rb_dynamic_add_force_on_init.py

import harfang as hg

def CreatePhysicCubeEx(scene, size, mtx, model_ref, materials, rb_type, mass):
    rb_type = rb_type or hg.RBT_Dynamic
    mass = mass or 0
    node = hg.CreateObject(scene, mtx, model_ref, materials)
    node.SetName("Physic Cube")
    rb = scene.CreateRigidBody()
    rb.SetType(rb_type)
    node.SetRigidBody(rb)
    # create custom cube collision
    col = scene.CreateCollision()
    col.SetType(hg.CT_Cube)
    col.SetSize(size)
    col.SetMass(mass)
    # set cube as collision shape
    node.SetCollision(0, col)
    return node, rb

hg.AddAssetsFolder('assets_compiled')

# main window
hg.InputInit()
hg.WindowSystemInit()

res_x, res_y = 1280, 720
win = hg.RenderInit('Physics Test', res_x, res_y, hg.RF_VSync | hg.RF_MSAA4X)

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

# physics debug
vtx_line_layout = hg.VertexLayoutPosFloatColorUInt8()
line_shader = hg.LoadProgramFromAssets("shaders/pos_rgb")

# create material
pbr_shader = hg.LoadPipelineProgramRefFromAssets('core/shader/pbr.hps', res, hg.GetForwardPipelineInfo())
mat_grey = hg.CreateMaterial(pbr_shader, 'uBaseOpacityColor', hg.Vec4(1, 1, 1), 'uOcclusionRoughnessMetalnessColor', hg.Vec4(1, 0.5, 0.05))

# create models
vtx_layout = hg.VertexLayoutPosFloatNormUInt8()

# cube
cube_size = hg.Vec3(1, 1, 1)
cube_ref = res.AddModel('cube', hg.CreateCubeModel(vtx_layout, cube_size.x, cube_size.y, cube_size.z))

# ground
ground_size = hg.Vec3(4, 0.05, 4)
ground_ref = res.AddModel('ground', hg.CreateCubeModel(vtx_layout, ground_size.x, ground_size.y, ground_size.z))

# setup the scene
scene = hg.Scene()

cam_mat = hg.TransformationMat4(hg.Vec3(0, 1.5, -5), hg.Vec3(hg.Deg(10), 0, 0))
cam = hg.CreateCamera(scene, cam_mat, 0.01, 1000)
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))

scene.SetCurrentCamera(cam)

lgt = hg.CreateLinearLight(scene, hg.TransformationMat4(hg.Vec3(0, 0, 0), hg.Vec3(hg.Deg(30), hg.Deg(30), 0)), hg.Color(1, 1, 1), hg.Color(1, 1, 1), 10, hg.LST_Map, 0.0001, hg.Vec4(2, 4, 10, 16))

cube_node, cube_rb = CreatePhysicCubeEx(scene, cube_size, hg.TranslationMat4(hg.Vec3(1.5, 0.5, 0)), cube_ref, [mat_grey], hg.RBT_Dynamic, 1.0)
cube_rb.SetFriction(0.0)
cube_rb.SetLinearDamping(0.0)
ground_node, ground_rb = CreatePhysicCubeEx(scene, ground_size, hg.TranslationMat4(hg.Vec3(0, -0.005, 0)), ground_ref, [mat_grey], hg.RBT_Static, 0)
ground_rb.SetFriction(0.0)

# scene physics
physics = hg.SceneBullet3Physics()
physics.SceneCreatePhysicsFromAssets(scene)
physics_step = hg.time_from_sec_f(1 / 60)
dt_frame_step = hg.time_from_sec_f(1 / 60)

clocks = hg.SceneClocks()

# apply force
physics.NodeAddForce(cube_node, hg.Vec3(-25.0, 0, 0))

# description
hg.SetLogLevel(hg.LL_Normal)
print(">>> Description:\n>>> Apply a force on a cube, only once, before entering the main rendering loop. No damping and no friction.")

# main loop
keyboard = hg.Keyboard()

while not keyboard.Down(hg.K_Escape) and hg.IsWindowOpen(win):
    keyboard.Update()

    physics.NodeWake(cube_node)

    view_id = 0
    hg.SceneUpdateSystems(scene, clocks, dt_frame_step, physics, physics_step, 3)
    view_id, pass_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)

    hg.Frame()
    hg.UpdateWindow(win)

scene.Clear()
scene.GarbageCollect()

hg.RenderShutdown()
hg.DestroyWindow(win)

hg.WindowSystemShutdown()
hg.InputShutdown()