Add diffuse lighting

CMakeLists.txt

@@ -2,6 +2,7 @@ cmake_minimum_required(VERSION 3.19)
 project(OpenGLTest CXX)
 
 set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
 find_package(OpenGL REQUIRED)
 find_package(GLEW REQUIRED)
@@ -11,6 +12,7 @@ find_package(glfw3 REQUIRED)
 file(GLOB SOURCES src/*.h src/*.cpp)
 add_executable(opengl_test ${SOURCES})
 
+target_include_directories(opengl_test PUBLIC include)
 target_link_libraries(opengl_test
     OpenGL::GL
     GLEW::GLEW

shaders/shader.frag

@@ -2,11 +2,25 @@
 
 in vec4 vertex_color;
 in vec2 texture_coord;
+in vec3 normal;
 
 out vec4 color;
 
+struct Directional_Light {
+    vec3 color;
+    float ambient_intensity;
+    vec3 direction;
+    float diffuse_intensity;
+};
+
 uniform sampler2D tex;
+uniform Directional_Light sun;
 
 void main() {
-    color = texture(tex, texture_coord);
+    vec4 ambient_color = vec4(sun.color, 1.0f) * sun.ambient_intensity;
+
+    float diffuse_factor = max(dot(normalize(normal), normalize(sun.direction)), 0.0f);
+    vec4 diffuse_color = vec4(sun.color, 1.0f) * sun.diffuse_intensity * diffuse_factor;
+
+    color = texture(tex, texture_coord) * (ambient_color + diffuse_color);
 }

shaders/shader.vert

@@ -2,9 +2,11 @@
 
 layout (location = 0) in vec3 pos;
 layout (location = 1) in vec2 tex;
+layout (location = 2) in vec3 norm;
 
 out vec4 vertex_color;
 out vec2 texture_coord;
+out vec3 normal;
 
 uniform mat4 projection;
 uniform mat4 model;
@@ -14,4 +16,5 @@ void main() {
     gl_Position = projection * view * model * vec4(pos, 1.0);
     vertex_color = vec4(clamp(pos, 0.0f, 1.0f), 1.0f);
     texture_coord = tex;
+    normal = mat3(transpose(inverse(model))) * norm;
 }

src/file.cpp

@@ -1,7 +1,7 @@
 #include "file.h"
 
-std::string read_entire_file(const char *path) {
-  std::string content;
+string read_entire_file(const char *path) {
+  string content;
 	std::ifstream file_stream(path, std::ios::in);
 
 	if (!file_stream.is_open()) {
@@ -9,7 +9,7 @@ std::string read_entire_file(const char *path) {
 		return "";
 	}
 
-	std::string line = "";
+	string line = "";
 	while (!file_stream.eof())
 	{
 		std::getline(file_stream, line);

src/file.h

@@ -1,7 +1,6 @@
 #pragma once
 
-#include <string>
-#include <iostream>
 #include <fstream>
+#include "math.h"
 
-std::string read_entire_file(const char *path);
+string read_entire_file(const char *path);

src/light.cpp

@@ -0,0 +1,12 @@
+#include "light.h"
+
+Light::Light(Vector3 color, f32 ambient_intensity, Vector3 direction, f32 diffuse_intensity) : color(color), ambient_intensity(ambient_intensity), direction(direction), diffuse_intensity(diffuse_intensity) {}
+
+void use_light(Light *light, f32 color_location, f32 ambient_intensity_location, f32 direction_location, f32 diffuse_intensity_location) {
+  glUniform3f(color_location, light->color.x, light->color.y, light->color.z);
+  glUniform1f(ambient_intensity_location, light->ambient_intensity);
+
+  glUniform3f(direction_location, light->direction.x, light->direction.y, light->direction.z);
+  glUniform1f(diffuse_intensity_location, light->diffuse_intensity);
+}
+

src/light.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#include <GL/glew.h>
+#include <glm/glm.hpp>
+#include "math.h"
+
+struct Light {
+  Vector3 color = Vector3(1.0f, 1.0f, 1.0f);
+  f32 ambient_intensity = 1.0f;
+
+  // For a directional light
+  Vector3 direction = Vector3(0.0f, -1.0f, 0.0f); // Default to down
+  f32 diffuse_intensity = 0.0f;
+
+  Light(Vector3 color, f32 ambient_intensity, Vector3 direction, f32 diffuse_intensity);
+  ~Light() = default;
+};
+
+void use_light(Light *light, f32 color_location, f32 ambient_intensity_location, f32 direction_location, f32 diffuse_intensity_location);

src/main.cpp

@@ -5,6 +5,7 @@
 #include "window.h"
 #include "camera.h"
 #include "texture.h"
+#include "light.h"
 
