The user saw kit grass, ferns and flowers lit up at night. Nothing was
emissive and every layer draw binds the scene's lighting; what differed was
occlusion. At night the sky's light is nearly all the light, and it is
scaled by ambient occlusion: the meadow's blades are heavily occluded near
the ground, while a kit plant's own AO map knows nothing of the grass around
it, so it took the full sky. By day the sun hides the difference.
model.vert hands on each vertex's height above the model's base (v_lh), and
a non-blade FOLIAGE plant under 2 m scales its AO from 0.35 at the ground to
1 at 0.9 m. Crowns and the blades are untouched.
Measured in the lab (R3D_AT=tree, same binary, old and new SPIR-V): the fern
against the meadow beside it was 2.05x at 23:00 and 1.66x at 13:00; now 1.58x
and 1.60x - the same relation by night as by day. The flowers' brightest
tenth at night 78 -> 52. The noon frame moves 8.4% of pixels past 8 (the fern
and flower bases a little darker; run-to-run noise is part of that).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The user's play found the aspens' branches swinging like rope. Three terms:
- the whole-tree bend reached 22% of the tree's height at a gust's top (three
metres on a 14 m aspen); 4.5% now, and the side-to-side part at a quarter of
that and slower;
- a branch term: nothing within 0.35 m of the trunk, growing with the distance
out, phased by the direction the branch leaves the trunk (constant along a
branch, so it moves as one piece and its neighbours are out of step);
- the aspen's leaf flutter took its phase from each vertex at eleven radians a
metre, which bent every twig along its length; about three now, and half the
amplitude.
Measured on the lab's `aspen` view (10-frame bursts, crowns only, same binary
with the old and new SPIR-V): pixels moving more than 8 over ten frames 16.8%
-> 9.7%, frame to frame 4.4% -> 2.1%. SPIR-V rebuilt with `ludic-dev shaders`
(vertex stages only; the manifest is unchanged).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A slice has carried { ptr, len, cap } since it existed and nothing ever read
the len: every index emitted a bare getelementptr. Running off the end of one
wrote into whatever the allocator had put next, and the program died somewhere
else entirely - a maroon-lake crash took a day to find because the stack named
a texture upload and the write was in a telemetry buffer five frames earlier.
Now each index loads the length and compares unsigned, which rejects a negative
index in the same instruction, and a failure aborts with the location the other
located errors use:
oob.ludic:9: index out of range: 7, len 3
`words` and the other raw buffers are unchanged - they are a bare malloc with no
length to check, which is the argument for moving off them.
The SPIR-V variants are regenerated in the same commit: shaders --check was
failing against the edited GLSL.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
layer_flutter(l, v) gives a scatter layer a per-leaf tremble. The vertex stage offsets
each leaf by a phase taken from its own place on the card, so neighbouring leaves are
never in step, and writes the result out as a varying the fragment stage uses to flash
the leaf's pale underside as it turns - which is the part that reads, since a still
frame of a tremble is a still frame of nothing. One uniform, one varying, no extra pass.
And the sway itself was measured in METRES: hgt * hgt * 0.35 is right for a 40 cm
flower and puts ten metres of sideways into a 14 m trunk, so every tall tree in the
valley stood bent over like a fishing rod. It is a fraction of the model's own height
now - the tip moves a few per cent of the tree whatever the tree is, and the base does
not move at all.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The grass had a gust built from two sines; the trees had no gust term AT ALL, only a
per-instance wobble. So the meadow rippled and the canopy above it swayed to an unrelated
rhythm, and nothing ever crossed the valley.
wind.glsl is prepended to every stage (programs.ludic, and shaders.ludic for the SPIR-V
build) so grass, crowns and water read the same field at the same world position. It
declares no uniforms on purpose: u_time and u_wind already exist in several of those
files and redeclaring them is a compile error in whichever stage includes both.
The wavelength is what made it work. At 0.030 the front was 209 m crest to crest -
longer than the meadow you can see - so the whole frame sat in one phase and the gust
read as everything breathing together. At 0.085 it is 74 m and a front crosses a view in
a couple of seconds.
R3D_DEBUG_WIND=1 paints the field on the ground. It is the only honest way to show a gust
in a still image, and two shots 0.3 s apart move by 39/255.
400 frames: GL 6.9 s, VK 7.2 s. Backends agree to 0.68/255.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The renderer's projections are OpenGL's, whose clip-space depth runs from -w to w; Vulkan clips
everything below 0. `ludic-dev shaders` now wraps each vertex stage - its own main runs, then
gl_Position.z = (z + w) / 2 - so every variant's depth lands in [0, w]. The GLSL the OpenGL
renderer compiles is untouched. No y flip is needed: a Vulkan target's row 0 is where OpenGL's is
(NDC y = -1), so render to texture, sampling and gl_FragCoord agree between the two, and only the
present and the screenshot flip.
45 vertex modules regenerated (spirv-val clean, manifest unchanged); ludic-dev test 140 passed.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Vulkan cannot compile GLSL when the game starts, so the programs render3d builds are listed
(shaders/variants.list, 45 of them, collected with R3D_PROGRAMS_LOG across the self-tests, the
screens, the viewpoints and the debug switches) and `ludic-dev shaders` compiles each into
shaders/spv/<id>.vert.spv and .frag.spv with a manifest of what the backend needs: each
stage's uniform block and member offsets, the samplers' bindings, the vertex inputs.
The GLSL is the renderer's own, assembled as programs.ludic assembles it, through glslang's
relaxed Vulkan mode, so gpu_uniform / u_* can write the same uniforms into a block on Vulkan.
Bindings are assigned by the tool (glslang's own numbering put several samplers of one stage
on binding 0): the vertex block is 0, the fragment block 1, samplers from 2 in name order,
shared across both stages. Every stage passes spirv-val; `ludic-dev test` rebuilds and compares
wherever the Vulkan SDK is installed.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
