FreeType的教程代碼. 使用GLUT.
在Nehe的代碼基礎上改的:
以下是基礎代碼:
struct xCharTexture
{
GLuint m_texID;
wchar_t m_chaID;
int m_Width;
int m_Height;
int m_adv_x;
int m_adv_y;
int m_delta_x;
int m_delta_y;
public:
xCharTexture()
{
m_texID = 0;
m_chaID = 0;
m_Width = 0;
m_Height = 0;
}
}g_TexID[65536];
class xFreeTypeLib
{
FT_Library m_FT2Lib;
FT_Face m_FT_Face;
int m_w;
int m_h;
public:
xFreeTypeLib()
{
if (FT_Init_FreeType( &m_FT2Lib) )
exit(0);
}
void load(const char* font_file , int _w , int _h)
{
//加載一個字體,取默認的Face,一般為Regualer
if (FT_New_Face( m_FT2Lib, font_file, 0, &m_FT_Face ))
exit(0);
FT_Select_Charmap(m_FT_Face, FT_ENCODING_UNICODE);
m_w = _w ; m_h = _h;
m_FT_Face->num_fixed_sizes;
//大小要乘64.這是規定。照做就可以了。
//FT_Set_Char_Size( m_FT_Face , 0 , m_w << 6, 96, 96);
FT_Set_Pixel_Sizes(m_FT_Face,m_w, m_h);
}
GLuint loadChar(wchar_t ch)
{
if(g_TexID[ch].m_texID)
return g_TexID[ch].m_texID;
if(FT_Load_Char(m_FT_Face, ch,FT_LOAD_RENDER|FT_LOAD_FORCE_AUTOHINT|
(true ? FT_LOAD_TARGET_NORMAL : FT_LOAD_MONOCHROME | FT_LOAD_TARGET_MONO) ) )
{
return 0;
}
xCharTexture& charTex = g_TexID[ch];
//得到字模
FT_Glyph glyph;
if(FT_Get_Glyph( m_FT_Face->glyph, &glyph ))
return 0;
//轉化成位圖
FT_Render_Glyph( m_FT_Face->glyph, FT_RENDER_MODE_LCD );//FT_RENDER_MODE_NORMAL );
FT_Glyph_To_Bitmap( &glyph, ft_render_mode_normal, 0, 1 );
FT_BitmapGlyph bitmap_glyph = (FT_BitmapGlyph)glyph;
//取道位圖數據
FT_Bitmap& bitmap=bitmap_glyph->bitmap;
//把位圖數據拷貝自己定義的數據區裡.這樣舊可以畫到需要的東西上面了。
int width = bitmap.width;
int height = bitmap.rows;
m_FT_Face->size->metrics.y_ppem;
m_FT_Face->glyph->metrics.horiAdvance;
charTex.m_Width = width;
charTex.m_Height = height;
charTex.m_adv_x = m_FT_Face->glyph->advance.x / 64.0f;
charTex.m_adv_y = m_FT_Face->size->metrics.y_ppem; //m_FT_Face->glyph->metrics.horiBearingY / 64.0f;
charTex.m_delta_x = (float)bitmap_glyph->left;
charTex.m_delta_y = (float)bitmap_glyph->top - height;
glGenTextures(1,&charTex.m_texID);
glBindTexture(GL_TEXTURE_2D,charTex.m_texID);
char* pBuf = new char[width * height * 4];
for(int j=0; j < height ; j++)
{
for(int i=0; i < width; i++)
{
unsigned char _vl = (i>=bitmap.width || j>=bitmap.rows) ? 0 : bitmap.buffer[i + bitmap.width*j];
pBuf[(4*i + (height - j - 1) * width * 4) ] = 0xff;
pBuf[(4*i + (height - j - 1) * width * 4)+1] = 0xff;
pBuf[(4*i + (height - j - 1) * width * 4)+2] = 0xff;
pBuf[(4*i + (height - j - 1) * width * 4)+3] = _vl;
}
}
glTexImage2D( GL_TEXTURE_2D,0,GL_RGBA,width, height,0,GL_RGBA,GL_UNSIGNED_BYTE,pBuf);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T, GL_CLAMP);
glTexParameteri ( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
glTexParameteri ( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
glTexEnvi(GL_TEXTURE_2D,GL_TEXTURE_ENV_MODE,GL_REPLACE);
delete[]pBuf;
return charTex.m_chaID;
}
}g_FreeTypeLib;
繪制代碼如下:
void drawText(wchar_t* _strText,int x , int y, int maxW , int h)
{
int sx = x;
int sy = y;
int maxH = h;
for(int i = 0 ; i < wcslen(_strText) ; i ++)
{
if(_strText[i] =='n')
{
sx = x ; sy += maxH + 12;
continue;
}
xCharTexture* pCharTex = getTextChar(_strText[i]);
glBindTexture(GL_TEXTURE_2D,pCharTex->m_texID);
glTexParameteri ( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
glTexParameteri ( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);
//glDisable(GL_TEXTURE_2D);
int w = pCharTex->m_Width;
int h = pCharTex->m_Height;
int ch_x = sx + pCharTex->m_delta_x;
int ch_y = sy - h - pCharTex->m_delta_y;
if(maxH < h) maxH = h;
glBegin ( GL_QUADS );
{
glTexCoord2f(0.0f, 1.0f); glVertex3f(ch_x , ch_y , 1.0f);
glTexCoord2f(1.0f, 1.0f); glVertex3f(ch_x + w, ch_y , 1.0f);
glTexCoord2f(1.0f, 0.0f); glVertex3f(ch_x + w, ch_y + h, 1.0f);
glTexCoord2f(0.0f, 0.0f); glVertex3f(ch_x , ch_y + h, 1.0f);
}
glEnd();
sx += pCharTex->m_adv_x;
if(sx > x + maxW)
{
sx = x ; sy += maxH + 12;
}
}
}
http://bbs.gameres.com/upload/sf_200692103510.png
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