Source code for gltext

'''
*gltext: draw OpenGL text*
==========================

Routines that render text on OpenGL without use of GLUT.

Code written by Christian Brugger & Stefan Hacker and
distributed under GNU General Public License.
'''

#!/usr/bin/env python
# -*- coding: utf-8
#
#    Provides some text display functions for wx + ogl
#    Copyright (C) 2007 Christian Brugger, Stefan Hacker
#
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License along
#    with this program; if not, write to the Free Software Foundation, Inc.,
#    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

import wx
import struct as st
import OpenGL.GL as GL
import platform

"""
Optimize with psyco if possible, this gains us about 50% speed when
creating our textures in trade for about 4MBytes of additional memory usage for
psyco. If you don't like loosing the memory you have to turn the lines following
"enable psyco" into a comment while uncommenting the line after "Disable psyco".
"""
#Try to enable psyco
#try:
#    import psyco
#    psyco_optimized = False
#except ImportError:
#    psyco = None
    
#Disable psyco
#          
[docs]class TextElement(object): """ A simple class for using system Fonts to display text in an OpenGL scene """ def __init__(self, text = '', font = None, foreground = wx.WHITE, centered = False): """ text (String) - Text font (wx.Font) - Font to draw with (None = System default) foreground (wx.Colour)- Color of the text or (wx.Bitmap)- Bitmap to overlay the text with centered (bool) - Center the text Initializes the TextElement """ # save given variables self._text = text self._lines = text.split('\n') self._font = font self._foreground = foreground self._centered = centered # init own variables self._owner_cnt = 0 #refcounter self._texture = None #OpenGL texture ID self._text_size = None #x/y size tuple of the text self._texture_size= None #x/y Texture size tuple # create Texture self.createTexture() #---Internal helpers def _getUpper2Base(self, value): """ Returns the lowest value with the power of 2 greater than 'value' (2^n>value) """ base2 = 1 while base2 < value: base2 *= 2 return base2 #---Functions
[docs] def draw_text(self, position = wx.RealPoint(0.,0.), scale = 1.0, rotation = 0): """ position (wx.RealPoint) - x/y Position to draw in scene scale (float) - Scale rotation (int) - Rotation in degree Draws the text to the scene """ #Enable necessary functions GL.glColor(1,1,1,1) GL.glEnable(GL.GL_TEXTURE_2D) GL.glEnable(GL.GL_ALPHA_TEST) #Enable alpha test GL.glAlphaFunc(GL.GL_GREATER, 0) GL.glEnable(GL.GL_BLEND) #Enable blending GL.glBlendFunc(GL.GL_SRC_ALPHA, GL.GL_ONE_MINUS_SRC_ALPHA) #Bind texture GL.glBindTexture(GL.GL_TEXTURE_2D, self._texture) ow, oh = self._text_size w , h = self._texture_size #Perform transformations GL.glPushMatrix() GL.glTranslatef(position.x, position.y, 0) GL.glRotate(-rotation, 0, 0, 1) GL.glScaled(scale, scale, scale) if self._centered: GL.glTranslate(-w/2, -oh/2, 0) #Draw vertices GL.glBegin(GL.GL_QUADS) GL.glTexCoord2f(0,0); GL.glVertex2f(0,0) GL.glTexCoord2f(0,1); GL.glVertex2f(0,h) GL.glTexCoord2f(1,1); GL.glVertex2f(w,h) GL.glTexCoord2f(1,0); GL.glVertex2f(w,0) GL.glEnd() GL.glPopMatrix() #Disable features GL.glDisable(GL.GL_BLEND) GL.glDisable(GL.GL_ALPHA_TEST) GL.glDisable(GL.GL_TEXTURE_2D)
[docs] def createTexture(self): """ Creates a texture from the settings saved in TextElement, to be able to use normal system fonts conviently a wx.MemoryDC is used to draw on a wx.Bitmap. As wxwidgets device contexts don't support alpha at all it is necessary to apply a little hack to preserve antialiasing without sticking to a fixed background color: We draw the bmp in b/w mode so we can use its data as a alpha channel for a solid color bitmap which after GL_ALPHA_TEST and GL_BLEND will show a nicely antialiased text on any surface. To access the raw pixel data the bmp gets converted to a wx.Image. Now we just have to merge our foreground color with the alpha data we just created and push it all into a OpenGL texture and we are DONE *inhalesdelpy* DRAWBACK of the whole conversion thing is a really long time for creating the texture. If you see any optimizations that could save time PLEASE CREATE A PATCH!!! """ # get a memory dc and assign a temporary bitmap dc = wx.MemoryDC() if 'phoenix' in wx.version(): dc.SelectObject(wx.Bitmap(100, 100)) else: dc.SelectObject(wx.EmptyBitmap(100, 100)) # set our font dc.SetFont(self._font) # Approximate