feat: directional lighting

frag.glsl

@@ -1,15 +1,29 @@
 #version 330 core
 
+in vec3 Normal;
+in vec3 FragPos;
+
 out vec4 FragColor;
 
 void main()
 {
     vec3 objectColor = vec3(1.0, 0.5, 0.2);
-    vec3 lightColor = vec3(1.0, 1.0, 1.0);
+    vec3 result;
+
+    // Ambient lighting
+    vec3 ambientLightColor = vec3(1.0, 1.0, 1.0);
     float ambientStrength = 0.1;
+    vec3 ambient = ambientStrength * ambientLightColor;
 
-    vec3 ambient = ambientStrength * lightColor;
-    vec3 result = ambient * objectColor;
+    // Directional lighting
+    vec3 directionalLightColor = vec3(1.0, 1.0, 1.0);
+    vec3 lightPos = vec3(10.0, 7.0, -8.0);
+    vec3 normal = normalize(Normal);
+    vec3 lightDir = normalize(lightPos - FragPos);
+    float diff = max(dot(normal, lightDir), 0.0);
+    vec3 diffuse = diff * directionalLightColor;
 
-    FragColor = vec4(ambient, 1.0);
+    result = (ambient + diffuse) * objectColor;
+
+    FragColor = vec4(result, 1.0);
 }

src/hello.cpp

@@ -60,6 +60,9 @@ int initGraphics(GLFWwindow** window)
         std::cerr << "Failed to initialize GLFW" << std::endl;
         return -1;
     }
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
+    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
 
     *window = glfwCreateWindow(640, 480, "Hello Astro", NULL, NULL);
     if (!window)
@@ -93,22 +96,37 @@ GLint getShaderUniformLocation(GLuint shaderProgram, const std::string& uniformN
     return location;
 }
 
-void updateModelViewProjectionMatrix(GLuint shaderProgram, float time)
+void updateProjectionMatrix(GLuint shaderProgram)
 {
     // Calculate matrices
     float left = -1.0, right = 1.0, bottom = -1.0, top = 1.0, near = -1.0, far = 1.0;
     glm::mat4 projection = glm::ortho(left, right, bottom, top, near, far);
+    GLint projectionLocation = getShaderUniformLocation(shaderProgram, "_Projection");
+    glUniformMatrix4fv(projectionLocation, 1, GL_FALSE, &projection[0][0]);
+}
 
+void updateModelMatrix(GLuint shaderProgram, float time)
+{
     constexpr float angle = glm::radians(10.0);
     glm::vec3 axis = glm::vec3(0.0, 1.0, 0.0);
     glm::mat4 model = glm::rotate(glm::mat4(1.0), angle * time, axis);
+    GLint modelLocation = getShaderUniformLocation(shaderProgram, "_Model");
+    glUniformMatrix4fv(modelLocation, 1, GL_FALSE, &model[0][0]);
+}
 
+void updateViewMatrix(GLuint shaderProgram)
+{
     glm::mat4 view = glm::mat4(1.0);
+    GLint viewLocation = getShaderUniformLocation(shaderProgram, "_View");
+    glUniformMatrix4fv(viewLocation, 1, GL_FALSE, &view[0][0]);
+}
 
-    glm::mat4 mvp = projection * model * view;
-
-    GLint mvpLocation = getShaderUniformLocation(shaderProgram, "_ModelViewProjectionMatrix");
-    glUniformMatrix4fv(mvpLocation, 1, GL_FALSE, &mvp[0][0]);
+void updateModelViewProjectionMatrix(GLuint shaderProgram, float time)
+{
+    // Calculate matrices
+    updateProjectionMatrix(shaderProgram);
+    updateModelMatrix(shaderProgram, time);
+    updateViewMatrix(shaderProgram);
 }
 
 int main()

src/icosphere.cpp

@@ -22,28 +22,43 @@ Icosphere::Icosphere(int subdivisions)
 
 	glBindVertexArray(_vao);
 
-	for (const auto& v : vertices)
-	{
-		_vertices.push_back(v[0]);
-		_vertices.push_back(v[1]);
-		_vertices.push_back(v[2]);
-	}
-	glBindBuffer(GL_ARRAY_BUFFER, _vbo);
-    size_t vboBufferSize = _vertices.size() * sizeof(float);
-	glBufferData(GL_ARRAY_BUFFER, vboBufferSize, &_vertices[0], GL_STATIC_DRAW);
-
 	for (const auto& tri : triangles)
 	{
 		_indices.push_back(tri.vertex[0]);
 		_indices.push_back(tri.vertex[1]);
 		_indices.push_back(tri.vertex[2]);
 	}
-	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _ebo);
-    size_t egoBufferSize = _indices.size() * sizeof(unsigned int);
-	glBufferData(GL_ELEMENT_ARRAY_BUFFER, egoBufferSize, &_indices[0], GL_STATIC_DRAW);
+	for (const auto& v : vertices)
+	{
+        // Vertex Data
+		_vertices.push_back(v[0]);
+		_vertices.push_back(v[1]);
+		_vertices.push_back(v[2]);
 
-	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
+        // Normal data
+        // The normal at each vertex is actually going to just be the vertex again, but
+        // normalised, because this is a sphere.
+        glm::vec3 normal = normalize(v);
+        _vertices.push_back(normal[0]);
+        _vertices.push_back(normal[1]);
+        _vertices.push_back(normal[2]);
+	}
+
+	glBindBuffer(GL_ARRAY_BUFFER, _vbo);
+    size_t vboBufferSize = _vertices.size() * sizeof(float);
+	glBufferData(GL_ARRAY_BUFFER, vboBufferSize, &_vertices[0], GL_STATIC_DRAW);
+
+	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _ebo);
+    size_t eboBufferSize = _indices.size() * sizeof(unsigned int);
+	glBufferData(GL_ELEMENT_ARRAY_BUFFER, eboBufferSize, &_indices[0], GL_STATIC_DRAW);
+
+    // Vertex position attribute
 	glEnableVertexAttribArray(0);
+	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
+
+    // Vertex normal attribute
+	glEnableVertexAttribArray(1);
+	glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
 
 	glBindBuffer(GL_ARRAY_BUFFER, 0);
 	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
@@ -116,4 +131,5 @@ Icosphere::~Icosphere()
 {
     glDeleteVertexArrays(1, &_vao);
     glDeleteBuffers(1, &_vbo);
+    glDeleteBuffers(1, &_ebo);
 }

vert.glsl

@@ -1,12 +1,27 @@
 #version 330 core
 
 layout (location = 0) in vec3 aPos;
+layout (location = 1) in vec3 aNormal;
 
-uniform mat4x4 _ModelViewProjectionMatrix;
+uniform mat4x4 _Model;
+uniform mat4x4 _View;
+uniform mat4x4 _Projection;
+
+out vec3 Normal;
+out vec3 FragPos;
 
 void main()
 {
-    vec4 pos = vec4(aPos.x, aPos.y, aPos.z, 1.0);
-    gl_Position = _ModelViewProjectionMatrix * pos;
-}
+    vec4 pos = vec4(aPos, 1.0);
+    mat4x4 mvp = _Projection * _Model * _View;
 
+    gl_Position = mvp * pos;
+    FragPos = vec3(_Model * pos);
+
+    // Convert the normal from model to world space
+    mat3 normalMatrix = mat3(mvp);
+    normalMatrix = inverse(normalMatrix);
+    normalMatrix = transpose(normalMatrix);
+    Normal = normalize(normalMatrix * aNormal);
+    //Normal = normalize(_Model * aNormal);
+}