2018/8/19--OpenGL学习笔记（八）Mesh/Model
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2023-12-25 18:43:39
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开篇的话：··········很久没有更新笔记了，因为这段时间忙于改简历和投简历还有面试，往后有看了几个章节，但是没有时间来回顾总结下，所以今天来把之前的补上
Assimp
（模型加载需要我们用到这个库，教程上让我们用Cmake来编译，因为第一章的时候，我Cmake就各种问题，索性我就网上找了别人编译好的包，直接来使用了。）
Mesh
#ifndef MESH_H
#define MESH_H
#include <glad/glad.h>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include "Shader.h"
#include <string>
#include <fstream>
#include <sstream>
#include <iostream>
#include <vector>
using namespace std;
//定义一个顶点
struct Vertex {
glm::vec3 Position;
glm::vec3 Normal;
glm::vec2 TexCoords;
glm::vec3 Tangent;
glm::vec3 Bitangent;
};
//将纹理数据整理到一个Texture结构体
struct Texture {
unsigned int id;
string type;
string path; //储存纹理的路径用于与其它纹理进行比较
};
class Mesh {
public:
/* 网格数据 */
vector<Vertex> vertices;
vector<unsigned int> indices;
vector<Texture> textures;
unsigned int VAO;
/* 函数 */
// 构造函数
Mesh(vector<Vertex> vertices, vector<unsigned int> indices, vector<Texture> textures)
{
this->vertices = vertices;
this->indices = indices;
this->textures = textures;
setupMesh();
}
// 渲染mesh
void Draw(Shader shader)
{
// 绑定适当的纹理
unsigned int diffuseNr = 1;
unsigned int specularNr = 1;
unsigned int normalNr = 1;
unsigned int heightNr = 1;
for (unsigned int i = 0; i < textures.size(); i++)
{
glActiveTexture(GL_TEXTURE0 + i); // 在绑定之前**相应的纹理单元
// 获取纹理序号（diffuse_textureN 中的 N）
string number;
string name = textures[i].type;
if (name == "texture_diffuse")
number = std::to_string(diffuseNr++);
else if (name == "texture_specular")
number = std::to_string(specularNr++); // transfer unsigned int to stream
else if (name == "texture_normal")
number = std::to_string(normalNr++); // transfer unsigned int to stream
else if (name == "texture_height")
number = std::to_string(heightNr++); // transfer unsigned int to stream
// 设置贴图
shader.setInt(((name + number).c_str()), i);
// 绑定纹理
glBindTexture(GL_TEXTURE_2D, textures[i].id);
}
// draw mesh
glBindVertexArray(VAO);
glDrawElements(GL_TRIANGLES, indices.size(), GL_UNSIGNED_INT, 0);
glBindVertexArray(0);
// 将配置文件设置为默认
glActiveTexture(GL_TEXTURE0);
}
private:
/* 渲染数据 */
unsigned int VBO, EBO;
/* 函数 */
// 初始化缓冲
void setupMesh()
{
// create buffers/arrays
glGenVertexArrays(1, &VAO);
glGenBuffers(1, &VBO);
glGenBuffers(1, &EBO);
glBindVertexArray(VAO);
// load data into vertex buffers
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(Vertex), &vertices[0], GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof(unsigned int), &indices[0], GL_STATIC_DRAW);
// vertex Positions
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)0);
// vertex normals
glEnableVertexAttribArray(1);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)offsetof(Vertex, Normal));
// vertex texture coords
glEnableVertexAttribArray(2);
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)offsetof(Vertex, TexCoords));
// vertex tangent
glEnableVertexAttribArray(3);
glVertexAttribPointer(3, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)offsetof(Vertex, Tangent));
// vertex bitangent
glEnableVertexAttribArray(4);
glVertexAttribPointer(4, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)offsetof(Vertex, Bitangent));
glBindVertexArray(0);
}
};
#endifModel
#ifndef MODEL_H
#define MODEL_H
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"
#include <Importer.hpp>
#include <scene.h>
#include <postprocess.h>
#include "Shader.h"
#include "mesh.h"
#include <string>
#include <fstream>
#include <sstream>
#include <iostream>
#include <map>
#include <vector>
using namespace std;
unsigned int TextureFromFile(const char *path, const string &directory, bool gamma = false);
class Model
{
public:
/* Model Data */
vector<Texture> textures_loaded; // stores all the textures loaded so far, optimization to make sure textures aren't loaded more than once.
vector<Mesh> meshes;
string directory;
bool gammaCorrection;
/* Functions */
// constructor, expects a filepath to a 3D model.
