MeshPackToVkGeometryKHR()

VulkanRayTracing::BlasInput Spices::MeshPack::MeshPackToVkGeometryKHR ( )

inherited

Convert MeshPack into the ray tracing geometry used to build the BLAS.

Returns

Returns VulkanRayTracing::BlasInput.

BLAS builder requires raw device addresses.

device pointer to the buffers holding triangle vertex/index data, along with information for interpreting it as an array (stride, data type, etc.)

wrapper around the above with the geometry type enum (triangles in this case) plus flags for the AS builder.

the indices within the vertex arrays to source input geometry for the BLAS.

Our blas is made from only one geometry, but could be made of many geometries.

BLAS builder requires raw device addresses.

device pointer to the buffers holding triangle vertex/index data, along with information for interpreting it as an array (stride, data type, etc.)

wrapper around the above with the geometry type enum (triangles in this case) plus flags for the AS builder.

the indices within the vertex arrays to source input geometry for the BLAS.

Our blas is made from only one geometry, but could be made of many geometries.

Definition at line 195 of file MeshPack.cpp.

    {
        SPICES_PROFILE_ZONE;
 
        const VkDeviceAddress vertexAddress          = m_MeshResource.positions.buffer->GetAddress();
        const VkDeviceAddress indicesAddress         = m_MeshResource.primitivePoints.buffer->GetAddress();
 
        const Lod& lod0                              = (*m_MeshResource.lods.attributes)[0];
        const uint32_t maxPrimitiveCount             = lod0.nPrimitives;
 
        VkAccelerationStructureGeometryTrianglesDataKHR triangles {};
        triangles.sType                              = VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_GEOMETRY_TRIANGLES_DATA_KHR;
        triangles.vertexFormat                       = VK_FORMAT_R32G32B32_SFLOAT;  // vec3 vertex position data.
        triangles.vertexData.deviceAddress           = vertexAddress;               /* @note position needs to be the first attribute of Vertex, otherwise correct offset is needs to be added here. */
        triangles.vertexStride                       = sizeof(glm::vec3);
        triangles.indexType                          = VK_INDEX_TYPE_UINT32;
        triangles.indexData.deviceAddress            = indicesAddress;
      //triangles.transformData = {};
        triangles.maxVertex                          = static_cast<uint32_t>(m_MeshResource.primitivePoints.buffer->GetSize() / sizeof(glm::uvec3) * 3 - 1);
 
        VkAccelerationStructureGeometryKHR             asGeom {};
        asGeom.sType                                 = VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_GEOMETRY_KHR;
        asGeom.geometryType                          = VK_GEOMETRY_TYPE_TRIANGLES_KHR;
        asGeom.flags                                 = VK_GEOMETRY_OPAQUE_BIT_KHR;
        asGeom.geometry.triangles                    = triangles;
 
        VkAccelerationStructureBuildRangeInfoKHR       offset {};
        offset.firstVertex                           = 0;
        offset.primitiveCount                        = maxPrimitiveCount;
        offset.primitiveOffset                       = lod0.primVertexOffset;
        offset.transformOffset                       = 0;
 
        VulkanRayTracing::BlasInput input;
        input.asGeometry.emplace_back(asGeom);
        input.asBuildOffsetInfo.emplace_back(offset);
        input.accel = &m_Accel;
 
        return input;
    }

References Spices::Lod::nPrimitives.