# glTF (/examples/libs/gltf)



Loads and renders 3D models in glTF format within LVGL. Enable with `LV_USE_GLTF` in `lv_conf.h`.

Spin a glTF model on a platter [#spin-a-gltf-model-on-a-platter]

<LvglExampleBrief>
  Load a glTF scene and spin it around the yaw axis with a timer.
</LvglExampleBrief>

`lv_gltf_create` attaches the viewer to the active screen and
`lv_obj_set_size` sizes it to fill the screen. `lv_gltf_load_model_from_file`
loads `webp_diffuse_transmission_plant.glb` from drive letter `A`. The first
embedded animation plays, the viewer is pitched down by 45 degrees, and a
timer running at `LV_DEF_REFR_PERIOD` advances yaw by one degree per tick,
wrapping at 360.

<LvglExample name="lv_example_gltf_1" path="libs/gltf/lv_example_gltf_1" />

Cycle glTF cameras and speeds [#cycle-gltf-cameras-and-speeds]

<LvglExampleBrief>
  Rotate through the scene cameras and animation speeds every 5 seconds.
</LvglExampleBrief>

`lv_gltf_create` fills the active screen with
`webp_diffuse_transmission_plant.glb` loaded from drive letter `A`. The
viewer starts at `LV_GLTF_ANIM_SPEED_HALF` with the first animation
playing and a 45 degree downward pitch. A 5000 ms timer advances the
active camera with `lv_gltf_set_camera` and doubles the playback rate
with `lv_gltf_model_set_animation_speed`, wrapping back to half once it
passes `LV_GLTF_ANIM_SPEED_4X`.

<LvglExample name="lv_example_gltf_2" path="libs/gltf/lv_example_gltf_2" />

Drag plants across a glTF scene [#drag-plants-across-a-gltf-scene]

<LvglExampleBrief>
  Pick and drag one of five glTF plants along the ground plane with a cursor model.
</LvglExampleBrief>

Five copies of `webp_diffuse_transmission_plant.glb` are loaded into a
single `lv_gltf` viewer and spaced across the ground at fixed x and z
offsets, while `support_assets.glb` contributes a `/cursor` node hidden
by zeroing its scale. Pointer events
cast a ray through `lv_gltf_get_ray_from_2d_coordinate` into the ground
plane built by `lv_get_ground_plane`. On `LV_EVENT_PRESSED` the nearest
plant within a squared distance of `0.1` is selected; `LV_EVENT_PRESSING`
moves the plant and cursor to the hit point and nudges rotation, and
`LV_EVENT_RELEASED` hides the cursor again.

<LvglExample name="lv_example_gltf_3" path="libs/gltf/lv_example_gltf_3" />

Share one glTF across four viewers [#share-one-gltf-across-four-viewers]

<LvglExampleBrief>
  Animate the scale of a logo shared by four 

  `lv_gltf`

   viewers arranged in a 2x2 grid.
</LvglExampleBrief>

`lv_gltf_data_load_from_file` loads `lvgl_logo.glb` once, and four
`lv_gltf` viewers sized `50%` by `50%` are aligned to each corner of the
active screen with pitch and yaw set to +/-30 degrees so each viewer
shows a different angle. `lv_gltf_add_model` attaches the shared model
to all four. An `lv_anim_t` drives the root node via `anim_scale_cb`
from 10 to 100 (0.1 to 1.0 scale) over 2000 ms with
`lv_anim_path_ease_in_out`, a 1000 ms reverse delay, a 1500 ms reverse
duration, a 500 ms repeat delay, and `LV_ANIM_REPEAT_INFINITE`.

<LvglExample name="lv_example_gltf_4" path="libs/gltf/lv_example_gltf_4" />