qt+opengl 加载三维obj文件

1前面我们已经熟悉了opengl自定义顶点生成一个立方体，并且我们实现了立方体的旋转，光照等功能。下面我们来用opengl来加载一个obj文件。准备我们首先准备一个简单的obj文件（head.obj）。资源在本页下载

2 在obj文件里面，我们关注下 v 字段和f字段

 v 字段就是顶点  f字段代表了面，意思是每个面的顶点编号。 结构如下

v -0.99179999 -2.98999995 4.05410025  表示顶点值

f 12791 127 126   表示这个面的三个点在 v 里面的index值是12791 也是就是v[12791]的值的顶点是这个面的顶点值。

3 下面我们来解析obj文件

bool load(QString fileName, QVector<float>& vPoints)
{if (fileName.mid(fileName.lastIndexOf('.')) != ".obj" && fileName.mid(fileName.lastIndexOf('.')) != ".OBJ"){qDebug() << "file is not a obj file.";return false;}QFile objFile(fileName);if (!objFile.open(QIODevice::ReadOnly)){qDebug() << "open" << fileName << "failed";return false;}else{qDebug() << "open" << fileName << "success!";}QVector<float> vertextPoints, texturePoints, normalPoints;QVector<Face> facesIndexs;while (!objFile.atEnd()){QByteArray lineData = objFile.readLine();QList<QByteArray> strValues = lineData.trimmed().split(' ');QString dataType = strValues.takeFirst();for(int i=0;i<strValues.size();i++){double nData = strValues.at(i).toDouble();QString strTemp = QString::number(nData,'f',4);if (dataType == "v"){vertextPoints.append(strTemp.toFloat());}else if (dataType == "vt"){texturePoints.append(strValues.at(i).toFloat());}else if (dataType == "vn"){normalPoints.append(strValues.at(i).toFloat());}else if (dataType == "f"){Face ondInfo;if(strValues.at(i).contains("/")){QList<QByteArray> strTemp = strValues.at(i).split('/');if(strTemp.size()==2){ondInfo.vertices  =  strTemp.at(0).toInt();ondInfo.texCoords =  strTemp.at(1).toInt();}else if(strTemp.size()==3){ondInfo.vertices  =  strTemp.at(0).toInt();ondInfo.texCoords =  strTemp.at(1).toInt();ondInfo.normals   =  strTemp.at(2).toInt();}}else{ondInfo.vertices = strValues.at(i).toInt();//qDebug()<<"Face ondInfo"<<ondInfo.vertices;}facesIndexs.append(ondInfo);}}}objFile.close();int count =0;for (int i=0;i<facesIndexs.size();i++){int vIndex = facesIndexs[i].vertices - 1;if(vIndex * 3 <=vertextPoints.size() ||vIndex * 3 + 1 <=vertextPoints.size()||vIndex * 3 + 2<=vertextPoints.size() ){vPoints << vertextPoints.at(vIndex * 3);vPoints << vertextPoints.at(vIndex * 3 + 1);vPoints << vertextPoints.at(vIndex * 3 + 2);// qDebug()<<"vIndex"<<i<<vertextPoints.size()<<vIndex * 3;}else{//  qDebug()<<"vIndex error"<<i<<vertextPoints.size()<<vIndex * 3;}}vertextPoints.clear();texturePoints.clear();normalPoints.clear();facesIndexs.clear();return true;
}

 接着我们来写加载代码

和以前的一样，就是写glsl语句，

#ifndef TESTOBJOPENGL_H
#define TESTOBJOPENGL_H#include <QObject>
#include <QWidget>
#include <QOpenGLWidget>
#include <QOpenGLExtraFunctions>
#include <QOpenGLBuffer>
#include <QOpenGLShaderProgram>
#include <QOpenGLVertexArrayObject>
#include <QTimer>
#include <QOpenGLTexture>
#include <QOpenGLWidget>
#include <QOpenGLFunctions>
#include <QOpenGLBuffer>
#include <QOpenGLVertexArrayObject>
#include <QTimer>
#include <QMouseEvent>QT_FORWARD_DECLARE_CLASS(QOpenGLShaderProgram);
QT_FORWARD_DECLARE_CLASS(QOpenGLTexture)
class testobjOpengl : public QOpenGLWidget, protected QOpenGLFunctions
{
public:testobjOpengl( QWidget *parent=nullptr);~testobjOpengl();
protected:void initializeGL() override;void paintGL() override;void resizeGL(int width, int height) override;void rotateBy(int xAngle, int yAngle, int zAngle);bool load(QString fileName, QVector<float>& vPoints);struct Face{int vertices;int texCoords;int normals;Face(){vertices = -1;texCoords = -1;normals = -1;}};
private:QVector<float> m_vPoints;int m_xRot;int m_yRot;int m_zRot;QOpenGLShaderProgram *m_program= nullptr;QOpenGLVertexArrayObject vao;QOpenGLBuffer vbo;QVector3D cameraPos;QVector3D cameraTarget;QVector3D cameraDirection;QOpenGLTexture *texture;int m_projMatrixLoc;int m_mvMatrixLoc;int m_normalMatrixLoc;int m_lightPosLoc;QMatrix4x4 m_proj;QMatrix4x4 m_camera;QMatrix4x4 m_world;QVector3D m_camera_pos;QTimer* timer;int  m_yPos=0;int  m_zPos=0;};#endif // TESTOBJOPENGL_H