Model(string const &path, bool gamma = false) : gammaCorrection(gamma)
{
loadModel(path);
}
// draws the model, and thus all its meshes
void Draw(Shader shader)
{
for (unsigned int i = 0; i < meshes.size(); i++)
meshes[i].Draw(shader);
}
private:
/* Functions */
// loads a model with supported ASSIMP extensions from file and stores the resulting meshes in the meshes vector.
void loadModel(string const &path)
{
// read file via ASSIMP
Assimp::Importer importer;
const aiScene* scene = importer.ReadFile(path, aiProcess_Triangulate | aiProcess_FlipUVs | aiProcess_CalcTangentSpace);
// check for errors
if (!scene || scene->mFlags & AI_SCENE_FLAGS_INCOMPLETE || !scene->mRootNode) // if is Not Zero
{
cout << "ERROR::ASSIMP:: " << importer.GetErrorString() << endl;
return;
}
// retrieve the directory path of the filepath
directory = path.substr(0, path.find_last_of('/'));
// process ASSIMP's root node recursively
processNode(scene->mRootNode, scene);
}
// processes a node in a recursive fashion. Processes each individual mesh located at the node and repeats this process on its children nodes (if any).
void processNode(aiNode *node, const aiScene *scene)
{
// 处理位于当前节点的每个网格
for (unsigned int i = 0; i < node->mNumMeshes; i++)
{
// the node object only contains indices to index the actual objects in the scene.
// the scene contains all the data, node is just to keep stuff organized (like relations between nodes).
aiMesh* mesh = scene->mMeshes[node->mMeshes[i]];
meshes.push_back(processMesh(mesh, scene));
}
// 在我们处理完所有网格（如果有的话）后，我们会递归处理每个子节点
for (unsigned int i = 0; i < node->mNumChildren; i++)
{
processNode(node->mChildren[i], scene);
}
}
Mesh processMesh(aiMesh *mesh, const aiScene *scene)
{
// data to fill
vector<Vertex> vertices;
vector<unsigned int> indices;
vector<Texture> textures;
// Walk through each of the mesh's vertices
for (unsigned int i = 0; i < mesh->mNumVertices; i++)
{
Vertex vertex;
glm::vec3 vector; // we declare a placeholder vector since assimp uses its own vector class that doesn't directly convert to glm's vec3 class so we transfer the data to this placeholder glm::vec3 first.
// positions
vector.x = mesh->mVertices[i].x;
vector.y = mesh->mVertices[i].y;
vector.z = mesh->mVertices[i].z;
vertex.Position = vector;
// normals
vector.x = mesh->mNormals[i].x;
vector.y = mesh->mNormals[i].y;
vector.z = mesh->mNormals[i].z;
vertex.Normal = vector;
// texture coordinates
if (mesh->mTextureCoords[0]) // does the mesh contain texture coordinates?
{
glm::vec2 vec;
// a vertex can contain up to 8 different texture coordinates. We thus make the assumption that we won't
// use models where a vertex can have multiple texture coordinates so we always take the first set (0).
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);
// tangent
vector.x = mesh->mTangents[i].x;
vector.y = mesh->mTangents[i].y;
vector.z = mesh->mTangents[i].z;
vertex.Tangent = vector;
// bitangent
vector.x = mesh->mBitangents[i].x;
vector.y = mesh->mBitangents[i].y;
vector.z = mesh->mBitangents[i].z;
vertex.Bitangent = vector;
vertices.push_back(vertex);
}
// now wak through each of the mesh's faces (a face is a mesh its triangle) and retrieve the corresponding vertex indices.
for (unsigned int i = 0; i < mesh->mNumFaces; i++)
{
aiFace face = mesh->mFaces[i];
// retrieve all indices of the face and store them in the indices vector
for (unsigned int j = 0; j < face.mNumIndices; j++)
indices.push_back(face.mIndices[j]);
}
// process materials
aiMaterial* material = scene->mMaterials[mesh->mMaterialIndex];
// we assume a convention for sampler names in the shaders. Each diffuse texture should be named
// as 'texture_diffuseN' where N is a sequential number ranging from 1 to MAX_SAMPLER_NUMBER.
