-1
QOpenGLBuffer를 픽셀 버퍼 객체로 사용하려고합니다. 목표는 고해상도 비디오 스트림 (4K, 60FPS)을 표시하여 성능이 좋도록하는 것입니다.Qt OpenGL에서 PBO를 사용하는 방법
저는 OpenGL부터 시작 했으므로 가능한 한 가장 좋은 방법으로 간단한 2D 텍스처를 표시하려고합니다. VBO와 VAO를 이미 포함 시켰습니다. 다음 단계는 더 나은 성능을 위해 PBO를 사용하는 것입니다.
QOpenGLBuffer가 아닌 PBO의 경우 glGenBufferARB()가있는 튜토리얼이 있습니다. 그러니까 기본적으로,이 코드에 PBO를 사용하도록 할 것입니다 방법
glwidget.h
#ifndef GLWIDGET_H
#define GLWIDGET_H
#include <QOpenGLWidget>
#include <QOpenGLFunctions>
#include <QOpenGLBuffer>
#include <QDebug>
#include <QOpenGLTexture>
#include <QOpenGLShader>
#include <QOpenGLShaderProgram>
#include <QOpenGLVertexArrayObject>
class GLWidget : public QOpenGLWidget, protected QOpenGLFunctions
{
Q_OBJECT
public:
explicit GLWidget(QWidget *parent = 0);
~GLWidget();
void initializeGL();
void paintGL();
void resizeGL(int w, int h);
void LoadGLTextures();
private :
QOpenGLShaderProgram *program;
QOpenGLBuffer vbo;
QOpenGLVertexArrayObject vao;
GLuint tex;
GLint vertexLocation;
GLint texcoordLocation;
int tailleVerticesBytes;
int tailleCoordTexturesBytes;
float vertices[8];
float coordTexture[8];
public slots:
private slots:
};
#endif // GLWIDGET_H
glwidget.cpp
#ifndef BUFFER_OFFSET
#define BUFFER_OFFSET(offset) ((char*)NULL + (offset))
#include "glwidget.h"
#include <QElapsedTimer>
GLWidget::GLWidget(QWidget *parent) :
QOpenGLWidget(parent)
{
tailleVerticesBytes = 8*sizeof(float);
tailleCoordTexturesBytes = 8*sizeof(float);
}
GLWidget::~GLWidget(){
vao.destroy();
vbo.destroy();
delete program;
glDeleteTextures(1, &tex);
}
void GLWidget::LoadGLTextures(){
QImage img;
if(!img.load("C:\\Users\\Adrien\\Desktop\\open3.bmp")){
qDebug()<<"Image loading failed";
}
QImage t = (img.convertToFormat(QImage::Format_RGBA8888)).mirrored();
glGenTextures(1, &tex);
glBindTexture(GL_TEXTURE_2D, tex);
glTexImage2D(GL_TEXTURE_2D, 0, 3, t.width(), t.height(), 0, GL_RGBA, GL_UNSIGNED_BYTE, t.bits());
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glBindTexture(GL_TEXTURE_2D, 0);
}
void GLWidget::initializeGL(){
float verticesTmp[] = {-1.0,-1.0, 1.0,-1.0, 1.0,1.0, -1.0,1.0};
float coordTextureTmp[] = {0.0,0.0, 1.0,0.0, 1.0,1.0, 0.0,1.0};
for(int i = 0; i<8; i++){
vertices[i] = verticesTmp[i];
coordTexture[i] = coordTextureTmp[i];
}
initializeOpenGLFunctions();
glClear(GL_COLOR_BUFFER_BIT);
glEnable(GL_TEXTURE_2D);
LoadGLTextures();
//Shader setup
QOpenGLShader *vshader = new QOpenGLShader(QOpenGLShader::Vertex, this);
const char *vsrc =
"#version 150 core\n"
"in vec2 in_Vertex;\n"
"in vec2 vertTexCoord;\n"
"out vec2 fragTexCoord;\n"
"void main(void)\n"
"{\n"
" gl_Position = vec4(in_Vertex, 0.0, 1.0);\n"
" fragTexCoord = vertTexCoord;\n"
"}\n";
vshader->compileSourceCode(vsrc);
QOpenGLShader *fshader = new QOpenGLShader(QOpenGLShader::Fragment, this);
const char *fsrc =
"#version 150 core\n"
"uniform sampler2D tex;\n"
"in vec2 fragTexCoord;\n"
"void main(void)\n"
"{\n"
" gl_FragColor = texture2D(tex,fragTexCoord);\n"
"}\n";
fshader->compileSourceCode(fsrc);
program = new QOpenGLShaderProgram;
program->addShader(vshader);
program->addShader(fshader);
program->link();
program->bind();
glActiveTexture(GL_TEXTURE0);
program->setUniformValue("tex", 0);
vertexLocation = glGetAttribLocation(program->programId(), "in_Vertex");
texcoordLocation = glGetAttribLocation(program->programId(), "vertTexCoord");
//VAO setup
vao.create();
vao.bind();
//VBO setup
vbo.create();
vbo.setUsagePattern(QOpenGLBuffer::StaticDraw);
vbo.bind();
vbo.allocate(tailleVerticesBytes + tailleCoordTexturesBytes);
vbo.write(0, vertices, tailleVerticesBytes);
vbo.write(tailleVerticesBytes, coordTexture, tailleCoordTexturesBytes);
program->enableAttributeArray(vertexLocation);
program->setAttributeBuffer(vertexLocation, GL_FLOAT, 0, 2);
program->enableAttributeArray(texcoordLocation);
program->setAttributeBuffer(texcoordLocation, GL_FLOAT, tailleVerticesBytes, 2);
vbo.release();
vao.release();
program->release();
}
void GLWidget::paintGL(){
glClear(GL_COLOR_BUFFER_BIT);
program->bind();
{
vao.bind();
glBindTexture(GL_TEXTURE_2D, tex);
glDrawArrays(GL_QUADS, 0, 4);
glBindTexture(GL_TEXTURE_2D, 0);
vao.release();
}
program->release();
}
void GLWidget::resizeGL(int w, int h){
glViewport(0, 0, (GLint)w, (GLint)h);
}
#endif
: 여기
내 코드입니다 ?먼저 QOpenGLBuffer 객체를 만들고 (QOpenglBuffer :: PixelUnpackBuffer) 형식을 지정하는 것이 좋습니다. 그런 다음 버퍼에 픽셀을 업로드하고 glTexImage2D 대신 사용해야합니다. 이것은 단지 세계적인 아이디어 일 뿐이며 어떻게 해야할지 잘 모릅니다.
감사합니다.