Typically, most people start off by manually entering vertex data into an array, to render basic shapes such as triangles, squares and cubes, but it’s practically impossible to create highly detailed models by taking that approach.
Graphics in modern computer games, can to some extent be considered cheating, simply because we now use sophisticated 3D modelling software to draw fancy looking models, and then import those models (with minimal effort, e.g. by using the ASSIMP model import library) into our games… and you couldn’t do that in the good old days.
Assisted by some graphics maths library such as GLM, we can then apply all sorts of fancy transformations to our ready-built models, as exported from Blender for example.
We can also enhance our already nice-looking models to look even more realistic by learning how to apply lighting, by implementing the Phong lighting model for example. We now potentially have the basis of some game that we might want to add various physics routines to…
Code updated: 24-06-2022 (Simply to demonstrate drawing two models via two for-loops within the main loop)
#include <glad/glad.h> // GLAD: https://github.com/Dav1dde/glad ... GLAD 2 also works via the web-service: https://gen.glad.sh/ (leaving all checkbox options unchecked) #include <GLFW/glfw3.h> #define STB_IMAGE_IMPLEMENTATION #include "stb_image.h" // OpenGL Mathematics(GLM) ... https://github.com/g-truc/glm/blob/master/manual.md // ------------------------------------ // GLM Headers // ------------------ #include <glm/glm.hpp> // Include all GLM core. // #include <glm/ext.hpp> // Include all GLM extensions. #include <glm/gtc/matrix_transform.hpp> // Specific extensions. #include <glm/gtc/type_ptr.hpp> #include <assimp/Importer.hpp> #include <assimp/scene.h> #include <assimp/postprocess.h> #include <vector> #include <iostream> #include <fstream> // Used in "shader_configure.h" to read the shader text files. #include "load_model_meshes.h" #include "shader_configure.h" // Used to create the shaders. int main() { // (1) GLFW: Initialise & Configure // ----------------------------------------- if (!glfwInit()) exit(EXIT_FAILURE); glfwWindowHint(GLFW_SAMPLES, 4); // Anti-aliasing glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4); glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2); glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); const GLFWvidmode* mode = glfwGetVideoMode(glfwGetPrimaryMonitor()); int monitor_width = mode->width; // Monitor's width. int monitor_height = mode->height; int window_width = (int)(monitor_width * 0.75f); // Window size will be 50% the monitor's size... int window_height = (int)(monitor_height * 0.75f); // ... Cast is simply to silence the compiler warning. GLFWwindow* window = glfwCreateWindow(window_width, window_height, "Assimp Model Loading - Blender Object Files", NULL, NULL); // GLFWwindow* window = glfwCreateWindow(window_width, window_height, "Assimp Model Loading - Blender Object Files", glfwGetPrimaryMonitor(), NULL); // Full Screen Mode ("Alt" + "F4" to Exit!) if (!window) { glfwTerminate(); exit(EXIT_FAILURE); } glfwMakeContextCurrent(window); // Set the window to be used and then centre that window on the monitor. glfwSetWindowPos(window, (monitor_width - window_width) / 2, (monitor_height - window_height) / 2); glfwSwapInterval(1); // Set VSync rate 1:1 with monitor's refresh rate. // (2) GLAD: Load OpenGL Function Pointers // ------------------------------------------------------- if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) // For GLAD 2 use the following instead: gladLoadGL(glfwGetProcAddress) { glfwTerminate(); exit(EXIT_FAILURE); } glEnable(GL_DEPTH_TEST); // Enabling depth testing allows rear faces of 3D objects to be hidden behind front faces. glEnable(GL_MULTISAMPLE); // Anti-aliasing glEnable(GL_BLEND); // GL_BLEND for OpenGL transparency which is further set within the fragment shader. glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); // (3) Compile Shaders Read from Text Files // ------------------------------------------------------ const char* vert_shader = "../../Shaders/shader_glsl.vert"; const char* frag_shader = "../../Shaders/shader_glsl.frag"; Shader