參考文獻：https://learnopengl.com/#!Getting-started/OpenGL
一、模型
有了mesh類之後，接下來就是實現一個model類將各個mesh拼成一個模型
首先是模型的創建：很好理解，就是一次繪製其所有的mesh：
public:
Model(const GLchar* path)
{
this->loadModel(path);
}
void Draw(Shader shader)
{
for (GLuint i = 0; i < this->meshes.size(); i++)
this->meshes[i].Draw(shader);
}
接下來就是模型的導入：
其中的scene對象是Assimp的數據結構的根對象（場景對象），一旦有了場景對象，就可以從已加載模型中獲取所有需要的數據
- importer.ReadFile：函數第一個參數爲模型的路徑，第二個參數可以讓Assimp導入數據時做一些額外的計算或操作
有以下幾種常見的設置：
- aiProcess_Triangulate：將模型三角化
- aiProcess_FlipUVs：沿y軸翻轉座標（這個在 OpenGL基礎9：紋理 這一章中有過類似的介紹：爲什麼要翻轉y軸）
- aiProcess_GenNormals : 如果模型沒有包含法線向量，就爲每個頂點創建法線（暫時不需要了解）
- aiProcess_SplitLargeMeshes : 把大的網格成幾個小的的下級網格，當渲染有一個最大數量頂點的限制時或者只能處理小塊網格時很有用（暫時不需要了解）
- aiProcess_OptimizeMeshes : 和上個選項相反，它把幾個網格結合爲一個更大的網格（暫時不需要了解）
void loadModel(string path)
{
Assimp::Importer importer;
const aiScene* scene = importer.ReadFile(path, aiProcess_Triangulate | aiProcess_FlipUVs);
if (!scene || scene->mFlags == AI_SCENE_FLAGS_INCOMPLETE || !scene->mRootNode)
{
cout << "ERROR::ASSIMP:: " << importer.GetErrorString() << endl;
return;
}
this->directory = path.substr(0, path.find_last_of('/'));
this->processNode(scene->mRootNode, scene);
}
注意一下代碼中的 this->directory 路徑，樣例中是指向了對應模型的文件夾，但是有的時候模型文件內的貼圖路徑是絕對路徑又或者默認退回上一層目錄，這個時候要不修改模型文件，要不就修改這裏的 this->directory
對於Assimp的結構，每個節點包含一個網格集合的索引，每個索引指向一個在場景對象中特定的網格位置，如果想要獲取並處理這些網格索引，就需要進行類似於樹遞歸的操作：
//依次處理所有的場景節點
void processNode(aiNode* node, const aiScene* scene)
{
for (GLuint i = 0; i < node->mNumMeshes; i++)
{
aiMesh* mesh = scene->mMeshes[node->mMeshes[i]];
this->meshes.push_back(this->processMesh(mesh, scene));
}
for (GLuint i = 0; i < node->mNumChildren; i++)
this->processNode(node->mChildren[i], scene);
}
用上面的方法，就可以獲得每個節點的網格了，當然對於原始的 aimesh 對象要將它們全部轉換成我們自己定義的網格對象：這個很好辦，只需要獲取每個網格相關的屬性並把這些屬性儲存到我們自己的對象就可以了，包括處理頂點座標、法線和紋理座標、頂點索引以及材質
- 關於紋理：Assimp允許一個模型的每個頂點有8個不同的紋理座標，暫時只關心第一組紋理座標，當然啦，網格也可能完全沒有紋理座標
- 關於頂點索引：Assimp的接口定義每個網格有一個以面(faces)爲單位的數組，每個面代表一個單獨的圖元，可以從其中獲取繪製的順序索引
- 關於材質：網格中有指向材質對象的索引，想要獲取網格的材質對象，需要索引場景的
mMaterials數組
//將所有原始的aimesh對象全部轉換成我們自己定義的網格對象
Mesh processMesh(aiMesh* mesh, const aiScene* scene)
{
vector<Vertex> vertices;
vector<GLuint> indices;
vector<Texture> textures;
//處理頂點座標、法線和紋理座標
for (GLuint i = 0; i < mesh->mNumVertices; i++)
{
Vertex vertex;
glm::vec3 vector;
vector.x = mesh->mVertices[i].x;
vector.y = mesh->mVertices[i].y;
vector.z = mesh->mVertices[i].z;
vertex.Position = vector;
vector.x = mesh->mNormals[i].x;
vector.y = mesh->mNormals[i].y;
vector.z = mesh->mNormals[i].z;
vertex.Normal = vector;
if (mesh->mTextureCoords[0])
{
glm::vec2 vec;
vec.x = mesh->mTextureCoords[0][i].x;
vec.y = mesh->mTextureCoords[0][i].y;
vertex.TexCoords = vec;
}
else
vertex.TexCoords = glm::vec2(0.0f, 0.0f);
vertices.push_back(vertex);
}
//處理頂點索引
for (GLuint i = 0; i < mesh->mNumFaces; i++)
{
aiFace face = mesh->mFaces[i];
for (GLuint j = 0; j < face.mNumIndices; j++)
indices.push_back(face.mIndices[j]);
}
//處理材質
aiMaterial* material = scene->mMaterials[mesh->mMaterialIndex];
vector<Texture> diffuseMaps = this->loadMaterialTextures(material, aiTextureType_DIFFUSE, "texture_diffuse");
textures.insert(textures.end(), diffuseMaps.begin(), diffuseMaps.end());
