From 12d5d5f1762a0c00405950b6ff5e564880f0ff36 Mon Sep 17 00:00:00 2001 From: skal Date: Sun, 22 Mar 2026 23:51:40 +0100 Subject: refactor(cnn_v3): simplify sphere SDF in shadow pass, remove per-frame alloc MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit gbuf_shadow.wgsl — dfWithID(): - Sphere: replace inv_model local-space transform with direct world-space formula (length(p - center) - radius). Exact, no matrix multiply, no floating-point error from matrix inversion that can corrupt soft-shadow penumbra over 64 march steps. - lp/scale now computed only inside the cases that need them (box/torus/plane) instead of eagerly for every object. gbuffer_effect.cc — upload_scene_data(): - Replace per-frame std::vector heap allocation with a file-static staging buffer s_obj_staging[256]: zero alloc per frame. handoff(Gemini): sphere SDF now exact; shadow march should be cleaner. --- cnn_v3/shaders/gbuf_shadow.wgsl | 34 ++++++++++++++++++++++++++-------- 1 file changed, 26 insertions(+), 8 deletions(-) (limited to 'cnn_v3/shaders') diff --git a/cnn_v3/shaders/gbuf_shadow.wgsl b/cnn_v3/shaders/gbuf_shadow.wgsl index 735e47c..6c81d66 100644 --- a/cnn_v3/shaders/gbuf_shadow.wgsl +++ b/cnn_v3/shaders/gbuf_shadow.wgsl @@ -28,7 +28,9 @@ struct GBufLightsUniforms { // Stub required by render/raymarching (shadow() / rayMarch() call df()). fn df(p: vec3f) -> f32 { return MAX_RAY_LENGTH; } -// SDF of the full scene: proxy box for each object transformed to local space. +// SDF of the full scene. +// Sphere: direct world-space formula (exact, no matrix multiply). +// Box/Torus/Plane: local-space transform + uniform-scale correction. fn dfWithID(p: vec3f) -> RayMarchResult { var res: RayMarchResult; res.distance = MAX_RAY_LENGTH; @@ -38,16 +40,32 @@ fn dfWithID(p: vec3f) -> RayMarchResult { let n = u32(globals.params.x); for (var i = 0u; i < n; i++) { let obj = object_data.objects[i]; - let lp = (obj.inv_model * vec4f(p, 1.0)).xyz; let obj_type = u32(obj.params.x); - // Scale factor: convert local-space SDF to world-space distance. - let scale = length(obj.model[0].xyz); var d: f32; switch obj_type { - case 1u: { d = sdSphere(lp, 1.0) * scale; } // SPHERE - case 2u: { d = sdPlane(lp, vec3f(0.0, 1.0, 0.0), obj.params.y); } // PLANE - case 3u: { d = sdTorus(lp, vec2f(0.8, 0.2)) * scale; } // TORUS - default: { d = sdBox(lp, vec3f(1.0)) * scale; } // CUBE (0) + fallback + case 1u: { + // SPHERE: direct world-space SDF — avoids matrix multiply, exact. + let c = obj.model[3].xyz; + let r = length(obj.model[0].xyz); + d = length(p - c) - r; + } + case 2u: { + // PLANE + let lp = (obj.inv_model * vec4f(p, 1.0)).xyz; + d = sdPlane(lp, vec3f(0.0, 1.0, 0.0), obj.params.y); + } + case 3u: { + // TORUS + let lp = (obj.inv_model * vec4f(p, 1.0)).xyz; + let scale = length(obj.model[0].xyz); + d = sdTorus(lp, vec2f(0.8, 0.2)) * scale; + } + default: { + // CUBE (0) + fallback — uniform scale assumed. + let lp = (obj.inv_model * vec4f(p, 1.0)).xyz; + let scale = length(obj.model[0].xyz); + d = sdBox(lp, vec3f(1.0)) * scale; + } } if (d < res.distance) { res.distance = d; -- cgit v1.2.3