  1.0f, 1.0f,
+   -0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,  0.0f, 0.0f,
+    0.5f, -0.5f,  0.5f,  0.0f,  0.0f, 1.0f,   1.0f, 0.0f,
+   -0.5f, -0.5f, -0.5f,  0.0f, -1.0f,  0.0f,  0.0f, 1.0f,
+    0.5f,  0.5f,  0.5f,  0.0f,  0.0f, 1.0f,   1.0f, 1.0f,
+    0.5f, -0.5f,  0.5f,  0.0f, -1.0f,  0.0f,  1.0f, 0.0f,
+   -0.5f, -0.5f,  0.5f,  0.0f, -1.0f,  0.0f,  0.0f, 0.0f,
+    0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,  1.0f, 1.0f,
+    0.5f,  0.5f,  0.5f,  0.0f,  1.0f,  0.0f,  1.0f, 0.0f,
+    0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,  1.0f, 0.0f,
+   -0.5f,  0.5f,  0.5f,  0.0f,  1.0f,  0.0f,  0.0f, 0.0f,
+   -0.5f,  0.5f, -0.5f,  0.0f,  1.0f,  0.0f,  0.0f, 1.0f,
+   -0.5f, -0.5f,  0.5f,  0.0f,  0.0f, 1.0f,   0.0f, 0.0f,
+   -0.5f, -0.5f,  0.5f, -1.0f,  0.0f,  0.0f,  0.0f, 0.0f,
+   -0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,  0.0f, 1.0f,
+   -0.5f,  0.5f, -0.5f, -1.0f,  0.0f,  0.0f,  1.0f, 1.0f,
+    0.5f,  0.5f, -0.5f,  0.0f,  1.0f,  0.0f,  1.0f, 1.0f,
+   -0.5f,  0.5f,  0.5f, -1.0f,  0.0f,  0.0f,  1.0f, 0.0f,
+    0.5f, -0.5f, -0.5f,  1.0f,  0.0f,  0.0f,  0.0f, 1.0f,
   };
 
   std::vector<GLuint> indices = {
-    14, 5, 9,
-    9, 7, 14,
-    4, 3, 12,
-    12, 8, 4,
-    1, 6, 13,
-    13, 4, 1,
-    2, 9, 15,
-    15, 0, 2,
-    13, 10, 3,
-    3, 4, 13,
-    7, 9, 2,
-    2, 11, 16
+     6, 14, 12,
+    12, 19,  6,
+    17,  7,  9,
+     9,  3, 17,
+    22, 20,  0,
+     0, 18, 22,
+     1,  2, 23,
+    23,  4,  1,
+     8,  5, 10,
+    10, 11,  8,
+    16, 21, 13,
+    13, 15, 16
   };
 
   GLuint vao = 0;
@@ -145,90 +173,130 @@ int main() {
   glBindBuffer(GL_ARRAY_BUFFER, vbo);
   glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(GLfloat), vertices.data(), GL_STATIC_DRAW);
 
-  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), (void *)0);
+  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (void *)0);
   glEnableVertexAttribArray(0);
-  glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), (void *)(3 * sizeof(GLfloat)));
+  glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (void *)(3 * sizeof(GLfloat)));
   glEnableVertexAttribArray(1);
+  glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (void *)(6 * sizeof(GLfloat)));
+  glEnableVertexAttribArray(2);
+
+  GLuint light_vao = 0;
+  glGenVertexArrays(1, &light_vao);
+  glBindVertexArray(light_vao);
+  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
+  glBindBuffer(GL_ARRAY_BUFFER, vbo);
+
+  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (void *)0);
+  glEnableVertexAttribArray(0);
 
   glBindVertexArray(0);
   glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
   glBindBuffer(GL_ARRAY_BUFFER, 0);
 
-  stbi_set_flip_vertically_on_load(true);
+  Shader main_shader  {"shaders/vert.glsl", "shaders/frag.glsl"};
+  Shader light_shader {"shaders/vert.glsl", "shaders/light_frag.glsl"};
 
