physics_overrides_matrix.lua

-- Physics overrides node matrix.
-- Manual changes of position/rotation/scale of a physics node won't affect its matrix.

hg = require("harfang")

hg.InputInit()
hg.WindowSystemInit()

res_x, res_y = 1280, 720
win = hg.RenderInit('Harfang - Physics Matrix Interaction', res_x, res_y, hg.RF_VSync | hg.RF_MSAA4X)

pipeline = hg.CreateForwardPipeline()
res = hg.PipelineResources()

hg.ImGuiInit(10, hg.LoadProgramFromFile('resources_compiled/core/shader/imgui'), hg.LoadProgramFromFile('resources_compiled/core/shader/imgui_image'))

-- physics debug
vtx_line_layout = hg.VertexLayoutPosFloatColorUInt8()
line_shader = hg.LoadProgramFromFile("resources_compiled/shaders/pos_rgb")

-- create models
vtx_layout = hg.VertexLayoutPosFloatNormUInt8()

cube_mdl = hg.CreateCubeModel(vtx_layout, 1, 1, 1)
cube_ref = res:AddModel('cube', cube_mdl)
ground_mdl = hg.CreateCubeModel(vtx_layout, 100, 0.02, 100)
ground_ref = res:AddModel('ground', ground_mdl)

prg_ref = hg.LoadPipelineProgramRefFromFile('resources_compiled/core/shader/default.hps', res, hg.GetForwardPipelineInfo())

-- create material
mat = hg.CreateMaterial(prg_ref, 'uDiffuseColor', hg.Vec4(0.5, 0.5, 0.5), 'uSpecularColor', hg.Vec4(1, 1, 1))

-- setup scene
scene = hg.Scene()

cam_mat = hg.TransformationMat4(hg.Vec3(0, 1.5, -5), hg.Deg3(5, 0, 0))
cam = hg.CreateCamera(scene, cam_mat, 0.01, 1000)
scene:SetCurrentCamera(cam)
view_matrix = hg.InverseFast(cam_mat)
c = cam:GetCamera()
projection_matrix = hg.ComputePerspectiveProjectionMatrix(c:GetZNear(), c:GetZFar(), hg.FovToZoomFactor(c:GetFov()), hg.Vec2(res_x / res_y, 1))

lgt = hg.CreatePointLight(scene, hg.TranslationMat4(hg.Vec3(3, 4, -6)), 0)

cube_node = hg.CreatePhysicCube(scene, hg.Vec3(1, 1, 1), hg.TranslationMat4(hg.Vec3(1.25, 2.5, 0)), cube_ref, {mat}, 2)
ground_node = hg.CreatePhysicCube(scene, hg.Vec3(100, 0.02, 100), hg.TranslationMat4(hg.Vec3(0, -0.005, 0)), ground_ref, {mat}, 0)

clocks = hg.SceneClocks()

-- scene physics
physics = hg.SceneBullet3Physics()
physics:SceneCreatePhysicsFromAssets(scene)

-- main loop
mouse, keyboard = hg.Mouse(), hg.Keyboard()

while not keyboard:Pressed(hg.K_Escape) and hg.IsWindowOpen(win) do
	keyboard:Update()
	mouse:Update()
	dt = hg.TickClock()

	-- scene view
	view_id = 0
	hg.SceneUpdateSystems(scene, clocks, dt, physics, hg.time_from_sec_f(1 / 60), 1)
	view_id,_ = hg.SubmitSceneToPipeline(view_id, scene, hg.IntRect(0, 0, res_x, res_y), true, pipeline, res)

    -- Debug physics display
    hg.SetViewClear(view_id, 0, 0, 1.0, 0)
    hg.SetViewRect(view_id, 0, 0, res_x, res_y)
    hg.SetViewTransform(view_id, view_matrix, projection_matrix)
    rs = hg.ComputeRenderState(hg.BM_Opaque, hg.DT_Disabled, hg.FC_Disabled)
    physics:RenderCollision(view_id, vtx_line_layout, line_shader, rs, 0)

	-- ImGui view
	hg.ImGuiBeginFrame(res_x, res_y, dt, mouse:GetState(), keyboard:GetState())

	if hg.ImGuiBegin('Transform and Physics', true, hg.ImGuiWindowFlags_AlwaysAutoResize) then
		hg.ImGuiTextWrapped('This tutorial demonstrates the interaction between the physics system and the Transform component of a node. The node position, rotation and scale are overriden by an active node rigid body.')

		hg.ImGuiSeparator()

		r, v = hg.ImGuiInputVec3('Transform.pos', cube_node:GetTransform():GetPos(), 2)
		if r then
			cube_node:GetTransform():SetPos(v)
		end

		if hg.ImGuiButton('Press to reset position using Transform.SetPos') then
			cube_node:GetTransform():SetPos(hg.Vec3(1.25, 2.5, 0))
		end

		hg.ImGuiSeparator()

		hg.ImGuiInputVec3('Transform.GetWorld().T', hg.GetT(cube_node:GetTransform():GetWorld()), 2, hg.ImGuiInputTextFlags_ReadOnly)

		if physics:NodeHasBody(cube_node) then
			if hg.ImGuiButton('Press to destroy the cube node physics') then
				physics:NodeDestroyPhysics(cube_node)
				physics:GarbageCollect(scene)
			end
		else
			if hg.ImGuiButton('Create to create the cube node physics') then
				physics:NodeCreatePhysicsFromAssets(cube_node)
			end
		end
	end

	hg.ImGuiEnd()

	hg.ImGuiEndFrame(255)

	hg.Frame()
	hg.UpdateWindow(win)
end

hg.RenderShutdown()
hg.DestroyWindow(win)

hg.WindowSystemShutdown()
hg.InputShutdown()