Add more IMGUI widgets for GGUI

[AmesingFlank]

Concisely describe the proposed feature
Currently, GGUI only supports 5 basic widgets (text,button,check_box,slider_float,color_edit_3). It would be nice to have support for more complicated widgets such as drop-down menus, menu bars, etc.

Describe the solution you'd like (if any)
GGUI uses dear imgui internally. It's quite simple to write a wrapper for a widget. Take button for example, here are all the relevant code:

taichi/taichi/ui/common/gui_base.h

Line 22 in 2f5c9df

virtual bool button(std::string text) = 0;

taichi/taichi/ui/backends/vulkan/gui.h

Line 43 in 2f5c9df

virtual bool button(std::string text) override;

taichi/taichi/ui/backends/vulkan/gui.cpp

Lines 159 to 164 in 2f5c9df

	bool Gui::button(std::string text) {
	if (!initialized()) {
	return false;
	}
	return ImGui::Button(text.c_str());
	}

taichi/taichi/python/export_ggui.cpp

Lines 60 to 62 in 2f5c9df

	bool button(std::string name) {
	return gui->button(name);
	}

taichi/python/taichi/ui/gui.py

Lines 68 to 74 in 2f5c9df

	def button(self, text):
	"""Declares a button, and returns whether or not it had just been clicked.
	Args:
	text (str): a line of text to be shown next to the button
	"""
	return self.gui.button(text)

[gaocegege]

Hi, I am new to Taichi and glad to help improve it.

I will start from an easy widget, maybe colored text. But I do not want to dibs the whole issue. Other people can also work on it since there are so many widgets in dear imgui, if I have understood well.

[gaocegege]

Additional info for the issue:

• You need to enable cuda and vulkan to compile GGUI to the taichi core before starting contributions on this issue. Ref https://github.com/taichi-dev/taichi/blob/master/cmake/TaichiCore.cmake#L36 Or you will get the error when you run GGUI examples:

python ./examples/ggui_examples/fem128_ggui.py
[Taichi] version 0.8.1, llvm 10.0.0, commit cc2dd342, osx, python 3.7.9
[Taichi] Starting on arch=metal
Traceback (most recent call last):
  File "./examples/ggui_examples/fem128_ggui.py", line 95, in <module>
    window = ti.ui.Window('FEM128', (512, 512))
  File "/Users/gaocedidi/code/taichi/python/taichi/ui/ui.py", line 30, in __init__
    err_no_ggui()
  File "/Users/gaocedidi/code/taichi/python/taichi/ui/ui.py", line 26, in err_no_ggui
    raise Exception("GGUI Not Available")
Exception: GGUI Not Availabl

[gaocegege]

@AmesingFlank Hi, it seems that there is only the Vulkan backend for GGUI, then why do we need to enable CUDA to compile GGUI here? https://github.com/taichi-dev/taichi/blob/master/cmake/TaichiCore.cmake#L36

set(TI_WITH_GGUI OFF)
if(TI_WITH_CUDA AND TI_WITH_VULKAN)
    set(TI_WITH_GGUI ON)
endif()

[AmesingFlank]

@AmesingFlank Hi, it seems that there is only the Vulkan backend for GGUI, then why do we need to enable CUDA to compile GGUI here? https://github.com/taichi-dev/taichi/blob/master/cmake/TaichiCore.cmake#L36

set(TI_WITH_GGUI OFF)
if(TI_WITH_CUDA AND TI_WITH_VULKAN)
    set(TI_WITH_GGUI ON)
endif()

Currently, the Vulkan backend for GGUI is only works with the CUDA/x64 compute backend of taichi. That is, you need ti.init(arch=ti.cuda) or ti.init(arch=ti.x64) for GGUI to work. This will be changed in the near future, as we are planning support for GGUI to work with other compute backends such as Vulkan itself and OpenGL.

[gaocegege]

OK, get it.

Thanks for your reply.

[gaocegege]

Hi @AmesingFlank

Do we have tests for GGUI? I am trying to add some new test cases for the widget, but I did not find any.

[AmesingFlank]

Hi @AmesingFlank

Do we have tests for GGUI? I am trying to add some new test cases for the widget, but I did not find any.

We don't, adding tests for GGUI is on the top of my to-do list right now, but I just haven't found the time to do it :((

[gaocegege]

I am trying to add a colored text widget. You can take it as an example https://github.com/taichi-dev/taichi/pull/3078/files about how to add a new GGUI widget in Taichi. There are so many widgets not supported now. Welcome contributions!

I am unassigning myself since it is an umbrella issue.