Add material for specular lighting

shaders/shader.frag

@@ -3,6 +3,7 @@
 in vec4 vertex_color;
 in vec2 texture_coord;
 in vec3 normal;
+in vec3 frag_pos;
 
 out vec4 color;
 
@@ -13,8 +14,16 @@ struct Directional_Light {
     float diffuse_intensity;
 };
 
+struct Material {
+    float shininess;
+    float specular_intensity;
+};
+
 uniform sampler2D tex;
 uniform Directional_Light sun;
+uniform Material material;
+uniform vec3 eye_position;
+
 
 void main() {
     vec4 ambient_color = vec4(sun.color, 1.0f) * sun.ambient_intensity;
@@ -22,5 +31,18 @@ void main() {
     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);
+    vec4 specular_color = vec4(0, 0, 0, 0);
+
+    if (diffuse_factor > 0.0f) {
+        vec3 frag_to_eye = normalize(eye_position - frag_pos);
+        vec3 reflected_vertex = normalize(reflect(sun.direction, normalize(normal)));
+        float specular_factor = dot(frag_to_eye, reflected_vertex);
+
+        if (specular_factor > 0) {
+            specular_factor = pow(specular_factor, material.shininess);
+            specular_color = vec4(sun.color * material.specular_intensity * specular_factor, 1.0f);
+        }
+    }
+
+    color = texture(tex, texture_coord) * (ambient_color + diffuse_color + specular_color);
 }

shaders/shader.vert

@@ -7,6 +7,7 @@ layout (location = 2) in vec3 norm;
 out vec4 vertex_color;
 out vec2 texture_coord;
 out vec3 normal;
+out vec3 frag_pos;
 
 uniform mat4 projection;
 uniform mat4 model;
@@ -17,4 +18,5 @@ void main() {
     vertex_color = vec4(clamp(pos, 0.0f, 1.0f), 1.0f);
     texture_coord = tex;
     normal = mat3(transpose(inverse(model))) * norm;
+    frag_pos = (model * vec4(pos, 1.0)).xyz;
 }

src/light.h

@@ -16,4 +16,5 @@ struct Light {
   ~Light() = default;
 };
 
+// Some of these should be u32
 void use_light(Light *light, f32 color_location, f32 ambient_intensity_location, f32 direction_location, f32 diffuse_intensity_location);

src/main.cpp

@@ -6,6 +6,7 @@
 #include "camera.h"
 #include "texture.h"
 #include "light.h"
+#include "material.h"
 
 
 static const char *vertex_shader_code = "shaders/shader.vert";
@@ -63,6 +64,9 @@ int main() {
   Texture plaster_texture = Texture((char *)"assets/textures/plaster_texture_1k.png");
   load_texture(&plaster_texture);
 
+  Material shiny_material(1.0f, 32.0f);
+  Material dull_material(0.3f, 4.0f);
+
   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);
@@ -96,32 +100,32 @@ int main() {
       shaders[0].uniform_diffuse_direction, shaders[0].uniform_diffuse_intensity
     );
 
+    glUniformMatrix4fv(shaders[0].uniform_projection, 1, GL_FALSE, glm::value_ptr(projection));
+    Matrix4 view = calculate_view_matrix(&camera);
+    glUniformMatrix4fv(shaders[0].uniform_view, 1, GL_FALSE, glm::value_ptr(view));
+    glUniform3f(shaders[0].uniform_eye_position, camera.position.x, camera.position.y, camera.position.z);
+
     {
       Matrix4 model(1.0f);
-      model = glm::translate(model, Vector3(0.0f, 0.0f, -2.5f));
-      model = glm::scale(model, Vector3(0.4f, 0.4f, 1.0f));
+      model = glm::translate(model, Vector3(0.0f, 3.0f, 2.5f));
+      // model = glm::scale(model, Vector3(0.4f, 0.4f, 1.0f));
 
       glUniformMatrix4fv(shaders[0].uniform_model, 1, GL_FALSE, glm::value_ptr(model));
-      glUniformMatrix4fv(shaders[0].uniform_projection, 1, GL_FALSE, glm::value_ptr(projection));
       use_texture(&clay_texture);
+      use_material(&shiny_material, shaders[0].uniform_shininess, shaders[0].uniform_specular_intensity);
       render_mesh(meshes[0]);
     }
 
