纹理

多纹理

#ifndef TRIANGLE_H
#define TRIANGLE_H

#include <QWidget>
#include <QGLWidget>
#include <QOpenGLShader>
#include <QOpenGLShaderProgram>
#include <QDebug>
#include <QOpenGLFunctions>
#include <QOpenGLFunctions_3_3_Core>
#include <QTime>
#include <QtMath>
#include <QTimer>
#include <QOpenGLTexture>

#include "shader.h"

namespace Ui {
class Triangle;
}

class Triangle : public QGLWidget, protected QOpenGLFunctions
{
    Q_OBJECT

public:
    explicit Triangle();
    ~Triangle();
protected:
    virtual void initializeGL();
    virtual void paintGL();
    virtual void resizeGL(int w, int h);
private:
    QOpenGLFunctions_3_3_Core *core;
    QOpenGLTexture *texture1, *texture2;
    Shader *ourShader;
};

#endif // TRIANGLE_H

#include "triangle.h"
#include "ui_triangle.h"

GLuint VBO, VAO, EBO;

Triangle::Triangle()
{

}

Triangle::~Triangle()
{
    delete ourShader;
    core->glDeleteVertexArrays(1, &VAO);
    core->glDeleteBuffers(1, &VBO);
    core->glDeleteBuffers(1, &EBO);
    texture1->destroy();
    texture2->destroy();
}

void Triangle::initializeGL()
{
    //着色器部分
    core = QOpenGLContext::currentContext()->versionFunctions<QOpenGLFunctions_3_3_Core>();
    if (!core) {
          qWarning() << "Could not obtain required OpenGL context version";
          exit(1);
    }
    ourShader = new Shader(":/vertexshader.vert", ":/fragmentshader.frag");

    //VAO，VBO数据部分
    GLfloat vertices[] = {
        0.5f,  0.5f, 0.0f,   1.0f, 0.0f, 0.0f,   1.0f, 1.0f, // top right //注意新的数据，有纹理单元
        0.5f, -0.5f, 0.0f,   0.0f, 1.0f, 0.0f,   1.0f, 0.0f, // bottom right
       -0.5f, -0.5f, 0.0f,   0.0f, 0.0f, 1.0f,   0.0f, 0.0f, // bottom left
       -0.5f,  0.5f, 0.0f,   1.0f, 1.0f, 0.0f,   0.0f, 1.0f  // top left
    };

    GLuint indices[] = {
        0, 1, 3, // first triangle
        1, 2, 3  // second triangle
    };

    core->glGenVertexArrays(1, &VAO);
    core->glGenBuffers(1, &VBO);
    core->glGenBuffers(1, &EBO);

    core->glBindVertexArray(VAO);

    core->glBindBuffer(GL_ARRAY_BUFFER, VBO);
    core->glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    core->glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
    core->glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
    //position attribute
    core->glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8*sizeof(GLfloat), nullptr);
    core->glEnableVertexAttribArray(0);
    //color attribute
    core->glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8*sizeof(GLfloat), (void*)(3 * sizeof(float)));
    core->glEnableVertexAttribArray(1);

    core->glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8*sizeof(GLfloat), (void *)(6*sizeof(float)));
    core->glEnableVertexAttribArray(2);

    //纹理1
    texture1 = new QOpenGLTexture(QImage(":/box.jpg").mirrored(), QOpenGLTexture::GenerateMipMaps); //直接生成绑定一个2d纹理, 并生成多级纹理MipMaps
    if(!texture1->isCreated()) {
        qDebug()<<"Failed to load texture" << endl;
    }
    texture1->setWrapMode(QOpenGLTexture::DirectionS, QOpenGLTexture::Repeat);
    texture1->setWrapMode(QOpenGLTexture::DirectionT, QOpenGLTexture::Repeat);

    texture1->setMinificationFilter(QOpenGLTexture::Linear);
    texture1->setMagnificationFilter(QOpenGLTexture::Linear);
    texture1->setFormat(QOpenGLTexture::RGBFormat);


    texture2 = new QOpenGLTexture(QImage(":/awesomeface.png").mirrored(), QOpenGLTexture::GenerateMipMaps); //直接生成绑定一个2d纹理, 并生成多级纹理MipMaps
    if(!texture2->isCreated()) {
        qDebug()<<"Failed to load texture" << endl;
    }
    texture2->setWrapMode(QOpenGLTexture::DirectionS, QOpenGLTexture::Repeat);
    texture2->setWrapMode(QOpenGLTexture::DirectionT, QOpenGLTexture::Repeat);

    texture2->setMinificationFilter(QOpenGLTexture::Linear);
    texture2->setMagnificationFilter(QOpenGLTexture::Linear);
    texture2->setFormat(QOpenGLTexture::RGBFormat);



}

void Triangle::paintGL()
{
    core->glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
    core->glClear(GL_COLOR_BUFFER_BIT);

    ourShader->use();
    ourShader->shaderProgram.setUniformValue("texture1", 0);
    ourShader->shaderProgram.setUniformValue("texture2", 1);
    core->glActiveTexture(GL_TEXTURE1);
    texture2->bind();
    core->glActiveTexture(GL_TEXTURE0);
    texture1->bind();

    core->glBindVertexArray(VAO);
    core->glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, nullptr);

}

void Triangle::resizeGL(int w, int h)
{
    core->glViewport(0, 0, w, h);
}

#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aColor;
layout (location = 2) in vec2 aTexCoord;

out vec3 ourColor;
out vec2 TexCoord;

void main(){
  gl_Position = vec4(aPos, 1.0f);
  ourColor = aColor;
  TexCoord = aTexCoord;
}

#version 330 core
out vec4 FragColor;

in vec3 ourColor;
in vec2 TexCoord;

uniform sampler2D texture1;
uniform sampler2D texture2;

void main()
{
    FragColor = mix(texture2D(texture1, TexCoord), texture2D(texture2, TexCoord), 0.2f);
}