// Same applies to other texture as the following list summarizes:
// diffuse: texture_diffuseN
// specular: texture_specularN
// normal: texture_normalN
// 1. diffuse maps
vector<Texture> diffuseMaps = loadMaterialTextures(material, aiTextureType_DIFFUSE, "texture_diffuse");
textures.insert(textures.end(), diffuseMaps.begin(), diffuseMaps.end());
// 2. specular maps
vector<Texture> specularMaps = loadMaterialTextures(material, aiTextureType_SPECULAR, "texture_specular");
textures.insert(textures.end(), specularMaps.begin(), specularMaps.end());
// 3. normal maps
std::vector<Texture> normalMaps = loadMaterialTextures(material, aiTextureType_HEIGHT, "texture_normal");
textures.insert(textures.end(), normalMaps.begin(), normalMaps.end());
// 4. height maps
std::vector<Texture> heightMaps = loadMaterialTextures(material, aiTextureType_AMBIENT, "texture_height");
textures.insert(textures.end(), heightMaps.begin(), heightMaps.end());
// return a mesh object created from the extracted mesh data
return Mesh(vertices, indices, textures);
}
// checks all material textures of a given type and loads the textures if they're not loaded yet.
// the required info is returned as a Texture struct.
vector<Texture> loadMaterialTextures(aiMaterial *mat, aiTextureType type, string typeName)
{
vector<Texture> textures;
for (unsigned int i = 0; i < mat->GetTextureCount(type); i++)
{
aiString str;
mat->GetTexture(type, i, &str);
// check if texture was loaded before and if so, continue to next iteration: skip loading a new texture
bool skip = false;
for (unsigned int j = 0; j < textures_loaded.size(); j++)
{
if (std::strcmp(textures_loaded[j].path.data(), str.C_Str()) == 0)
{
textures.push_back(textures_loaded[j]);
skip = true; // a texture with the same filepath has already been loaded, continue to next one. (optimization)
break;
}
}
if (!skip)
{ // if texture hasn't been loaded already, load it
Texture texture;
texture.id = TextureFromFile(str.C_Str(), this->directory);
texture.type = typeName;
texture.path = str.C_Str();
textures.push_back(texture);
textures_loaded.push_back(texture); // store it as texture loaded for entire model, to ensure we won't unnecesery load duplicate textures.
}
}
return textures;
}
};
unsigned int TextureFromFile(const char *path, const string &directory, bool gamma)
{
string filename = string(path);
filename = directory + '/' + filename;
unsigned int textureID;
glGenTextures(1, &textureID);
int width, height, nrComponents;
unsigned char *data = stbi_load(filename.c_str(), &width, &height, &nrComponents, 0);
if (data)
{
GLenum format;
if (nrComponents == 1)
format = GL_RED;
else if (nrComponents == 3)
format = GL_RGB;
else if (nrComponents == 4)
format = GL_RGBA;
glBindTexture(GL_TEXTURE_2D, textureID);
glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, format, GL_UNSIGNED_BYTE, data);
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);
stbi_image_free(data);
}
else
{
std::cout << "Texture failed to load at path: " << path << std::endl;
stbi_image_free(data);
}
return textureID;
}
#endif此时我们已经写好了mesh.h和model.h，接下在主函数：
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include "Shader.h"
#include "camera.h"
#include "model.h"
#include <iostream>
void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void mouse_callback(GLFWwindow* window, double xpos, double ypos);
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset);
void processInput(GLFWwindow *window);
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;
Camera camera(glm::vec3(0.0f, 0.0f, 3.0f));
float lastX = SCR_WIDTH / 2.0f;
float lastY = SCR_HEIGHT / 2.0f;
bool firstMouse = true;
float deltaTime = 0.0f;
float lastFrame = 0.0f;
int main()
{
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "mesh_load", NULL, NULL);
if (window == NULL)
{
