Qt::QOpenGLWidget渲染带光照的立方体

本文主要是介绍Qt::QOpenGLWidget渲染带光照的立方体，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

一学前知识准备

二动手实践

三参考文章

一学前知识准备

这里为了方便不用之前的方法，之前的方法需要引入很多三方的数学库和纹理，模型等库，这里我们班用Qt工具来做更加简单方便。在看过前面几篇文章之后，在正式开始之前还需要了解opengl渲染流程上的一些东西。

opengl坐标系统了解opengl整个渲染流程坐标是如何转换的

OpenGL图形渲染管线、VBO、VAO、EBO概念及用例 opengl渲染cpu和gpu怎么传递大块数据

透视投影详解理解摄像机的透视原理

OpenGL ES着色器语言之变量和数据类型了解着色器程序中的基本变量类型

opengl如何渲染一个三角形学会如何编写最简单着色器程序渲染最基本的渲染单位三角形

摄像机原理理解3d场景中摄像机的实现原理

二动手实践

立方体顶点着色器

#version 330 core
//顶点着色器uniform mat4 mvp_matrix;
uniform mat4 model_matrix;layout (location = 0) in vec3 a_position;   //空间坐标
layout (location = 1) in vec2 a_texcoord;   //纹理坐标
layout (location = 2) in vec3 a_normal;	    //法线向量out vec2 v_texcoord;
out vec3 FragPos;
out vec3 Normal;void main()
{FragPos = vec3(model_matrix * vec4(a_position, 1.0));Normal =  mat3(transpose(inverse(model_matrix))) * a_normal;  v_texcoord = a_texcoord;gl_Position = mvp_matrix * vec4(a_position,1);
}

立方体像素着色器

#version 330 core
//像素着色器in vec3 Normal;  
in vec3 FragPos;  uniform vec3 lightPos; 
uniform vec3 viewPos; 
uniform vec3 lightColor;
uniform sampler2D texture;in vec2 v_texcoord;void main()
{//环境光照float ambientStrength = 0.3;vec3 ambient = ambientStrength * lightColor;// 漫反射光照 vec3 norm = normalize(Normal);vec3 lightDir = normalize(lightPos - FragPos);float diff = max(dot(norm, lightDir), 0.0);vec3 diffuse = diff * lightColor;// 镜面光照float specularStrength = 1.0;vec3 viewDir = normalize(viewPos - FragPos);vec3 reflectDir = reflect(-lightDir, norm);  float spec = pow(max(dot(viewDir, reflectDir), 0.0), 2);vec3 specular = specularStrength * spec * lightColor;  //获取纹理中对应的颜色vec4 textureColor = texture2D(texture, v_texcoord);//把纹理中的颜色和光照参数相乘gl_FragColor = vec4(ambient + diffuse + specular, 1.0) * textureColor;
}

c++设置gpu数据

class MainWidget : public QOpenGLWidget, protected QOpenGLFunctions
{Q_OBJECT
public:explicit MainWidget(QWidget *parent = 0);~MainWidget();
protected:void mousePressEvent(QMouseEvent *e) override;void mouseReleaseEvent(QMouseEvent *e) override;void wheelEvent(QWheelEvent *event) override;void timerEvent(QTimerEvent *e) override;void initializeGL() override;void resizeGL(int w, int h) override;void paintGL() override;void initShaders();void initTextures();
private:QBasicTimer timer;QOpenGLShaderProgram cubeProgram;QOpenGLShaderProgram lightinhProgram;GeometryEngine *geometries;QOpenGLTexture *texture;QMatrix4x4 projection;QVector2D mousePressPosition;QVector3D rotationAxis;qreal angularSpeed;qreal viewChageDisOld;qreal viewChageDisNew;QQuaternion rotation;
};

#include "mainwidget.h"
#include <QMouseEvent>
#include <math.h>
#include <QTime>
#include <QDebug>//模型主动刷新帧率
#define ACTION_FPS  60
#define LIGHT_COLOR QVector3D(1.2f, 1.0f, 2.0f)
#define EYE_CENTER  QVector3D(0.0, 0.0, 8.0)
#define LIGHT_POS   QVector3D(2.5f, 2.0f, -1.0f)void MainWidget::initShaders()
{if (!lightinhProgram.addShaderFromSourceFile(QOpenGLShader::Vertex, ":/base_lighting.vs"))close();if (!lightinhProgram.addShaderFromSourceFile(QOpenGLShader::Fragment, ":/base_lighting.fs"))	close();if (!lightinhProgram.link())	close();if (!cubeProgram.addShaderFromSourceFile(QOpenGLShader::Vertex, ":/shader.vs"))close();if (!cubeProgram.addShaderFromSourceFile(QOpenGLShader::Fragment, ":/shader.fs"))close();if (!cubeProgram.link())close();geometries->setCubeGLData(&cubeProgram);geometries->setLightingGLData(&lightinhProgram);
}
void MainWidget::initTextures()
{texture = new QOpenGLTexture(QImage(":/cube.png").mirrored());texture->setMinificationFilter(QOpenGLTexture::Nearest);texture->setMagnificationFilter(QOpenGLTexture::Linear);texture->setWrapMode(QOpenGLTexture::Repeat);
}void MainWidget::resizeGL(int w, int h)
{qreal aspect = qreal(w) / qreal(h ? h : 1);const qreal zNear = 2.0, zFar = 20.0, fov = 45.0;projection.setToIdentity();projection.perspective(fov, aspect, zNear, zFar);
}//opengl渲染函数
void MainWidget::paintGL()
{glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);//开启深度测试glEnable(GL_DEPTH_TEST);//开启遮挡剔除glEnable(GL_CULL_FACE);texture->bind();qreal viewChangeRate = viewChageDisNew / 1000.f;viewChageDisOld = viewChageDisNew;QMatrix4x4 viewmatrix;//计算view矩阵viewmatrix.lookAt(EYE_CENTER, QVector3D(0, 0, -20), QVector3D(0, 1, 0));//模型坐标转换矩阵坐标QMatrix4x4 modelmatrix;//平移至左下角modelmatrix.translate(-1.6, -0.8, 0);//鼠标滚动旋转角度modelmatrix.rotate(rotation);//滚轮缩放modelmatrix.scale(1.0 * (1 + viewChangeRate));//设置cube着色器变量QMatrix4x4 mvpmatrix = projection * viewmatrix * modelmatrix;cubeProgram.bind();cubeProgram.setUniformValue("lightColor", LIGHT_COLOR);cubeProgram.setUniformValue("lightPos", LIGHT_POS);cubeProgram.setUniformValue("viewPos", EYE_CENTER);cubeProgram.setUniformValue("mvp_matrix", mvpmatrix);cubeProgram.setUniformValue("texture", 0);cubeProgram.setUniformValue("model_matrix", modelmatrix);geometries->drawCubeGeometry(&cubeProgram);//设置光源cube着色器变量QMatrix4x4 lampmodelmatrix;lampmodelmatrix.translate(LIGHT_POS);//缩放lampmodelmatrix.scale(0.4);QMatrix4x4 lampmvpmatrix = projection * viewmatrix * lampmodelmatrix;lightinhProgram.bind();lightinhProgram.setUniformValue("mvp_matrix", lampmvpmatrix);lightinhProgram.setUniformValue("lightColor", LIGHT_COLOR);geometries->drawLighting(&lightinhProgram);
}

这里只展示一些关键的代码，完整的代码地址：

gitee地址

github地址

最终效果展示：