add sliders to settings

builtin/mainmenu/settings/components.lua

@@ -126,6 +126,40 @@ end, is_valid_number)
 make.string = make_field(tostring, nil)
 
 
+function make.slider(setting)
+	local steps = tonumber(setting.steps) or 100
+
+	return {
+		info_text = setting.comment,
+		setting = setting,
+
+		get_formspec = function(self, avail_w)
+			local value = core.settings:get(setting.name) or setting.default
+			local scrollbar_value = (value - setting.min)/(setting.max - setting.min)*steps
+
+			self.resettable = true
+
+			local setting_label = ("label[0,0.25;%s]"):format(
+				setting.readable_name)
+			local scrollbar_options = ("scrollbaroptions[min=0;max=%f;smallstep=1;largestep=10]"):format(
+				steps)
+			local scrollbar_formspec = ("scrollbar[0,0.5;%f,0.4;horizontal;%s;%f]"):format(
+				avail_w - 1, setting.name, scrollbar_value)
+			local formspec = setting_label..scrollbar_options..scrollbar_formspec
+
+			return formspec, 1.1
+		end,
+
+		on_submit = function(self, fields)
+			local raw_value = core.explode_scrollbar_event(fields[setting.name]).value
+			local value = (raw_value/steps) * (setting.max - setting.min) + setting.min
+			core.settings:set(setting.name, tostring(value))
+			return false
+		end
+	}
+end
+
+
 function make.bool(setting)
 	return {
 		info_text = setting.comment,

builtin/mainmenu/settings/settingtypes.lua

@@ -295,6 +295,35 @@ local function parse_setting_line(settings, line, read_all, base_level, allow_se
 		return
 	end
 
+	if setting_type == "slider" then
+		local default, min, max, steps = remaining_line:match("^"
+				-- first 3 floats are required, the last is optional
+				.. "(" .. CHAR_CLASSES.FLOAT .. "+)" .. CHAR_CLASSES.SPACE .. "*"
+				.. "(" .. CHAR_CLASSES.FLOAT .. "+)" .. CHAR_CLASSES.SPACE .. "*"
+				.. "(" .. CHAR_CLASSES.FLOAT .. "+)" .. CHAR_CLASSES.SPACE .. "*"
+				.. "(" .. CHAR_CLASSES.FLOAT .. "*)"
+				.."$")
+
+		if not default or not tonumber(default) then
+			return "Invalid float setting"
+		end
+
+		min = tonumber(min)
+		max = tonumber(max)
+		table.insert(settings, {
+			name = name,
+			readable_name = readable_name,
+			type = "slider",
+			default = default,
+			min = min,
+			max = max,
+			steps = steps,
+			requires = requires,
+			comment = comment,
+		})
+		return
+	end
+
 	if setting_type == "enum" then
 		local default, values = remaining_line:match("^"
 				-- first value (default) may be empty (i.e. is optional)

builtin/settingtypes.txt

@@ -134,7 +134,7 @@ invert_mouse (Invert mouse) bool false
 #    Mouse sensitivity multiplier.
 #
 #    Requires: keyboard_mouse
-mouse_sensitivity (Mouse sensitivity) float 0.2 0.001 10.0
+mouse_sensitivity (Mouse sensitivity) slider 0.2 0.001 1.0 500
 
 #    Enable mouse wheel (scroll) for item selection in hotbar.
 #
@@ -646,10 +646,10 @@ enable_volumetric_lighting (Volumetric lighting) bool false
 
 #    Volume of all sounds.
 #    Requires the sound system to be enabled.
-sound_volume (Volume) float 0.8 0.0 1.0
+sound_volume (Volume) slider 0.8 0.0 1.0
 
 #    Volume multiplier when the window is unfocused.
-sound_volume_unfocused (Volume when unfocused) float 0.3 0.0 1.0
+sound_volume_unfocused (Volume when unfocused) slider 0.3 0.0 1.0
 
 #    Whether to mute sounds. You can unmute sounds at any time, unless the
 #    sound system is disabled (enable_sound=false).
@@ -704,7 +704,7 @@ menu_clouds (Clouds in menu) bool true
 [**HUD]
 
 #    Modifies the size of the HUD elements.
-hud_scaling (HUD scaling) float 1.0 0.5 20
+hud_scaling (HUD scaling) slider 1.0 0.5 20 1000
 
 #    Whether name tag backgrounds should be shown by default.
 #    Mods may still set a background.