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diff --git a/indra/newview/gltf/primitive.cpp b/indra/newview/gltf/primitive.cpp
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+++ b/indra/newview/gltf/primitive.cpp
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+/**
+ * @file primitive.cpp
+ * @brief LL GLTF Implementation
+ *
+ * $LicenseInfo:firstyear=2024&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2024, Linden Research, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only. 
+ *
+ * This library 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 GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+
+#include "../llviewerprecompiledheaders.h"
+
+#include "asset.h"
+#include "buffer_util.h"
+
+#include "../lltinygltfhelper.h"
+
+using namespace LL::GLTF;
+
+void Primitive::allocateGLResources(Asset& asset)
+{
+    // allocate vertex buffer
+    // We diverge from the intent of the GLTF format here to work with our existing render pipeline
+    // GLTF wants us to copy the buffer views into GPU storage as is and build render commands that source that data.
+    // For our engine, though, it's better to rearrange the buffers at load time into a layout that's more consistent.
+    // The GLTF native approach undoubtedly works well if you can count on VAOs, but VAOs perform much worse with our scenes.
+
+    // load vertex data
+    for (auto& it : mAttributes)
+    {
+        const std::string& attribName = it.first;
+        Accessor& accessor = asset.mAccessors[it.second];
+
+        // load vertex data
+        if (attribName == "POSITION")
+        {
+            copy(asset, accessor, mPositions);
+        }
+        else if (attribName == "NORMAL")
+        {
+            copy(asset, accessor, mNormals);
+        }
+        else if (attribName == "TANGENT")
+        {
+            copy(asset, accessor, mTangents);
+        }
+        else if (attribName == "COLOR_0")
+        {
+            copy(asset, accessor, mColors);
+        }
+        else if (attribName == "TEXCOORD_0")
+        {
+            copy(asset, accessor, mTexCoords);
+        }
+        else if (attribName == "JOINTS_0")
+        {
+            copy(asset, accessor, mJoints);
+        }
+        else if (attribName == "WEIGHTS_0")
+        {
+            copy(asset, accessor, mWeights);
+        }
+    }
+
+    // copy index buffer
+    if (mIndices != INVALID_INDEX)
+    {
+        Accessor& accessor = asset.mAccessors[mIndices];
+        copy(asset, accessor, mIndexArray);
+    }
+
+    U32 mask = ATTRIBUTE_MASK;
+    
+    if (!mWeights.empty())
+    {
+        mask |= LLVertexBuffer::MAP_WEIGHT4;
+    }
+
+    mVertexBuffer = new LLVertexBuffer(mask);
+    mVertexBuffer->allocateBuffer(mPositions.size(), mIndexArray.size()*2); // double the size of the index buffer for 32-bit indices
+
+    mVertexBuffer->setBuffer();
+    mVertexBuffer->setPositionData(mPositions.data());
+
+    if (!mIndexArray.empty())
+    {
+        mVertexBuffer->setIndexData(mIndexArray.data());
+    }
+
+    if (mTexCoords.empty())
+    {
+        mTexCoords.resize(mPositions.size());
+    }
+
+    // flip texcoord y, upload, then flip back (keep the off-spec data in vram only)
+    for (auto& tc : mTexCoords)
+    {
+        tc[1] = 1.f - tc[1];
+    }
+    mVertexBuffer->setTexCoordData(mTexCoords.data());
+
+    for (auto& tc : mTexCoords)
+    {
+        tc[1] = 1.f - tc[1];
+    }
+
+    if (mColors.empty())
+    {
+        mColors.resize(mPositions.size(), LLColor4U::white);
+    }
+    
+    // bake material basecolor into color array
+    if (mMaterial != INVALID_INDEX)
+    {
+        const Material& material = asset.mMaterials[mMaterial];
+        LLColor4 baseColor = material.mMaterial->mBaseColor;
+        for (auto& dst : mColors)
+        {
+            dst = LLColor4U(baseColor * LLColor4(dst));
+        }
+    }
+
+    mVertexBuffer->setColorData(mColors.data());
+
+    if (mNormals.empty())
+    {
+        mNormals.resize(mPositions.size(), LLVector4a(0, 0, 1, 0));
+    }
+    
+    mVertexBuffer->setNormalData(mNormals.data());
+
+    if (mTangents.empty())
+    {
+        // TODO: generate tangents if needed
+        mTangents.resize(mPositions.size(), LLVector4a(1, 0, 0, 1));
+    }
+
+    mVertexBuffer->setTangentData(mTangents.data());
+
+    if (!mWeights.empty())
+    {
+        std::vector<LLVector4a> weight_data;
+        weight_data.resize(mWeights.size());
+
