/// <summary>
    /// Draw some text on the screen
    /// </summary>
    public void DrawText(float xpos, float ypos, Color color, string text, RenderFlags flags)
    {
        if (text == null)
            return;

        // Setup renderstate
        savedStateBlock.Capture();
        drawTextStateBlock.Apply();
        device.SetTexture(0, fontTexture);
        device.VertexFormat = CustomVertex.TransformedColoredTextured.Format;
        device.PixelShader = null;
        device.SetStreamSource(0, vertexBuffer, 0);

        // Set filter states
        if ((flags & RenderFlags.Filtered) != 0)
        {
            samplerState0.MinFilter = TextureFilter.Linear;
            samplerState0.MagFilter = TextureFilter.Linear;
        }

        // Adjust for character spacing
        xpos -= spacingPerChar;
        float fStartX = xpos;

        // Fill vertex buffer
        int iv = 0;
        int dwNumTriangles = 0;

        foreach (char c in text)
        {
            if (c == '\n')
            {
                xpos = fStartX;
                ypos += (textureCoords[0,3]-textureCoords[0,1])*textureHeight;
            }

            if ((c-32) < 0 || (c-32) >= 128-32)
                continue;

            float tx1 = textureCoords[c-32,0];
            float ty1 = textureCoords[c-32,1];
            float tx2 = textureCoords[c-32,2];
            float ty2 = textureCoords[c-32,3];

            float w = (tx2-tx1) *  textureWidth / textureScale;
            float h = (ty2-ty1) * textureHeight / textureScale;

            int intColor = color.ToArgb();
            if (c != ' ')
            {
                fontVertices[iv++] = new CustomVertex.TransformedColoredTextured(new Vector4(xpos+0-0.5f,ypos+h-0.5f,0.9f,1.0f), intColor, tx1, ty2);
                fontVertices[iv++] = new CustomVertex.TransformedColoredTextured(new Vector4(xpos+0-0.5f,ypos+0-0.5f,0.9f,1.0f), intColor, tx1, ty1);
                fontVertices[iv++] = new CustomVertex.TransformedColoredTextured(new Vector4(xpos+w-0.5f,ypos+h-0.5f,0.9f,1.0f), intColor, tx2, ty2);
                fontVertices[iv++] = new CustomVertex.TransformedColoredTextured(new Vector4(xpos+w-0.5f,ypos+0-0.5f,0.9f,1.0f), intColor, tx2, ty1);
                fontVertices[iv++] = new CustomVertex.TransformedColoredTextured(new Vector4(xpos+w-0.5f,ypos+h-0.5f,0.9f,1.0f), intColor, tx2, ty2);
                fontVertices[iv++] = new CustomVertex.TransformedColoredTextured(new Vector4(xpos+0-0.5f,ypos+0-0.5f,0.9f,1.0f), intColor, tx1, ty1);
                dwNumTriangles += 2;

                if (dwNumTriangles*3 > (MaxNumfontVertices-6))
                {
                    // Set the data for the vertexbuffer
                    vertexBuffer.SetData(fontVertices, 0, LockFlags.Discard);
                    device.DrawPrimitives(PrimitiveType.TriangleList, 0, dwNumTriangles);
                    dwNumTriangles = 0;
                    iv = 0;
                }
            }

            xpos += w - (2 * spacingPerChar);
        }

        // Set the data for the vertex buffer
        vertexBuffer.SetData(fontVertices, 0, LockFlags.Discard);
        if (dwNumTriangles > 0)
            device.DrawPrimitives(PrimitiveType.TriangleList, 0, dwNumTriangles);

        // Restore the modified renderstates
        savedStateBlock.Apply();
    }




    /// <summary>
    /// Draws scaled 2D text.  Note that x and y are in viewport coordinates
    /// (ranging from -1 to +1).  fXScale and fYScale are the size fraction 
    /// relative to the entire viewport.  For example, a fXScale of 0.25 is
    /// 1/8th of the screen width.  This allows you to output text at a fixed
    /// fraction of the viewport, even if the screen or window size changes.
    /// </summary>
    public void DrawTextScaled(float x, float y, float z, 
                               float fXScale, float fYScale, 
                               System.Drawing.Color color,
                               string text, RenderFlags flags)
    {
        if (device == null)
            throw new System.ArgumentNullException();

        // Set up renderstate
        savedStateBlock.Capture();
        drawTextStateBlock.Apply();
        device.VertexFormat = CustomVertex.TransformedColoredTextured.Format;
        device.PixelShader = null;
        device.SetStreamSource(0, vertexBuffer, 0);

