#define FONTLISTRANGE 128
GLuint list;
list = glGenLists(FONTLISTRANGE);
wglUseFontBitmapsW(hDC, 0, FONTLISTRANGE, list);
仅仅这样做是不够的,因为您无法为所有Unicode字符创建足够的列表。
我建议你像上面已经建议的那样使用FTGL。不过,我自己实现了一个FreeType/OpenGL渲染器,如果你想重复造轮子,可能会发现我的代码很有用。不过,我还是非常推荐使用FTGL,因为它使用起来更加方便。
* glTextRender class by Semi Essessi
*
* FreeType2 empowered text renderer
*
*/
#include "glTextRender.h"
#include "jEngine.h"
#include "glSystem.h"
#include "jMath.h"
#include "jProfiler.h"
#include "log.h"
#include <windows.h>
FT_Library glTextRender::ftLib = 0;
//TODO::maybe fix this so it use wchar_t for the filename
glTextRender::glTextRender(jEngine* j, const char* fontName, int size = 12)
{
#ifdef _DEBUG
jProfiler profiler = jProfiler(L"glTextRender::glTextRender");
#endif
char fontName2[1024];
memset(fontName2,0,sizeof(char)*1024);
sprintf(fontName2,"fonts\\%s",fontName);
if(!ftLib)
{
#ifdef _DEBUG
wchar_t fn[128];
mbstowcs(fn,fontName,strlen(fontName)+1);
LogWriteLine(L"\x25CB\x25CB\x25CF Font: %s was requested before FreeType was initialised", fn);
#endif
return;
}
// constructor code for glTextRender
e=j;
gl = j->gl;
red=green=blue=alpha=1.0f;
face = 0;
// remember that for some weird reason below font size 7 everything gets scrambled up
height = max(6,(int)floorf((float)size*((float)gl->getHeight())*0.001666667f));
aHeight = ((float)height)/((float)gl->getHeight());
setPosition(0.0f,0.0f);
// look in base fonts dir
if(FT_New_Face(ftLib, fontName2, 0, &face ))
{
// if we dont have it look in windows fonts dir
char buf[1024];
GetWindowsDirectoryA(buf,1024);
strcat(buf, "\\fonts\\");
strcat(buf, fontName);
if(FT_New_Face(ftLib, buf, 0, &face ))
{
//TODO::check in mod fonts directory
#ifdef _DEBUG
wchar_t fn[128];
mbstowcs(fn,fontName,strlen(fontName)+1);
LogWriteLine(L"\x25CB\x25CB\x25CF Request for font: %s has failed", fn);
#endif
face = 0;
return;
}
}
// FreeType uses 64x size and 72dpi for default
// doubling size for ms
FT_Set_Char_Size(face, mulPow2(height,7), mulPow2(height,7), 96, 96);
// set up cache table and then generate the first 256 chars and the console prompt character
for(int i=0;i<65536;i++)
{
cached[i]=false;
width[i]=0.0f;
}
for(unsigned short i = 0; i < 256; i++) getChar((wchar_t)i);
getChar(CHAR_PROMPT);
#ifdef _DEBUG
wchar_t fn[128];
mbstowcs(fn,fontName,strlen(fontName)+1);
LogWriteLine(L"\x25CB\x25CB\x25CF Font: %s loaded OK", fn);
#endif
}
glTextRender::~glTextRender()
{
// destructor code for glTextRender
for(int i=0;i<65536;i++)
{
if(cached[i])
{
glDeleteLists(listID[i],1);
glDeleteTextures(1,&(texID[i]));
}
}
// TODO:: work out stupid freetype crashz0rs
try
{
static int foo = 0;
if(face && foo < 1)
{
foo++;
FT_Done_Face(face);
face = 0;
}
}
catch(...)
{
face = 0;
}
}
// return true if init works, or if already initialised
bool glTextRender::initFreeType()
{
if(!ftLib)
{
if(!FT_Init_FreeType(&ftLib)) return true;
else return false;
} else return true;
}
void glTextRender::shutdownFreeType()
{
if(ftLib)
{
FT_Done_FreeType(ftLib);
ftLib = 0;
}
}
void glTextRender::print(const wchar_t* str)
{
// store old stuff to set start position
glPushAttrib(GL_TRANSFORM_BIT);
// get viewport size
GLint viewport[4];
glGetIntegerv(GL_VIEWPORT, viewport);
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
gluOrtho2D(viewport[0],viewport[2],viewport[1],viewport[3]);
glPopAttrib();
float color[4];
glGetFloatv(GL_CURRENT_COLOR, color);
glPushAttrib(GL_LIST_BIT | GL_CURRENT_BIT | GL_ENABLE_BIT | GL_TRANSFORM_BIT);
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glLoadIdentity();
glEnable(GL_TEXTURE_2D);
//glDisable(GL_DEPTH_TEST);
// set blending for AA
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glTranslatef(xPos,yPos,0.0f);
glColor4f(red,green,blue,alpha);
// call display lists to render text
glListBase(0u);
for(unsigned int i=0;i<wcslen(str);i++) glCallList(getChar(str[i]));
// restore old states
glMatrixMode(GL_MODELVIEW);
glPopMatrix();
glPopAttrib();
glColor4fv(color);
glPushAttrib(GL_TRANSFORM_BIT);
glMatrixMode(GL_PROJECTION);
glPopMatrix();
glPopAttrib();
}
void glTextRender::printf(const wchar_t* str, ...)