extend to next power of 2 and create our bitmap # REMARK: You wouldn't believe how much fucking speed this little # sucker gains compared to sizes not of the power of 2. It's like # 500ms --> 0.5ms (on my ATI-GPU powered Notebook). On Sams nvidia # machine there don't seem to occur any losses...bad drivers? ow, oh = dc.GetMultiLineTextExtent(self._text)[:2] w, h = self._getUpper2Base(ow), self._getUpper2Base(oh) self._text_size = wx.Size(ow,oh) self._texture_size = wx.Size(w,h) if 'phoenix' in wx.version(): bmp = wx.Bitmap(wx.Size(w,h)) else: bmp = wx.EmptyBitmap(w,h) #Draw in b/w mode to bmp so we can use it as alpha channel dc.SelectObject(bmp) dc.SetBackground(wx.BLACK_BRUSH) dc.Clear() dc.SetTextForeground(wx.WHITE) x,y = 0,0 centered = self.centered for line in self._lines: if not line: line = ' ' tw, th = dc.GetTextExtent(line) if centered: x = int(round((w-tw)//2)) dc.DrawText(line, x, y) x = 0 y += th #Release the dc dc.SelectObject(wx.NullBitmap) del dc #Generate a correct RGBA data string from our bmp """ NOTE: You could also use wx.AlphaPixelData to access the pixel data in 'bmp' directly, but the iterator given by it is much slower than first converting to an image and using wx.Image.GetData(). """ if 'phoenix' in wx.version(): img = wx.Bitmap.ConvertToImage(bmp) alpha = img.GetData() else: img = wx.ImageFromBitmap(bmp) alpha = img.GetData() # if isinstance(self._foreground, wx.Colour): """ If we have a static color... """ r,g,b = self._foreground.Get()[:3] if '2' in platform.python_version_tuple()[0]: color = "%c%c%c" % (chr(r), chr(g), chr(b)) else: color = st.pack('3B',r,g,b) data = b'' for i in range(0, len(alpha)-1, 3): if '2' in platform.python_version_tuple()[0]: data += (color + str(alpha[i])) else: data += (color + st.pack('B',alpha[i])) # elif isinstance(self._foreground, wx.Bitmap): # """ # If we have a bitmap... # """ # bg_img = wx.ImageFromBitmap(self._foreground) # bg = bg_img.GetData() # bg_width = self._foreground.GetWidth() # bg_height = self._foreground.GetHeight() # # data = '' # # for y in range(0, h): # for x in range(0, w): # if (y > (bg_height-1)) or (x > (bg_width-1)): # color = "%c%c%c" % (chr(0),chr(0),chr(0)) # else: # pos = (x+y*bg_width) * 3 # color = bg[pos:pos+3] # data += color + alpha[(x+y*w)*3] # now convert it to ogl texture self._texture = GL.glGenTextures(1) GL.glBindTexture(GL.GL_TEXTURE_2D, self._texture) GL.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MAG_FILTER, GL.GL_LINEAR) GL.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MIN_FILTER, GL.GL_LINEAR) GL.glPixelStorei(GL.GL_UNPACK_ROW_LENGTH, 0) GL.glPixelStorei(GL.GL_UNPACK_ALIGNMENT, 2) GL.glTexImage2D(GL.GL_TEXTURE_2D, 0, GL.GL_RGBA, w, h, 0, GL.GL_RGBA, GL.GL_UNSIGNED_BYTE, data)
[docs] def deleteTexture(self): """ Deletes the OpenGL texture object """ if self._texture: if GL.glIsTexture(self._texture): GL.glDeleteTextures(self._texture) else: self._texture = None
[docs] def bind(self): """ Increase refcount """ self._owner_cnt += 1
[docs] def release(self): """ Decrease refcount """ self._owner_cnt -= 1
[docs] def isBound(self): """ Return refcount """ return self._owner_cnt
def __del__(self): """ Destructor """ # self.deleteTexture() del self._texture #---Getters/Setters def getText(self): return self._text def getFont(self): return self._font def getForeground(self): return self._foreground def getCentered(self): return self._centered def getTexture(self): return self._texture def getTexture_size(self): return self._texture_size def getOwner_cnt(self): return self._owner_cnt def setOwner_cnt(self, value): self._owner_cnt = value #---Properties text = property(getText, None, None, "Text of the object") font = property(getFont, None, None, "Font of the object") foreground = property(getForeground, None, None, "Color of the text") centered = property(getCentered, None, None, "Is text centered") owner_cnt = property(getOwner_cnt, setOwner_cnt, None, "Owner count") texture = property(getTexture, None, None, "Used texture") texture_size = property(getTexture_size, None, None, "Size of the used texture")
[docs]class Text(object): """ A simple class for using System Fonts to display text in an OpenGL scene. The Text adds a global Cache of already created text elements to TextElement's base functionality so you can save some memory and increase speed """ _texts = [] #Global cache for TextElements def __init__(self, text = 'Text', font = None, font_size = 8, foreground = wx.WHITE, centered = False): """ text (string) - displayed text font (wx.Font) - if None, system default font will be used with font_size font_size (int) - font size in points foreground (wx.Colour) - Color of the text or (wx.Bitmap) - Bitmap to overlay the text with centered (bool) - should the text drawn centered towards position? Initializes the text object """ #Init/save variables self._aloc_text = None self._text = text self._font_size = font_size self._foreground= foreground self._centered = centered #Check if we are offered a font if not font: #if not use the system default self._font = wx.SystemSettings.GetFont(wx.SYS_DEFAULT_GUI_FONT) else: #save it self._font = font #Bind us to our texture self._initText() #---Internal helpers def _initText(self): """ Initializes/Reinitializes the Text object by binding it to a TextElement suitable for its current settings """ #Check if we already bound to a texture if self._aloc_text: #if so release it self._aloc_text.release() if not self._aloc_text.isBound(): self._texts.remove(self._aloc_text) self._aloc_text = None #Adjust our font self._font.SetPointSize(self._font_size) #Search for existing element in our global buffer for element in self._texts: if element.text == self._text and\ element.font == self._font and\ element.foreground == self._foreground and\ element.centered == self._centered: # We already exist in global buffer ;-) element.bind() self._aloc_text = element break if not self._aloc_text: # We are not in the global buffer, let's create ourselves aloc_text = self._aloc_text = TextElement(self._text, self._font, self._foreground, self._centered) aloc_text.bind() self._texts.append(aloc_text) def __del__(self): """ Destructor """ aloc_text = self._aloc_text aloc_text.release() if not aloc_text.isBound(): self._texts.remove(aloc_text) #---Functions
[docs] def draw_text(self, position = wx.RealPoint(0.,0.), scale = 1.0, rotation = 0): """ position (wx.RealPoint) - x/y Position to draw in scene scale (float) - Scale rotation (int) - Rotation in degree Draws the text to the scene """ self._aloc_text.draw_text(position, scale, rotation)
#---Setter/Getter def getText(self): return self._text
[docs] def setText(self, value, reinit = True): """ value (bool) - New Text reinit (bool) - Create a new texture Sets a new text """ self._text = value if reinit: self._initText()
def getFont(self): return self._font
[docs] def setFont(self, value, reinit = True): """ value (bool) - New Font reinit (bool) - Create a new texture Sets a new font """ self._font = value if reinit: self._initText()
def getFont_size(self): return self._font_size
[docs] def setFont_size(self, value, reinit = True): """ value (bool) - New font size reinit (bool) - Create a new texture Sets a new font size """ self._font_size = value if reinit: self._initText()
def getForeground(self): return self._foreground
[docs] def setForeground(self, value, reinit = True): """ value (bool) - New centered value reinit (bool) - Create a new texture Sets a new value for 'centered' """ self._foreground = value if reinit: self._initText()
def getCentered(self): return self._centered
[docs] def setCentered(self, value, reinit = True): """ value (bool) - New centered value reinit (bool) - Create a new texture Sets a new value for 'centered' """ self._centered = value if reinit: self._initText()
[docs] def getTexture_size(self): """ Returns a texture size tuple """ return self._aloc_text.texture_size
[docs] def getTextElement(self): """ Returns the text element bound to the Text class """ return self._aloc_text
[docs] def getTexture(self): """ Returns the texture of the bound TextElement """ return self._aloc_text.texture
#---Properties text = property(getText, setText, None, "Text of the object") font = property(getFont, setFont, None, "Font of the object") font_size = property(getFont_size, setFont_size, None, "Font size") foreground = property(getForeground, setForeground, None, "Color/Overlay bitmap of the text") centered = property(getCentered, setCentered, None, "Display the text centered") texture_size = property(getTexture_size, None, None, "Size of the used texture") texture = property(getTexture, None, None, "Texture of bound TextElement") text_element = property(getTextElement,None , None, "TextElement bound to this class")
#Optimize critical functions #if psyco and not psyco_optimized: # psyco.bind(TextElement.createTexture) # psyco_optimized = True