        // Set filter states
        if ((flags & RenderFlags.Filtered) != 0)
        {
            samplerState0.MinFilter = TextureFilter.Linear;
            samplerState0.MagFilter = TextureFilter.Linear;
        }

        Viewport vp = device.Viewport;
        float xpos = (x+1.0f)*vp.Width/2;
        float ypos = (y+1.0f)*vp.Height/2;
        float sz = z;
        float rhw = 1.0f;
        float fLineHeight = (textureCoords[0,3] - textureCoords[0,1]) * textureHeight;

        // Adjust for character spacing
        xpos -= spacingPerChar * (fXScale*vp.Height)/fLineHeight;
        float fStartX = xpos;

        // Fill vertex buffer
        int numTriangles = 0;
        int realColor = color.ToArgb();
        int iv = 0;

        foreach (char c in text)
        {
            if (c == '\n')
            {
                xpos  = fStartX;
                ypos += fYScale*vp.Height;
            }

            if ((c-32) < 0 || (c-32) >= 128-32)
                continue;

            float tx1 = textureCoords[c-32,0];
            float ty1 = textureCoords[c-32,1];
            float tx2 = textureCoords[c-32,2];
            float ty2 = textureCoords[c-32,3];

            float w = (tx2-tx1)*textureWidth;
            float h = (ty2-ty1)*textureHeight;

            w *= (fXScale*vp.Height)/fLineHeight;
            h *= (fYScale*vp.Height)/fLineHeight;

            if (c != ' ')
            {
                fontVertices[iv++] = new CustomVertex.TransformedColoredTextured(new Vector4(xpos+0-0.5f,ypos+h-0.5f,sz,rhw), realColor, tx1, ty2);
                fontVertices[iv++] = new CustomVertex.TransformedColoredTextured(new Vector4(xpos+0-0.5f,ypos+0-0.5f,sz,rhw), realColor, tx1, ty1);
                fontVertices[iv++] = new CustomVertex.TransformedColoredTextured(new Vector4(xpos+w-0.5f,ypos+h-0.5f,sz,rhw), realColor, tx2, ty2);
                fontVertices[iv++] = new CustomVertex.TransformedColoredTextured(new Vector4(xpos+w-0.5f,ypos+0-0.5f,sz,rhw), realColor, tx2, ty1);
                fontVertices[iv++] = new CustomVertex.TransformedColoredTextured(new Vector4(xpos+w-0.5f,ypos+h-0.5f,sz,rhw), realColor, tx2, ty2);
                fontVertices[iv++] = new CustomVertex.TransformedColoredTextured(new Vector4(xpos+0-0.5f,ypos+0-0.5f,sz,rhw), realColor, tx1, ty1);
                numTriangles += 2;

                if (numTriangles*3 > (MaxNumfontVertices-6))
                {
                    // Unlock, render, and relock the vertex buffer
                    vertexBuffer.SetData(fontVertices, 0, LockFlags.Discard);
                    device.DrawPrimitives(PrimitiveType.TriangleList , 0, numTriangles);
                    numTriangles = 0;
                    iv = 0;
                }
            }

            xpos += w - (2 * spacingPerChar) * (fXScale*vp.Height)/fLineHeight;
        }

        // Unlock and render the vertex buffer
        vertexBuffer.SetData(fontVertices, 0, LockFlags.Discard);
        if (numTriangles > 0)
            device.DrawPrimitives(PrimitiveType.TriangleList , 0, numTriangles);

        // Restore the modified renderstates
        savedStateBlock.Apply();
    }




    /// <summary>
    /// Draws scaled 2D text.  Note that x and y are in viewport coordinates
    /// (ranging from -1 to +1).  fXScale and fYScale are the size fraction 
    /// relative to the entire viewport.  For example, a fXScale of 0.25 is
    /// 1/8th of the screen width.  This allows you to output text at a fixed
    /// fraction of the viewport, even if the screen or window size changes.
    /// </summary>
    public void DrawTextScaled(float x, float y, float z, 
                               float fXScale, float fYScale, 
                               System.Drawing.Color color,
                               string text)
    {
        this.DrawTextScaled(x,y,z,fXScale, fYScale, color, text, 0);
    }




    /// <summary>
    /// Renders 3D text
    /// </summary>
    public void Render3DText(string text, RenderFlags flags)
    {
        if (device == null)
            throw new System.ArgumentNullException();

        // Set up renderstate
        savedStateBlock.Capture();
        drawTextStateBlock.Apply();
        device.VertexFormat = CustomVertex.PositionNormalTextured.Format;
        device.PixelShader = null;
        device.SetStreamSource(0, vertexBuffer, 0, VertexInformation.GetFormatSize(CustomVertex.PositionNormalTextured.Format));