     {
       Matrix4 model(1.0f);
-      model = glm::translate(model, Vector3(0.0f, 0.0f, -3.5f));
-      model = glm::scale(model, Vector3(0.4f, 0.4f, 1.0f));
+      model = glm::translate(model, Vector3(0.0f, 0.0f, 3.5f));
 
       glUniformMatrix4fv(shaders[0].uniform_model, 1, GL_FALSE, glm::value_ptr(model));
-      glUniformMatrix4fv(shaders[0].uniform_projection, 1, GL_FALSE, glm::value_ptr(projection));
       use_texture(&plaster_texture);
+      use_material(&dull_material, shaders[0].uniform_shininess, shaders[0].uniform_specular_intensity);
       render_mesh(meshes[1]);
     }
 
-    Matrix4 view = calculate_view_matrix(&camera);
-    glUniformMatrix4fv(shaders[0].uniform_view, 1, GL_FALSE, glm::value_ptr(view));
-
-
     glUseProgram(0);
 
     // We usually have two buffers, the first is hidden and that's

src/material.cpp

@@ -0,0 +1,10 @@
+#include "material.h"
+
+
+Material::Material(f32 specular_intensity, f32 shininess) : specular_intensity(specular_intensity), shininess(shininess) {}
+
+void use_material(Material *material, u32 shininess_location, u32 specular_intensity_location) {
+  glUniform1f(shininess_location, material->shininess);
+  glUniform1f(specular_intensity_location, material->specular_intensity);
+}
+

src/material.h

@@ -0,0 +1,17 @@
+#pragma once
+
+#include <GL/glew.h>
+#include "math.h"
+
+/*
+The kind of a thing
+*/
+struct Material {
+  f32 shininess;
+  f32 specular_intensity;
+
+  Material(f32 specular_intensity, f32 shininess);
+  ~Material() = default;
+};
+
+void use_material(Material *material, u32 shininess_location, u32 specular_intensity_location);

src/mesh.h

@@ -3,6 +3,9 @@
 #include "math.h"
 #include <GL/glew.h>
 
+/*
+The shape of a thing
+*/
 struct Mesh {
   u32 VAO, VBO, IBO;
   u32 index_count;

src/shader.cpp

@@ -64,13 +64,16 @@ bool create_shader(Shader *shader, const char *vertex_shader_path, const char *f
   shader->uniform_projection = glGetUniformLocation(shader->id, "projection");
   shader->uniform_model = glGetUniformLocation(shader->id, "model");
   shader->uniform_view = glGetUniformLocation(shader->id, "view");
+  shader->uniform_eye_position = glGetUniformLocation(shader->id, "eye_position");
 
   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");
 
+  shader->uniform_shininess = glGetUniformLocation(shader->id, "material.shininess");
+  shader->uniform_specular_intensity = glGetUniformLocation(shader->id, "material.specular_intensity");
+
   return true;
 }
 

src/shader.h

@@ -15,11 +15,17 @@ struct Shader {
   u32 uniform_projection;
   u32 uniform_model;
   u32 uniform_view;
+  u32 uniform_eye_position;
+
   u32 uniform_ambient_color;
   u32 uniform_ambient_intensity;
+
   u32 uniform_diffuse_direction;
   u32 uniform_diffuse_intensity;
 
+  u32 uniform_shininess;
+  u32 uniform_specular_intensity;
+
   Shader();
   ~Shader();
 };

src/window.h

@@ -9,7 +9,7 @@
 #include "math.h"
 
 struct Window {
-  u32 width = 800, height = 600;
+  u32 width = 1024, height = 768;
   s32 buffer_width, buffer_height;
   GLFWwindow *gl_window = nullptr;
   bool ascii_keys[1024];