vector<Texture> specularMaps = this->loadMaterialTextures(material, aiTextureType_SPECULAR, "texture_specular");
textures.insert(textures.end(), specularMaps.begin(), specularMaps.end());
return Mesh(vertices, indices, textures);
}
對於紋理的讀取：
獲取了aimaterial對象後，可以從中加載網格的diffuse或/和specular紋理，每個材質都儲存了一個數組，這個數組爲每個紋理類型提供紋理位置，不同的紋理類型都以aiTextureType_爲前綴
- GetTextureCount((aiTextureType)type)：檢驗材質中儲存的紋理，獲取對應類型的紋理
- GetTexture((aiTextureType)type, i, &str)：獲取對應紋理的位置，前兩個參數爲類型和下標，獲取的位置會存入第三個參數
//遍歷所有給定紋理類型的紋理位置，獲取紋理的文件位置，然後加載生成紋理
vector<Texture> loadMaterialTextures(aiMaterial* mat, int type, string typeName)
{
vector<Texture> textures;
for (GLuint i = 0; i < mat->GetTextureCount((aiTextureType)type); i++)
{
aiString str;
mat->GetTexture((aiTextureType)type, i, &str);
GLboolean skip = false;
for (GLuint j = 0; j < textures_loaded.size(); j++)
{
if (std::strcmp(textures_loaded[j].path.C_Str(), str.C_Str()) == 0)
{
textures.push_back(textures_loaded[j]);
skip = true;
break;
}
}
if (!skip)
{
Texture texture;
texture.id = TextureFromFile(str.C_Str(), this->directory);
texture.type = typeName;
texture.path = str;
textures.push_back(texture);
this->textures_loaded.push_back(texture);
}
}
return textures;
}
二、測試
有了model.h和mesh.h之後，在主代碼中生成模型就非常簡單了，只需要考慮其光照和空間變換
可以將之前的“正方體箱子”替換成全新的箱子模型
主代碼如下（刪除了之前的所有箱子，保留了所有光源）：
#include<iostream>
#include<opengl/glew.h>
#define GLEW_STATIC
#include<GLFW/glfw3.h>
#include"Shader.h"
#include"Camera.h"
#include<glm/glm.hpp>
#include<glm/gtc/matrix_transform.hpp>
#include<glm/gtc/type_ptr.hpp>
#include"Mesh.h"
#include"Model.h"
#include<opengl/freeglut.h>
#include<SOIL.h>
bool keys[1024];
Camera camera;
GLfloat lastX, lastY;
bool firstMouse = true;
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode);
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset);
void mouse_callback(GLFWwindow* window, double xpos, double ypos);
void cameraMove();
const GLuint WIDTH = 800, HEIGHT = 600;
int main()
{
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
GLFWwindow* window = glfwCreateWindow(WIDTH, HEIGHT, "LearnOpenGL", nullptr, nullptr);
glfwMakeContextCurrent(window);
glfwSetKeyCallback(window, key_callback);
glfwSetCursorPosCallback(window, mouse_callback);
glfwSetScrollCallback(window, scroll_callback);
glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
glewExperimental = GL_TRUE;
glewInit();
int width, height;
glfwGetFramebufferSize(window, &width, &height);
glViewport(0, 0, width, height);
Shader shaderObj("ObjVShader.vert", "ObjFShader.frag");
Shader shaderLight("LightVShader.vert", "LightFShader.frag");
GLfloat vertices[] =
{
-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, 0.0f, -1.0f, 1.0f, 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, 0.0f, -1.0f, 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, 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, 0.0f, 1.0f, 1.0f, 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, 0.0f, 1.0f, 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, 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, -1.0f, 0.0f, 0.0f, 0.0f, 1.0f,
-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, 0.0f, 0.0f,
-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, 0.0f,
