在OpenGL中绘制3D场景中的2D文本（C++）

我正在OpenGL中尝试3D图形，并设法创建3D级别。但是，我还想在屏幕上显示一些2D文本（类似于您在第一人称射击中看到的HP或弹药统计）。这是我用来渲染关卡的整个方法。一切都按照我想要的那样工作，除了文字（根本没有出现在屏幕上）。我如何使文本正确显示？在OpenGL中绘制3D场景中的2D文本（C++）

void render_Scene(void) 
{ 
    int i; 
    int j; 

    glClearColor(0.0, 0.0, 0.0, 1.0); 
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 
    glLoadIdentity(); 



    //Camera perspective 
    gluLookAt(x, y, 1.0, x + lx, y + ly, 1.0, 0.0, 0.0, 1.0); 
    glColor3f(0.4, 0.4, 0.4); 



    //Draw walls around the level 
    glEnable(GL_TEXTURE_2D); 
    glBindTexture(GL_TEXTURE_2D, wall_Texture); 
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); 
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); 

    glBegin(GL_QUADS); 
    glNormal3f(0.0, 1.0f, 0.0f); 
    glTexCoord2f(0.0f, 0.0f); 
    glVertex3f(-75, -75, 0); 
    glTexCoord2f(1.0f, 0.0f); 
    glVertex3f(-75, -75, 1.2); 
    glTexCoord2f(1.0f, 1.0f); 
    glVertex3f(75, -75, 1.2); 
    glTexCoord2f(0.0f, 1.0f); 
    glVertex3f(75, -75, 0); 
    glEnd(); 

    glBegin(GL_QUADS); 
    glNormal3f(0.0, 1.0f, 0.0f); 
    glTexCoord2f(0.0f, 0.0f); 
    glVertex3f(-75, 72, 0); 
    glTexCoord2f(1.0f, 0.0f); 
    glVertex3f(-75, 72, 1.2); 
    glTexCoord2f(1.0f, 1.0f); 
    glVertex3f(75, 72, 1.2); 
    glTexCoord2f(0.0f, 1.0f); 
    glVertex3f(75, 72, 0); 
    glEnd(); 

    glBegin(GL_QUADS); 
    glNormal3f(0.0, 1.0f, 0.0f); 
    glTexCoord2f(0.0f, 0.0f); 
    glVertex3f(-75, -75, 0); 
    glTexCoord2f(1.0f, 0.0f); 
    glVertex3f(-75, 72, 0); 
    glTexCoord2f(1.0f, 1.0f); 
    glVertex3f(-75, 72, 1.2); 
    glTexCoord2f(0.0f, 1.0f); 
    glVertex3f(-75, -75, 1.2); 
    glEnd(); 

    glBegin(GL_QUADS); 
    glNormal3f(0.0, 1.0f, 0.0f); 
    glTexCoord2f(0.0f, 0.0f); 
    glVertex3f(75, -75, 0); 
    glTexCoord2f(1.0f, 0.0f); 
    glVertex3f(75, 72, 0); 
    glTexCoord2f(1.0f, 1.0f); 
    glVertex3f(75, 72, 1.2); 
    glTexCoord2f(0.0f, 1.0f); 
    glVertex3f(75, -75, 1.2); 
    glEnd(); 

    glDisable(GL_TEXTURE_2D); 



    //Draw ground texture 
    for (int m = -150; m <= 140; m += 10) 
    { 
     for (int n = -150; n <= 140; n += 10) 
     { 
      glEnable(GL_TEXTURE_2D); 
      glBindTexture(GL_TEXTURE_2D, ground_Texture); 
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); 
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); 

      glBegin(GL_QUADS); 
      glNormal3f(0.0, 1.0f, 0.0f); 
      glTexCoord2f(0.0f, 0.0f); 
      glVertex3f(n, m, 0.0); 
      glTexCoord2f(1.0f, 0.0f); 
      glVertex3f(n, m + 10, 0.0); 
      glTexCoord2f(1.0f, 1.0f); 
      glVertex3f(n + 10, m + 10, 0.0); 
      glTexCoord2f(0.0f, 1.0f); 
      glVertex3f(n + 10, m, 0.0); 
      glEnd(); 

