08——qt opengl 点精灵 贴图 混合

  qmyopenglwidget.h

#ifndef QMYOPENGLWIDGET_H
#define QMYOPENGLWIDGET_H

#include 
#include 
#include 
#include 

class QMyOpenglWidget : public QOpenGLWidget, QOpenGLFunctions_3_3_Core
{
public:
    enum EType {
        eNone,
        eFull,
        eLine,
        ePoint,

    };

    Q_OBJECT
public:
    explicit QMyOpenglWidget(QWidget* parent = nullptr);

protected:
    virtual void initializeGL();
    virtual void resizeGL(int w, int h);
    virtual void paintGL();

public:
    void cretaeShader();
    void initDrawData(GLuint &vao, float *vertices, int vSize, GLuint &ebo);
    void modeChange(EType type = eLine);
    unsigned int setImage(const char *filename);

private:
    unsigned int vao1;
    unsigned int ebo1;
    QOpenGLShaderProgram program;

    GLuint programId;
    GLint mLocation;
    GLint vLocation;
    GLint pLocation;
    GLint mixLocation;

    GLint vertexLocation;
    GLint colorLocation;
    GLint uvLocation;

    QMatrix4x4 mMatrix;
    QMatrix4x4 vMatrix;
    QMatrix4x4 pMatrix;

    unsigned int texture0;
    unsigned int texture1;


signals:

public slots:


};

#endif // QMYOPENGLWIDGET_H

qmyopenglwidget.cpp

#include "qmyopenglwidget.h"
#include 
#include 

int count = 10000;

QMyOpenglWidget::QMyOpenglWidget(QWidget* parent):QOpenGLWidget(parent)
{

}


void QMyOpenglWidget::initializeGL()
{
    initializeOpenGLFunctions();

    cretaeShader();

    //三角形顶点坐标
    float s = 2.0f/2;
    float s2 = 2.0f;


    GLfloat *vertices = new float[count*3];


    for(int i = 0; i < count * 3;)
    {
        vertices[i++] = rand()%1000 - 500;
        vertices[i++] = rand()%1000 - 500;
        vertices[i++] = rand()%1000 - 500;
    }

    initDrawData(vao1, vertices, count*3, ebo1);

    glEnable(GL_CULL_FACE); //启动了背面裁剪
    glFrontFace(GL_CCW); //设置逆时针为正面
    glEnable(GL_BLEND); //启动混合
    glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA); //混合模式选择
    glEnable(GL_PROGRAM_POINT_SIZE); //开启shader 设置点大小
    glPointParameteri(GL_POINT_SPRITE_COORD_ORIGIN, GL_LOWER_LEFT); //设置点精灵中 贴图的原点 位置为 左下角
    glEnable(GL_POINT_SPRITE_ARB); //启动点精灵贴图绘制
}

void QMyOpenglWidget::resizeGL(int w, int h)
{
    glViewport(0, 0, w, h);
    pMatrix.setToIdentity();
    float aspect = float(w*1.0)/ float(h);
    //printf("aspect = %f \n", aspect);
    qDebug()<<"aspect = "<0 && height > 0);
    //unsigned char *data = stbi_load("container.jpg", &width, &height, &nrChannels, 0);
    if (image.bits())
    {
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, image.bits());
        glGenerateMipmap(GL_TEXTURE_2D);
    }
    else
    {
        //std::cout << "Failed to load texture" << std::endl;
        Q_ASSERT(0);
    }


    return texture;

}

void QMyOpenglWidget::modeChange(QMyOpenglWidget::EType type)
{
    makeCurrent(); //设置当前opengl 渲染环境
    switch(type)
    {
        case eLine: {glPolygonMode(GL_FRONT_AND_BACK, GL_LINE); break;}
        case eFull: {glPolygonMode(GL_FRONT_AND_BACK, GL_FILL); break;}
        case ePoint: {glPolygonMode(GL_FRONT_AND_BACK, GL_POINT); break;}
        default: {glPolygonMode(GL_FRONT_AND_BACK, GL_FILL); break;}
    }


    //glBindVertexArray(vao1);
    //glDrawArrays(GL_TRIANGLES, 0, 3);
    update();
    doneCurrent();
}

vertex.vert

#version 330 core
uniform mat4 pMatrix;
uniform mat4 vMatrix;
uniform mat4 mMatrix;
in vec3 pos;
//in vec4 color;
//in vec2 uv0;
//out vec4 fcolor;
out vec2 TexCoord0;
void main(void)
{
    //fcolor = color;
    gl_PointSize = 32;
    gl_Position = pMatrix  * vMatrix * mMatrix * vec4(pos, 1.0);
    //TexCoord0 = uv0;
}

frag.frag

#version 330 core
//in vec4 fcolor;
out vec4 FragColor; //片段着色器输出
//in vec2 TexCoord0;
uniform sampler2D texture0;
uniform sampler2D texture1;
uniform float mix;
void main(void)
{
    //FragColor = fcolor*0.3 +  (texture2D(texture0, TexCoord0) * mix) + ((1 - mix) * texture2D(texture1, TexCoord0));
    //FragColor = fcolor*0.3 +  (texture2D(texture0, gl_PointCoord) * mix);//+ ((1 - mix) * texture2D(texture1, gl_PointCoord));
    FragColor = (texture2D(texture0, gl_PointCoord)* mix) + (1 - mix) *(texture2D(texture1, gl_PointCoord));//+ ((1 - mix) * texture2D(texture1, gl_PointCoord));
}