0.5f, 0.5f, -0.5f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f,
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, 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, 1.0f, 0.0f, 0.0f, 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, -1.0f, 0.0f, 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, 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, 1.0f, 0.0f, 0.0f, 1.0f,
0.5f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f,
0.5f, 0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f,
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, 1.0f, 0.0f, 0.0f, 1.0f
};
glm::vec3 positions[] =
{
glm::vec3(0.0f, -1.78f, 0.0f),
glm::vec3(0.0f, -0.89f, 0.0f),
glm::vec3(0.0f, -0.0f, 0.0f),
glm::vec3(-2.0f, -1.78f, 0.0f),
glm::vec3(-2.0f, -0.89f, 0.0f),
glm::vec3(-3.0f, -1.78f, 0.0f),
glm::vec3(-2.0f, -1.78f, 1.0f),
glm::vec3(-1.0f, -1.78f, -4.0f),
};
glm::vec3 pointLightPositions[] =
{
glm::vec3(-1.0f, 0.0f, -2.0f),
glm::vec3(0.0f, -1.0f, 2.0f),
glm::vec3(-5.0f, -1.0f, 1.0f),
};
GLuint VBO, VAO;
glGenVertexArrays(1, &VAO);
glGenBuffers(1, &VBO);
glBindVertexArray(VAO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)0);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
glEnableVertexAttribArray(1);
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(6 * sizeof(GLfloat)));
glEnableVertexAttribArray(2);
GLuint lightVAO;
glGenVertexArrays(1, &lightVAO);
glBindVertexArray(lightVAO);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)0);
//VBO數據已經綁定且我們就用之前的頂點數據，所以無需再管理VBO
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
glEnable(GL_DEPTH_TEST);
Model ourModel("Object/wood/file.fbx");
while (!glfwWindowShouldClose(window))
{
glfwPollEvents();
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
glClear(GL_DEPTH_BUFFER_BIT);
cameraMove();
shaderLight.Use();
glm::mat4 view = camera.GetViewMatrix();
glm::mat4 projection = glm::perspective(glm::radians(camera.Zoom), (GLfloat)WIDTH / (GLfloat)HEIGHT, 0.1f, 100.0f);
glm::mat4 model = glm::mat4(1.0f);
GLint modelLoc = glGetUniformLocation(shaderLight.Program, "model");
GLint viewLoc = glGetUniformLocation(shaderLight.Program, "view");
GLint projLoc = glGetUniformLocation(shaderLight.Program, "projection");
glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(view));
glUniformMatrix4fv(projLoc, 1, GL_FALSE, glm::value_ptr(projection));
glBindVertexArray(lightVAO);
for (int i = 0; i <= 2; i++)
{
model = glm::translate(glm::mat4(1.0f), pointLightPositions[i]);
model = glm::scale(model, glm::vec3(0.2f));
glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
glDrawArrays(GL_TRIANGLES, 0, 36);
}
shaderObj.Use();
glUniform3f(glGetUniformLocation(shaderObj.Program, "sunLight.direction"), -0.2f, -1.0f, -0.3f);
glUniform3f(glGetUniformLocation(shaderObj.Program, "sunLight.diffuse"), 0.4f, 0.4f, 0.4f);
glUniform3f(glGetUniformLocation(shaderObj.Program, "sunLight.specular"), 0.5f, 0.5f, 0.5f);
glUniform3f(glGetUniformLocation(shaderObj.Program, "pointLights[0].position"), pointLightPositions[0].x, pointLightPositions[0].y, pointLightPositions[0].z);
glUniform3f(glGetUniformLocation(shaderObj.Program, "pointLights[0].diffuse"), 0.8f, 0.8f, 0.8f);
