Question

我正在尝试创建一个2d纹理以显示在我的Qt / OpenGL应用程序上。然后我创建了一个填充屏幕以放置它的Quad，但我得到的是一个没有任何错误的白色屏幕。有人看到我的代码有什么问题吗？

#include "AppGLWidget.h"

#include <iostream>

AppGLWidget::AppGLWidget(QWidget *parent) : QGLWidget(parent),
  mnRange(100),
  mcDisplayedImage(512,512,QImage::Format_ARGB32)
{
  mcDisplayedImage.fill(qRgb(100,0,0));

  mcDisplayedImage = QGLWidget::convertToGLFormat(mcDisplayedImage);

  int value;
  glGetIntegerv(GL_MAX_TEXTURE_SIZE, &value);
}

AppGLWidget::~AppGLWidget(void)
{
}

void AppGLWidget::initializeGL() {
  glClearColor(0, 1, 0, 1);
  glPushMatrix();
  glOrtho(0, size().width(), size().height(), 0, -1, 1);
  glViewport(0, 0, (GLint)size().width(), (GLint)size().height());
  glDisable(GL_DEPTH_TEST);
  glShadeModel(GL_FLAT);

  glEnable(GL_TEXTURE_2D);
  glGenTextures(1,&mcTextureObj);
  glBindTexture(GL_TEXTURE_2D,mcTextureObj);    
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);       
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, mcDisplayedImage.width(), mcDisplayedImage.height(), 0, 
      GL_RGBA, GL_UNSIGNED_BYTE, NULL);

  glDisable(GL_TEXTURE_2D);

  // check OpenGL error
  GLenum err;
  while ((err = glGetError()) != GL_NO_ERROR) {
    std::cerr << "OpenGL error: " << err << std::endl;
  }
}

void AppGLWidget::resizeGL(int w, int h)
{
  glPopMatrix();
  glPushMatrix();
  glOrtho(0, w, h, 0, -1, 1);
  glViewport(0, 0, w, h);
}

void AppGLWidget::paintGL() {

  glBindTexture(GL_TEXTURE_2D, mcTextureObj);   

  glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, mcDisplayedImage.width(), mcDisplayedImage.height(),  
    GL_RGBA, GL_UNSIGNED_BYTE, mcDisplayedImage.bits());

  glBegin(GL_QUADS);

  glTexCoord2i(0,0); glVertex2i(0,lnHeight);  
  glTexCoord2i(0,1); glVertex2i(0,0);
  glTexCoord2i(1,1); glVertex2i(lnWidth,0);
  glTexCoord2i(1,0); glVertex2i(lnWidth,lnHeight);

  glEnd();

  // check OpenGL error
  GLenum err;
  while ((err = glGetError()) != GL_NO_ERROR) {
    std::cerr << "OpenGL error: " << err << std::endl;
  }
}

Answer 1

GL_TEXTURE_2D需要glEnable()来呈现。

现在你glDisable() initializeGL()将其留在SELECT a.eid, a.cid, b.e_date FROM table_A a JOIN table_B b ON a.eid = b.eid JOIN table_A_trans c ON a.cid = c.cid WHERE c.someDateColumn <= '2014-06-01 AND a.eid NOT IN(123,124,200)并保持这种状态。

尝试使用glTexImage2D加载2d纹理，但只是变空白

1 个答案: