[英]Draw and rotate the text along z axis in opengl/opentk
我需要在opengl / opentk中繪制字符串/文本,然后從文本本身的中心沿z軸旋轉它。
到目前為止,這是我嘗試過的:
void drawstring(string text, Font font, float fontsize, SolidBrush brush, float x, float y)
{
if (text == null || text == "")
return;
/*
OpenTK.Graphics.Begin();
OpenTK.Graphics.OpenGL.GL.PushMatrix();
OpenTK.Graphics.OpenGL.GL.Translate(x, y, 0);
printer.Print(text, font, c);
OpenTK.Graphics.OpenGL.GL.PopMatrix(); printer.End();
*/
float maxy = 1;
foreach (char cha in text)
{
int charno = (int)cha;
int charid = charno ^ (int)(fontsize * 1000) ^ brush.Color.ToArgb();
if (!charDict.ContainsKey(charid))
{
charDict[charid] = new character()
{
bitmap = new Bitmap(128, 128, System.Drawing.Imaging.PixelFormat.Format32bppArgb),
size = (int)fontsize
};
charDict[charid].bitmap.MakeTransparent(Color.Transparent);
//charbitmaptexid
float maxx = this.Width / 150; // for space
// create bitmap
using (var gfx = Graphics.FromImage(charDict[charid].bitmap))
{
var pth = new GraphicsPath();
if (text != null)
pth.AddString(cha + "", font.FontFamily, 0, fontsize + 5, new Point((int)0, (int)0),
StringFormat.GenericTypographic);
charDict[charid].pth = pth;
gfx.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
gfx.DrawPath(this._p, pth);
//Draw the face
gfx.FillPath(brush, pth);
if (pth.PointCount > 0)
{
foreach (PointF pnt in pth.PathPoints)
{
if (pnt.X > maxx)
maxx = pnt.X;
if (pnt.Y > maxy)
maxy = pnt.Y;
}
}
}
charDict[charid].width = (int)(maxx + 2);
//charbitmaps[charid] = charbitmaps[charid].Clone(new RectangleF(0, 0, maxx + 2, maxy + 2), charbitmaps[charid].PixelFormat);
//charbitmaps[charno * (int)fontsize].Save(charno + " " + (int)fontsize + ".png");
// create texture
int textureId;
OpenTK.Graphics.OpenGL.GL.TexEnv(OpenTK.Graphics.OpenGL.TextureEnvTarget.TextureEnv, OpenTK.Graphics.OpenGL.TextureEnvParameter.TextureEnvMode,
(float)TextureEnvModeCombine.Replace); //Important, or wrong color on some computers
Bitmap bitmap = charDict[charid].bitmap;
OpenTK.Graphics.OpenGL.GL.GenTextures(1, out textureId);
OpenTK.Graphics.OpenGL.GL.BindTexture(OpenTK.Graphics.OpenGL.TextureTarget.Texture2D, textureId);
BitmapData data = bitmap.LockBits(new System.Drawing.Rectangle(0, 0, bitmap.Width, bitmap.Height),
ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
OpenTK.Graphics.OpenGL.GL.TexImage2D(OpenTK.Graphics.OpenGL.TextureTarget.Texture2D, 0, OpenTK.Graphics.OpenGL.PixelInternalFormat.Rgba, data.Width, data.Height, 0,
OpenTK.Graphics.OpenGL.PixelFormat.Bgra, OpenTK.Graphics.OpenGL.PixelType.UnsignedByte, data.Scan0);
OpenTK.Graphics.OpenGL.GL.TexParameter(OpenTK.Graphics.OpenGL.TextureTarget.Texture2D, OpenTK.Graphics.OpenGL.TextureParameterName.TextureMinFilter,
(int)TextureMinFilter.Linear);
OpenTK.Graphics.OpenGL.GL.TexParameter(OpenTK.Graphics.OpenGL.TextureTarget.Texture2D, OpenTK.Graphics.OpenGL.TextureParameterName.TextureMagFilter,
(int)TextureMagFilter.Linear);
// OpenTK.Graphics.OpenGL.GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMagFilter, (int)All.Nearest);
//OpenTK.Graphics.OpenGL.GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMinFilter, (int)All.Nearest);
