1
One brick, drawn thousands of times
Every brick shares one mesh (a box plus four 12-sided studs = 462 vertices), uploaded to the GPU once. Each brick only adds 8 numbers: position, layer, turn and color. GPU instancing reads one set per brick, so the whole field is a single draw call.
brick_count = grid_size × grid_size (wave) e.g. 24 × 24 = 576
per_brick_data = (brick_x, brick_z, layer, brick_yaw) + (red, green, blue, rand)
vertex_attrib_divisor(attr, 1) → advance once per brick
draw_arrays_instanced(triangles, 0, 462, brick_count) → draw_calls = 1
Sources: [1]
[2]
2
Placing each brick on the GPU
The vertex shader turns each brick around the vertical axis, lifts it to its layer, adds the animation height, then projects it through the camera. Projection uses the standard perspective matrix.
x_rot = x·cos(brick_yaw) − z·sin(brick_yaw)
z_rot = x·sin(brick_yaw) + z·cos(brick_yaw)
world_pos = (x_rot, y, z_rot) + (brick_x, 1.15·layer + anim_height, brick_z)
clip_pos = proj_matrix · view_matrix · world_pos
focal = 1 / tan(field_of_view / 2)
field_of_view = 0.75 rad near = 0.5 far = 600
proj_matrix = | focal/aspect 0 0 0 |
| 0 focal 0 0 |
| 0 0 (near+far)/(near−far) 2·near·far/(near−far) |
| 0 0 −1 0 |
Sources: [3]
3
The wave and the hover bump
Wave height is a sine of each brick’s distance from the center, so rings ripple outward. Your pointer adds a Gaussian bump, measured in screen space so it follows the cursor at any camera angle. With reduced motion on, both are scaled down.
dist_center = √(x² + z²)
wave_height = 2.8 · (½ + ½·sin(0.3·dist_center − 1.8·time)) · amplitude
pointer_dist = |brick_screen_pos − pointer_pos| (aspect_corrected)
bump_height = 4 · e^(−14·pointer_dist²) · amplitude
anim_height = wave_height + bump_height
amplitude = 1 (0.35 with prefers-reduced-motion)
Sources: [4]
4
The drop and the bounce
In Pyramid and Helix, each brick starts after a small random delay, plus a little more per layer, so the build rains down bottom-up. It falls along a parabola, then bounces with a decaying sine.
drop_time = 1.4·(time − drop_start) − 1.4·rand − 0.16·layer rand ∈ [0, 1) per brick
fall = clamp(1 − drop_time, 0, 1)
bounce_time = max(drop_time − 1, 0)
anim_height = 36·fall² + 0.9·|sin(9·bounce_time)|·e^(−6·bounce_time)
drop_time < 0 → brick not drawn yet
Sources: [4]
5
Light, shine and haze
Lighting runs per pixel: Lambert diffuse for the matte plastic, a hemisphere term so tops are brighter than sides, a Blinn–Phong highlight for the toy shine, and distance fog toward the sky color.
color = albedo · (0.34 + 0.24·(½ + ½·normal_y) + 0.6·max(normal·light_dir, 0))
+ 0.22 · max(normal·half_vec, 0)^36
light_dir = normalize(0.45, 0.85, 0.32)
half_vec = normalize(light_dir + (0, 0.5, 0.85)) (fixed view direction)
fog_amount = clamp((clip_w − fog_start) / (1.4·fog_start), 0, 1)
fog_start = 0.95 · camera_dist
final_color = mix(color, sky_color, 0.8 · fog_amount)
Sources: [5]
[6]
6
Camera and frame loop
The camera orbits on a sphere around the scene, turning slowly on its own until you drag. Each frame is scheduled with requestAnimationFrame, and an IntersectionObserver pauses the loop when the demo is off screen.
eye_pos = target + camera_dist · (sin(cam_yaw)·cos(cam_pitch), sin(cam_pitch), cos(cam_yaw)·cos(cam_pitch))
cam_yaw += 0.07 rad/s (auto_orbit)
cam_pitch ∈ [0.15, 1.35] rad
fps = frame_count / elapsed_sec (updated every 0.5 s)
Sources: [3]
[7]