因为本案例只是获取了模型的顶点，法线，uv，纹理。因为我们还没研究光照暂时先拿到这些去研究Phong Lighting Model着色已经足够，到研究漫反射和镜面反射贴图再来完善。
大型模型都是有很多个mesh对象构成如learnOpengl中说到一栋别墅，会有游泳池，石柱等这些小的模型组装出来的，而这些小的模型就叫做mesh对象，。因此先来写mesh对象
MyMesh .h
#pragma once
#include"vector"
#include "MyShader.h"
#include"Camera.h"
using namespace std;
struct Vertex
{
QVector3D Position;
QVector3D Normal;
QVector2D TexCoords;
};
struct Texture {
GLint id;
QString type;
QString path;
};
class MyMesh : protected QOpenGLFunctions_4_3_Core
{
public:
vector vertices;//顶点属性向量
vectorindices;//索引向量
vectortextures;//纹理属性向量
//一个网格对象需要顶点，索引和纹理，这是一般建模软件的结构建模网格的数据结构
MyMesh(vector vertices, vector indices, vector texture);
void init(QOpenGLShaderProgram* shaderProgram);
void draw(Camera camera);
void setLocation(float x,float y,float z);
private:
float locationX=0.0f, locationY=0.0f, locationZ=-7.0f;
QMatrix4x4 mv;
QOpenGLShaderProgram* shaderProgram;
QOpenGLVertexArrayObject vao;
QOpenGLBuffer vbo,ebo;
GLuint vPosition,normal,uv, mv_loc;
};
MyMesh.cpp
#include "stdafx.h"
#include "MyMesh.h"
MyMesh::MyMesh(vector vertices, vector indices, vector textures): ebo(QOpenGLBuffer::IndexBuffer)
{
this->vertices = vertices;
this->indices = indices;
this->textures = textures;
}
void MyMesh::init(QOpenGLShaderProgram* shaderProgram)
{
initializeOpenGLFunctions();
this->shaderProgram = shaderProgram;
shaderProgram->bind();
vao.create();
vbo.create();
ebo.create();
vao.bind();
vbo.bind();
vbo.setUsagePattern(QOpenGLBuffer::StaticDraw);
vbo.allocate(&vertices[0], this->vertices.size() * sizeof(Vertex));
// 设置顶点坐标指针
vPosition = shaderProgram->attributeLocation("vPosition");
shaderProgram->setAttributeBuffer(vPosition, GL_FLOAT, 0, 3, sizeof(Vertex));
glEnableVertexAttribArray(vPosition);
// 设置法线指针
normal= shaderProgram->attributeLocation("normal");
shaderProgram->setAttributeBuffer("normal", GL_FLOAT, offsetof(Vertex, Normal), 3, sizeof(Vertex));//shader变量索引，参数类型，偏移量，元素大小，步长
glEnableVertexAttribArray(normal);
// 设置顶点的纹理坐标
uv = shaderProgram->attributeLocation("uv");
shaderProgram->setAttributeBuffer(uv, GL_FLOAT, offsetof(Vertex, TexCoords), 2, sizeof(Vertex));
glEnableVertexAttribArray(uv);
ebo.bind();
ebo.setUsagePattern(QOpenGLBuffer::StaticDraw);
ebo.allocate(&this->indices[0], this->indices.size() * sizeof(GLuint));
vao.release();
ebo.release();
vbo.release();
shaderProgram->release();
vertices.clear();
}
void MyMesh::draw(Camera camera) {
shaderProgram->bind();
mv_loc = shaderProgram->uniformLocation("mv_matrix");
//构建视图矩阵
QMatrix4x4 m;
m.translate(locationX, locationY, locationZ);
QMatrix4x4 v;
v.lookAt(QVector3D(camera.location.x, camera.location.y, camera.location.z),
QVector3D(camera.viewPoint.x, camera.viewPoint.y, camera.viewPoint.z),
QVector3D(camera.worldY.x, camera.worldY.y, camera.worldY.z));
mv = v * m;
shaderProgram->setUniformValue(mv_loc, mv);
vao.bind();
glDrawElements(GL_TRIANGLES, this->indices.size(), GL_UNSIGNED_INT, 0);
vao.release();
shaderProgram->release();
}
void MyMesh::setLocation(float x, float y, float z) {