glUniform3f(glGetUniformLocation(shaderObj.Program, "pointLights[0].specular"), 1.0f, 1.0f, 1.0f);
glUniform1f(glGetUniformLocation(shaderObj.Program, "pointLights[0].k0"), 1.0f);
glUniform1f(glGetUniformLocation(shaderObj.Program, "pointLights[0].k1"), 0.09);
glUniform1f(glGetUniformLocation(shaderObj.Program, "pointLights[0].k2"), 0.032);
glUniform3f(glGetUniformLocation(shaderObj.Program, "pointLights[1].position"), pointLightPositions[1].x, pointLightPositions[1].y, pointLightPositions[1].z);
glUniform3f(glGetUniformLocation(shaderObj.Program, "pointLights[1].diffuse"), 0.8f, 0.8f, 0.8f);
glUniform3f(glGetUniformLocation(shaderObj.Program, "pointLights[1].specular"), 1.0f, 1.0f, 1.0f);
glUniform1f(glGetUniformLocation(shaderObj.Program, "pointLights[1].k0"), 1.0f);
glUniform1f(glGetUniformLocation(shaderObj.Program, "pointLights[1].k1"), 0.09);
glUniform1f(glGetUniformLocation(shaderObj.Program, "pointLights[1].k2"), 0.032);
glUniform3f(glGetUniformLocation(shaderObj.Program, "pointLights[2].position"), pointLightPositions[2].x, pointLightPositions[2].y, pointLightPositions[2].z);
glUniform3f(glGetUniformLocation(shaderObj.Program, "pointLights[2].diffuse"), 0.8f, 0.8f, 0.8f);
glUniform3f(glGetUniformLocation(shaderObj.Program, "pointLights[2].specular"), 1.0f, 1.0f, 1.0f);
glUniform1f(glGetUniformLocation(shaderObj.Program, "pointLights[2].k0"), 1.0f);
glUniform1f(glGetUniformLocation(shaderObj.Program, "pointLights[2].k1"), 0.09);
glUniform1f(glGetUniformLocation(shaderObj.Program, "pointLights[2].k2"), 0.032);
glUniform3f(glGetUniformLocation(shaderObj.Program, "spotLight.position"), camera.Position.x, camera.Position.y, camera.Position.z);
glUniform3f(glGetUniformLocation(shaderObj.Program, "spotLight.direction"), camera.Front.x, camera.Front.y, camera.Front.z);
glUniform3f(glGetUniformLocation(shaderObj.Program, "spotLight.diffuse"), 1.0f, 1.0f, 1.0f);
glUniform3f(glGetUniformLocation(shaderObj.Program, "spotLight.specular"), 1.0f, 1.0f, 1.0f);
glUniform1f(glGetUniformLocation(shaderObj.Program, "spotLight.k0"), 1.0f);
glUniform1f(glGetUniformLocation(shaderObj.Program, "spotLight.k1"), 0.09);
glUniform1f(glGetUniformLocation(shaderObj.Program, "spotLight.k2"), 0.032);
glUniform1f(glGetUniformLocation(shaderObj.Program, "spotLight.cutOff"), glm::cos(glm::radians(12.5f)));
glUniform1f(glGetUniformLocation(shaderObj.Program, "spotLight.outCutOff"), glm::cos(glm::radians(16.0f)));
glUniform3f(glGetUniformLocation(shaderObj.Program, "ambient"), 0.2f, 0.2f, 0.2f);
glUniform3f(glGetUniformLocation(shaderObj.Program, "viewPos"), camera.Position.x, camera.Position.y, camera.Position.z);
modelLoc = glGetUniformLocation(shaderObj.Program, "model");
viewLoc = glGetUniformLocation(shaderObj.Program, "view");
projLoc = glGetUniformLocation(shaderObj.Program, "projection");
glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(view));
glUniformMatrix4fv(projLoc, 1, GL_FALSE, glm::value_ptr(projection));
for (int i = 0; i <= 7; i++)
{
model = glm::translate(glm::mat4(1.0f), positions[i]);
model = glm::scale(model, glm::vec3(0.01f));
glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
ourModel.Draw(shaderObj);
}