{
if(!str) return;
wchar_t* buf = 0;
va_list parg;
va_start(parg, str);
// allocate buffer
int len = (_vscwprintf(str, parg)+1);
buf = new wchar_t[len];
if(!buf) return;
vswprintf(buf, str, parg);
va_end(parg);
print(buf);
delete[] buf;
}
GLuint glTextRender::getChar(const wchar_t c)
{
int i = (int)c;
if(cached[i]) return listID[i];
// load glyph and get bitmap
if(FT_Load_Glyph(face, FT_Get_Char_Index(face, i), FT_LOAD_DEFAULT )) return 0;
FT_Glyph glyph;
if(FT_Get_Glyph(face->glyph, &glyph)) return 0;
FT_Glyph_To_Bitmap(&glyph, FT_RENDER_MODE_NORMAL, 0, 1);
FT_BitmapGlyph bitmapGlyph = (FT_BitmapGlyph)glyph;
FT_Bitmap& bitmap = bitmapGlyph->bitmap;
int w = roundPow2(bitmap.width);
int h = roundPow2(bitmap.rows);
// convert to texture in memory
GLubyte* texture = new GLubyte[2*w*h];
for(int j=0;j<h;j++)
{
bool cond = j>=bitmap.rows;
for(int k=0;k<w;k++)
{
texture[2*(k+j*w)] = 0xFFu;
texture[2*(k+j*w)+1] = ((k>=bitmap.width)||cond) ? 0x0u : bitmap.buffer[k+bitmap.width*j];
}
}
// store char width and adjust max height
// note .5f
float ih = 1.0f/((float)gl->getHeight());
width[i] = ((float)divPow2(face->glyph->advance.x, 7))*ih;
aHeight = max(aHeight,(.5f*(float)bitmap.rows)*ih);
glPushAttrib(GL_LIST_BIT | GL_CURRENT_BIT | GL_ENABLE_BIT | GL_TRANSFORM_BIT);
// create gl texture
glGenTextures(1, &(texID[i]));
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, texID[i]);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, w, h, 0, GL_LUMINANCE_ALPHA, GL_UNSIGNED_BYTE, texture);
glPopAttrib();
delete[] texture;
// create display list
listID[i] = glGenLists(1);
glNewList(listID[i], GL_COMPILE);
glBindTexture(GL_TEXTURE_2D, texID[i]);
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
// adjust position to account for texture padding
glTranslatef(.5f*(float)bitmapGlyph->left, 0.0f, 0.0f);
glTranslatef(0.0f, .5f*(float)(bitmapGlyph->top-bitmap.rows), 0.0f);
// work out texcoords
float tx=((float)bitmap.width)/((float)w);
float ty=((float)bitmap.rows)/((float)h);
// render
// note .5f
glBegin(GL_QUADS);
glTexCoord2f(0.0f, 0.0f);
glVertex2f(0.0f, .5f*(float)bitmap.rows);
glTexCoord2f(0.0f, ty);
glVertex2f(0.0f, 0.0f);
glTexCoord2f(tx, ty);
glVertex2f(.5f*(float)bitmap.width, 0.0f);
glTexCoord2f(tx, 0.0f);
glVertex2f(.5f*(float)bitmap.width, .5f*(float)bitmap.rows);
glEnd();
glPopMatrix();
// move position for the next character
// note extra div 2
glTranslatef((float)divPow2(face->glyph->advance.x, 7), 0.0f, 0.0f);
glEndList();
// char is succesfully cached for next time
cached[i] = true;
return listID[i];
}
void glTextRender::setPosition(float x, float y)
{
float fac = ((float)gl->getHeight());
xPos = fac*x+FONT_BORDER_PIXELS; yPos = fac*(1-y)-(float)height-FONT_BORDER_PIXELS;
}
float glTextRender::getAdjustedWidth(const wchar_t* str)
{
float w = 0.0f;
for(unsigned int i=0;i<wcslen(str);i++)
{
if(cached[str[i]]) w+=width[str[i]];
else
{
getChar(str[i]);
w+=width[str[i]];
}
}
return w;
}
更新:查看了这个Pango引擎,发现它就像香蕉、大猩猩和整个丛林的故事。首先,它依赖于Glib,因为它使用了GObjects;其次,它不能直接将内容渲染到字节缓冲区中。它有Cario和FreeType后端,因此您必须使用其中一个来呈现文本并最终导出位图。目前情况看起来不太好。
此外,如果您想将结果存储在纹理中,请在设置文本后使用pango_layout_get_pixel_extents
获取渲染文本所需的矩形大小。Ink矩形是包含整个文本的矩形,其左上角位置相对于逻辑矩形的左上角位置(逻辑矩形的底线是基准线)。希望这可以帮助您。
标题栏支持Unicode。我刚在Mac上尝试过,应该也适用于其他地方。如果您有(比如说)包含文本标签的一些导入数据,并且其中一些标签可能包含Unicode,您可以添加一个工具,将标签回显在标题栏中。
这不是一个很好的解决方案,但非常容易实现。
你也可以按语言分组字符。根据需要加载每个语言表,当你需要切换语言时,卸载先前的语言表并加载新的语言表。