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>
Three things the first Vulkan frames on the RTX 3070 Ti showed against OpenGL on the same PC:
- Exposure: the adaptation pass reads the HDR scene's smallest mip, and a render target made
without pixels had one level, so exposure came from a single texel. A target asked for mipmaps
now grows a full chain (level 0 kept), and passes draw through level-0 views keyed by the
image's generation.
- Foliage: the depth prepass and the lit pass (depth EQUAL) are different variants. Vulkan vertex
stages now declare an invariant gl_Position so both land on the same depth.
- Alpha to coverage is enabled only on a multisampled pass. OpenGL ignores it without MSAA; Vulkan
with one sample dropped every fragment under half alpha.
vk_resources also checks a big-endian 16-bit RGB upload (a normal map). VKRES OK; ludic-dev test
140 passed; the PC's Vulkan frame is validation-clean; OpenGL frames byte-identical at the five
viewpoints with 59 self-tests passing.
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>
