如何使用 QPainter 在 QOpenGLWidget 中进行叠加 [关闭]
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【中文标题】如何使用 QPainter 在 QOpenGLWidget 中进行叠加 [关闭]【英文标题】：How to use QPainter for overlaying in QOpenGLWidget [closed] 【发布时间】：2015-03-09 04:05:10 【问题描述】：我收到了问题，使用QPainter 覆盖在QOpenGLWidget Qt 中。
我创建了一个CameraSurface_GL 类来绘制从 ip camera 接收到的 yuv 图像。
这是我的代码：
#include "camerasurface_gl.h"
#include <QtWidgets>
#include <QtGui>
#include <QOpenGLFunctions_3_0>
const char* YUV420P_VS = ""
"#version 330\n"
""
"uniform mat4 u_pm;"
"uniform vec4 draw_pos;"
""
"const vec2 verts[4] = vec2[] ("
" vec2(-0.5, 0.5), "
" vec2(-0.5, -0.5), "
" vec2( 0.5, 0.5), "
" vec2( 0.5, -0.5) "
");"
""
"const vec2 texcoords[4] = vec2[] ("
" vec2(0.0, 1.0), "
" vec2(0.0, 0.0), "
" vec2(1.0, 1.0), "
" vec2(1.0, 0.0) "
"); "
""
"out vec2 v_coord; "
""
"void main() "
" vec2 vert = verts[gl_VertexID];"
" vec4 p = vec4((0.5 * draw_pos.z) + draw_pos.x + (vert.x * draw_pos.z), "
" (0.5 * draw_pos.w) + draw_pos.y + (vert.y * draw_pos.w), "
" 0, 1);"
" gl_Position = u_pm * p;"
" v_coord = texcoords[gl_VertexID];"
""
"";
const char* YUV420P_FS = ""
"#version 330\n"
"uniform sampler2D y_tex;"
"uniform sampler2D u_tex;"
"uniform sampler2D v_tex;"
"in vec2 v_coord;"
"layout( location = 0 ) out vec4 fragcolor;"
""
"const vec3 R_cf = vec3(1, 0.000000, 1.13983);"
"const vec3 G_cf = vec3(1, -0.39465, -0.58060);"
"const vec3 B_cf = vec3(1, 2.03211, 0.000000);"
"const vec3 offset = vec3(-0.0625, -0.5, -0.5);"
""
"void main() "
" float y = texture(y_tex, v_coord).r;"
" float u = texture(u_tex, v_coord).r;"
" float v = texture(v_tex, v_coord).r;"
" vec3 yuv = vec3(y,u,v);"
" yuv += offset;"
" fragcolor = vec4(0.0, 0.0, 0.0, 1.0);"
" fragcolor.r = dot(yuv, R_cf);"
" fragcolor.g = dot(yuv, G_cf);"
" fragcolor.b = dot(yuv, B_cf);"
""
"";
CameraSurface_GL::CameraSurface_GL(QWidget *parent) :
QOpenGLWidget(parent)
,vid_w(0)
,vid_h(0)
,win_w(0)
,win_h(0)
,vao(0)
,vao1(0)
,y_tex(0)
,u_tex(0)
,v_tex(0)
,vert(0)
,frag(0)
,prog(0)
,u_pos(-1)
,textures_created(false)
,shader_created(false)
qRegisterMetaType<YUVFrame>("YUVFrame");
m_ipCamera = new IpCamera;
m_yuvWidth = 0;
m_yuvHeight = 0;
connect(m_ipCamera, SIGNAL(frameChanged(YUVFrame)), this, SLOT(slotFrameChanged(YUVFrame)));
m_frameCount = 0;
m_setup = 0;
CameraSurface_GL::~CameraSurface_GL()
glDeleteTextures(1, &y_tex);
glDeleteTextures(1, &u_tex);
glDeleteTextures(1, &v_tex);
glDeleteProgram(prog);
void CameraSurface_GL::openCamera(QString ipAddress, QString userName, QString password)
if(m_ipCamera->isRunning())
m_ipCamera->close();
qDebug() << "open camera";
bool opend = m_ipCamera->open(ipAddress, userName, password);
if(opend == false)
return;
void CameraSurface_GL::closeCamera()
m_ipCamera->close();
void CameraSurface_GL::slotFrameChanged(YUVFrame frame)
m_yuvData = QByteArray((char*)frame.yuvData, frame.width * frame.height * 3 / 2);
m_yuvWidth = frame.width;
m_yuvHeight = frame.height;
if(m_setup == 0)