      glDisable(GL_TEXTURE_2D); 
     } 
    } 



    //Draw trees in level (uses a seperate method) 
    for (i = -9; i < 9; i++) 
    { 
     for (j = -9; j < 9; j++) 
     { 
      glPushMatrix(); 
      glTranslatef(i*7.5, j*7.5, 0); 
      draw_Trees(); 
      glPopMatrix(); 
     } 
    } 

    //Create light 
    GLfloat lightColor0[] = { 1.0, 1.0f, 1.0f, 1.0f }; 
    GLfloat lightPos0[] = { lx, ly, deltaMove, 1.0f }; 

    glLightfv(GL_LIGHT0, GL_DIFFUSE, lightColor0); 
    glLightfv(GL_LIGHT0, GL_POSITION, lightPos0); 



    //Here's where I'm trying to render the text (I've heard that glPushAttrib and glPopAttrib may be important for this part) but it does not appear anywhere on the screen 
    glColor3f(1.0, 1.0, 1.0); 
    glPushMatrix(); 
    glPushAttrib(GL_LIGHTING); 
    glDisable(GL_TEXTURE_2D); 
    glDisable(GL_LIGHTING); 
    glLoadIdentity(); 

    glRasterPos2i(10, 30); 

    void * font = GLUT_BITMAP_8_BY_13; 

    for (string::iterator i = strings[stage].begin(); i != strings[stage].end(); ++i) 
    { 
     glutBitmapCharacter(font, *i); 
    } 

    glPopAttrib(); 
    glPopMatrix(); 

    glutSwapBuffers(); 
}

编辑：我被告知应该使用glWindowPos2i而不是glRasterPos2i。这个解决方案的问题是，glWindowPos2i没有被识别并导致构建错误。继一些在线调查，我添加以下代码行：

PFNGLWINDOWPOS2IPROC glWindowPos2i; 

glWindowPos2i = (PFNGLWINDOWPOS2IPROC)glutGetProcAddress("glWindowPos2i");

现在程序运行正常，但是当我尝试使用glWindowPos2i功能崩溃。我正在使用和作为包含的头文件，以帮助任何人想出解决方案让glWindowPos2i正常工作。

来源

2014-09-20 user3277234

我不知道glutBitmapCharacter但我敢肯定GL_LIGHTING是'glPushAttrib'没有有效的参数。这使我缺乏任何'glGetError'，它可以让你检测更多的错误...... – Thomas 2014-09-20 21:56:56

确实，'glPushAttrib（...）'使用了一个位掩码，因此所有有效的枚举都将以'_BIT'结尾。 – 2014-09-20 22:02:15

这有帮助吗？ http://stackoverflow.com/questions/9430852/glutbitmapcharacter-positions-text-wrong – jozxyqk 2014-09-21 06:12:17

使用glWindowPos2i而不是glRasterPos2i。 glRasterPos2i使用世界坐标位置。 glWindowPos2i在屏幕坐标中使用位置。 https://www.opengl.org/sdk/docs/man2/xhtml/glWindowPos.xml https://www.opengl.org/sdk/docs/man2/xhtml/glRasterPos.xml

来源

2014-09-20 23:53:42 programmerjake

我试过了，但glWindowPos2i没有被识别。在进行一些在线研究之后，我添加了以下几行代码：“PFNGLWINDOWPOS2IPROC glWindowPos2i;” \\“glWindowPos2i =（PFNGLWINDOWPOS2IPROC）glutGetProcAddress（”glWindowPos2i“）;”现在程序运行了，但是当我尝试使用glWindowPos2i函数时它崩溃了。 – user3277234 2014-09-21 12:21:39

在OpenGL中绘制3D场景中的2D文本（C++）

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