如何使用pyglet保存当前视图矩阵

Question

我正在使用 pyglet 并希望有一个可以为场景背景绘制颜色的函数。我目前只是在屏幕上绘制一个从左下角到右上角的矩形。在我开始应用转换之前，这很好用。例如，如果我使用旋转命令，'background' 矩形也会旋转

我试过使用 glGetFloatv 获取当前矩阵，将其重置为恒等式，然后再将其重置。

a = (GLfloat * 16)() # do something?
modelMat = glGetFloatv(GL_MODELVIEW_MATRIX, a) # save matrix
glLoadIdentity() # reset matrix
x1, y1, x2, y2 = 0, 0, self.width, self.height # get the coords
# self.width / self.height give the width and height of the screen
quad = pyglet.graphics.vertex_list(4,
    ('v2i', (x1, y1,  x2, y1, x2, y2, x1, y2)),
    ('c4B', (
    r, g, b, a, 
    r, g, b, a, 
    r, g, b, a, 
    r, g, b, a))
    ) # define the rectangle
quad.draw(GL_QUADS) # draw rectangle
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA) # do alpha
glMultMatrixf(modelMat) # reset matrix

此代码returns此错误：

Traceback (most recent call last):
  File "/Users/jakemonsky/Development/pythonApps/PygletTest/main.py", line 34, in <module>
    APP.run()
  File "/Users/jakemonsky/Development/pythonApps/PygletTest/processing.py", line 364, in run
    pyglet.app.run()
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pyglet/app/__init__.py", line 138, in run
    event_loop.run()
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pyglet/app/base.py", line 142, in run
    self._run()
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pyglet/app/base.py", line 154, in _run
    timeout = self.idle()
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pyglet/app/base.py", line 281, in idle
    window.dispatch_event('on_draw')
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pyglet/window/__init__.py", line 1232, in dispatch_event
    if EventDispatcher.dispatch_event(self, *args) != False:
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pyglet/event.py", line 371, in dispatch_event
    event_type, args, getattr(self, event_type))
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pyglet/event.py", line 367, in dispatch_event
    if getattr(self, event_type)(*args):
  File "/Users/jakemonsky/Development/pythonApps/PygletTest/processing.py", line 223, in on_draw
    self.bind_draw(dt)
  File "/Users/jakemonsky/Development/pythonApps/PygletTest/processing.py", line 41, in __call__
    func(*args, **kwargs)
  File "/Users/jakemonsky/Development/pythonApps/PygletTest/main.py", line 14, in draw
    Background(0,0,0,255)
  File "/Users/jakemonsky/Development/pythonApps/PygletTest/processingLocalizer.py", line 62, in Background
    Application.Background(r, g, b, a)
  File "/Users/jakemonsky/Development/pythonApps/PygletTest/processing.py", line 449, in Background
    r, g, b, a))
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pyglet/graphics/__init__.py", line 292, in vertex_list
    return _get_default_batch().add(count, 0, None, *data)
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pyglet/graphics/__init__.py", line 372, in add
    vlist._set_attribute_data(i, array)
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pyglet/graphics/vertexdomain.py", line 443, in _set_attribute_data
    region.array[:] = data
TypeError: incompatible types, c_float_Array_16 instance instead of c_ubyte instance
[Finished in 2.3s with exit code 1]

我不确定是什么原因造成的，或者我是否正确地解决了这个问题。我是 openGL 和 pyglet 的新手，不确定是什么导致了这个错误。有没有更好的方法来 'reset' 转换或在屏幕 space 中将某些东西绘制到屏幕上而不是我缺少的转换 space 的方法？

编辑：错误是因为我愚蠢地将 a 重用于矩阵（也是我的 alpha 通道）但现在我只得到输出

2019-07-05 11:03:46.789 Python[853:21283] ApplePersistenceIgnoreState: Existing state will not be touched. New state will be written to (null)
[Finished in 2.1s with exit code -11]

调用命令且程序刚刚结束时。 OSX 还会弹出一个 window 询问是否正常关闭

Answer 1

How to save the current view matrix using pyglet

当前矩阵有一堆矩阵。可以通过 glPushMatrix glPopMatrix.

将矩阵推入堆栈并从堆栈弹出

变换前压入矩阵，变换后弹出：

glPushMatrix()

glLoadIdentity() # reset matrix
x1, y1, x2, y2 = 0, 0, self.width, self.height # get the coords
# self.width / self.height give the width and height of the screen
quad = pyglet.graphics.vertex_list(4,
    ('v2i', (x1, y1,  x2, y1, x2, y2, x1, y2)),
    ('c4B', (
    r, g, b, a, 
    r, g, b, a, 
    r, g, b, a, 
    r, g, b, a))
    ) # define the rectangle
quad.draw(GL_QUADS) # draw rectangle
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA) # do alpha

glPopMatrix()

请注意，每个矩阵模式都有一堆矩阵（GL_MODELVIEW、GL_PROJECTION、GL_TEXTURE 和 GL_COLOR）。参见 glMatrixMode。

错误是因为glGetFloatv没有return任何值。它将矩阵读取到传递给函数的内存中。
您必须将数组传递给 glMultMatrixf

modelMat = (GLfloat * 16)()
glGetFloatv(GL_MODELVIEW_MATRIX, modelMat) # read to array "modelMat"
glLoadIdentity() 

# [...]

glMultMatrixf(modelMat) # multiply matrix in the array "modelMat"

注意，顾名思义，glMultMatrixf 将矩阵乘以当前矩阵。这适用于您的情况，因为当前矩阵是 Identity matrix. A matrix can be loaded to the current matrix by glLoadMatrix。

如何使用pyglet保存当前视图矩阵

How to save the current view matrix using pyglet

python

opengl

pyglet

opengl-compat