OpenTK.Graphics.OpenGL.GL.Flush();
bitmap.UnlockBits(data);
charDict[charid].gltextureid = textureId;
}
float scale = 1.0f;
// dont draw spaces
if (cha != ' ')
{
/*
TranslateTransform(x, y);
DrawPath(this._p, charDict[charid].pth);
//Draw the face
FillPath(brush, charDict[charid].pth);
TranslateTransform(-x, -y);
*/
//OpenTK.Graphics.OpenGL.GL.Enable(EnableCap.Blend);
//OpenTK.Graphics.OpenGL.GL.BlendFunc(BlendingFactorSrc.SrcAlpha, BlendingFactorDest.OneMinusSrcAlpha);
OpenTK.Graphics.OpenGL.GL.BlendFunc(OpenTK.Graphics.OpenGL.BlendingFactor.SrcAlpha, OpenTK.Graphics.OpenGL.BlendingFactor.OneMinusSrcAlpha);
OpenTK.Graphics.OpenGL.GL.Enable(OpenTK.Graphics.OpenGL.EnableCap.Texture2D);
OpenTK.Graphics.OpenGL.GL.BindTexture(OpenTK.Graphics.OpenGL.TextureTarget.Texture2D, charDict[charid].gltextureid);
OpenTK.Graphics.OpenGL.GL.Begin(OpenTK.Graphics.OpenGL.PrimitiveType.TriangleFan);
OpenTK.Graphics.OpenGL.GL.TexCoord2(0, 0);
OpenTK.Graphics.OpenGL.GL.Vertex2(x, y);
OpenTK.Graphics.OpenGL.GL.TexCoord2(1, 0);
OpenTK.Graphics.OpenGL.GL.Vertex2(x + charDict[charid].bitmap.Width * scale, y);
OpenTK.Graphics.OpenGL.GL.TexCoord2(1, 1);
OpenTK.Graphics.OpenGL.GL.Vertex2(x + charDict[charid].bitmap.Width * scale, y + charDict[charid].bitmap.Height * scale);
OpenTK.Graphics.OpenGL.GL.TexCoord2(0, 1);
OpenTK.Graphics.OpenGL.GL.Vertex2(x + 0, y + charDict[charid].bitmap.Height * scale);
OpenTK.Graphics.OpenGL.GL.End();
//OpenTK.Graphics.OpenGL.GL.Disable(EnableCap.Blend);
OpenTK.Graphics.OpenGL.GL.Disable(OpenTK.Graphics.OpenGL.EnableCap.Texture2D);
}
x += charDict[charid].width * scale;
}
}
我可以用它來寫文本,但是不能旋轉。 而且對於某些字符來說,它占用了太多空間,從而導致文本之間出現間隙。
我可以用它來寫文字,但無法旋轉
您必須將旋轉矩陣應用於模型視圖矩陣。
選擇模型視圖矩陣堆棧glMatrixMode(GL_MODELVIEW)
。
將當前矩陣推入矩陣堆棧glPushMatrix
。
將當前矩陣乘以圍繞z軸的旋轉矩陣glRotate
OpenTK.Graphics.OpenGL.GL.MatrixMode(OpenTK.Graphics.OpenGL.MatrixMode.ModelView);
OpenTK.Graphics.OpenGL.GL.PushMatrix();
OpenTK.Graphics.OpenGL.GL.Rotated( angle_degree, 0.0, 0.0, 1.0);
OpenTK.Graphics.OpenGL.GL.Begin(OpenTK.Graphics.OpenGL.PrimitiveType.TriangleFan);
OpenTK.Graphics.OpenGL.GL.TexCoord2(0, 0);
OpenTK.Graphics.OpenGL.GL.Vertex2(x, y);
OpenTK.Graphics.OpenGL.GL.TexCoord2(1, 0);
OpenTK.Graphics.OpenGL.GL.Vertex2(x + charDict[charid].bitmap.Width * scale, y);
OpenTK.Graphics.OpenGL.GL.TexCoord2(1, 1);
OpenTK.Graphics.OpenGL.GL.Vertex2(x + charDict[charid].bitmap.Width * scale, y + charDict[charid].bitmap.Height * scale);
OpenTK.Graphics.OpenGL.GL.TexCoord2(0, 1);
OpenTK.Graphics.OpenGL.GL.Vertex2(x + 0, y + charDict[charid].bitmap.Height * scale);
OpenTK.Graphics.OpenGL.GL.End();
OpenTK.Graphics.OpenGL.GL.PopMatrix();
注意,如果要“重置”當前矩陣,則可以通過glLoadIdentity
來完成。
如果要更改旋轉點,則必須平移到旋轉點,然后旋轉,最后從旋轉點平移回去。 翻譯可以通過glTranslate
。 可能會在您的情況下使用TranslateTransform
,但是由於我無法“看到”它在做什么,所以我不確定。
OpenTK.Graphics.OpenGL.GL.PushMatrix();
OpenTK.Graphics.OpenGL.GL.Translate( rotate_center_x, rotate_center_y, 0.0);
OpenTK.Graphics.OpenGL.GL.Rotated( angle_degree, 0.0, 0.0, 1.0);
OpenTK.Graphics.OpenGL.GL.Translate( -rotate_center_x, -rotate_center_y, 0.0);
.....
OpenTK.Graphics.OpenGL.GL.PopMatrix();
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