glBindVertexArray(0);
glfwSwapBuffers(window);
}
glDeleteVertexArrays(1, &VAO);
glDeleteBuffers(1, &VBO);
glfwTerminate();
return 0;
}
GLfloat deltaTime = 0.0f;
GLfloat lastFrame = 0.0f;
void cameraMove()
{
GLfloat currentFrame = glfwGetTime();
deltaTime = currentFrame - lastFrame;
lastFrame = currentFrame;
GLfloat cameraSpeed = 1.0f * deltaTime;
if (keys[GLFW_KEY_W])
camera.ProcessKeyboard(Camera_Movement(FORWARD), deltaTime);
if (keys[GLFW_KEY_S])
camera.ProcessKeyboard(Camera_Movement(BACKWARD), deltaTime);
if (keys[GLFW_KEY_A])
camera.ProcessKeyboard(Camera_Movement(LEFT), deltaTime);
if (keys[GLFW_KEY_D])
camera.ProcessKeyboard(Camera_Movement(RIGHT), deltaTime);
}
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode)
{
if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
glfwSetWindowShouldClose(window, GL_TRUE);
if (action == GLFW_PRESS) //如果當前是按下操作
keys[key] = true;
else if (action == GLFW_RELEASE) //鬆開鍵盤
keys[key] = false;
}
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
{
camera.ProcessMouseScroll(yoffset);
}
void mouse_callback(GLFWwindow* window, double xpos, double ypos)
{
if (firstMouse)
{
lastX = xpos;
lastY = ypos;
firstMouse = false;
}
GLfloat xoffset = xpos - lastX;
GLfloat yoffset = lastY - ypos;
lastX = xpos;
lastY = ypos;
GLfloat sensitivity = 0.05;
xoffset *= sensitivity;
yoffset *= sensitivity;
camera.ProcessMouseMovement(xoffset, yoffset);
}
完整的model.h代碼：
#ifndef MODEL_H
#define MODEL_H
#include<vector>
#include<string>
#include"Shader.h"
#include"Mesh.h"
#include<opengl/glew.h>
#include<SOIL.h>
#include<glm/glm.hpp>
#include<glm/gtc/matrix_transform.hpp>
#include<assimp/Importer.hpp>
#include<assimp/scene.h>
#include<assimp/postprocess.h>
using namespace std;
GLint TextureFromFile(const char* path, string directory);
class Model
{
public:
Model(const GLchar* path)
{
this->loadModel(path);
}
void Draw(Shader shader)
{
for (GLuint i = 0; i < this->meshes.size(); i++)
this->meshes[i].Draw(shader);
}
private:
vector<Mesh> meshes;
string directory;
vector<Texture> textures_loaded;
void loadModel(string path)
{
Assimp::Importer importer;
const aiScene* scene = importer.ReadFile(path, aiProcess_Triangulate | aiProcess_FlipUVs);
if (!scene || scene->mFlags == AI_SCENE_FLAGS_INCOMPLETE || !scene->mRootNode)
{
cout << "ERROR::ASSIMP:: " << importer.GetErrorString() << endl;
return;
}
this->directory = path.substr(0, path.find_last_of('/'));
this->processNode(scene->mRootNode, scene);
}
//依次處理所有的場景節點
void processNode(aiNode* node, const aiScene* scene)
{
for (GLuint i = 0; i < node->mNumMeshes; i++)
{
aiMesh* mesh = scene->mMeshes[node->mMeshes[i]];
this->meshes.push_back(this->processMesh(mesh, scene));
}
for (GLuint i = 0; i < node->mNumChildren; i++)
this->processNode(node->mChildren[i], scene);
}
//將所有原始的aimesh對象全部轉換成我們自己定義的網格對象
Mesh processMesh(aiMesh* mesh, const aiScene* scene)
{
vector<Vertex> vertices;
vector<GLuint> indices;
vector<Texture> textures;
//處理頂點座標、法線和紋理座標
for (GLuint i = 0; i < mesh->mNumVertices; i++)
{
Vertex vertex;
glm::vec3 vector;
vector.x = mesh->mVertices[i].x;
vector.y = mesh->mVertices[i].y;
vector.z = mesh->mVertices[i].z;
vertex.Position = vector;