-  // Load texture
-  int32_t width[2], height[2], channels[2];
-  uint8_t *container   = stbi_load("images/container.jpg",   &width[0], &height[0], &channels[0], 0);
-  uint8_t *awesomeface = stbi_load("images/awesomeface.png", &width[1], &height[1], &channels[1], 0);
-
-  GLuint textures[2];
-  glGenTextures(2, textures);
-
-  glActiveTexture(GL_TEXTURE0); // activate the texture unit first before binding texture
-  glBindTexture(GL_TEXTURE_2D, textures[0]);
-  if (container) {
-    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width[0], height[0], 0, GL_RGB, GL_UNSIGNED_BYTE, container);
-    glGenerateMipmap(GL_TEXTURE_2D);
-
-    stbi_image_free(container);
-  } else {
-    printf("Failed to load container texture \n");
-  }
-
-  glActiveTexture(GL_TEXTURE1); // activate the texture unit first before binding texture
-  glBindTexture(GL_TEXTURE_2D, textures[1]);
-  if (awesomeface) {
-    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width[1], height[1], 0, GL_RGBA, GL_UNSIGNED_BYTE, awesomeface);
-    glGenerateMipmap(GL_TEXTURE_2D);
-
-    stbi_image_free(awesomeface);
-  } else {
-    printf("Failed to load container texture \n");
-  }
-
-  glBindTexture(GL_TEXTURE_2D, 0);
-
-  Shader main_shader {"shaders/vert.glsl", "shaders/frag.glsl"};
-  main_shader.activate();
-  glUniform1i(glGetUniformLocation(main_shader.program, "texture0"), 0);
-  glUniform1i(glGetUniformLocation(main_shader.program, "texture1"), 1);
-
-  float texture_mix_factor = 0.2f;
-
-  glm::vec3 cube_positions[] = {
-      glm::vec3( 0.0f,  0.0f,  0.0f), 
-      glm::vec3( 4.0f,  6.0f, -15.0f), 
-      glm::vec3(-3.5f, -3.2f, -2.5f),  
-      glm::vec3(-5.8f, -3.0f, -12.3f),  
-      glm::vec3( 4.4f, -1.4f, -3.5f),  
-      glm::vec3(-3.7f,  4.0f, -7.5f),  
-      glm::vec3( 3.3f, -3.0f, -2.5f),  
-      glm::vec3( 3.5f,  3.0f, -2.5f), 
-      glm::vec3( 3.5f,  1.2f, -1.5f), 
-      glm::vec3(-3.3f,  2.0f, -1.5f)  
-  };
+  Texture2D diffuse_map  = Texture2D("images/container2.png", GL_TEXTURE0);
+  Texture2D specular_map = Texture2D("images/container2_specular.png", GL_TEXTURE1);
+  main_shader.set_int("material.diffuse", 0);
+  main_shader.set_int("material.specular", 1);
 
   const float camera_speed   = 25.0f;
-  glm::vec3 camera_position  = glm::vec3(0.0f, 0.0f, 4.0f);
+  glm::vec3 camera_position  = glm::vec3(-2.0f, 0.0f, 6.0f);
   glm::vec3 camera_forward   = glm::vec3(0.0f);
   glm::vec3 world_up         = glm::vec3(0.0f, 1.0f, 0.0f);
+  glm::vec3 light_ambient    = glm::vec3(0.2f, 0.2f, 0.2f);
+  glm::vec3 light_diffuse    = glm::vec3(0.75f, 0.75f, 0.75f);
+  glm::vec3 light_specular   = glm::vec3(1.0f, 1.0f, 1.0f);
 