std::cout << "Failed to create GLFW window" << std::endl;
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
{
std::cout << "Failed to initialize GLAD" << std::endl;
return -1;
}
glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
glfwSetCursorPosCallback(window, mouse_callback);
glfwSetScrollCallback(window, scroll_callback);
glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
glEnable(GL_DEPTH_TEST);
// build and compile shaders
// -------------------------
Shader ourShader("shader/mesh_vertexshader.vs", "shader/mesh_fragmentshader.vs");
Model ourModel("nanosuit/nanosuit.obj");
while (!glfwWindowShouldClose(window))
{
// per-frame time logic
// --------------------
float currentFrame = glfwGetTime();
deltaTime = currentFrame - lastFrame;
lastFrame = currentFrame;
// input
// -----
processInput(window);
// render
// ------
glClearColor(0.05f, 0.05f, 0.05f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// don't forget to enable shader before setting uniforms
ourShader.use();
ourShader.setVec3("viewPos", camera.Position);
ourShader.setFloat("material.shininess", 32.0f);
// directional light
ourShader.setVec3("dirLight.direction", -0.2f, -1.0f, -0.3f);
ourShader.setVec3("dirLight.ambient", 0.05f, 0.05f, 0.05f);
ourShader.setVec3("dirLight.diffuse", 0.4f, 0.4f, 0.4f);
ourShader.setVec3("dirLight.specular", 0.5f, 0.5f, 0.5f);
// spotLight
ourShader.setVec3("spotLight.position", camera.Position);
ourShader.setVec3("spotLight.direction", camera.Front);
ourShader.setVec3("spotLight.ambient", 0.0f, 0.0f, 0.0f);
ourShader.setVec3("spotLight.diffuse", 1.0f, 1.0f, 1.0f);
ourShader.setVec3("spotLight.specular", 1.0f, 1.0f, 1.0f);
ourShader.setFloat("spotLight.constant", 1.0f);
ourShader.setFloat("spotLight.linear", 0.09);
ourShader.setFloat("spotLight.quadratic", 0.032);
ourShader.setFloat("spotLight.cutOff", glm::cos(glm::radians(12.5f)));
ourShader.setFloat("spotLight.outerCutOff", glm::cos(glm::radians(15.0f)));
// view/projection transformations
glm::mat4 projection = glm::perspective(glm::radians(camera.Zoom), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f);
glm::mat4 view = camera.GetViewMatrix();
ourShader.setMat4("projection", projection);
ourShader.setMat4("view", view);
// render the loaded model
glm::mat4 model;
model = glm::translate(model, glm::vec3(0.0f, -1.75f, 0.0f)); // translate it down so it's at the center of the scene
model = glm::scale(model, glm::vec3(0.2f, 0.2f, 0.2f)); // it's a bit too big for our scene, so scale it down
ourShader.setMat4("model", model);
ourModel.Draw(ourShader);
glfwSwapBuffers(window);
glfwPollEvents();
}
glfwTerminate();
return 0;
}
//回调函数
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
//glViewport函数前两个参数控制窗口左下角的位置。第三个和第四个参数控制渲染窗口的宽度和高度（像素）
glViewport(0, 0, width, height);
}
void processInput(GLFWwindow* window)
{
if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
glfwSetWindowShouldClose(window, true);
if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)
camera.ProcessKeyboard(FORWARD, deltaTime);
if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)
camera.ProcessKeyboard(BACKWARD, deltaTime);
if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
camera.ProcessKeyboard(LEFT, deltaTime);
if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)
camera.ProcessKeyboard(RIGHT, deltaTime);
}
void mouse_callback(GLFWwindow*window, double xpos, double ypos)
{
if (firstMouse)
{
lastX = xpos;
lastY = ypos;
firstMouse = false;
}
float xoffset = xpos - lastX;
float yoffset = lastY - ypos; // reversed since y-coordinates go from bottom to top
lastX = xpos;
lastY = ypos;
camera.ProcessMouseMovement(xoffset, yoffset);
}
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
{
camera.ProcessMouseScroll(yoffset);
}
unsigned int loadTexture(char const * path)
{
unsigned int textureID;