main_shader(vert_shader, frag_shader); main_shader.use(); unsigned int view_matrix_loc = glGetUniformLocation(main_shader.ID, "view"); unsigned int projection_matrix_loc = glGetUniformLocation(main_shader.ID, "projection"); unsigned int camera_position_loc = glGetUniformLocation(main_shader.ID, "camera_position"); glm::vec3 camera_position(0.0f, 0.0f, 3.0f); // -Z is into the screen. glm::vec3 camera_target(0.0f, 0.0f, 0.0f); glm::vec3 camera_up(0.0f, 1.0f, 0.0f); glUniform3f(camera_position_loc, camera_position.x, camera_position.y, camera_position.z); glm::mat4 view = glm::lookAt(camera_position, camera_target, camera_up); glUniformMatrix4fv(view_matrix_loc, 1, GL_FALSE, glm::value_ptr(view)); // Uniform: Transfer view matrix to vertex shader. glm::mat4 projection = glm::perspective(glm::radians(55.0f), (float)window_width / (float)window_height, 0.1f, 100.0f); glUniformMatrix4fv(projection_matrix_loc, 1, GL_FALSE, glm::value_ptr(projection)); // (4) Enter the Main-Loop // -------------------------------- srand((unsigned)time(NULL)); // Initialise random seed. float x_spin = 1.0f / (rand() % 10 + 1); // Generate random number between 1 and 10 float y_spin = 1.0f / (rand() % 10 + 1); float z_spin = 1.0f / (rand() % 10 + 1); float spin_speed = (float)(rand() % 5 + 1); // Cast is simply to silence the compiler warning. float spin_vary = 0.0f; int spin_dir = 1; glm::mat4 spinning_mat(1.0f); unsigned int animate_loc = glGetUniformLocation(main_shader.ID, "animate"); // https://www.turbosquid.com/Search/3D-Models/free/commercial (Free Models) // ---------------------------------------------------------------------------------------- Model model_testing("model_testing.obj"); Model black_smith("black_smith.obj"); // Model model("The_Beast_Helicopter.obj"); // Model model("Plane_CAP_232.obj"); glActiveTexture(GL_TEXTURE0); // Reusing the same texture unit for each model mesh. unsigned int image_sampler_loc = glGetUniformLocation(main_shader.ID, "image"); glUniform1i(image_sampler_loc, 0); while (!glfwWindowShouldClose(window)) // Main-Loop { // (5) Randomise the Model's Spinning Speed & Axis // ------------------------------------------------------------------ spin_vary += 0.05f * spin_dir; if (spin_vary > 6 || spin_vary < 0) { spin_dir = -spin_dir; // Reverse the spinning direction. x_spin = 1.0f / (rand() % 10 + 1); y_spin = 1.0f / (rand() % 10 + 1); z_spin = 1.0f / (rand() % 10 + 1); spin_speed = (float)(rand() % 50 + 1) / 20; // std::cout << "\n Spin speed: " << spin_speed; } spinning_mat = glm::rotate(spinning_mat, glm::radians(spin_speed), glm::normalize(glm::vec3(x_spin, y_spin, z_spin))); glUniformMatrix4fv(animate_loc, 1, GL_FALSE, glm::value_ptr(spinning_mat)); // Pass rotation matrix to vertex shader. // (6) Clear the Screen & Draw Model Meshes // --------------------------------------------------------- glClearColor(0.30f, 0.55f, 0.65f, 1.0f); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); for (unsigned int i = 0; i < model_testing.num_meshes; ++i) { glBindTexture(GL_TEXTURE_2D, model_testing.mesh_list[i].tex_handle); // Bind texture for the current mesh. glBindVertexArray(model_testing.mesh_list[i].VAO); glDrawElements(GL_TRIANGLES, (GLsizei)model_testing.mesh_list[i].vert_indices.size(), GL_UNSIGNED_INT, 0); glBindVertexArray(0); } for (unsigned int i = 0; i < black_smith.num_meshes; ++i) { glBindTexture(GL_TEXTURE_2D, black_smith.mesh_list[i].tex_handle); // Bind texture for the current mesh. glBindVertexArray(black_smith.mesh_list[i].VAO); glDrawElements(GL_TRIANGLES, (GLsizei)black_smith.mesh_list[i].vert_indices.size(), GL_UNSIGNED_INT, 0); glBindVertexArray(0); } glfwSwapBuffers(window); glfwPollEvents(); } // (7) Exit the Application // ------------------------------ glDeleteProgram(main_shader.ID); // This OpenGL function call is talked about in: shader_configure.h /* glfwDestroyWindow(window) // Call this function to destroy a specific window */ glfwTerminate(); // Destroys all remaining windows and cursors, restores modified gamma ramps, and frees resources. exit(EXIT_SUCCESS); // Function call: exit() is a C/C++ function that performs various tasks to help clean up resources. }
