Sign in to follow this  
crslimin

OpenGL How to display chinese characters with wglUseFontOutlines?

Recommended Posts

Is there anyone has experience in using wglUseFontOutlines or Do you have any sample code about draw chinese characters with OpenGL? I am using wglUseFontOutlines, glCallLists, but it doesn't work. Please see my program(modified from nehe program) below: GLvoid BuildFont(GLvoid) // Build Our Bitmap Font { HFONT font; // Windows Font ID base = glGenLists(256); // Storage For 256 Characters font = CreateFont( -12, // Height Of Font 0, // Width Of Font 0, // Angle Of Escapement 0, // Orientation Angle FW_BOLD, // Font Weight FALSE, // Italic FALSE, // Underline FALSE, // Strikeout CHINESEBIG5_CHARSET, // Character Set Identifier OUT_TT_PRECIS, // Output Precision CLIP_DEFAULT_PRECIS, // Clipping Precision ANTIALIASED_QUALITY, // Output Quality FF_DONTCARE|DEFAULT_PITCH, // Family And Pitch " 宋体"); // Font Name SelectObject(hDC, font); // Selects The Font We Created wglUseFontOutlines( hDC, // Select The Current DC 0, // Starting Character 255, // Number Of Display Lists To Build base, // Starting Display Lists 0.0f, // Deviation From The True Outlines 0.2f, // Font Thickness In The Z Direction WGL_FONT_POLYGONS, // Use Polygons, Not Lines gmf); } GLvoid glPrint(const char *fmt, ...) // Custom GL "Print" Routine { float length=0; // Used To Find The Length Of The Text char text[256]; // Holds Our String va_list ap; // Pointer To List Of Arguments if (fmt == NULL) // If There's No Text return; // Do Nothing va_start(ap, fmt); // Parses The String For Variables vsprintf(text, fmt, ap); // And Converts Symbols To Actual Numbers va_end(ap); // Results Are Stored In Text for (unsigned int loop=0;loop<(strlen(text));loop++) // Loop To Find Text Length { length+=gmf[text[loop]].gmfCellIncX; // Increase Length By Each Characters Width } glTranslatef(-length/2,0.0f, 0.0f); // Center Our Text On The Screen glPushAttrib(GL_LIST_BIT); // Pushes The Display List Bits glListBase(base); // Sets The Base Character to 0 glCallLists(strlen(text), GL_UNSIGNED_BYTE, text); // Draws The Display List Text glPopAttrib(); } int DrawGLScene(GLvoid) // Here's Where We Do All The Drawing { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear Screen And Depth Buffer glLoadIdentity(); // Reset The Current Modelview Matrix glTranslatef(0.0f,0.0f,-1.0f); // Move One Unit Into The Screen glScalef(0.04, 0.04, 0.04); glRotatef(-20.0f,0.0f,1.0f,0.0f); // Rotate On The Y Axis // Pulsing Colors Based On Text Position glColor3f(1.0f,0.0f,0.5f); glPrint("Active OpenGL Text With NeHe abc中文def-%7.2f", 10.0); // Print GL Text To The Screen return TRUE; // Everything Went OK } After runing the program, I can see English characters only, no chinese characters. It will be grateful if you can let me know what it is wrong in the program.

Share this post


Link to post
Share on other sites
I'm rather ignorant on the subject, but surely there's more than one byte to a character in any Chinese encoding? And won't there be more than 255 glyphs? You're only making display lists for the first 255, which are probably just the normal ASCII ones.

Since you're using a char array, I'm guessing you're using UTF-8. If you are, then even if you had enough display lists, you'd still need to redo your glPrint to handle UTF-8 correctly.

Even if the WGL functions can do it, I'd see about using FreeType as Promit suggests. It's generally more featureful, and it'll be useful knowledge to have if you ever need to develop for a platform which doesn't have WGL. Google says you might like to look here and here, amongst other places.