glGenTextures(1, &textureID);
int width, height, nrComponents;
unsigned char *data = stbi_load(path, &width, &height, &nrComponents, 0);
if (data)
{
GLenum format;
if (nrComponents == 1)
format = GL_RED;
else if (nrComponents == 3)
format = GL_RGB;
else if (nrComponents == 4)
format = GL_RGBA;
glBindTexture(GL_TEXTURE_2D, textureID);
glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, format, GL_UNSIGNED_BYTE, data);
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);
stbi_image_free(data);
}
else
{
std::cout << "Texture failed to load at path: " << path << std::endl;
stbi_image_free(data);
}
return textureID;
}
我们在场景中添加了平行光和手电筒
vertexshader:
#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aNormal;
layout (location = 2) in vec2 aTexCoords;
out vec2 TexCoords;
out vec3 FragPos;
out vec3 Normal;
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
void main()
{
FragPos = vec3(model * vec4(aPos, 1.0));
Normal = mat3(transpose(inverse(model))) * aNormal;
TexCoords = aTexCoords;
gl_Position = projection * view * vec4(FragPos, 1.0);
}fragmentshader:
#version 330 core
out vec4 FragColor;
in vec3 FragPos;
in vec3 Normal;
in vec2 TexCoords;
struct Material {
sampler2D texture_diffuse1;
sampler2D texture_specular1;
float shininess;
};
uniform Material material;
struct DirLight{
vec3 direction;
vec3 ambient;
vec3 diffuse;
vec3 specular;
};
uniform DirLight dirLight;
struct SpotLight {
vec3 position;
vec3 direction;
float cutOff;
float outerCutOff;
float constant;
float linear;
float quadratic;
vec3 ambient;
vec3 diffuse;
vec3 specular;
};
uniform SpotLight spotLight;
uniform vec3 viewPos;
vec3 CalcDirLight(DirLight light, vec3 normal, vec3 viewDir);
vec3 CalcSpotLight(SpotLight light, vec3 normal, vec3 fragPos, vec3 viewDir);
void main()
{
// 属性
vec3 normal = normalize(Normal);
vec3 viewDir = normalize(viewPos - FragPos);
// 第一阶段：定向光照
vec3 result = CalcDirLight(dirLight, normal, viewDir);
// 第三阶段：聚光
result += CalcSpotLight(spotLight, normal, FragPos, viewDir);
FragColor = vec4(result, 1.0);
}
vec3 CalcDirLight(DirLight light, vec3 normal, vec3 viewDir)
{
vec3 lightDir = normalize(-light.direction);
// 漫反射着色
float diff = max(dot(normal, lightDir), 0.0);
// 镜面光着色
vec3 reflectDir = reflect(-lightDir, normal);
float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
// 合并结果
vec3 ambient = light.ambient * vec3(texture(material.texture_diffuse1, TexCoords));
vec3 diffuse = light.diffuse * diff * vec3(texture(material.texture_diffuse1, TexCoords));
vec3 specular = light.specular * spec * vec3(texture(material.texture_specular1, TexCoords));
return (ambient + diffuse + specular);
}
vec3 CalcSpotLight(SpotLight light, vec3 normal, vec3 fragPos, vec3 viewDir)
{
vec3 lightDir = normalize(light.position - fragPos);
//diffuse
float diff = max(dot(normal, lightDir), 0.0);
//specular
vec3 reflectDir = reflect(-lightDir, normal);
float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
// spotlight (soft edges)
float theta = dot(lightDir, normalize(-light.direction));
float epsilon = (light.cutOff - light.outerCutOff);
float intensity = clamp((theta - light.outerCutOff) / epsilon, 0.0, 1.0);
vec3 ambient = light.ambient * vec3(texture(material.texture_diffuse1, TexCoords));
vec3 diffuse = light.diffuse * diff * vec3(texture(material.texture_diffuse1, TexCoords));
vec3 specular = light.specular * spec * vec3(texture(material.texture_specular1, TexCoords));
float distance = length(light.position - fragPos);
float attenuation = 1.0 / (light.constant + light.linear * distance + light.quadratic * (distance * distance));
ambient *= attenuation * intensity;
diffuse *= attenuation * intensity;
specular *= attenuation * intensity;
return (ambient + diffuse + specular);
}
这章模型加载，我并没有写很多的东西，很多我也没有看很懂，也不是很想深入了解下，就差不多知道了流程，copy的源码，能够运行出来结果，再自己加上灯光，实现最后的效果。