Files
IfcOpenShell/src/ifcviewer/VertexQuantization.h
T
Dion Moult 8b8fafa698 Unify sidecar production via SidecarBuilder
Renamed HeadlessSidecarBuilder to SidecarBuilder and reused it for live
loads. SceneLoader now constructs one per stream load, forwards meshReady
/instanceReady chunks alongside the viewport upload, and finalizes +
writes the sidecar at onStreamerFinished — no more GPU readback path
via ViewportWindow::snapshotModel (removed). Same code path now produces
sidecars for both live loads and the .rdbview offline export.

Sidecar use is opt-in per direction via SceneLoader::setShouldReadSidecar
and setShouldWriteSidecar; both default off so embedders that don't want
caching get a pure-streaming loader. ifcviewer-full and ifcviewer-minimal
opt in.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-25 16:34:18 +10:00

81 lines
3.9 KiB
C++

/********************************************************************************
* *
* This file is part of IfcOpenShell. *
* *
* IfcOpenShell is free software: you can redistribute it and/or modify *
* it under the terms of the Lesser GNU General Public License as published by *
* the Free Software Foundation, either version 3.0 of the License, or *
* (at your option) any later version. *
* *
* IfcOpenShell is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* Lesser GNU General Public License for more details. *
* *
* You should have received a copy of the Lesser GNU General Public License *
* along with this program. If not, see <http://www.gnu.org/licenses/>. *
* *
********************************************************************************/
// Inline helpers that turn streamer-format vertices (7 floats per vertex:
// pos3 + normal3 + color-as-float) into the 12 B quantized VBO layout used
// by both the viewport's GPU buffers and the .ifcview sidecar. Shared
// between ViewportWindow::uploadMeshChunk and SidecarBuilder so the
// on-disk format stays identical to what the viewport renders.
#ifndef VERTEXQUANTIZATION_H
#define VERTEXQUANTIZATION_H
#include "InstancedGeometry.h"
#include <cmath>
#include <cstdint>
#include <cstring>
// Meyer et al. octahedral normal encode. Input unit vector -> [-1,1]^2.
inline void octEncodeNormal(const float n[3], float out[2]) {
float ax = std::fabs(n[0]), ay = std::fabs(n[1]), az = std::fabs(n[2]);
float denom = ax + ay + az;
if (denom < 1e-12f) { out[0] = 0.0f; out[1] = 0.0f; return; }
float px = n[0] / denom;
float py = n[1] / denom;
if (n[2] < 0.0f) {
float sx = px >= 0.0f ? 1.0f : -1.0f;
float sy = py >= 0.0f ? 1.0f : -1.0f;
float nx = (1.0f - std::fabs(py)) * sx;
float ny = (1.0f - std::fabs(px)) * sy;
px = nx; py = ny;
}
out[0] = px;
out[1] = py;
}
// Quantize a streamer-format vertex (pos3 + normal3 + color-as-float) into
// the 12 B VBO record, given the mesh's tight local AABB. `extent_recip`
// is 1/(max-min) per axis, or 0 for degenerate axes.
inline void quantizeVertex(const float src[INSTANCED_VERTEX_STRIDE_FLOATS],
const float aabb_min[3],
const float extent_recip[3],
uint8_t dst[INSTANCED_VERTEX_STRIDE_BYTES]) {
// Position -> u16 normalized.
uint16_t* p = reinterpret_cast<uint16_t*>(dst + INSTANCED_VERTEX_POS_OFFSET);
for (int a = 0; a < 3; ++a) {
float t = (src[a] - aabb_min[a]) * extent_recip[a];
if (t < 0.0f) t = 0.0f; else if (t > 1.0f) t = 1.0f;
p[a] = static_cast<uint16_t>(t * 65535.0f + 0.5f);
}
// Normal -> oct i8x2. int8 gives ~1.4° worst-case error — fine for BIM.
float oct[2];
octEncodeNormal(src + 3, oct);
int8_t* n = reinterpret_cast<int8_t*>(dst + INSTANCED_VERTEX_NORMAL_OFFSET);
for (int a = 0; a < 2; ++a) {
float v = oct[a];
if (v < -1.0f) v = -1.0f; else if (v > 1.0f) v = 1.0f;
n[a] = static_cast<int8_t>(std::lrintf(v * 127.0f));
}
// Color passes through — streamer packs 4 bytes into the 7th float slot.
std::memcpy(dst + INSTANCED_VERTEX_COLOR_OFFSET, src + 6, 4);
}
#endif // VERTEXQUANTIZATION_H