 
 static const char *vertex_shader_code = "shaders/shader.vert";
@@ -24,11 +25,11 @@ int main() {
   {
     // Create a mesh
     f32 vertices[] = {
-    // x      y      z     u     v
-      -1.0f, -1.0f,  0.0f, 0.0f, 0.0f,
-       0.0f, -1.0f,  1.0f, 1.0f, 0.0f,
-       1.0f, -1.0f,  0.0f, 1.0f, 0.0f,
-       0.0f,  1.0f,  0.0f, 0.0f, 1.0f
+    // x      y      z      u      v      nx     ny     nz
+      -1.0f, -1.0f,  0.0f,  0.0f,  0.0f,  0.0f,  0.0f,  0.0f,
+       0.0f, -1.0f,  1.0f,  1.0f,  0.0f,  0.0f,  0.0f,  0.0f,
+       1.0f, -1.0f,  0.0f,  1.0f,  0.0f,  0.0f,  0.0f,  0.0f,
+       0.0f,  1.0f,  0.0f,  0.0f,  1.0f,  0.0f,  0.0f,  0.0f
     };
 
     u32 indices[] = {
@@ -38,12 +39,14 @@ int main() {
       0, 1, 2
     };
 
+    calculate_normals_avg(vertices, 32, 8, indices, 12, 5);
+
     Mesh *pyramid1 = new Mesh();
-    create_mesh(pyramid1, vertices, indices, 20, 12);
+    create_mesh(pyramid1, vertices, indices, 32, 12);
     meshes[0] = pyramid1;
 
     Mesh *pyramid2 = new Mesh();
-    create_mesh(pyramid2, vertices, indices, 20, 12);
+    create_mesh(pyramid2, vertices, indices, 32, 12);
     meshes[1] = pyramid2;
   }
 
@@ -60,9 +63,9 @@ int main() {
   Texture plaster_texture = Texture((char *)"assets/textures/plaster_texture_1k.png");
   load_texture(&plaster_texture);
 
-  Matrix4 projection = glm::perspective(
-      45.0f, (f32)window.buffer_width / (f32)window.buffer_height, 0.1f,
-      100.0f);
+  Light sun_light(Vector3(1.0f, 1.0f, 1.0f), 0.2f, Vector3(2.0f, -1.0, -2.0f), 1.0f);
+
+  Matrix4 projection = glm::perspective(45.0f, (f32)window.buffer_width / (f32)window.buffer_height, 0.1f, 100.0f);
 
   Camera camera(Vector3(0.0f, 0.0f, 0.0f), Vector3(0.0f, 1.0f, 0.0f), 90.0f, 0.0f, 5.0f, 1.0f);
 
@@ -74,9 +77,6 @@ int main() {
     dt = now - last_dt;
     last_dt = now;
 
-    // Get and handle user input events
-    glfwPollEvents();
-
     key_control(&camera, window.ascii_keys, dt);
     mouse_control(&camera, window.x_change_position, window.y_change_position);
 
@@ -90,6 +90,12 @@ int main() {
 
     glUseProgram(shaders[0].id);
 
+    use_light(
+      &sun_light,
+      shaders[0].uniform_ambient_color, shaders[0].uniform_ambient_intensity,
+      shaders[0].uniform_diffuse_direction, shaders[0].uniform_diffuse_intensity
+    );
+
     {
       Matrix4 model(1.0f);
       model = glm::translate(model, Vector3(0.0f, 0.0f, -2.5f));
@@ -125,6 +131,9 @@ int main() {
     // that it now shows. We then can start drawing on the other
     // buffer.
     glfwSwapBuffers(window.gl_window);
+
+    // Get and handle user input events
+    glfwPollEvents();
   }
 
   return 0;

src/math.h

@@ -1,6 +1,7 @@
 #pragma once
 
-#include <cstdint>
+// #include <cstdint>
+#include <string>
 #include <glm/glm.hpp>
 #include <glm/gtc/matrix_transform.hpp>
 #include <glm/gtc/type_ptr.hpp>
@@ -34,5 +35,7 @@ typedef double f64;
 
 using Matrix4 = glm::mat4;
 using Vector3 = glm::vec3;
+using string = std::string;
 
 const f32 RADIAN_FACTOR = 3.14159265f / 180.0f;
+

src/mesh.cpp

@@ -32,13 +32,16 @@ void create_mesh(
   glBufferData(GL_ARRAY_BUFFER, sizeof(vertices[0]) * vertices_count, vertices, GL_STATIC_DRAW);
 
   // Position vertices
-  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(vertices[0]) * 5, 0);
+  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(vertices[0]) * 8, 0);
   glEnableVertexAttribArray(0);
 
   // Texture coordinates
-  glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(vertices[0]) * 5, (void *)(sizeof(vertices[0]) * 3));
+  glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(vertices[0]) * 8, (void *)(sizeof(vertices[0]) * 3));
   glEnableVertexAttribArray(1);
 