locationX = x;
locationY = y;
locationZ = z;
}
之所以选择结构体，是因为c++的结构体类型中的变量是连续的，因此很容易知道他的大小如：
struct Vertex
{
QVector3D Position;
QVector3D Normal;
QVector2D TexCoords;
};
他的大小就是sizeof(Vertex);
offsetof(Vertex, TexCoords)函数能自动运算出变量间的偏移量。第一个参数是结构体名，第二个参数是哪一个变量名，返回要便宜的量。
接着就可以获取模型数据了。
Model.h
#include "assimp/scene.h"
#include "assimp/postprocess.h"
#include "MyMesh.h"
#include"iostream"
using namespace std;
class Model
{
public:
/* 成员函数 */
Model();
~Model();
void draw(Camera camera);
void init(string path, QOpenGLShaderProgram* shaderProgram);
void setModelLocation(QVector3D location);
private:
///* 模型数据 */
vector meshes;
QString directory;
QOpenGLShaderProgram* shaderProgram;
///* 私有成员函数 */
void loadModel(string path);
void processNode(aiNode* node, const aiScene* scene);
MyMesh* processMesh(aiMesh* mesh, const aiScene* scene);
vector loadMaterialTextures(aiMaterial* mat, aiTextureType type, QString typeName);
};
Model.cpp
#include "stdafx.h"
#include "Model.h"
Model::Model(){
}
Model::~Model() {
meshes.clear();
}
void Model::init(string path, QOpenGLShaderProgram* shaderProgram) {
this->shaderProgram = shaderProgram;
loadModel(path);
}
void Model::setModelLocation(QVector3D location) {
for (GLuint i = 0; i < this->meshes.size(); i++)
{
this->meshes[i]->setLocation(location.x(), location.y(), location.z());
}
}
void Model::draw(Camera camera)
{
for (GLuint i = 0; i < this->meshes.size(); i++)
{
this->meshes[i]->draw(camera);
}
}
void Model::loadModel(string path)
{
Assimp::Importer import;
const aiScene* scene = import.ReadFile(path, aiProcess_Triangulate | aiProcess_FlipUVs);
if (!scene || scene->mFlags == AI_SCENE_FLAGS_INCOMPLETE || !scene->mRootNode)
{
qDebug() << "ERROR::ASSIMP::" << import.GetErrorString() << endl;
return;
}
this->directory =QString::fromStdString(path.substr(0, path.find_last_of('/')));
//qDebug() <<"directory:"<< directory;//全路径
this->processNode(scene->mRootNode, scene);
}
void Model::processNode(aiNode* node, const aiScene* scene)
{
// 添加当前节点中的所有Mesh
//qDebug() << "mNumMeshes:"<mNumMeshes;
for (GLuint i = 0; i < node->mNumMeshes; i++)
{
aiMesh* mesh = scene->mMeshes[node->mMeshes[i]];
this->meshes.push_back(this->processMesh(mesh, scene));
}
// 递归处理该节点的子孙节点
//qDebug() << "mNumChildren:" << node->mNumChildren;
for (GLuint i = 0; i < node->mNumChildren; i++)
{
this->processNode(node->mChildren[i], scene);
}
}
MyMesh* Model::processMesh(aiMesh* mesh, const aiScene* scene)
{
vector vertices;
vector indices;
vector textures;
//qDebug() << "mNumVertices:" << mesh->mNumVertices;
for (GLuint i = 0; i < mesh->mNumVertices; i++)
{
Vertex vertex;
// 处理顶点坐标、法线和纹理坐标
vertex.Position.setX(mesh->mVertices[i].x);
vertex.Position.setY(mesh->mVertices[i].y);
vertex.Position.setZ(mesh->mVertices[i].z);
vertex.Normal.setX(mesh->mNormals[i].x);
vertex.Normal.setY(mesh->mNormals[i].y);
vertex.Normal.setZ(mesh->mNormals[i].z);
if (mesh->mTextureCoords[0]) // Does the mesh contain texture coordinates?
