自己编译运行过程中遇到的一些问题
下载Assimp已编译的lib(因为我们公司的电脑有很多权限和限制,也不能自己安装一些没有报备的软件,所以愁方便我就没有用cMake自己编译了)找到一位免费分享的博主的。
https://blog.csdn.net/lady_killer9/article/details/89429092
系统找不到zlib.dll文件的解决方法
https://blog.csdn.net/LHXvs2015/article/details/120674525
https://www.cnblogs.com/yangjinbang/p/8330786.html
下载Assimp可识别的模型地址
https://learnopengl-cn.github.io/03%20Model%20Loading/03%20Model/
现实生活中,我们都是美术同学通过一些现代的绘图工具,为我们导出模型来绘制,建模工具会自己生成所有的顶点坐标、顶点法线和纹理坐标,我们开发者就不需要去关注这些细节了。
Mesh
Mesh俗称网格,一个网格代表可绘制的实体。我们自定义一个网格类
至少要包含一组顶点数据,这组顶点数据应该包含顶点坐标,顶点法线,已经顶点的uv坐标。
一组绘制顺序索引,用于EBO绑定。
一组贴图数据,用于纹理映射。
#pragma once
// Std. Includes
#include <string>
#include <fstream>
#include <sstream>
#include <iostream>
#include <vector>
using namespace std;
// GL Includes
#include <GL/glew.h> // Contains all the necessery OpenGL includes
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
struct Vertex {
// Position
glm::vec3 Position;
// Normal
glm::vec3 Normal;
// TexCoords
glm::vec2 TexCoords;
};
struct Texture {
GLuint id;
string type;
aiString path;
};
class Mesh {
public:
vector<Vertex> vertices;
vector<GLuint> indices;
vector<Texture> textures;
//构造函数
Mesh(vector<Vertex> vertices, vector<GLuint> indices, vector<Texture> textures)
{
this->vertices = vertices;
this->indices = indices;
this->textures = textures;
// Now that we have all the required data, set the vertex buffers and its attribute pointers.
this->setupMesh();
}
void Draw(Shader shader)
{
GLuint diffuseNr = 1;
GLuint specularNr = 1;
//绑定贴图与采样器
for (GLuint i = 0; i < this->textures.size(); i++)
{
glActiveTexture(GL_TEXTURE0 + i);
stringstream ss;
string number;
string name = this->textures[i].type;
if (name == "texture_diffuse")
ss << diffuseNr++;
else if (name == "texture_specular")
ss << specularNr++;
number = ss.str();
//保证每个uniform采样器对应着正确的纹理单元
glUniform1i(glGetUniformLocation(shader.Program, (name + number).c_str()), i);
glBindTexture(GL_TEXTURE_2D, this->textures[i].id);
}
glUniform1f(glGetUniformLocation(shader.Program, "material.shininess"), 16.0f);
glBindVertexArray(this->VAO);
glDrawElements(GL_TRIANGLES, this->indices.size(), GL_UNSIGNED_INT, 0);
glBindVertexArray(0);
for (GLuint i = 0; i < this->textures.size(); i++)
{
glActiveTexture(GL_TEXTURE0 + i);
glBindTexture(GL_TEXTURE_2D, 0);
}
}
private:
GLuint VAO, VBO, EBO;
//初始化各种缓冲和链接数据
void setupMesh()
{
//初始化VAO,VBO,EBO 缓冲对象
glGenVertexArrays(1, &this->VAO);
glGenBuffers(1, &this->VBO);
glGenBuffers(1, &this->EBO);
glBindVertexArray(this->VAO);
//将顶点数据初始化至缓冲中
glBindBuffer(GL_ARRAY_BUFFER, this->VBO);
glBufferData(GL_ARRAY_BUFFER, this->vertices.size() * sizeof(Vertex), &this->vertices[0], GL_STATIC_DRAW);
//将绘制顺序索引初始到缓冲中
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, this->EBO);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, this->indices.size() * sizeof(GLuint), &this->indices[0], GL_STATIC_DRAW);
glEnableVertexAttribArray(0);
//将数据链接到顶点属性,告诉openGL如何解析这些数据
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (GLvoid*)0);
glEnableVertexAttribArray(1);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (GLvoid*)offsetof(Vertex, Normal));
glEnableVertexAttribArray(2);
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (GLvoid*)offsetof(Vertex, TexCoords));
glBindVertexArray(0);
}
};
模型类
现实生活中一个我们看到的模型都是由很多部位组成的,也可以说成是由很多mesh组合而成的,比如一张桌子,是由一个桌板加四个桌脚拼成的为了方便抽象,我们又封装了一层模型的类。
这个类主要就是去解析美术给我们的一个从Blender,Maya等工具导出的模型,将其拆分为一个Mesh数组,然后再调用Mesh类的绘制。
#pragma once
// Std. Includes
#include <string>
#include <fstream>
#include <sstream>
#include <iostream>
#include <map>
#include <vector>
using namespace std;
// GL Includes
#include <GL/glew.h> // Contains all the necessery OpenGL includes
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <SOIL.h>
#include <assimp/Importer.hpp>
#include <assimp/scene.h>
#include <assimp/postprocess.h>
#include "Mesh.h"
GLint TextureFromFile(const char* path, string directory);
class Model
{
public:
/* Functions */
// Constructor, expects a filepath to a 3D model.