-  float yaw   = -90.0f;
-  float pitch = 0.0f;
+  float yaw   = -70.0f;
+  float pitch =   0.0f;
 
   glm::mat4 model      = glm::mat4(1.0f);
   glm::mat4 view       = glm::mat4(1.0f);
   glm::mat4 projection = glm::perspective(glm::radians(45.0f), (float)WINDOW_WIDTH / (float)WINDOW_HEIGHT, 0.1f, 100.0f);
+  glm::mat3 normal_mat = glm::mat3(1.0f);
 
-  glUniformMatrix4fv(glGetUniformLocation(main_shader.program, "projection"), 1, GL_FALSE, glm::value_ptr(projection));
+  main_shader.set_mat4 ("projection", projection);
+  main_shader.set_vec3 ("material.specular", glm::vec3(0.5f, 0.5f, 0.5f));
+  main_shader.set_float("material.shininess", 32.0f);
 
-  const float sensitivity = 0.1f;
-  int last_mouse_x        = WINDOW_HALF_WIDTH;
-  int last_mouse_y        = WINDOW_HALF_HEIGHT;
-  uint32_t last_frame     = SDL_GetTicks();
-  float delta             = 0.0f;
-  bool running            = true;
-  SDL_Event event         = {};
+  light_shader.set_mat4("projection", projection);
+
+  std::vector<glm::vec3> cube_positions = {
+      glm::vec3( 0.0f,  0.0f,  0.0f),
+      glm::vec3( 4.0f,  6.0f, -15.0f),
+      glm::vec3(-3.5f, -3.2f, -2.5f),
+      glm::vec3(-5.8f, -3.0f, -12.3f),
+      glm::vec3( 4.4f, -1.4f, -3.5f),
+      glm::vec3(-3.7f,  4.0f, -7.5f),
+      glm::vec3( 3.3f, -3.0f, -2.5f),
+      glm::vec3( 3.5f,  3.0f, -2.5f),
+      glm::vec3( 3.5f,  1.2f, -1.5f),
+      glm::vec3(-3.3f,  2.0f, -1.5f)
+  };
+
+  std::vector<glm::vec3> point_light_positions = {
+    glm::vec3( 0.7f,  0.2f,  2.0f),
+    glm::vec3( 2.3f, -3.3f, -4.0f),
+    glm::vec3(-4.0f,  2.0f, -12.0f),
+    glm::vec3( 0.0f,  0.0f, -3.0f)
+  };
+
+  // Setup lights
+  main_shader.set_vec3("directional_light.direction", glm::vec3(-0.2f, -1.0f, -0.3f));
+  main_shader.set_vec3("directional_light.ambient", light_ambient);
+  main_shader.set_vec3("directional_light.diffuse", light_diffuse);
+  main_shader.set_vec3("directional_light.specular", light_specular);
+
+  main_shader.set_vec3("spot_light.ambient", light_ambient);
+  main_shader.set_vec3("spot_light.diffuse", light_diffuse);
+  main_shader.set_vec3("spot_light.specular", light_specular);
+
+  for (int i = 0; i < point_light_positions.size(); ++i) {
+    char base[256]      = {0};
+    char position[512]  = {0};
+    char ambient[512]   = {0};
+    char diffuse[512]   = {0};
+    char specular[512]  = {0};
+    char constant[512]  = {0};
+    char linear[512]    = {0};
+    char quadratic[512] = {0};
+
+    snprintf(base, sizeof(base) - 1, "point_lights[%d]", i);
+    snprintf(position, sizeof(position) - 1, "%s.position", base);
+    snprintf(ambient, sizeof(ambient) - 1, "%s.ambient", base);
+    snprintf(diffuse, sizeof(diffuse) - 1, "%s.diffuse", base);
+    snprintf(specular, sizeof(specular) - 1, "%s.specular", base);
+    snprintf(constant, sizeof(constant) - 1, "%s.constant", base);
+    snprintf(linear, sizeof(linear) - 1, "%s.linear", base);
+    snprintf(quadratic, sizeof(quadratic) - 1, "%s.quadratic", base);
+
+    main_shader.set_vec3(position, point_light_positions[i]);
+    main_shader.set_vec3(ambient, light_ambient);
+    main_shader.set_vec3(diffuse, light_diffuse);
+    main_shader.set_vec3(specular, light_specular);
+    main_shader.set_float(constant, 1.0f);
+    main_shader.set_float(linear, 0.09f);
+    main_shader.set_float(quadratic, 0.032f);
+
+    memset(base,      0, sizeof(base));
+    memset(position,  0, sizeof(position));
+    memset(ambient,   0, sizeof(ambient));
+    memset(diffuse,   0, sizeof(diffuse));
+    memset(specular,  0, sizeof(specular));
+    memset(constant,  0, sizeof(constant));
+    memset(linear,    0, sizeof(linear));
+    memset(quadratic, 0, sizeof(quadratic));
+  }
+
+  const float sensitivity   = 0.1f;
+  int last_mouse_x          = WINDOW_HALF_WIDTH;
+  int last_mouse_y          = WINDOW_HALF_HEIGHT;
+  uint32_t last_frame       = SDL_GetTicks();
+  float delta               = 0.0f;
+  bool running              = true;
+  SDL_Event event           = {};
 