setup_gl(frame.width, frame.height);
resize_gl(rect().width(), rect().height());
m_setup = 1;
update();
m_frameCount ++;
void CameraSurface_GL::setup_gl(int width, int height)
vid_w = width;
vid_h = height;
if(!vid_w || !vid_h)
printf("Invalid texture size.\n");
return;
if(!setupTextures())
return;
if(!setupShader())
return;
return;
void CameraSurface_GL::resize_gl(int width, int height)
win_w = width;
win_h = height;
pm.setToIdentity();
pm.ortho(0, win_w, win_h, 0, 0.0, 100.0f);
glUseProgram(prog);
glUniformMatrix4fv(glGetUniformLocation(prog, "u_pm"), 1, GL_FALSE, pm.data());
void CameraSurface_GL::resizeGL(int width, int height)
glViewport(0, 0, width, height);
if(m_setup)
resize_gl(width, height);
bool CameraSurface_GL::setupTextures()
if(textures_created)
printf("Textures already created.\n");
return false;
glGenTextures(1, &y_tex);
glBindTexture(GL_TEXTURE_2D, y_tex);
glTexImage2D(GL_TEXTURE_2D, 0, GL_R8, vid_w, vid_h, 0, GL_RED, GL_UNSIGNED_BYTE, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glGenTextures(1, &u_tex);
glBindTexture(GL_TEXTURE_2D, u_tex);
glTexImage2D(GL_TEXTURE_2D, 0, GL_R8, vid_w/2, vid_h/2, 0, GL_RED, GL_UNSIGNED_BYTE, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glGenTextures(1, &v_tex);
glBindTexture(GL_TEXTURE_2D, v_tex);
glTexImage2D(GL_TEXTURE_2D, 0, GL_R8, vid_w/2, vid_h/2, 0, GL_RED, GL_UNSIGNED_BYTE, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
textures_created = true;
return true;
bool CameraSurface_GL::setupShader()
if(shader_created)
printf("Already creatd the shader.\n");
return false;
vert = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vert, 1, &YUV420P_VS, 0);
glCompileShader(vert);
frag = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(frag, 1, &YUV420P_FS, 0);
glCompileShader(frag);
prog = glCreateProgram();
glAttachShader(prog, vert);
glAttachShader(prog, frag);
glLinkProgram(prog);
glUseProgram(prog);
glUniform1i(glGetUniformLocation(prog, "y_tex"), 0);
glUniform1i(glGetUniformLocation(prog, "u_tex"), 1);
glUniform1i(glGetUniformLocation(prog, "v_tex"), 2);
u_pos = glGetUniformLocation(prog, "draw_pos");
glUseProgram(0);
return true;
void CameraSurface_GL::setYPixels(uint8_t* pixels, int stride)
glBindTexture(GL_TEXTURE_2D, y_tex);
glPixelStorei(GL_UNPACK_ROW_LENGTH, stride);
glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, vid_w, vid_h, GL_RED, GL_UNSIGNED_BYTE, pixels);
void CameraSurface_GL::setUPixels(uint8_t* pixels, int stride)
glBindTexture(GL_TEXTURE_2D, u_tex);
glPixelStorei(GL_UNPACK_ROW_LENGTH, stride);
glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, vid_w/2, vid_h/2, GL_RED, GL_UNSIGNED_BYTE, pixels);
void CameraSurface_GL::setVPixels(uint8_t* pixels, int stride)
glBindTexture(GL_TEXTURE_2D, v_tex);
glPixelStorei(GL_UNPACK_ROW_LENGTH, stride);
glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, vid_w/2, vid_h/2, GL_RED, GL_UNSIGNED_BYTE, pixels);
void CameraSurface_GL::initializeGL()