+        F32 max_weight = 1.f - FLT_EPSILON*100.f;
+        LLVector4a maxw(max_weight, max_weight, max_weight, max_weight);
+        for (U32 i = 0; i < mWeights.size(); ++i)
+        {
+            LLVector4a& w = weight_data[i];
+            w.setMin(mWeights[i], maxw);
+            w.add(mJoints[i]);
+        };
+
+        mVertexBuffer->setWeight4Data(weight_data.data());
+    }
+    
+    createOctree();
+    
+    mVertexBuffer->unbind();
+}
+
+void initOctreeTriangle(LLVolumeTriangle* tri, F32 scaler, S32 i0, S32 i1, S32 i2, const LLVector4a& v0, const LLVector4a& v1, const LLVector4a& v2)
+{
+    //store pointers to vertex data
+    tri->mV[0] = &v0;
+    tri->mV[1] = &v1;
+    tri->mV[2] = &v2;
+
+    //store indices
+    tri->mIndex[0] = i0;
+    tri->mIndex[1] = i1;
+    tri->mIndex[2] = i2;
+
+    //get minimum point
+    LLVector4a min = v0;
+    min.setMin(min, v1);
+    min.setMin(min, v2);
+
+    //get maximum point
+    LLVector4a max = v0;
+    max.setMax(max, v1);
+    max.setMax(max, v2);
+
+    //compute center
+    LLVector4a center;
+    center.setAdd(min, max);
+    center.mul(0.5f);
+
+    tri->mPositionGroup = center;
+
+    //compute "radius"
+    LLVector4a size;
+    size.setSub(max, min);
+
+    tri->mRadius = size.getLength3().getF32() * scaler;
+}
+
+void Primitive::createOctree()
+{
+    // create octree
+    mOctree = new LLVolumeOctree();
+
+    F32 scaler = 0.25f;
+
+    if (mMode == TINYGLTF_MODE_TRIANGLES)
+    {
+        const U32 num_triangles = mVertexBuffer->getNumIndices() / 3;
+        // Initialize all the triangles we need
+        mOctreeTriangles.resize(num_triangles);
+
+        for (U32 triangle_index = 0; triangle_index < num_triangles; ++triangle_index)
+        { //for each triangle
+            const U32 index = triangle_index * 3;
+            LLVolumeTriangle* tri = &mOctreeTriangles[triangle_index];
+            S32 i0 = mIndexArray[index];
+            S32 i1 = mIndexArray[index + 1];
+            S32 i2 = mIndexArray[index + 2];
+
+            const LLVector4a& v0 = mPositions[i0];
+            const LLVector4a& v1 = mPositions[i1];
+            const LLVector4a& v2 = mPositions[i2];
+            
+            initOctreeTriangle(tri, scaler, i0, i1, i2, v0, v1, v2);
+            
+            //insert
+            mOctree->insert(tri);
+        }
+    }
+    else if (mMode == TINYGLTF_MODE_TRIANGLE_STRIP)
+    {
+        const U32 num_triangles = mVertexBuffer->getNumIndices() - 2;
+        // Initialize all the triangles we need
+        mOctreeTriangles.resize(num_triangles);
+
+        for (U32 triangle_index = 0; triangle_index < num_triangles; ++triangle_index)
+        { //for each triangle
+            const U32 index = triangle_index + 2;
+            LLVolumeTriangle* tri = &mOctreeTriangles[triangle_index];
+            S32 i0 = mIndexArray[index];
+            S32 i1 = mIndexArray[index - 1];
+            S32 i2 = mIndexArray[index - 2];
+
+            const LLVector4a& v0 = mPositions[i0];
+            const LLVector4a& v1 = mPositions[i1];
+            const LLVector4a& v2 = mPositions[i2];
+
+            initOctreeTriangle(tri, scaler, i0, i1, i2, v0, v1, v2);
+
+            //insert
+            mOctree->insert(tri);
+        }
+    }
+    else if (mMode == TINYGLTF_MODE_TRIANGLE_FAN)
+    {
+        const U32 num_triangles = mVertexBuffer->getNumIndices() - 2;
+        // Initialize all the triangles we need
+        mOctreeTriangles.resize(num_triangles);
+
+        for (U32 triangle_index = 0; triangle_index < num_triangles; ++triangle_index)
+        { //for each triangle
+            const U32 index = triangle_index + 2;
+            LLVolumeTriangle* tri = &mOctreeTriangles[triangle_index];
+            S32 i0 = mIndexArray[0];
+            S32 i1 = mIndexArray[index - 1];
+            S32 i2 = mIndexArray[index - 2];
+
+            const LLVector4a& v0 = mPositions[i0];
+            const LLVector4a& v1 = mPositions[i1];
+            const LLVector4a& v2 = mPositions[i2];
+
+            initOctreeTriangle(tri, scaler, i0, i1, i2, v0, v1, v2);
+
+            //insert
+            mOctree->insert(tri);
+        }
+    }
+    else if (mMode == TINYGLTF_MODE_POINTS ||
+            mMode == TINYGLTF_MODE_LINE ||
+        mMode == TINYGLTF_MODE_LINE_LOOP ||
+        mMode == TINYGLTF_MODE_LINE_STRIP)
+    {
+        // nothing to do, no volume... maybe add some collision geometry around these primitive types?
