Support for unsigned int in shaders code

[Czaki]

As I check, it is not possible to use uint and uvecn in the shaders code. (lack of definition of proper constraints).

In napari, we implement a lookup table (see napari/napari#3308 and napari/napari#6182) for coloring labels. I want to use uint to ensure everything fits, but even if they are in OpenGL specification, they cannot be used with vispy.

Is this intentional, or no one request such a feature and you are open to such a contribution?

[djhoese]

What error do you get when you use uint?

[Czaki]

Traceback (most recent call last):
  File "/home/czaki/.pyenv/versions/napari/lib/python3.9/site-packages/vispy/app/backends/_qt.py", line 903, in paintGL
    self._vispy_canvas.events.draw(region=None)
  File "/home/czaki/.pyenv/versions/napari/lib/python3.9/site-packages/vispy/util/event.py", line 453, in __call__
    self._invoke_callback(cb, event)
  File "/home/czaki/.pyenv/versions/napari/lib/python3.9/site-packages/vispy/util/event.py", line 471, in _invoke_callback
    _handle_exception(self.ignore_callback_errors,
  File "/home/czaki/.pyenv/versions/napari/lib/python3.9/site-packages/vispy/util/event.py", line 469, in _invoke_callback
    cb(event)
  File "/home/czaki/.pyenv/versions/napari/lib/python3.9/site-packages/vispy/scene/canvas.py", line 218, in on_draw
    self._draw_scene()
  File "/home/czaki/.pyenv/versions/napari/lib/python3.9/site-packages/vispy/scene/canvas.py", line 277, in _draw_scene
    self.draw_visual(self.scene)
  File "/home/czaki/.pyenv/versions/napari/lib/python3.9/site-packages/vispy/scene/canvas.py", line 315, in draw_visual
    node.draw()
  File "/home/czaki/.pyenv/versions/napari/lib/python3.9/site-packages/vispy/scene/visuals.py", line 103, in draw
    self._visual_superclass.draw(self)
  File "/home/czaki/.pyenv/versions/napari/lib/python3.9/site-packages/vispy/visuals/visual.py", line 451, in draw
    self._program.draw(self._vshare.draw_mode,
  File "/home/czaki/.pyenv/versions/napari/lib/python3.9/site-packages/vispy/visuals/shaders/program.py", line 101, in draw
    self.update_variables()
  File "/home/czaki/.pyenv/versions/napari/lib/python3.9/site-packages/vispy/visuals/shaders/program.py", line 158, in update_variables
    self._process_pending_variables()
  File "/home/czaki/.pyenv/versions/napari/lib/python3.9/site-packages/vispy/gloo/program.py", line 303, in _process_pending_variables
    self[name] = data
  File "/home/czaki/.pyenv/versions/napari/lib/python3.9/site-packages/vispy/gloo/program.py", line 372, in __setitem__
    dtype, numel = self._gtypes[type_]
KeyError: 'uint'

uvec2 is missed from different dict

[djhoese]

I'm going to guess an oversight. A quick google doesn't suggest that these types are not in the OpenGL standards we support. Pull requests welcome!

vispy/vispy/gloo/program.py

Lines 114 to 134 in 6b68262

	_gtypes = { # DTYPE, NUMEL
	'float': (np.float32, 1),
	'vec2': (np.float32, 2),
	'vec3': (np.float32, 3),
	'vec4': (np.float32, 4),
	'int': (np.int32, 1),
	'ivec2': (np.int32, 2),
	'ivec3': (np.int32, 3),
	'ivec4': (np.int32, 4),
	'bool': (np.int32, 1),
	'bvec2': (bool, 2),
	'bvec3': (bool, 3),
	'bvec4': (bool, 4),
	'mat2': (np.float32, 4),
	'mat3': (np.float32, 9),
	'mat4': (np.float32, 16),
	'sampler1D': (np.uint32, 1),
	'sampler2D': (np.uint32, 1),
	'sampler3D': (np.uint32, 1),
	'samplerCube': (np.uint32, 1),
	}