#pragma once // Instead of using include guards. class Shader { public: GLuint ID; // Public Program ID. // Constructor // --------------- Shader(const char* vert_path, const char* frag_path) { char character; std::string vert_string; std::string frag_string; std::ifstream vert_stream; std::ifstream frag_stream; // Read vertex shader text file // ------------------------------------ vert_stream.open(vert_path); // I decided not to implement: Exception handling try catch method. if (vert_stream.is_open()) // Note: There are various other methods for accessing the stream, i.e., vert_stream.get() is just one option. { while (vert_stream.get(character)) // Loop getting single characters until EOF (value false) is returned. vert_string += character; // "The first signature returns the character read, or the end-of-file value (EOF) if no characters are available in the stream..." vert_stream.close(); std::cout << "File: " << vert_path << " opened successfully.\n\n"; } else std::cout << "ERROR!... File: " << vert_path << " could not be opened.\n\n"; // Read fragment shader text file // ---------------------------------------- frag_stream.open(frag_path); if (frag_stream.is_open()) { while (frag_stream.get(character)) frag_string += character; frag_stream.close(); std::cout << "File: " << frag_path << " opened successfully.\n\n"; } else std::cout << "ERROR!... File: " << frag_path << " could not be opened.\n\n"; std::cout << vert_string << "\n\n"; // Output the shader files to display in the console window. std::cout << frag_string << "\n\n"; const char* vert_pointer = vert_string.c_str(); const char* frag_pointer = frag_string.c_str(); // Compile shaders // ---------------------- GLuint vert_shad, frag_shad; // Declare in here locally. Being attached to the public Program ID allows the shaders to be used publicly. // Create vertex shader // --------------------------- vert_shad = glCreateShader(GL_VERTEX_SHADER); glShaderSource(vert_shad, 1, &vert_pointer, NULL); glCompileShader(vert_shad); Check_Shaders_Program(vert_shad, "vert_shader"); // Create fragment shader // ------------------------------- frag_shad = glCreateShader(GL_FRAGMENT_SHADER); glShaderSource(frag_shad, 1, &frag_pointer, NULL); glCompileShader(frag_shad); Check_Shaders_Program(frag_shad, "frag_shader"); // Create shader program // ------------------------------ ID = glCreateProgram(); glAttachShader(ID, vert_shad); // This also avoids deletion via: glDeleteShader(vert_shad) as called below. glAttachShader(ID, frag_shad); glLinkProgram(ID); Check_Shaders_Program(ID, "shader_program"); // Note: Flagging the program object for deletion before calling "glUseProgram" would accidentally stop the program installation of the rendering state // ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- glDeleteShader(vert_shad); // Flag shader object for automatic deletion (freeing memory) when no longer attached to a program object... glDeleteShader(frag_shad); // ... program object is deleted (glDeleteProgram ) within: main() when the application ends. // glUseProgram(ID); // Typically this is called within: main() to select individual shaders that have been created. // glDeleteProgram(ID); // Alternatively the program object can be deleted here after 1st calling: glUseProgram(ID) } // Activate the shader // ------------------------- void use() { glUseProgram(ID); // Function called from within main() to select an individual shader to be used. } private: // Check shader compilations and program object for linking errors // ------------------------------------------------------------------------------------- void Check_Shaders_Program(GLuint type, std::string name) { int success; int error_log_size; char info_log[1000]; // 1000 characters max. Typically it's less than 500 even for multiple shader errors. if (name == "vert_shader" || name == "frag_shader") { glGetShaderiv(type, GL_COMPILE_STATUS, &success); if (!success) { glGetShaderInfoLog(type, 1024, &error_log_size, info_log); std::cout << "\n--- Shader Compilation Error: " << name << "\n\n" << info_log << "\n" << "Error Log Number of Characters: " << error_log_size << "\n\n"; } } else // "shader_program" { glGetProgramiv(type, GL_LINK_STATUS, &success); if (!success) { glGetProgramInfoLog(type, 1024, &error_log_size, info_log); std::cout << "\n--- Program Link Error: " << name << "\n\n" << info_log << "\n" << "Error Log Number of Characters: " << error_log_size << "\n"; } } } };
