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我想在OpenGL中繪製文本。我用一個小的C＃程序將所有字符從0x21到0x7E繪製到位圖中。我將它作爲紋理加載並嘗試使用它來繪製文本。它似乎工作，但我似乎有一些奇怪的問題。 http://i54.tinypic.com/mmd7k8.png注意'a'旁邊的額外像素以及'c'被略微切斷的事實。看起來整個事情略有轉移。有人知道我爲什麼會遇到這個問題嗎？我不想使用像gltext這樣的庫，因爲我不想依賴libfreetype，因爲我只繪製了幾個字符串。下面是我使用的代碼：試圖在OpenGL中繪製文本，但紋理略微偏移
static void textDrawChar(char c, int x, int y)
{
GLfloat vert[8];
GLfloat texcoord[8];
vert[0] = x; vert[1] = y;
vert[2] = x; vert[3] = y + TEXT_HEIGHT;
vert[4] = x + font_char_width[c-0x21]; vert[5] = y + TEXT_HEIGHT;
vert[6] = x + font_char_width[c-0x21]; vert[7] = y;
texcoord[0] = (float)(font_char_pos[c-0x21])/TOTAL_WIDTH;
texcoord[1] = 1.0f;
texcoord[2] = (float)(font_char_pos[c-0x21])/TOTAL_WIDTH;
texcoord[3] = 0.0f;
texcoord[4] = (float)(font_char_pos[c-0x21] + font_char_width[c-0x21])/TOTAL_WIDTH;
texcoord[5] = 0.0f;
texcoord[6] = (float)(font_char_pos[c-0x21] + font_char_width[c-0x21])/TOTAL_WIDTH;
texcoord[7] = 1.0f;
glBindTexture(GL_TEXTURE_2D, texture);
glVertexPointer(2, GL_FLOAT, 0, vert);
glTexCoordPointer(2, GL_FLOAT, 0, texcoord);
glDrawElements(GL_TRIANGLE_STRIP, 4, GL_UNSIGNED_BYTE, indices);
}
void textDraw(void)
{
textDrawChar('a', 300, 300);
textDrawChar('b', 300+font_char_width['a'-0x21], 300);
textDrawChar('c', 300+font_char_width['a'-0x21]+font_char_width['b'-0x21], 300);
}
編輯我加4到紋理座標（0,2,4,6），這似乎已經解決了這一問題。但是，現在我需要知道這是否會繼續工作或可能因不明原因而中斷。這裏是位圖創建代碼，以防出現問題。
using System;
using System.Drawing;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Collections;
namespace font_to_bmp
{
class Program
{
static void Main(string[] args)
{
Bitmap b = new Bitmap(1715, 36);
Graphics g = Graphics.FromImage(b);
g.FillRectangle(new SolidBrush(Color.Transparent), 0, 0, 1715, 36);
Font f = new Font("Liberation Sans", 24, GraphicsUnit.Point);
g.PageUnit = GraphicsUnit.Pixel;
int curx = 0;
StreamWriter w = new StreamWriter(new FileStream("font_width.h", FileMode.Create, FileAccess.Write, FileShare.Read));
w.WriteLine("static const int font_char_width[] = {");
ArrayList hax = new ArrayList();
for (int i = 0x21; i <= 0x7E; i++)
{
char c = (char)i;
string s = c.ToString();
SizeF sz = g.MeasureString(s, f);
StringFormat sf = new StringFormat();
sf.SetMeasurableCharacterRanges(new CharacterRange[] {new CharacterRange(0,1)});
Region r = g.MeasureCharacterRanges(s, f, new RectangleF(0, 0, 1000, 1000), sf)[0];
RectangleF r2 = r.GetBounds(g);
Console.WriteLine("{0} is {1}x{2}", s, r2.Width, r2.Height);
int w_int = (int)(Math.Ceiling(r2.Width));
g.DrawString(s, f, new SolidBrush(Color.Black), curx, 0);
hax.Add(curx);
curx += w_int;
w.WriteLine("\t{0},", w_int);
}
Console.WriteLine("Total width {0}", curx);
w.WriteLine("};");
w.WriteLine();
w.WriteLine("static const int font_char_pos[] = {");
foreach(int z in hax)
{
w.WriteLine("\t{0},", z);
}
w.WriteLine("};");
w.Close();
b.Save("font.png");
}
}
}