+  glVertexAttribPointer(2, 3, GL_FLOAT, GL_FALSE, sizeof(vertices[0]) * 8, (void *)(sizeof(vertices[0]) * 5));
+  glEnableVertexAttribArray(2);
+
   // Unbinding
   glBindBuffer(GL_ARRAY_BUFFER, 0);
   glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
@@ -73,3 +76,51 @@ void clear_mesh(Mesh *mesh) {
 
   mesh->index_count = 0;
 }
+
+void calculate_normals_avg(f32 *vertices, u32 vertices_count, u32 vertices_length, u32 *indices, u32 indices_count, u32 normal_offset) {
+  for (size_t i = 0; i< indices_count; i+=3) {
+    u32 in0 = indices[i]   * vertices_length;
+    u32 in1 = indices[i+1] * vertices_length;
+    u32 in2 = indices[i+2] * vertices_length;
+
+    Vector3 v1;
+    v1.x = vertices[in1]   - vertices[in0];
+    v1.y = vertices[in1+1] - vertices[in0+1];
+    v1.z = vertices[in1+2] - vertices[in0+2];
+
+    Vector3 v2;
+    v2.x = vertices[in2]   - vertices[in0];
+    v2.y = vertices[in2+1] - vertices[in0+1];
+    v2.z = vertices[in2+2] - vertices[in0+2];
+    
+    Vector3 normal = glm::cross(v1, v2);
+    normal = glm::normalize(normal);
+
+    in0 += normal_offset;
+    in1 += normal_offset;
+    in2 += normal_offset;
+
+    vertices[in0]   += normal.x;
+    vertices[in0+1] += normal.y;
+    vertices[in0+2] += normal.z;
+
+    vertices[in1]   += normal.x;
+    vertices[in1+1] += normal.y;
+    vertices[in1+2] += normal.z;
+
+    vertices[in2]   += normal.x;
+    vertices[in2+1] += normal.y;
+    vertices[in2+2] += normal.z;
+  }
+
+  for(size_t i=0; i<vertices_count/vertices_length; i++) {
+    u32 n_offset = i * vertices_length + normal_offset;
+    Vector3 vector(vertices[n_offset], vertices[n_offset+1], vertices[n_offset+2]);
+    vector = glm::normalize(vector);
+
+    vertices[n_offset]   = vector.x;
+    vertices[n_offset+1] = vector.y;
+    vertices[n_offset+2] = vector.z;
+  }
+}
+

src/mesh.h

@@ -14,4 +14,5 @@ struct Mesh {
 void create_mesh(Mesh *mesh, f32 *vertices, u32 *indices, u32 vertices_count, u32 indices_count);
 void render_mesh(Mesh *mesh);
 void clear_mesh(Mesh *mesh);
+void calculate_normals_avg(f32 *vertices, u32 vertices_count, u32 vertices_length, u32 *indices, u32 indices_count, u32 normal_offset);
 

src/shader.cpp

@@ -11,8 +11,8 @@ Shader::~Shader() {
 }
 
 bool create_shader(Shader *shader, const char *vertex_shader_path, const char *fragment_shader_path) {
-  std::string vertex_shader_code = read_entire_file(vertex_shader_path);
-  std::string fragment_shader_code = read_entire_file(fragment_shader_path);
+  string vertex_shader_code = read_entire_file(vertex_shader_path);
+  string fragment_shader_code = read_entire_file(fragment_shader_path);
   
 
   shader->id = glCreateProgram();
@@ -65,6 +65,12 @@ bool create_shader(Shader *shader, const char *vertex_shader_path, const char *f
   shader->uniform_model = glGetUniformLocation(shader->id, "model");
   shader->uniform_view = glGetUniformLocation(shader->id, "view");
 
+  shader->uniform_ambient_color = glGetUniformLocation(shader->id, "sun.color");
+  shader->uniform_ambient_intensity = glGetUniformLocation(shader->id, "sun.ambient_intensity");
+
+  shader->uniform_diffuse_direction = glGetUniformLocation(shader->id, "sun.direction");
+  shader->uniform_diffuse_intensity = glGetUniformLocation(shader->id, "sun.diffuse_intensity");
+
   return true;
 }
 

src/shader.h

@@ -15,6 +15,10 @@ struct Shader {
   u32 uniform_projection;
   u32 uniform_model;
   u32 uniform_view;
+  u32 uniform_ambient_color;
+  u32 uniform_ambient_intensity;
+  u32 uniform_diffuse_direction;
+  u32 uniform_diffuse_intensity;
 
   Shader();
   ~Shader();

src/texture.h

@@ -1,8 +1,8 @@
 #pragma once
 
 #include <GL/glew.h>
+#include <stb_image.h>
 #include "math.h"
-#include "../lib/stb_image.h"
 
 struct Texture {
   u32 id = 0;