+    }
+    
+    else
+    {
+        LL_ERRS() << "Unsupported Primitive mode" << LL_ENDL;
+    }
+
+    //remove unneeded octree layers
+    while (!mOctree->balance()) {}
+
+    //calculate AABB for each node
+    LLVolumeOctreeRebound rebound;
+    rebound.traverse(mOctree);
+}
+
+const LLVolumeTriangle* Primitive::lineSegmentIntersect(const LLVector4a& start, const LLVector4a& end,
+    LLVector4a* intersection, LLVector2* tex_coord, LLVector4a* normal, LLVector4a* tangent_out)
+{
+    if (mOctree.isNull())
+    {
+        return nullptr;
+    }
+
+    LLVector4a dir;
+    dir.setSub(end, start);
+
+    F32 closest_t = 2.f; // must be larger than 1
+
+    //create a proxy LLVolumeFace for the raycast
+    LLVolumeFace face;
+    face.mPositions = mPositions.data();
+    face.mTexCoords = mTexCoords.data();
+    face.mNormals = mNormals.data();
+    face.mTangents = mTangents.data();
+    face.mIndices = nullptr; // unreferenced
+
+    face.mNumIndices = mIndexArray.size();
+    face.mNumVertices = mPositions.size();
+
+    LLOctreeTriangleRayIntersect intersect(start, dir, &face, &closest_t, intersection, tex_coord, normal, tangent_out);
+    intersect.traverse(mOctree);
+
+    // null out proxy data so it doesn't get freed
+    face.mPositions = face.mNormals = face.mTangents = nullptr;
+    face.mIndices = nullptr;
+    face.mTexCoords = nullptr;
+
+    return intersect.mHitTriangle;
+}
+
+Primitive::~Primitive()
+{
+    mOctree = nullptr;
+}
+
+
+const Primitive& Primitive::operator=(const tinygltf::Primitive& src)
+{
+    // load material
+    mMaterial = src.material;
+
+    // load mode
+    mMode = src.mode;
+
+    // load indices
+    mIndices = src.indices;
+
+    // load attributes
+    for (auto& it : src.attributes)
+    {
+        mAttributes[it.first] = it.second;
+    }
+
+    switch (mMode)
+    {
+    case TINYGLTF_MODE_POINTS:
+        mGLMode = LLRender::POINTS;
+        break;
+    case TINYGLTF_MODE_LINE:
+        mGLMode = LLRender::LINES;
+        break;
+    case TINYGLTF_MODE_LINE_LOOP:
+        mGLMode = LLRender::LINE_LOOP;
+        break;
+    case TINYGLTF_MODE_LINE_STRIP:
+        mGLMode = LLRender::LINE_STRIP;
+        break;
+    case TINYGLTF_MODE_TRIANGLES:
+        mGLMode = LLRender::TRIANGLES;
+        break;
+    case TINYGLTF_MODE_TRIANGLE_STRIP:
+        mGLMode = LLRender::TRIANGLE_STRIP;
+        break;
+    case TINYGLTF_MODE_TRIANGLE_FAN:
+        mGLMode = LLRender::TRIANGLE_FAN;
+        break;
+    default:
+        mGLMode = GL_TRIANGLES;
+    }
+
+    return *this;
+}