{
vertex.TexCoords.setX(mesh->mTextureCoords[0][i].x);
vertex.TexCoords.setY(mesh->mTextureCoords[0][i].y);
}
else { vertex.TexCoords.setX(0.0);
vertex.TexCoords.setY(0.0);}
vertices.push_back(vertex);
}
// 处理顶点索引
//qDebug() << "mNumFaces:" << mesh->mNumFaces;
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]);
}
}
//处理材质
if(mesh->mMaterialIndex >= 0)
{
aiMaterial* material = scene->mMaterials[mesh->mMaterialIndex];
vector diffuseMats = this->loadMaterialTextures(material,
aiTextureType_DIFFUSE, "texture_diffuse");
textures.insert(textures.end(), diffuseMats.begin(), diffuseMats.end());//把区间[start,end]插入到迭代器的指定位置
vector specularMats = this->loadMaterialTextures(material,
aiTextureType_SPECULAR, "texture_specular");
textures.insert(textures.end(), specularMats.begin(), specularMats.end());
}
MyMesh* myMesh = new MyMesh( vertices, indices, textures);
myMesh->init(shaderProgram);
return myMesh;
}
vector Model::loadMaterialTextures(aiMaterial* mat, aiTextureType type, QString typeName)
{
vector textures;
if (mat->GetTextureCount(type) == 0) {//没有纹理我们也创建一个空的，避免纹理不更新，被上次的覆盖。
cout<< typeName <<":no find texture"<GetTextureCount(type); i++)
{
aiString folderPath;
mat->GetTexture(type, i, &folderPath);
qDebug() << "folderPath:" << folderPath.C_Str();
GLboolean skip = false;
for (GLuint j = 0; j < textures.size(); j++)
{
if (textures[j].path == folderPath.C_Str())
{
textures.push_back(textures[j]);
skip = true;
break;
}
}
if (!skip)
{ // 如果纹理没有被加载过，加载之
Texture texture;
QString fileName = this->directory;
fileName += '/';
fileName += folderPath.C_Str();
qDebug() << fileName;
QOpenGLTexture loadTexture(QImage(fileName).mirrored());
texture.id = loadTexture.textureId();
texture.type = typeName;
texture.path = folderPath.C_Str();
textures.push_back(texture);
}
}
return textures;
}
前面一章说的比较清楚对于节点中的内容，这里就不解释了
使用
Model model;
MyShader shaderModel;
//注意我们前面写好的着色器类，添加新的着色器就ok了
shaderModel.creatShader(":/QtGuiApplication1/Resources/config/shaderMode.vs",":/QtGuiApplication1/Resources/config/shaderMode.fs");
QString fileName = QDir::currentPath();//当前工作路径
fileName += "/Resources/model/Sphere.obj";
mt.init(shaderModel.getShader());
model.init(fileName.toStdString(), shaderModel.getShader());
model.setModelLocation(QVector3D(-2.0,0.0,-4.0));
model.draw(camera);
这时我们按照前面章节讲的添加一个新的着色器，且只包含顶点，和颜色（红色）。
效果：
image.png
出现了球体，因为模型里没有没有纹理贴图数据，所以我给了个红色在shader中。
球体模型，单独的纹理提取
链接：https://pan.baidu.com/s/1Z2Rft6otGfYLcr7bBt6KCw
提取码：jsdd
复制这段内容后打开百度网盘手机App，操作更方便哦
修改着色器代码：
shaderMode.vs
#version 430
uniform mat4 mv_matrix;
uniform mat4 proj_matrix;
in vec3 vPosition;
in vec3 normal;
in vec2 uv;
out vec2 texcoord;
void main(void)
{
gl_Position=proj_matrix*mv_matrix*vec4(vPosition,1.0);
texcoord=uv;
}
shaderMode.fs
#version 430
out vec4 color;
uniform mat4 mv_matrix;
uniform mat4 proj_matrix;
uniform sampler2D textureID;