   while (running) {
     uint32_t ticks = SDL_GetTicks();
@@ -243,10 +311,6 @@ int main() {
         case SDL_KEYDOWN:
           if (event.key.keysym.sym == SDLK_ESCAPE) {
             running = false;
-          } else if (event.key.keysym.sym == SDLK_UP) {
-            texture_mix_factor += 0.1f;
-          } else if (event.key.keysym.sym == SDLK_DOWN) {
-            texture_mix_factor -= 0.1f;
           } else if (event.key.keysym.sym == SDLK_w) {
             camera_position += camera_speed * delta * camera_forward;
           } else if (event.key.keysym.sym == SDLK_s) {
@@ -294,35 +358,45 @@ int main() {
       }
     }
 
-    texture_mix_factor = texture_mix_factor < 0.0f ?
-                         0.0f : texture_mix_factor > 1.0f ?
-                         1.0f : texture_mix_factor;
-
     camera_forward.x = cos(glm::radians(yaw)) * cos(glm::radians(pitch));
     camera_forward.y = sin(glm::radians(pitch));
     camera_forward.z = sin(glm::radians(yaw)) * cos(glm::radians(pitch));
     camera_forward   = glm::normalize(camera_forward);
 
     view = glm::lookAt(camera_position, camera_position + camera_forward, world_up);
-    glUniformMatrix4fv(glGetUniformLocation(main_shader.program, "view"), 1, GL_FALSE, glm::value_ptr(view));
+    main_shader.set_vec3("camera_position", camera_position);
+    main_shader.set_vec3("spot_light.position", camera_position);
+    main_shader.set_vec3("spot_light.direction", camera_forward);
+    main_shader.set_float("spot_light.cutoff", glm::cos(glm::radians(12.5)));
+    main_shader.set_float("spot_light.outer_cutoff", glm::cos(glm::radians(17.5)));
+    main_shader.set_mat4("view", view);
+    light_shader.set_mat4("view", view);
 