Share this post


Link to post
Share on other sites
Having examined the source on the other end of the links I posted, it looks like neither of them are exactly what you want. NeHe's still can't cope with UCS2 or UTF-8 strings, and the other will do Unicode if you want to link it with Qt. Unless another library turns up which can do Unicode text in OpenGL using FreeType, I'd go with modifying NeHe's, since it's probably the easier starting point.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Sign in to follow this  

  • Partner Spotlight

  • Forum Statistics

    • Total Topics
      627644
    • Total Posts
      2978372
  • Similar Content

    • By xhcao
      Before using void glBindImageTexture(    GLuint unit, GLuint texture, GLint level, GLboolean layered, GLint layer, GLenum access, GLenum format), does need to make sure that texture is completeness. 
    • By cebugdev
      hi guys, 
      are there any books, link online or any other resources that discusses on how to build special effects such as magic, lightning, etc. in OpenGL? i mean, yeah most of them are using particles but im looking for resources specifically on how to manipulate the particles to look like an effect that can be use for games,. i did fire particle before, and I want to learn how to do the other 'magic' as well.
      Like are there one book or link(cant find in google) that atleast featured how to make different particle effects in OpenGL (or DirectX)? If there is no one stop shop for it, maybe ill just look for some tips on how to make a particle engine that is flexible enough to enable me to design different effects/magic 
      let me know if you guys have recommendations.
      Thank you in advance!
    • By dud3
      How do we rotate the camera around x axis 360 degrees, without having the strange effect as in my video below? 
      Mine behaves exactly the same way spherical coordinates would, I'm using euler angles.
      Tried googling, but couldn't find a proper answer, guessing I don't know what exactly to google for, googled 'rotate 360 around x axis', got no proper answers.
       
      References:
      Code: https://pastebin.com/Hcshj3FQ
      The video shows the difference between blender and my rotation:
       
    • By Defend
      I've had a Google around for this but haven't yet found some solid advice. There is a lot of "it depends", but I'm not sure on what.
      My question is what's a good rule of thumb to follow when it comes to creating/using VBOs & VAOs? As in, when should I use multiple or when should I not? My understanding so far is that if I need a new VBO, then I need a new VAO. So when it comes to rendering multiple objects I can either:
      * make lots of VAO/VBO pairs and flip through them to render different objects, or
      * make one big VBO and jump around its memory to render different objects. 
      I also understand that if I need to render objects with different vertex attributes, then a new VAO is necessary in this case.
      If that "it depends" really is quite variable, what's best for a beginner with OpenGL, assuming that better approaches can be learnt later with better understanding?
       
    • By test opty
      Hello all,
       
      On my Windows 7 x64 machine I wrote the code below on VS 2017 and ran it.
      #include <glad/glad.h>  #include <GLFW/glfw3.h> #include <std_lib_facilities_4.h> using namespace std; void framebuffer_size_callback(GLFWwindow* window , int width, int height) {     glViewport(0, 0, width, height); } //****************************** void processInput(GLFWwindow* window) {     if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)         glfwSetWindowShouldClose(window, true); } //********************************* int main() {     glfwInit();     glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);     glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);     glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);     //glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);     GLFWwindow* window = glfwCreateWindow(800, 600, "LearnOpenGL", nullptr, nullptr);     if (window == nullptr)     {         cout << "Failed to create GLFW window" << endl;         glfwTerminate();         return -1;     }     glfwMakeContextCurrent(window);     if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))     {         cout << "Failed to initialize GLAD" << endl;         return -1;     }     glViewport(0, 0, 600, 480);     glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);     glClearColor(0.2f, 0.3f, 0.3f, 1.0f);     glClear(GL_COLOR_BUFFER_BIT);     while (!glfwWindowShouldClose(window))     {         processInput(window);         glfwSwapBuffers(window);         glfwPollEvents();     }     glfwTerminate();     return 0; }  
      The result should be a fixed dark green-blueish color as the end of here. But the color of my window turns from black to green-blueish repeatedly in high speed! I thought it might be a problem with my Graphics card driver but I've updated it and it's: NVIDIA GeForce GTX 750 Ti.
      What is the problem and how to solve it please?
  • Popular Now