imgui_edit.lua

-- ImGui basics

hg = require("harfang")

hg.InputInit()
hg.WindowSystemInit()

res_x, res_y = 1280, 720
win = hg.RenderInit('Harfang - ImGui Edit', res_x, res_y, hg.RF_VSync)

hg.AddAssetsFolder('resources_compiled')

-- initialize ImGui
imgui_prg = hg.LoadProgramFromAssets('core/shader/imgui')
imgui_img_prg = hg.LoadProgramFromAssets('core/shader/imgui_image')

hg.ImGuiInit(10, imgui_prg, imgui_img_prg)

imgui_output_view = 255
imgui_view_clear_color = hg.Color(0, 0, 0)
imgui_clear_color_preset = 0

-- main loop
while not hg.ReadKeyboard():Key(hg.K_Escape) and hg.IsWindowOpen(win) do
	render_was_reset, res_x, res_y = hg.RenderResetToWindow(win, res_x, res_y, hg.RF_VSync)
	dt = hg.TickClock()

	-- ImGui frame
	hg.ImGuiBeginFrame(res_x, res_y, dt, hg.ReadMouse(), hg.ReadKeyboard())

	hg.ImGuiSetNextWindowPosCenter(hg.ImGuiCond_Once)

	if hg.ImGuiBegin('ImGui Controls', true, hg.ImGuiWindowFlags_AlwaysAutoResize) then
		val_modified, imgui_clear_color_preset = hg.ImGuiCombo('Set Clear Color', imgui_clear_color_preset, {'Red', 'Green', 'Blue'})

		-- apply preset if a combo entry was selected
		if val_modified then
			if imgui_clear_color_preset == 0 then
				imgui_view_clear_color = hg.Color(1, 0, 0)
			elseif imgui_clear_color_preset == 1 then
				imgui_view_clear_color = hg.Color(0, 1, 0)
			else
				imgui_view_clear_color = hg.Color(0, 0, 1)
			end
		end

		-- reset clear color to black on button click
		if hg.ImGuiButton('Reset Clear Color') then
			imgui_view_clear_color = hg.Color.Black
		end
		-- custom clear color edit
		val_modified, imgui_view_clear_color = hg.ImGuiColorEdit('Edit Clear Color', imgui_view_clear_color)

		-- edit the ImGui output view
		val_modified, imgui_output_view = hg.ImGuiInputInt('ImGui Output View', imgui_output_view)
		if val_modified then
			imgui_output_view = math.max(0, math.min(imgui_output_view, 255))  -- keep output view in [0;255] range
		end
	end
	hg.ImGuiEnd()

	hg.SetView2D(imgui_output_view, 0, 0, res_x, res_y, -1, 0, hg.CF_Color | hg.CF_Depth, imgui_view_clear_color, 1, 0)
	hg.ImGuiEndFrame(imgui_output_view)

	-- rendering frame
	hg.Frame()

	hg.UpdateWindow(win)
end

hg.RenderShutdown()
hg.DestroyWindow(win)