#include "testobjopengl.h"static const char *vertexShaderSourceCore ="#version 330\n""layout (location = 0) in vec4 vertex;\n""layout (location = 1) in vec3 normal;\n""out vec3 vert;\n""out vec3 vertNormal;\n""uniform  mat4 matrix;\n""uniform  mat4 view;\n""uniform  mat4 projection;\n""uniform  mat3 normalMatrix;\n""void main() {\n""   vert = vertex.xyz;\n""   vertNormal = normalMatrix * normal;\n""   gl_Position = projection*view* matrix * vertex;\n""}\n";
static const char *fragmentShaderSourceCore ="#version 150\n""in highp vec3 vert;\n""in highp vec3 vertNormal;\n""out highp vec4 fragColor;\n""uniform highp vec3 lightPos;\n""void main() {\n""   highp vec3 L = normalize(lightPos - vert);\n""   highp float NL = max(dot(normalize(vertNormal), L), 0.0);\n""   highp vec3 color = vec3(1.0, 1.0, 0.0);\n""   highp vec3 col = clamp(color * 0.2 + color * 0.8 * NL, 0.0, 1.0);\n""   fragColor = vec4(col, 1.0);\n""}\n";testobjOpengl::testobjOpengl(QWidget *parent): QOpenGLWidget(parent),m_xRot(0),m_yRot(0),m_zRot(0)
{m_vPoints.clear();cameraPos = QVector3D(0, 0, 3);QString strTemp = "F:/Tree2/head.obj";bool ret = load(strTemp,m_vPoints);if(ret){timer = new QTimer;timer->setInterval(100);connect(timer,&QTimer::timeout,this,[=]{qDebug()<<"timeout";rotateBy(10 * 16, +10 * 16, -1 * 16);});timer->start();}else{qDebug()<<"1111111111111111";}}
void testobjOpengl::rotateBy(int xAngle, int yAngle, int zAngle)
{float cameraSpeed = 0.2;m_camera_pos -= cameraSpeed * QVector3D(0, 0, -1);//由远到近if(m_yPos>=100){m_yPos = 0;}m_yPos+=10;if(m_zPos>=100){m_zPos = 0;}m_zPos+=10;// m_camera_pos = QVector3D(0, m_yPos, m_zPos);//由远到近// m_camera_pos.setY(m_yPos);m_xRot += xAngle;m_yRot += yAngle;m_zRot += zAngle;update();//timer->stop();
}
testobjOpengl::~testobjOpengl()
{}void testobjOpengl::initializeGL()
{initializeOpenGLFunctions();m_program = new QOpenGLShaderProgram;m_program->addShaderFromSourceCode(QOpenGLShader::Vertex, vertexShaderSourceCore);m_program->addShaderFromSourceCode(QOpenGLShader::Fragment, fragmentShaderSourceCore);if (m_program->link()){qDebug() << "link success!";}else{qDebug() << "link failed";}m_program->bindAttributeLocation("vertex", 0);m_program->bindAttributeLocation("normal", 1);m_program->link();m_program->bind();//    m_projMatrixLoc = m_program->uniformLocation("projection");
//    m_mvMatrixLoc = m_program->uniformLocation("matrix");
//    m_normalMatrixLoc = m_program->uniformLocation("normalMatrix");
//    m_lightPosLoc = m_program->uniformLocation("lightPos");vbo.create();vbo.bind();vbo.allocate(m_vPoints.data(), m_vPoints.size() * sizeof(float));QOpenGLFunctions *f = QOpenGLContext::currentContext()->functions();f->glEnableVertexAttribArray(0);f->glEnableVertexAttribArray(1);f->glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(GLfloat), nullptr);f->glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(GLfloat), reinterpret_cast<void *>(3 * sizeof(GLfloat)));vbo.release();m_program->setUniformValue(m_lightPosLoc, QVector3D(10, 10, 10)); 
}void testobjOpengl::paintGL()
{glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);glEnable(GL_DEPTH_TEST);glEnable(GL_CULL_FACE);QMatrix4x4 m;//m.ortho(-0.5f, +0.5f, +0.5f, -0.5f, 4.0f, 15.0f);m.setToIdentity();m.translate(0.0f, 0.0f, 0.0f);m.rotate(m_xRot / 16.0f, 1.0f, 0.0f, 0.0f);m.rotate(90, 0.0f, 1.0f, 0.0f);m.rotate(0, 0.0f, 0.0f, 1.0f);m.scale(0.5);QMatrix4x4 view;view.setToIdentity();view.lookAt(QVector3D(0, 20, 20), QVector3D(0,0,0), QVector3D(1,0,0));m_program->bind();m_program->setUniformValue("projection", m_proj);m_program->setUniformValue("matrix", m);m_program->setUniformValue("view", view);m_program->setUniformValue("lightPos", QVector3D(10, 10, 0));QMatrix3x3 normalMatrix = m.normalMatrix();m_program->setUniformValue("normalMatrix", normalMatrix);glDrawArrays(GL_TRIANGLES, 0, m_vPoints.size()/3);m_program->release();
}void testobjOpengl::resizeGL(int width, int height)
{m_proj.setToIdentity();m_proj.perspective(45.0f, GLfloat(width) / height, 0.01f, 100.0f);
}
bool testobjOpengl::load(QString fileName, QVector<float>& vPoints)
{if (fileName.mid(fileName.lastIndexOf('.')) != ".obj" && fileName.mid(fileName.lastIndexOf('.')) != ".OBJ"){qDebug() << "file is not a obj file.";return false;}QFile objFile(fileName);if (!objFile.open(QIODevice::ReadOnly)){qDebug() << "open" << fileName << "failed";return false;}else{qDebug() << "open" << fileName << "success!";}QVector<float> vertextPoints, texturePoints, normalPoints;QVector<Face> facesIndexs;while (!objFile.atEnd()){QByteArray lineData = objFile.readLine();QList<QByteArray> strValues = lineData.trimmed().split(' ');QString dataType = strValues.takeFirst();for(int i=0;i<strValues.size();i++){double nData = strValues.at(i).toDouble();QString strTemp = QString::number(nData,'f',4);if (dataType == "v"){vertextPoints.append(strTemp.toFloat());}else if (dataType == "vt"){texturePoints.append(strValues.at(i).toFloat());}else if (dataType == "vn"){normalPoints.append(strValues.at(i).toFloat());}else if (dataType == "f"){Face ondInfo;if(strValues.at(i).contains("/")){QList<QByteArray> strTemp = strValues.at(i).split('/');if(strTemp.size()==2){ondInfo.vertices  =  strTemp.at(0).toInt();ondInfo.texCoords =  strTemp.at(1).toInt();}else if(strTemp.size()==3){ondInfo.vertices  =  strTemp.at(0).toInt();ondInfo.texCoords =  strTemp.at(1).toInt();ondInfo.normals   =  strTemp.at(2).toInt();}}else{ondInfo.vertices = strValues.at(i).toInt();//qDebug()<<"Face ondInfo"<<ondInfo.vertices;}facesIndexs.append(ondInfo);}}}objFile.close();int count =0;for (int i=0;i<facesIndexs.size();i++){int vIndex = facesIndexs[i].vertices - 1;if(vIndex * 3 <=vertextPoints.size() ||vIndex * 3 + 1 <=vertextPoints.size()||vIndex * 3 + 2<=vertextPoints.size() ){vPoints << vertextPoints.at(vIndex * 3);vPoints << vertextPoints.at(vIndex * 3 + 1);vPoints << vertextPoints.at(vIndex * 3 + 2);// qDebug()<<"vIndex"<<i<<vertextPoints.size()<<vIndex * 3;}else{//  qDebug()<<"vIndex error"<<i<<vertextPoints.size()<<vIndex * 3;}}vertextPoints.clear();texturePoints.clear();normalPoints.clear();facesIndexs.clear();return true;
}

 我们开始调用

testobjOpengl w;

w.show();

运行结果：