Allow setting custom third person front view camera offset

[grorp]

Inspired by #11965.

This PR adds a third argument called thirdperson_front to the set_eye_offset Lua API function. It sets the camera offset in third-person front view and defaults to thirdperson in order not to break backwards compatibility. This was suggested by @srifqi in #11965 (comment).

Because the thirdperson_front argument defaults to thirdperson, not to vector.new(thirdperson.x, thirdperson.y, -thirdperson.z), this PR effectively reverts #13369. I did that because #13369 theoretically broke backwards compatibility by changing the behavior of set_eye_offset, and this compatibility break is now no longer necessary.

^ This part is up for discussion.

To do

This PR is a Ready for Review.

How to test

Use the thirdperson_front argument of set_eye_offset.

Test some mods that use set_eye_offset. Verify that they behave the same as they do before this PR (i.e. that thirdperson_front falls back to thirdperson if not specified).

Join an old server, verify that the third person camera offset sent by the server is used in third person front view as well.

[lhofhansl]

I'm obviously against reverting #13369.

[grorp]

I'm obviously against reverting #13369.

It wasn't obvious to me that you would be against that :) In that case, I'll change this PR to preserve the new behavior introduced by #13369.

[grorp]

In that case, I'll change this PR to preserve the new behavior introduced by #13369.

Done.

[srifqi]

It would be nice to also change thirdperson to thirdperson_back (and _third to _third_back etc.) instead of implying it for the back-side.

PS Thank you for creating this PR!

[lhofhansl]

Missed the updates here... It just "obvious" because I had added #13369. :)

Lemme test this.

[grorp]

It would be nice to also change thirdperson to thirdperson_back (and _third to _third_back etc.) instead of implying it for the back-side.

That "third person" means "third person back view" goes quite far:

minetest/src/client/camera.h

Line 75 in 7b3ed32

enum CameraMode {CAMERA_MODE_FIRST, CAMERA_MODE_THIRD, CAMERA_MODE_THIRD_FRONT};

I'd prefer not to change this everywhere. However, I did change thirdperson to thirdperson_back in lua_api.md, as you requested: f848584.

[srifqi]

Except for a single line, this PR looks good.

[SmallJoker]

Testing mod: (N°144)

local V = vector.new
local PP = minetest.pos_to_string

local views = {
	reset = {},
	[""] = {},

	-- (P1 view) up deplacement
	y_z = { V(0, 10, 0), V(0, 15, 0), V() },
	y_p = { V(0, 10, 0), V(0, 15, 0), V(0, 10, 0) },
	y_n = { V(0, -5, 0), V(0, -10, 0), V(0, -10, 0) },

	-- (P1 view) right deplacement
	x_z = { V(5, 0, 0), V(10, 0, 0), V() },
	x_p = { V(5, 0, 0), V(10, 0, 0), V(10, 0, 0) },
	x_n = { V(-5, 0, 0), V(-10, 0, 0), V(-10, 0, 0) },

	-- (P1 view) forward deplacement
	z_z = { V(0, 0, 5), V(0, 0, 5), V() },
	z_p = { V(0, 0, 5), V(0, 0, 5), V(0, 0, 5) },
	z_n = { V(0, 0, -5), V(0, 0, -5), V(0, 0, -5) },
}

minetest.register_chatcommand("view", {
	func = function(name, param)
		local player = minetest.get_player_by_name(name)
		local vals = views[param]
		if not vals then
			return false, "Unknown view type"
		end
		player:set_eye_offset(vals[1], vals[2], vals[3])
		local v1, v3b, v3f = player:get_eye_offset()
		print(PP(v1), PP(v3b), PP(v3f))
    end
})

x and z work as expected but negative y values cause a close-up of the character with negative values. This behaviour does however not seem to be caused by this PR.