Model(string path)
{
this->loadModel(path);
}
// Draws the model, and thus all its meshes
void Draw(Shader shader)
{
for (GLuint i = 0; i < this->meshes.size(); i++)
this->meshes[i].Draw(shader);
}
private:
/* Model Data */
vector<Mesh> meshes;
string directory;
vector<Texture> textures_loaded; // Stores all the textures loaded so far, optimization to make sure textures aren't loaded more than once.
int mycount = 0;
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) // if is Not Zero
{
cout << "ERROR::ASSIMP:: " << importer.GetErrorString() << endl;
return;
}
this->directory = path.substr(0, path.find_last_of('/'));
this->processNode(scene->mRootNode, scene);
//printf("mesh个数: %d", mycount);
}
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);
}
}
Mesh processMesh(aiMesh* mesh, const aiScene* scene)
{
mycount++;
vector<Vertex> vertices;
vector<GLuint> indices;
vector<Texture> textures;
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);
}
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]);
}
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);
}
vector<Texture> loadMaterialTextures(aiMaterial* mat, aiTextureType type, string typeName)
{
vector<Texture> textures;
for (GLuint i = 0; i < mat->GetTextureCount(type); i++)
{
aiString str;
mat->GetTexture(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;
}
};
GLint TextureFromFile(const char* path, string directory)
{
string filename = string(path);
filename = directory + '/' + filename;
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;
}
最后就是渲染代码
```cpp
// Std. Includes
#include <string>
// GLEW
#define GLEW_STATIC
#include <GL/glew.h>
// GLFW
#include <GLFW/glfw3.h>
// GL includes
#include "Shader.h"
#include "Camera.h"
#include "Model.h"
// GLM Mathemtics
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
// Other Libs
#include <SOIL.h>
// Properties
GLuint screenWidth = 800, screenHeight = 600;
// Function prototypes
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 Do_Movement();
const GLuint WIDTH = 800, HEIGHT = 600;
// Camera
glm::vec3 cameraPos = glm::vec3(0.0f, 0.0f, 3.0f);
glm::vec3 cameraFront = glm::vec3(0.0f, 0.0f, -1.0f);
glm::vec3 cameraUp = glm::vec3(0.0f, 1.0f, 0.0f);
GLfloat yaw = -90.0f; // Yaw is initialized to -90.0 degrees since a yaw of 0.0 results in a direction vector pointing to the right (due to how Eular angles work) so we initially rotate a bit to the left.