vector.x = mesh->mNormals[i].x;
vector.y = mesh->mNormals[i].y;
vector.z = mesh->mNormals[i].z;
vertex.Normal = vector;
if (mesh->mTextureCoords[0]) //不一定有紋理座標
{
glm::vec2 vec;
//暫時只考慮第一組紋理座標，Assimp允許一個模型的每個頂點有8個不同的紋理座標，只是可能用不到
vec.x = mesh->mTextureCoords[0][i].x;
vec.y = mesh->mTextureCoords[0][i].y;
vertex.TexCoords = vec;
}
else
vertex.TexCoords = glm::vec2(0.0f, 0.0f);
vertices.push_back(vertex);
}
//處理頂點索引
for (GLuint i = 0; i < mesh->mNumFaces; i++)
{
aiFace face = mesh->mFaces[i];
for (GLuint j = 0; j < face.mNumIndices; j++)
{
indices.push_back(face.mIndices[j]);
}
}
//處理材質
if (mesh->mMaterialIndex >= 0)
{
aiMaterial* material = scene->mMaterials[mesh->mMaterialIndex];
vector<Texture> diffuseMaps = this->loadMaterialTextures(material, aiTextureType_DIFFUSE, "texture_diffuse");
textures.insert(textures.end(), diffuseMaps.begin(), diffuseMaps.end());
vector<Texture> specularMaps = this->loadMaterialTextures(material, aiTextureType_SPECULAR, "texture_specular");
textures.insert(textures.end(), specularMaps.begin(), specularMaps.end());
}
return Mesh(vertices, indices, textures);
}
//遍歷所有給定紋理類型的紋理位置，獲取紋理的文件位置，然後加載生成紋理
vector<Texture> loadMaterialTextures(aiMaterial* mat, int type, string typeName)
{
vector<Texture> textures;
cout << typeName << endl;
for (GLuint i = 0; i < mat->GetTextureCount((aiTextureType)type); i++)
{
aiString str;
mat->GetTexture((aiTextureType)type, i, &str);
GLboolean skip = false;
for (GLuint j = 0; j < textures_loaded.size(); j++)
{
if (std::strcmp(textures_loaded[j].path.C_Str(), str.C_Str()) == 0)
{
textures.push_back(textures_loaded[j]);
skip = true;
break;
}
}
//對應材質已存在就沒必要再次讀取了
if (!skip)
{
Texture texture;
texture.id = TextureFromFile(str.C_Str(), this->directory);
texture.type = typeName;
texture.path = str;
textures.push_back(texture);
this->textures_loaded.push_back(texture);
}
}
return textures;
}
};
GLint TextureFromFile(const char* path, string directory)
{
string filename = string(path);
filename = directory + '/' + filename;
cout << filename << endl;
GLuint textureID;
glGenTextures(1, &textureID);
int width, height;
unsigned char* image = SOIL_load_image(filename.c_str(), &width, &height, 0, SOIL_LOAD_RGB);
glBindTexture(GL_TEXTURE_2D, textureID);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
glGenerateMipmap(GL_TEXTURE_2D);
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);
glBindTexture(GL_TEXTURE_2D, 0);
SOIL_free_image_data(image);
return textureID;
}
#endif
對於着色器，只需要修改材質的名字就好了：
#version 330 core
layout (location = 0) in vec3 position;
layout (location = 1) in vec3 normal;
layout (location = 2) in vec2 texture;
out vec2 texIn;
out vec3 normalIn;
out vec3 fragPosIn;
uniform mat4 model; //模型矩陣
uniform mat4 view; //觀察矩陣
uniform mat4 projection; //投影矩陣
void main()
{
gl_Position = projection * view * model * vec4(position, 1.0);
texIn = texture;
fragPosIn = vec3(model * vec4(position, 1.0f));
normalIn = mat3(transpose(inverse(model))) * normal;
}
///////////////////////////////////////////////////////////////////////////
#version 330 core
struct Material
{
sampler2D texture_diffuse1; //貼圖
sampler2D texture_specular1; //鏡面貼圖
sampler2D emission; //放射貼圖
float shininess; //反光度
};