in vec2 texcoord;
void main(void)
{
color =texture(textureID,texcoord) ;
}
然后我们自己添加一张纹理：
myMesh.h添加
QOpenGLTexture texture;
.cpp中启用这张纹理：（注意初始化在构造函数列表中了）
#include "stdafx.h"
#include "MyMesh.h"
MyMesh::MyMesh(vector vertices, vector indices, vector textures): ebo(QOpenGLBuffer::IndexBuffer), texture(QImage("./Resources/model/earth.bmp"))
{
this->vertices = vertices;
this->indices = indices;
this->textures = textures;
}
void MyMesh::init(QOpenGLShaderProgram* shaderProgram)
{
initializeOpenGLFunctions();
this->shaderProgram = shaderProgram;
shaderProgram->bind();
vao.create();
vbo.create();
ebo.create();
vao.bind();
vbo.bind();
vbo.setUsagePattern(QOpenGLBuffer::StaticDraw);
vbo.allocate(&vertices[0], this->vertices.size() * sizeof(Vertex));
// 设置顶点坐标指针
vPosition = shaderProgram->attributeLocation("vPosition");
shaderProgram->setAttributeBuffer(vPosition, GL_FLOAT, 0, 3, sizeof(Vertex));
glEnableVertexAttribArray(vPosition);
// 设置法线指针
normal= shaderProgram->attributeLocation("normal");
shaderProgram->setAttributeBuffer("normal", GL_FLOAT, offsetof(Vertex, Normal), 3, sizeof(Vertex));//shader变量索引，参数类型，偏移量，元素大小，步长
glEnableVertexAttribArray(normal);
// 设置顶点的纹理坐标
uv = shaderProgram->attributeLocation("uv");
shaderProgram->setAttributeBuffer(uv, GL_FLOAT, offsetof(Vertex, TexCoords), 2, sizeof(Vertex));
glEnableVertexAttribArray(uv);
ebo.bind();
ebo.setUsagePattern(QOpenGLBuffer::StaticDraw);
ebo.allocate(&this->indices[0], this->indices.size() * sizeof(GLuint));
vao.release();
ebo.release();
vbo.release();
shaderProgram->release();
vertices.clear();
}
void MyMesh::draw(Camera camera) {
shaderProgram->bind();
texture.bind(texture.textureId());
shaderProgram->setUniformValue("textureID", texture.textureId());
mv_loc = shaderProgram->uniformLocation("mv_matrix");
//构建视图矩阵
QMatrix4x4 m;
m.translate(locationX, locationY, locationZ);
QMatrix4x4 v;
v.lookAt(QVector3D(camera.location.x, camera.location.y, camera.location.z),
QVector3D(camera.viewPoint.x, camera.viewPoint.y, camera.viewPoint.z),
QVector3D(camera.worldY.x, camera.worldY.y, camera.worldY.z));
mv = v * m;
shaderProgram->setUniformValue(mv_loc, mv);
vao.bind();
glDrawElements(GL_TRIANGLES, this->indices.size(), GL_UNSIGNED_INT, 0);
vao.release();
texture.release();
shaderProgram->release();
}
void MyMesh::setLocation(float x, float y, float z) {
locationX = x;
locationY = y;
locationZ = z;
}
效果：
image.png
这时我们shader中有了法线就可以研究冯氏（Phong）光照模型了。
目录
VSC++2019+QT+OpenGL
QT+OpenGL一之绘制立方体（三角形图元）
QT+OpenGL二之纹理贴图
QT+OpenGL三之矩阵简解
QT+OpenGL四之相机的移动和旋转
QT+OpenGL五之绘制不同的模型（vao,vbo机制）
QT+OpenGL六之天空盒
QT+OpenGL七之使用EBO
QT+OPenGL八之模型准备
QT+OPenGL九之模型解码
QT+OPenGL十之光照模型
QT+OPenGL十一之漫反射和镜面反射贴图
QT+OPenGL十二之定向光
QT+OPenGL十三之真正的点光源和聚光灯
QT+OPenGL十四之多光源混合的问题
QT+OPenGL十五之深度缓冲区
QT+OPenGL十六之模板缓冲区
QT+OPenGL十七帧缓冲区（离屏渲染）
QT+OPenGL十八抗锯齿
QT+OPenGL十九镜面反射效率调整
QT+OPenGL二十Gamma校正