#pragma once // Instead of using include guards. class Model { private: Assimp::Importer importer; // https://assimp-docs.readthedocs.io/en/v5.1.0/ ... (An older Assimp website: http://assimp.sourceforge.net/lib_html/index.html) const aiScene* scene = nullptr; aiNode* root_node = nullptr; // Only being used in the: load_model_cout_console() function. struct Mesh { unsigned int VAO, VBO1, VBO2, VBO3, EBO; // Buffer handles (Typically type: GLuint is used) std::vector<glm::vec3> vert_positions; std::vector<glm::vec3> vert_normals; std::vector<glm::vec2> tex_coords; std::vector<unsigned int> vert_indices; unsigned int tex_handle; }; struct Texture { unsigned int textureID; std::string image_name; }; public: unsigned int num_meshes; std::vector<Mesh> mesh_list; std::vector<Texture> texture_list; Model(const char* model_path) // Constructor { // http://assimp.sourceforge.net/lib_html/postprocess_8h.html (See: aiPostProcessSteps) (Flag options) // scene = importer.ReadFile(model_path, aiProcess_JoinIdenticalVertices | aiProcess_Triangulate | aiProcess_FlipUVs | aiProcess_CalcTangentSpace); scene = importer.ReadFile(model_path, aiProcess_JoinIdenticalVertices | aiProcess_Triangulate | aiProcess_FlipUVs); // scene = importer.ReadFile(model_path, aiProcess_JoinIdenticalVertices | aiProcess_FlipUVs); // scene = importer.ReadFile(model_path, aiProcess_Triangulate | aiProcess_FlipUVs); // scene = importer.ReadFile(model_path, NULL); load_model(); // Uncomment only one of these two load model functions. // load_model_cout_console(); } private: void load_model() { if (!scene || !scene->mRootNode || scene->mFlags & AI_SCENE_FLAGS_INCOMPLETE) std::cout << "Assimp importer.ReadFile (Error) -- " << importer.GetErrorString() << "\n"; else { num_meshes = scene->mNumMeshes; mesh_list.resize(num_meshes); aiMesh* mesh{}; int indices_offset = 0; // Not being used yet... i.e. indices_offset += mesh->mNumVertices; is commented further down. // (1) Loop through all the model's meshes // ----------------------------------------------------- for (unsigned int i = 0; i < num_meshes; ++i) { mesh = scene->mMeshes[i]; // http://assimp.sourceforge.net/lib_html/structai_mesh.html aiMaterial* material = scene->mMaterials[mesh->mMaterialIndex]; // http://assimp.sourceforge.net/lib_html/structai_material.html // This loop will only run once (i.e. there's only 1 texture per mesh) for (unsigned int tex_count = 0; tex_count < material->GetTextureCount(aiTextureType_DIFFUSE); ++tex_count) // Also, only using: aiTextureType_DIFFUSE. { aiString string; material->GetTexture(aiTextureType_DIFFUSE, tex_count, &string); // Acquire the name of the image file to be loaded. // (2) Load mesh [i]'s texture if not already loaded // --------------------------------------------------------------- int already_loaded = is_image_loaded(string.C_Str()); // Returns -1 if texture Not already loaded, otherwise returns Existing texture handle. if (already_loaded == -1) // Image not yet loaded so now attempt to load it. { bool load_success = false; unsigned int texture_handle = load_texture_image(string.C_Str(), load_success); if (load_success) // Although do nothing if the image fails to load. { Texture texture; texture.image_name = string.C_Str(); texture.textureID = texture_handle; texture_list.push_back(texture); mesh_list[i].tex_handle = texture_handle; } } else mesh_list[i].tex_handle = already_loaded; // Assign existing texture handle. } // (3) Loop through all mesh [i]'s vertices // --------------------------------------------------- for (unsigned int i2 = 0; i2 < mesh->mNumVertices; ++i2) { glm::vec3 position{}; position.x = mesh->mVertices[i2].x; position.y = mesh->mVertices[i2].y; position.z = mesh->mVertices[i2].z; mesh_list[i].vert_positions.push_back(position); if (mesh->HasNormals()) { glm::vec3 normal{}; normal.x = mesh->mNormals[i2].x; normal.y = mesh->mNormals[i2].y; normal.z = mesh->mNormals[i2].z; mesh_list[i].vert_normals.push_back(normal); } else mesh_list[i].vert_normals.push_back(glm::vec3(0.0f, 0.0f, 0.0f)); if (mesh->HasTextureCoords(0)) // Only slot [0] is in question. { glm::vec2 tex_coords{}; tex_coords.x = mesh->mTextureCoords[0][i2].x; tex_coords.y = mesh->mTextureCoords[0][i2].y; mesh_list[i].tex_coords.push_back(tex_coords); } else mesh_list[i].tex_coords.push_back(glm::vec2(0.0f, 0.0f)); } // (4) Loop through all mesh [i]'s Indices // -------------------------------------------------- for (unsigned int i3 = 0; i3 < mesh->mNumFaces; ++i3) for (unsigned int i4 = 0; i4 < mesh->mFaces[i3].mNumIndices; ++i4) mesh_list[i].vert_indices.push_back(mesh->mFaces[i3].mIndices[i4] + indices_offset); // indices_offset += mesh->mNumVertices; // Disabled for tutorial: Model Loading (Part 1 of 3) set_buffer_data(i); // Set up: VAO, VBO and EBO. } } } void load_model_cout_console() { // Briefly looking at the node structure // ------------------------------------------------ if (!scene || !scene->mRootNode || scene->mFlags & AI_SCENE_FLAGS_INCOMPLETE) std::cout << "Assimp importer.ReadFile (Error) -- " << importer.GetErrorString() << "\n"; else { num_meshes = scene->mNumMeshes; mesh_list.resize(num_meshes); std::cout << "\n\n Start of Assimp Loading Meshes & Analysis"; std::cout << "\n -----------------------------------------"; root_node = scene->mRootNode; std::cout << "\n node->mNumMeshes: " << root_node->mNumMeshes; std::cout << "\n node->mName.C_Str(): " << root_node->mName.C_Str(); std::cout << "\n\n node->mNumChildren: " << root_node->mNumChildren; // ------------------------------------------------------------------------------------------ for (unsigned int i = 0; i < root_node->mNumChildren; ++i) { std::cout << "\n node->mChildren[i]->mName.C_Str(): " << root_node->mChildren[i]->mName.C_Str(); std::cout << "\n node->mChildren[i]->mNumMeshes: " << root_node->mChildren[i]->mNumMeshes; } std::cout << "\n\n scene->HasMaterials(): " << scene->HasMaterials(); // ------------------------------------------------------------------------------------------ for (unsigned int i = 0; i < scene->mNumMaterials; ++i) std::cout << "\n scene->mMaterials[i]->GetName(): " << scene->mMaterials[i]->GetName().C_Str(); std::cout << "\n\n scene->HasTextures(): " << scene->HasTextures(); aiMesh* mesh{}; int total_num_indices = 0; int indices_offset = 0; // Not being used yet... i.e. indices_offset += mesh->mNumVertices; is commented further down. // (1) Loop through all the model's meshes // ----------------------------------------------------- std::cout << "\n scene->mNumMeshes: " << num_meshes; std::cout << "\n ********************\n"; // --------------------------------------------------------- for (unsigned int i = 0; i < num_meshes; ++i) // In this case... scene->mNumMeshes = node->mChildren[i]->mNumMeshes { mesh = scene->mMeshes[i]; // http://assimp.sourceforge.net/lib_html/structai_mesh.html std::cout << "\n\n mesh->mMaterialIndex: " << mesh->mMaterialIndex; std::cout << "\n ----------------------- "; std::cout << "\n mesh->mName.C_Str(): " << mesh->mName.C_Str(); aiMaterial* material = scene->mMaterials[mesh->mMaterialIndex]; // http://assimp.sourceforge.net/lib_html/structai_material.html std::cout << "\n\n material->GetTexture(aiTextureType_DIFFUSE, tex_count, &string): " << material->GetTextureCount(aiTextureType_DIFFUSE); std::cout << "\n material->GetTexture(aiTextureType_SPECULAR, tex_count, &string): " << material->GetTextureCount(aiTextureType_SPECULAR); std::cout << "\n material->GetTexture(aiTextureType_AMBIENT, tex_count, &string): " << material->GetTextureCount(aiTextureType_AMBIENT) << "\n\n"; unsigned int tex_count = 0; for (; tex_count < material->GetTextureCount(aiTextureType_DIFFUSE); ++tex_count) // The above std::cout reveals that only using: aiTextureType_DIFFUSE { aiString string; material->GetTexture(aiTextureType_DIFFUSE, tex_count, &string); // Acquire the name of the image file to be loaded. std::cout << " material->GetTexture(aiTextureType_DIFFUSE, tex_count, &string): " << string.C_Str() << "\n\n"; // (2) Load mesh [i]'s texture if not already loaded // --------------------------------------------------------------- int already_loaded = is_image_loaded(string.C_Str()); // Returns -1 if texture Not already loaded, otherwise returns Existing texture handle. std::cout << " Loading Image\n"; if (already_loaded == -1) // Image not yet loaded. { bool load_complete = false; unsigned int texture_handle = load_texture_image(string.C_Str(), load_complete); if (load_complete) // Although do nothing if the image fails to load. { Texture texture; texture.image_name = string.C_Str(); texture.textureID = texture_handle; texture_list.push_back(texture); mesh_list[i].tex_handle = texture_handle; } } else // Assign existing texture handle. { std::string edited = string.C_Str(); std::size_t position = edited.find_last_of("\\"); std::cout << " Image file: " << edited.substr(position + 1) << " (is already loaded)"; mesh_list[i].tex_handle = already_loaded; } } if (tex_count == 0) std::cout << " material->GetTexture(aiTextureType_DIFFUSE, tex_count, &string): No image has been applied to this mesh\n\n"; else std::cout << "\n"; for (unsigned int slot = 0; slot < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++slot) std::cout << " mesh->HasTextureCoords(" << slot << "): " << mesh->HasTextureCoords(slot) << "\n"; std::cout << "\n Mesh index: " << i << " (mesh->mNumVertices: " << mesh->mNumVertices << ")"; std::cout << "\n ------------------------------------- "; // (3) Loop through all mesh [i]'s vertices // --------------------------------------------------- for (unsigned int i2 = 0; i2 < mesh->mNumVertices; ++i2) { glm::vec3 position{}; position.x = mesh->mVertices[i2].x; position.y = mesh->mVertices[i2].y; position.z = mesh->mVertices[i2].z; mesh_list[i].vert_positions.push_back(position); std::cout << "\n Count: " << i2; std::cout << "\n mesh->mVertices[" << i2 << "].x: " << position.x; std::cout << "\n mesh->mVertices[" << i2 << "].y: " << position.y; std::cout << "\n mesh->mVertices[" << i2 << "].z: " << position.z; if (mesh->HasNormals()) { glm::vec3 normal{}; normal.x = mesh->mNormals[i2].x; normal.y = mesh->mNormals[i2].y; normal.z = mesh->mNormals[i2].z; mesh_list[i].vert_normals.push_back(normal); std::cout << "\n mesh->mNormals[" << i2 << "] X: " <<normal.x << " Y: " << normal.y << " Z: " << normal.z; } else mesh_list[i].vert_normals.push_back(glm::vec3(0.0f, 0.0f, 0.0f)); if (mesh->HasTextureCoords(0)) // Above for loop: AI_MAX_NUMBER_OF_TEXTURECOORDS reveals that only slot [0] is in question. { glm::vec2 tex_coords{}; tex_coords.x = mesh->mTextureCoords[0][i2].x; tex_coords.y = mesh->mTextureCoords[0][i2].y; mesh_list[i].tex_coords.push_back(tex_coords); std::cout << "\n mesh->mTextureCoords[0][" << i2 << "] X: " << tex_coords.x << " Y: " << tex_coords.y; } else mesh_list[i].tex_coords.push_back(glm::vec2(0.0f, 0.0f)); } std::cout << "\n\n mesh->mNumFaces: " << mesh->mNumFaces << "\n"; std::cout << " ------------------ "; // (4) Loop through all mesh [i]'s Indices // -------------------------------------------------- for (unsigned int i3 = 0; i3 < mesh->mNumFaces; ++i3) { std::cout << "\n"; for (unsigned int i4 = 0; i4 < mesh->mFaces[i3].mNumIndices; ++i4) { std::cout << " mesh->mFaces[" << i3 << "].mIndices[" << i4 << "]: " << mesh->mFaces[i3].mIndices[i4] << "\n"; mesh_list[i].vert_indices.push_back(mesh->mFaces[i3].mIndices[i4] + indices_offset); ++total_num_indices; } } std::cout << "\n Total number of indices: " << total_num_indices; std::cout << "\n **************************"; total_num_indices = 0; // indices_offset += mesh->mNumVertices; // Disabled for tutorial: Model Loading (Part 1 of 3) std::cout << "\n Indices offset (Total 'mesh->mNumVertices' so far): " << indices_offset; std::cout << "\n *****************************************************\n\n"; set_buffer_data(i); // Set up: VAO, VBO and EBO. } // Look to see if each mesh's texture handle corresponds correctly to the loaded image // ---------------------------------------------------------------------------------------------------------------- if (texture_list.size() > 0) for (unsigned int i = 0; i < texture_list.size(); ++i) { std::cout << " image_list[" << i << "].imageID: " << texture_list[i].textureID << "... image_list[" << i << "].image_name: " << texture_list[i].image_name << "\n"; for (unsigned int i2 = 0; i2 < num_meshes; ++i2) if (texture_list[i].textureID == mesh_list[i2].tex_handle) std::cout << " mesh_list[" << i2 << "].tex_handle: " << mesh_list[i2].tex_handle << "\n"; std::cout << "\n"; } else std::cout << " ***** No images have been loaded\n"; } } void set_buffer_data(unsigned int index) { glGenVertexArrays(1, &mesh_list[index].VAO); glGenBuffers(1, &mesh_list[index].VBO1); // Alternative to using 3 separate VBOs, instead use only 1 VBO and set glVertexAttribPointer's offset... glGenBuffers(1, &mesh_list[index].VBO2); // like was done in tutorial 3... Orbiting spinning cubes. glGenBuffers(1, &mesh_list[index].VBO3); glGenBuffers(1, &mesh_list[index].EBO); glBindVertexArray(mesh_list[index].VAO); // Vertex Positions // --------------------- glBindBuffer(GL_ARRAY_BUFFER, mesh_list[index].VBO1); glBufferData(GL_ARRAY_BUFFER, sizeof(glm::vec3) * mesh_list[index].vert_positions.size(), &mesh_list[index].vert_positions[0], GL_STATIC_DRAW); glEnableVertexAttribArray(0); // Void pointer below is for legacy reasons. Two possible meanings: "offset for buffer objects" & "address for client state arrays" glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0); // Vertex Normals // -------------------- glBindBuffer(GL_ARRAY_BUFFER, mesh_list[index].VBO2); glBufferData(GL_ARRAY_BUFFER, sizeof(glm::vec3) * mesh_list[index].vert_normals.size(), &mesh_list[index].vert_normals[0], GL_STATIC_DRAW); glEnableVertexAttribArray(1); glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0); // Texture Coordinates // --------------------------- glBindBuffer(GL_ARRAY_BUFFER, mesh_list[index].VBO3); glBufferData(GL_ARRAY_BUFFER, sizeof(glm::vec2) * mesh_list[index].tex_coords.size(), &mesh_list[index].tex_coords[0], GL_STATIC_DRAW); glEnableVertexAttribArray(2); glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(float), (void*)0); // Indices for: glDrawElements() // --------------------------------------- glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mesh_list[index].EBO); glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(unsigned int) * mesh_list[index].vert_indices.size(), &mesh_list[index].vert_indices[0], GL_STATIC_DRAW); glBindVertexArray(0); // Unbind VAO } int is_image_loaded(std::string file_name) { for (unsigned int i = 0; i < texture_list.size(); ++i) if (file_name.compare(texture_list[i].image_name) == 0) return texture_list[i].textureID; return -1; } unsigned int load_texture_image(std::string file_name, bool& load_complete) { // stbi_set_flip_vertically_on_load(1); // Call this function if the image is upside-down. std::size_t position = file_name.find_last_of("\\"); file_name = "Images\\" + file_name.substr(position + 1); int width, height, num_components; unsigned char* image_data = stbi_load(file_name.c_str(), &width, &height, &num_components, 0); unsigned int textureID; glGenTextures(1, &textureID); if (image_data) { GLenum format{}; if (num_components == 1) format = GL_RED; else if (num_components == 3) format = GL_RGB; else if (num_components == 4) format = GL_RGBA; glBindTexture(GL_TEXTURE_2D, textureID); glPixelStorei(GL_UNPACK_ALIGNMENT, 1); // Recommended by NVIDIA Rep: https://devtalk.nvidia.com/default/topic/875205/opengl/how-does-gl_unpack_alignment-work-/ glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, format, GL_UNSIGNED_BYTE, image_data); glGenerateMipmap(GL_TEXTURE_2D); // https://www.khronos.org/registry/OpenGL-Refpages/gl4/html/glTexParameter.xhtml // ---------------------------------------------------------------------------------------------------------------- glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_MIRRORED_REPEAT); // GL_REPEAT... GL_MIRRORED_REPEAT... GL_CLAMP_TO_EDGE... GL_CLAMP_TO_BORDER. glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_MIRRORED_REPEAT); // float border_colour[] = {0.45, 0.55, 0.95}; // glTexParameterfv(GL_TEXTURE_2D, GL_TEXTURE_BORDER_COLOR, border_colour); // For above when using: GL_CLAMP_TO_BORDER 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_MIN_FILTER, GL_LINEAR); // GL_NEAREST... GL_LINEAR... GL_NEAREST_MIPMAP_NEAREST (See above link for full list) glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); // GL_NEAREST or GL_LINEAR. load_complete = true; stbi_image_free(image_data); std::cout << " Image loaded OK: " << file_name << "\n"; } else { load_complete = false; stbi_image_free(image_data); std::cout << " Image failed to load: " << file_name << "\n"; } return textureID; } };