GLfloat pitch = 0.0f;
GLfloat lastX = WIDTH / 2.0;
GLfloat lastY = HEIGHT / 2.0;
bool keys[1024];
bool firstMouse = true;
GLfloat deltaTime = 0.0f;
GLfloat lastFrame = 0.0f;
// The MAIN function, from here we start our application and run our Game loop
int main()
{
// Init GLFW
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(screenWidth, screenHeight, "LearnOpenGL", nullptr, nullptr); // Windowed
glfwMakeContextCurrent(window);
// Set the required callback functions
glfwSetKeyCallback(window, key_callback);
glfwSetCursorPosCallback(window, mouse_callback);
glfwSetScrollCallback(window, scroll_callback);
// Options
glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
// Initialize GLEW to setup the OpenGL Function pointers
glewExperimental = GL_TRUE;
glewInit();
// Define the viewport dimensions
glViewport(0, 0, screenWidth, screenHeight);
// Setup some OpenGL options
glEnable(GL_DEPTH_TEST);
// Setup and compile our shaders
Shader shader("VertexShaderSource2_2_1.txt", "FragmentShaderSource2_2_1.txt");
// Load models
Model ourModel("nanosuit/nanosuit.obj");
// Draw in wireframe
//glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
// Game loop
while (!glfwWindowShouldClose(window))
{
// Set frame time
GLfloat currentFrame = glfwGetTime();
deltaTime = currentFrame - lastFrame;
lastFrame = currentFrame;
// Check and call events
glfwPollEvents();
Do_Movement();
// Clear the colorbuffer
glClearColor(0.05f, 0.05f, 0.05f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
shader.Use(); // <-- Don't forget this one!
// Transformation matrices
glm::mat4 view(1);
glm::mat4 projection(1);
view = glm::lookAt(cameraPos, cameraPos + cameraFront, cameraUp);
projection = glm::perspective(45.0f, (GLfloat)WIDTH / (GLfloat)HEIGHT, 0.1f, 100.0f);
// Get the uniform locations
glUniformMatrix4fv(glGetUniformLocation(shader.Program, "projection"), 1, GL_FALSE, glm::value_ptr(projection));
glUniformMatrix4fv(glGetUniformLocation(shader.Program, "view"), 1, GL_FALSE, glm::value_ptr(view));
// Draw the loaded model
glm::mat4 model(1);
model = glm::translate(model, glm::vec3(0.0f, -1.75f, 0.0f)); // Translate it down a bit 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
glUniformMatrix4fv(glGetUniformLocation(shader.Program, "model"), 1, GL_FALSE, glm::value_ptr(model));
ourModel.Draw(shader);
// Swap the buffers
glfwSwapBuffers(window);
}
glfwTerminate();
return 0;
}
#pragma region "User input"
// Moves/alters the camera positions based on user input
void Do_Movement()
{
// Camera controls
GLfloat cameraSpeed = 5.0f * deltaTime;
if (keys[GLFW_KEY_W])
cameraPos += cameraSpeed * cameraFront;
if (keys[GLFW_KEY_S])
cameraPos -= cameraSpeed * cameraFront;
if (keys[GLFW_KEY_A])
cameraPos -= glm::normalize(glm::cross(cameraFront, cameraUp)) * cameraSpeed;
if (keys[GLFW_KEY_D])
cameraPos += glm::normalize(glm::cross(cameraFront, cameraUp)) * cameraSpeed;
}
// Is called whenever a key is pressed/released via GLFW
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)
keys[key] = true;
else if (action == GLFW_RELEASE)
keys[key] = false;
}
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; // Reversed since y-coordinates go from bottom to left
lastX = xpos;
lastY = ypos;
GLfloat sensitivity = 0.05; // Change this value to your liking
xoffset *= sensitivity;
yoffset *= sensitivity;
yaw += xoffset;
pitch += yoffset;
// Make sure that when pitch is out of bounds, screen doesn't get flipped
if (pitch > 89.0f)
pitch = 89.0f;
if (pitch < -89.0f)
pitch = -89.0f;
glm::vec3 front;
front.x = cos(glm::radians(yaw)) * cos(glm::radians(pitch));
front.y = sin(glm::radians(pitch));
front.z = sin(glm::radians(yaw)) * cos(glm::radians(pitch));
cameraFront = glm::normalize(front);*/
}
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
{
}
#pragma endregion
顶点着色器代码
#version 330 core
layout (location = 0) in vec3 position;
layout (location = 1) in vec3 normal;
layout (location = 2) in vec2 texCoords;
out vec2 TexCoords;
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
void main()
{
gl_Position = projection * view * model * vec4(position, 1.0f);
TexCoords = texCoords;
}
片段着色器代码
#version 330 core
in vec2 TexCoords;
out vec4 color;
uniform sampler2D texture_diffuse1;
void main()
{
color = vec4(texture(texture_diffuse1, TexCoords));
}
参考链接:https://learnopengl-cn.readthedocs.io/zh/latest/03%20Model%20Loading/03%20Model/