Orkuncakilkaya
1675eb451f
The first generation pass's R32F height is kept as ter_height_tex (not copied into an RGBA32F), so every reader of the height - placement, the read-back, physics, selftest16's 9 mm - sees the same 32 bits. ternormal.frag writes the baked normal's x and z into ter_normal_tex (RG16F), and the six places that read it (terrain.frag twice, tersun.frag, grass.vert, grass.mesh, grass_cull.comp, which takes a third texture at binding 6) rebuild y. SPIR-V regenerated. Maroon Lake's play, headless Vulkan: 2793 -> 2647 MB. The camp's frame: 0.066% of pixels differ by more than 8 (mean 0.024/255), isolated grass blades at the slope gate. ludic-dev test 307/307. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
34 lines
1.9 KiB
GLSL
34 lines
1.9 KiB
GLSL
// tersun.frag — the terrain's sun visibility, on its own, one screen-sized R8 buffer.
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//
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// The ground's shading shader is large: it blends four scanned materials, a photograph
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// and a dozen noise fields. Adding a read of the cascade shadow map to it costs about
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// six milliseconds a frame on this driver — and costs the same whether the map is tapped
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// once or eight times, filtered or texelFetched, compared in hardware or by hand. It is
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// a cliff the big shader falls off, not work it performs. The same read from a small
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// shader is nearly free, so the read happens here instead: this pass rasterises the same
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// CDLOD patches, evaluates the cascades once per pixel, and writes the answer for
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// terrain.frag to look up by fragment coordinate.
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in vec3 v_wpos;
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in vec2 v_huv;
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out float o_sh;
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uniform sampler2D u_height;
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// the baked terrain normal: x and z in RG16F, y rebuilt (a terrain normal always points up)
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uniform sampler2D u_ter_normal;
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vec3 terNormal(vec2 uv) { vec2 xz = texture(u_ter_normal, uv).rg; return vec3(xz.x, sqrt(max(1.0 - dot(xz, xz), 0.0)), xz.y); }
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uniform mat4 u_view;
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uniform float u_far_split;
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uniform float u_far_band;
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void main() {
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vec3 p = v_wpos;
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if (p.y < u_clip_y) discard;
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vec3 N = terNormal(v_huv);
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float dist = length(p - u_cam_pos);
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float viewDepth = -(u_view * vec4(p, 1.0)).z;
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// The same tier choice the ground makes, cross-faded over the same band: the near tier
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// keeps its filtered penumbra, the far tier its single tap, and the boundary between
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// them is not a contour you can find on the hillside.
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if (dist > u_far_split + u_far_band) o_sh = sunShadowCheap(p, N, viewDepth);
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else if (dist < u_far_split - u_far_band) o_sh = sunShadow(p, N, viewDepth);
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else o_sh = mix(sunShadow(p, N, viewDepth), sunShadowCheap(p, N, viewDepth),
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smoothstep(u_far_split - u_far_band, u_far_split + u_far_band, dist));
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}
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