struct SunLight //平行光
{
vec3 direction;
vec3 diffuse;
vec3 specular;
};
struct PointLight //點光源
{
vec3 position;
vec3 diffuse;
vec3 specular;
float k0, k1, k2;
};
struct SpotLight //聚光燈
{
vec3 position;
vec3 direction;
vec3 diffuse;
vec3 specular;
float k0, k1, k2;
float cutOff, outCutOff;
};
uniform vec3 ambient;
uniform Material material;
uniform SunLight sunLight;
uniform PointLight pointLights[3];
uniform SpotLight spotLight;
vec3 CalcSunLight(SunLight light, vec3 normal, vec3 viewDir);
vec3 CalcPointLight(PointLight light, vec3 normal, vec3 fragPos, vec3 viewDir);
vec3 CalcSpotLight(SpotLight light, vec3 normal, vec3 fragPos, vec3 viewDir);
out vec4 color;
uniform vec3 viewPos;
in vec2 texIn;
in vec3 fragPosIn;
in vec3 normalIn;
void main()
{
//環境光
vec3 ambient = ambient * vec3(texture(material.texture_diffuse1, texIn));
vec3 viewDir = normalize(viewPos - fragPosIn);
vec3 normal = normalize(normalIn);
vec3 result = CalcSunLight(sunLight, normal, viewDir);
for (int i = 0; i <= 2; i++)
result = result + CalcPointLight(pointLights[i], normal, fragPosIn, viewDir);
result = result + CalcSpotLight(spotLight, normal, fragPosIn, viewDir);
color = vec4(result, 1.0f);
}
vec3 CalcSunLight(SunLight light, vec3 normal, vec3 viewDir)
{
vec3 lightDir = normalize(-light.direction);
float diff = max(dot(normal, lightDir), 0.0f);
vec3 diffuse = light.diffuse * (diff * vec3(texture(material.texture_diffuse1, texIn)));
vec3 reflectDir = reflect(-lightDir, normal);
float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
vec3 specular = light.specular * (spec * vec3(texture(material.texture_specular1, texIn)));
return diffuse + specular;
}
vec3 CalcPointLight(PointLight light, vec3 normal, vec3 fragPos, vec3 viewDir)
{
vec3 lightDir = normalize(light.position - fragPos);
float diff = max(dot(normal, lightDir), 0.0f);
vec3 diffuse = light.diffuse * (diff * vec3(texture(material.texture_diffuse1, texIn)));
vec3 reflectDir = reflect(-lightDir, normal);
float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
vec3 specular = light.specular * (spec * vec3(texture(material.texture_specular1, texIn)));
float dis = length(light.position - fragPos);
float attenuation = 1.0f / (light.k0 + light.k1 * dis + light.k2 * (dis * dis));
diffuse *= attenuation;
specular *= attenuation;
return diffuse + specular;
}
vec3 CalcSpotLight(SpotLight light, vec3 normal, vec3 fragPos, vec3 viewDir)
{
vec3 lightDir = normalize(light.position - fragPos);
float theta = dot(lightDir, normalize(-light.direction));
float lightSoft = clamp((theta - light.outCutOff) / (light.cutOff - light.outCutOff), 0.0f, 1.0f);
float diff = max(dot(normal, lightDir), 0.0f);
vec3 diffuse = light.diffuse * (diff * vec3(texture(material.texture_diffuse1, texIn)));
vec3 reflectDir = reflect(-lightDir, normal);
float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
vec3 specular = light.specular * (spec * vec3(texture(material.texture_specular1, texIn)));
float dis = length(light.position - fragPos);
float attenuation = 1.0f / (light.k0 + light.k1 * dis + light.k2 * (dis * dis));
diffuse *= attenuation * lightSoft;
specular *= attenuation * lightSoft;
return diffuse + specular;
}