initializeOpenGLFunctions();
glClearColor(0, 0, 0, 1);
void CameraSurface_GL::paintEvent(QPaintEvent* e)
QPainter painter;
painter.begin(this);
painter.beginNativePainting();
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
if(m_yuvData.size())
setYPixels((unsigned char*)m_yuvData.data(), m_yuvWidth);
setUPixels((unsigned char*)m_yuvData.data() + m_yuvWidth * m_yuvHeight, m_yuvWidth / 2);
setVPixels((unsigned char*)m_yuvData.data() + m_yuvWidth * m_yuvHeight * 5 / 4, m_yuvWidth / 2);
glBindVertexArray(vao);
glUseProgram(prog);
glUniform4f(u_pos, rect().left(), rect().top(), rect().width(), rect().height());
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, y_tex);
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, u_tex);
glActiveTexture(GL_TEXTURE2);
glBindTexture(GL_TEXTURE_2D, v_tex);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
glUseProgram(0);
painter.endNativePainting();
painter.end();
我想在yuv层上绘制内容，所以我在void paintEvent(QPaintEvent* e)函数中附加了如下代码：
void CameraSurface_GL::paintEvent(QPaintEvent* e)
QPainter painter;
painter.begin(this);
painter.beginNativePainting();
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
if(m_yuvData.size())
setYPixels((unsigned char*)m_yuvData.data(), m_yuvWidth);
setUPixels((unsigned char*)m_yuvData.data() + m_yuvWidth * m_yuvHeight, m_yuvWidth / 2);
setVPixels((unsigned char*)m_yuvData.data() + m_yuvWidth * m_yuvHeight * 5 / 4, m_yuvWidth / 2);
glBindVertexArray(vao);
glUseProgram(prog);
glUniform4f(u_pos, rect().left(), rect().top(), rect().width(), rect().height());
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, y_tex);
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, u_tex);
glActiveTexture(GL_TEXTURE2);
glBindTexture(GL_TEXTURE_2D, v_tex);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
glUseProgram(0);
painter.endNativePainting();
//////new appended code//////
QPixmap memPix(rect().width(), rect().height());
QPainter memDC;
memDC.setPen(Qt::red);
memDC.drawRect(QRect(0, 0, 100, 100));
painter.drawPixmap(rect(), memPix);
/////end/////
painter.end();
此时，我收到了导致程序崩溃的问题。
而且，当我也更改为以下内容时，我收到了相同的结果：
void CameraSurface_GL::paintEvent(QPaintEvent* e)
QPainter painter;
painter.begin(this);
painter.beginNativePainting();
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
if(m_yuvData.size())
setYPixels((unsigned char*)m_yuvData.data(), m_yuvWidth);
setUPixels((unsigned char*)m_yuvData.data() + m_yuvWidth * m_yuvHeight, m_yuvWidth / 2);
setVPixels((unsigned char*)m_yuvData.data() + m_yuvWidth * m_yuvHeight * 5 / 4, m_yuvWidth / 2);
painter.endNativePainting();
QPixmap memPix(rect().width(), rect().height());
QPainter memDC;
memDC.setPen(Qt::red);
memDC.drawRect(QRect(0, 0, 100, 100));
painter.drawPixmap(rect(), memPix);
painter.end();
而且，当我删除调用setYPixels、setUPixels 和setVPixels 的部分时，我的程序并没有崩溃。
我不知道为什么会收到错误消息。我想知道这个问题的原因。
【问题讨论】：
【参考方案1】：您应该取消绑定任何纹理、缓冲区等。我在未绑定的 VBO 上遇到过类似的问题。
【讨论】：
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