-    glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
+    glClearColor(0.04f, 0.08f, 0.08f, 1.0f);
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
-    main_shader.activate();
-    glUniform1f(glGetUniformLocation(main_shader.program, "mix_factor"), texture_mix_factor);
-    glActiveTexture(GL_TEXTURE0);
-    glBindTexture(GL_TEXTURE_2D, textures[0]);
-    glActiveTexture(GL_TEXTURE1);
-    glBindTexture(GL_TEXTURE_2D, textures[1]);
-    glBindVertexArray(vao);
-
-    for (int i = 0; i < sizeof(cube_positions) / sizeof(cube_positions[0]); ++i) {
-      float angle = 20.0f * i;
+    for (int i = 0; i < cube_positions.size(); ++i) {
       model = glm::translate(glm::mat4(1.0f), cube_positions[i]);
-      model = glm::rotate(model, glm::radians(angle), glm::vec3(1.0f, 0.3f, 0.5f));
-      glUniformMatrix4fv(glGetUniformLocation(main_shader.program, "model"), 1, GL_FALSE, glm::value_ptr(model));
-      glDrawElements(GL_TRIANGLES, 36, GL_UNSIGNED_INT, (void *)0);
+      model = glm::rotate(model, glm::radians(10.0f * i), glm::vec3(1.0f, 0.3f, 0.5f));
+      normal_mat = glm::transpose(glm::inverse(model));
+      main_shader.activate();
+      main_shader.set_mat4("model", model);
+      main_shader.set_mat3("normal_mat", normal_mat);
+      diffuse_map.activate();
+      specular_map.activate();
+      glBindVertexArray(vao);
+      glDrawElements(GL_TRIANGLES, indices.size(), GL_UNSIGNED_INT, (void *)0);
+    }
+
+    // Draw light source
+    for (int i = 0; i < point_light_positions.size(); ++i) {
+      model = glm::translate(glm::mat4(1.0f), point_light_positions[i]);
+      model = glm::scale(model, glm::vec3(0.2f));
+      light_shader.activate();
+      light_shader.set_mat4("model", model);
+      light_shader.set_vec3("light_diffuse", light_diffuse);
+      glBindVertexArray(light_vao);
+      glDrawElements(GL_TRIANGLES, indices.size(), GL_UNSIGNED_INT, (void *)0);
     }
 
     SDL_GL_SwapWindow(window);
@@ -356,6 +430,36 @@ void Shader::activate() {
   }
 }
 
+void Shader::set_int(const char *name, int value) {
+  activate();
+  glUniform1i(glGetUniformLocation(program, name), value);
+}
+
+void Shader::set_float(const char *name, float value) {
+  activate();
+  glUniform1f(glGetUniformLocation(program, name), value);
+}
+
+void Shader::set_vec3(const char *name, glm::vec3 vector) {
+  activate();
+  glUniform3f(glGetUniformLocation(program, name), vector.x, vector.y, vector.z);
+}
+
+void Shader::set_vec4(const char *name, glm::vec4 vector) {
+  activate();
+  glUniform4f(glGetUniformLocation(program, name), vector.x, vector.y, vector.z, vector.w);
+}
+
+void Shader::set_mat3(const char *name, glm::mat3 matrix) {
+  activate();
+  glUniformMatrix3fv(glGetUniformLocation(program, name), 1, GL_FALSE, glm::value_ptr(matrix));
+}
+
+void Shader::set_mat4(const char *name, glm::mat4 matrix) {
+  activate();
+  glUniformMatrix4fv(glGetUniformLocation(program, name), 1, GL_FALSE, glm::value_ptr(matrix));
+}
+
 void Shader::link_program(GLuint vert, GLuint frag) {
   program = glCreateProgram();
   glAttachShader(program, vert);
@@ -441,3 +545,34 @@ const char *Shader::get_shader_type_string(GLenum shader_type) {
 
   return output;
 }
+
+Texture2D::Texture2D(const char *filename, GLint texture_unit) : texture_unit(texture_unit) {
+  uint8_t *image = stbi_load(filename, &width, &height, &channels, 0);
+  if (!image) {
+    return;
+  }
+
+  // TODO (Abdelrahman): This doesn't handle all formats
+  format = channels > 3 ? GL_RGBA : GL_RGB;
+
+  glGenTextures(1, &texture);
+  activate();
+
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+
+  glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, format, GL_UNSIGNED_BYTE, image);
+  glGenerateMipmap(GL_TEXTURE_2D);
+
+  glBindTexture(GL_TEXTURE_2D, 0);
+  stbi_image_free(image);
+}
+
+Texture2D::~Texture2D() {}
+
+void Texture2D::activate() {
+  glActiveTexture(texture_unit);
+  glBindTexture(GL_TEXTURE_2D, texture);
+}