#version 420 core layout (location = 0) in vec3 aPos; // Attribute data: vertex(s) X, Y, Z position via VBO set up on the CPU side. layout (location = 1) in vec3 aNormal; layout (location = 2) in vec2 aTexCoord; out vec3 vert_pos_varying; // Vertex position coordinates passed to the fragment shader as interpolated per-vertex. out vec3 vert_pos_transformed; // Transformed cube vertex position coordinates also passed as interpolated. out vec3 vertex_normal; out vec2 texture_coordinates; uniform mat4 view; uniform mat4 projection; uniform mat4 animate; void main() { vert_pos_varying = aPos; // Send aPos vertex position values to fragment shader, which can be used as colour values instead of using texture images. vert_pos_transformed = vec3(animate * vec4(aPos, 1.0)); // Send transformed position values, which are used for the lighting effects. texture_coordinates = aTexCoord; mat3 normal_matrix = transpose(inverse(mat3(animate))); vertex_normal = normal_matrix * aNormal; if (length(vertex_normal) > 0) vertex_normal = normalize(vertex_normal); //Never try to normalise zero vectors (0,0,0) // https://www.khronos.org/opengl/wiki/Vertex_Post-Processing gl_Position = projection * view * animate * vec4(aPos, 1.0); // Output to vertex stream for the "Vertex Post-Processing" stage. }
#version 420 core out vec4 fragment_colour; // Must be the exact same name as declared in the vertex shader // ----------------------------------------------------------------------------------- in vec3 vert_pos_varying; // Vertex position coordinates received from the fragment shader as interpolated per-vertex. in vec3 vert_pos_transformed; // Transformed cube vertex position coordinates also received as interpolated. in vec3 vertex_normal; in vec2 texture_coordinates; uniform sampler2D image; uniform vec3 camera_position; // -Z is into the screen... camera_position is set in main() on CPU side. void main() { // This initial fragment colour is simply overridden via the Phong lighting "fragment_colour = " further down (But is used via "fragment... +=") // --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- // fragment_colour = vec4(abs(vert_pos_varying) / 1.25, 1.0); // fragment_colour = vec4(abs(vert_pos_transformed) / 2.95, 1.0); // 3.75 vec3 view_direction = normalize(camera_position - vert_pos_transformed); vec3 light_position = vec3(0.0, 5.0, 0.0); // A position used as a light source acts as a point light (Not a directional light) vec3 light_direction = normalize(vec3(light_position - vert_pos_transformed)); vec4 image_colour = texture(image, texture_coordinates); float ambient_factor = 0.65; // Intensity multiplier. vec4 ambient_result = vec4(ambient_factor * image_colour.rgb, 1.0); // Perpendicular vectors dot product = 0 // Parallel vectors in same direction dot product = 1 // Parallel vectors in opposite direction dot product = -1 // ---------------------------------------------------------------------- float diffuse_factor = 0.85; float diffuse_angle = max(dot(light_direction, vertex_normal), -0.45); // [-1.0 to 0] down to -1 results in darker lighting past 90 degrees. vec4 diffuse_result = vec4(diffuse_factor * diffuse_angle * image_colour.rgb, 1.0); vec3 specular_colour = vec3(0.5, 0.5, 0.5); vec3 reflect_direction = normalize(reflect(-light_direction, vertex_normal)); // Light direction is negated here. float specular_strength = pow(max(dot(view_direction, reflect_direction), 0), 32); vec4 specular_result = vec4(specular_colour * specular_strength, 1.0); fragment_colour = ambient_result + diffuse_result + specular_result; // fragment_colour = ambient_result; // fragment_colour = diffuse_result; // fragment_colour = specular_result; // fragment_colour = ambient_result + diffuse_result; // fragment_colour = ambient_result + specular_result; // fragment_colour = image_colour; // Enable this to have no lighting effects. // Comment all the above "fragment_colour =" if using these // ----------------------------------------------------------------------------- // fragment_colour += diffuse_result; // Adds image texture to the initial vert_pos... varying or transformed colour values. // fragment_colour += specular_result; }