阿勇的blog

immediate mode

The easiest way to do drawing in OpenGL is using the Immediate Mode. For this, you use the glBegin() function which takes as one parameter the “mode” or type of object you want to draw.

glBegin(GL_LINE_LOOP);//start drawing a line loop
    glVertex3f(-1.0f,0.0f,0.0f);//left of window
    glVertex3f(0.0f,-1.0f,0.0f);//bottom of window
    glVertex3f(1.0f,0.0f,0.0f);//right of window
    glVertex3f(0.0f,1.0f,0.0f);//top of window
glEnd();//end drawing of line loop

display list

Display list is a group of OpenGL commands that have been stored (compiled) for later execution. Once a display list is created, all vertex and pixel data are evaluated and copied into the display list memory on the server machine. It is only one time process. After the display list has been prepared (compiled), you can reuse it repeatedly without re-evaluating and re-transmitting data over and over again to draw each frame.

// create one display list
GLuint index = glGenLists(1);
// compile the display list, store a triangle in it
glNewList(index, GL_COMPILE);
    glBegin(GL_TRIANGLES);
        glVertex3fv(v0);
        glVertex3fv(v1);
        glVertex3fv(v2);
    glEnd();
glEndList();
...
// draw the display list
glCallList(index);

vertex array

This means that your vertices and vertex attributes and indices are in RAM.

glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_COLOR_ARRAY);
glColorPointer(3, GL_FLOAT, 0, Colors);
glVertexPointer(3, GL_FLOAT, 0, Vertices);
glDrawArrays(GL_TRIANGLES, 0, 3);
glDisableClientState(GL_VERTEX_ARRAY);
glDisableClientState(GL_COLOR_ARRAY);

glBlendFunc — specify pixel arithmetic
void glBlendFunc(GLenum sfactor, GLenum dfactor);void glBlendFunci(GLuint buf, GLenum sfactor, GLenum dfactor);Parameters
bufFor glBlendFunci, specifies the index of the draw buffer for which to set the blend function.sfactor

其實視窗置中和openGL一點關係都沒有
問題在你的視窗是誰建立的
是用glfw? glut? or ??
至於置中，就還簡單了
視窗的左上角位置 ＝ 0.5 X（ 桌面大小 － 視窗大小 ）

prevent opening a console window in addition to your GLUT window when it is run
in vc
menu option ( Project → Properties )
From the Configuration: list box, select All Configurations.
select the Linker subtree and then Command Line option in the left pane. Then add the following code to the Additional Options: text box

先看一下wxPython官網關於opengl的教學try:
import wx
from wx import glcanvas
except ImportError:
raise ImportError, "Required dependency wx.glcanvas not present"
try:
from OpenGL.GL import *
except ImportError:
raise ImportError, "Required dependency OpenGL not present"
class GLFrame(wx.Frame):
"""A simple class for using OpenGL with wxPython."""
def __init__(self, parent, id, title, pos=wx.DefaultPosition,
size=wx.DefaultSize, style=wx.DEFAULT_FRAME_STYLE,
name='frame'):
#
# Forcing a specific style on the window.
# Should this include styles passed?
style = wx.DEFAULT_FRAME_STYLE | wx.NO_FULL_REPAINT_ON_RESIZE
super(GLFrame, self).__init__(parent, id, title, pos, size, style, name)
self.GLinitialized = False
attribList = (glcanvas.WX_GL_RGBA, # RGBA
glcanvas.WX_GL_DOUBLEBUFFER, # Double Buffered
glcanvas.WX_GL_DEPTH_SIZE, 24) # 24 bit
#
# Create the canvas
self.canvas = glcanvas.GLCanvas(self, attribList=attribList)
#
# Set the event handlers.
self.canvas.Bind(wx.EVT_ERASE_BACKGROUND, self.processEraseBackgroundEvent)
self.canvas.Bind(wx.EVT_SIZE, self.processSizeEvent)
self.canvas.Bind(wx.EVT_PAINT, self.processPaintEvent)
#
# Canvas Proxy Methods
def GetGLExtents(self):
"""Get the extents of the OpenGL canvas."""
return self.canvas.GetClientSize()
def SwapBuffers(self):
"""Swap the OpenGL buffers."""
self.canvas.SwapBuffers()
#
# wxPython Window Handlers
def processEraseBackgroundEvent(self, event):
"""Process the erase background event."""
pass # Do nothing, to avoid flashing on MSWin
def processSizeEvent(self, event):
"""Process the resize event."""
if self.canvas.GetContext():
# Make sure the frame is shown before calling SetCurrent.
self.Show()
self.canvas.SetCurrent()
size = self.GetGLExtents()
self.OnReshape(size.width, size.height)
self.canvas.Refresh(False)
event.Skip()
def processPaintEvent(self, event):
"""Process the drawing event."""
self.canvas.SetCurrent()
# This is a 'perfect' time to initialize OpenGL ... only if we need to
if not self.GLinitialized:
self.OnInitGL()
self.GLinitialized = True
self.OnDraw()
event.Skip()
#
# GLFrame OpenGL Event Handlers
def OnInitGL(self):
"""Initialize OpenGL for use in the window."""
glClearColor(1, 1, 1, 1)
def OnReshape(self, width, height):
"""Reshape the OpenGL viewport based on the dimensions of the window."""
glViewport(0, 0, width, height)
glMatrixMode(GL_PROJECTION)
glLoadIdentity()
glOrtho(-0.5, 0.5, -0.5, 0.5, -1, 1)
glMatrixMode(GL_MODELVIEW)
glLoadIdentity()
def OnDraw(self, *args, **kwargs):
"Draw the window."
glClear(GL_COLOR_BUFFER_BIT)
# Drawing an example triangle in the middle of the screen
glBegin(GL_TRIANGLES)
glColor(0, 0, 0)
glVertex(-.25, -.25)
glVertex(.25, -.25)
glVertex(0, .25)
glEnd()
self.SwapBuffers()
app = wx.PySimpleApp()
frame = GLFrame(None, -1, 'GL Window')
frame.Show()
app.MainLoop()
app.Destroy()

發生問題
error: GL/gl.h: No such file or directory
error: GL/glu.h: No such file or directory
解決辦法
將
#include <GL/gl.h>
#include <GL/glu.h>
改成
#include <OpenGL/gl.h>
#include <OpenGL/glu.h>
編譯時注意-lGLU -lGL -framework OpenGL