        // Set filter states
        if ((flags & RenderFlags.Filtered) != 0)
        {
            samplerState0.MinFilter = TextureFilter.Linear;
            samplerState0.MagFilter = TextureFilter.Linear;
        }

        // Position for each text element
        float x = 0.0f;
        float y = 0.0f;

        // Center the text block at the origin
        if ((flags & RenderFlags.Centered) != 0)
        {
            System.Drawing.SizeF sz = GetTextExtent(text);
            x = -(((float)sz.Width)/10.0f)/2.0f;
            y = -(((float)sz.Height)/10.0f)/2.0f;
        }

        // Turn off culling for two-sided text
        if ((flags & RenderFlags.TwoSided) != 0)
            renderState.CullMode = Cull.None;

        // Adjust for character spacing
        x -= spacingPerChar / 10.0f;
        float fStartX = x;

        // Fill vertex buffer
        GraphicsStream strm = vertexBuffer.Lock(0, 0, LockFlags.Discard);
        int numTriangles = 0;

        foreach (char c in text)
        {
            if (c == '\n')
            {
                x = fStartX;
                y -= (textureCoords[0,3]-textureCoords[0,1])*textureHeight/10.0f;
            }

            if ((c-32) < 0 || (c-32) >= 128-32)
                continue;

            float tx1 = textureCoords[c-32,0];
            float ty1 = textureCoords[c-32,1];
            float tx2 = textureCoords[c-32,2];
            float ty2 = textureCoords[c-32,3];

            float w = (tx2-tx1) * textureWidth  / (10.0f * textureScale);
            float h = (ty2-ty1) * textureHeight / (10.0f * textureScale);

            if (c != ' ')
            {
                strm.Write(new CustomVertex.PositionNormalTextured(new Vector3(x+0,y+0,0), new Vector3(0,0,-1), tx1, ty2));
                strm.Write(new CustomVertex.PositionNormalTextured(new Vector3(x+0,y+h,0), new Vector3(0,0,-1), tx1, ty1));
                strm.Write(new CustomVertex.PositionNormalTextured(new Vector3(x+w,y+0,0), new Vector3(0,0,-1), tx2, ty2));
                strm.Write(new CustomVertex.PositionNormalTextured(new Vector3(x+w,y+h,0), new Vector3(0,0,-1), tx2, ty1));
                strm.Write(new CustomVertex.PositionNormalTextured(new Vector3(x+w,y+0,0), new Vector3(0,0,-1), tx2, ty2));
                strm.Write(new CustomVertex.PositionNormalTextured(new Vector3(x+0,y+h,0), new Vector3(0,0,-1), tx1, ty1));
                numTriangles += 2;

                if (numTriangles*3 > (MaxNumfontVertices-6))
                {
                    // Unlock, render, and relock the vertex buffer
                    vertexBuffer.Unlock();
                    device.DrawPrimitives(PrimitiveType.TriangleList , 0, numTriangles);
                    strm = vertexBuffer.Lock(0, 0, LockFlags.Discard);
                    numTriangles = 0;
                }
            }

            x += w - (2 * spacingPerChar) / 10.0f;
        }

        // Unlock and render the vertex buffer
        vertexBuffer.Unlock();
        if (numTriangles > 0)
            device.DrawPrimitives(PrimitiveType.TriangleList , 0, numTriangles);

        // Restore the modified renderstates
        savedStateBlock.Apply();
    }




    /// <summary>
    /// Get the dimensions of a text string
    /// </summary>
    private System.Drawing.SizeF GetTextExtent(string text)
    {
        if (null == text || text == string.Empty)
            throw new System.ArgumentNullException();

        float fRowWidth  = 0.0f;
        float fRowHeight = (textureCoords[0,3]-textureCoords[0,1])*textureHeight;
        float fWidth     = 0.0f;
        float fHeight    = fRowHeight;

        foreach (char c in text)
        {
            if (c == '\n')
            {
                fRowWidth = 0.0f;
                fHeight  += fRowHeight;
            }

            if ((c-32) < 0 || (c-32) >= 128-32)
                continue;

            float tx1 = textureCoords[c-32,0];
            float tx2 = textureCoords[c-32,2];

            fRowWidth += (tx2-tx1)*textureWidth - 2*spacingPerChar;

            if (fRowWidth > fWidth)
                fWidth = fRowWidth;
        }

        return new System.Drawing.SizeF(fWidth, fHeight);
    }




    /// <summary>
    /// Cleanup any resources being used
    /// </summary>
    public void Dispose(object sender, EventArgs e)
    {
        if (systemFont != null)
            systemFont.Dispose();

        systemFont = null;
    }
}