Basic Example for Metal
The following walkthrough is a basic example for the Metal backend.
CHECK_RR_CALL is a macro asserting RadeonRays calls finished with RR_SUCCESS.
void Build2LvlScene()
{
auto device = ChooseDevice();
auto cmd_queue = [device newCommandQueue];
Create a library context.
RRContext context = nullptr; CHECK_RR_CALL(rrCreateContextMTL(RR_API_VERSION, device, cmd_queue, &context));
Load shapes from a file.
MeshData mesh_data("example.obj");
Load indices and vertices to MTL buffers.
size_t vertex_size = sizeof(float) * mesh_data.positions.size(); size_t indices_size = sizeof(uint32_t) * mesh_data.indices.size(); id<MTLBuffer> indices_buf = [device newBufferWithLength:indices_size options:MTLResourceStorageModeManaged]; memcpy(indices_buf.contents, mesh_data.indices.data(), indices_buf.length); id<MTLBuffer> vertices_buf = [device newBufferWithLength:vertex_size options:MTLResourceStorageModeManaged]; memcpy(vertices_buf.contents, mesh_data.positions.data(), vertices_buf.length);
Update buffers and get a RadeonRays device pointer wrapper to use it in the library.
[indices_buf didModifyRange:NSMakeRange(0, indices_buf.length)]; [vertices_buf didModifyRange:NSMakeRange(0, vertices_buf.length)]; RRDevicePtr vertex_ptr = nullptr; RRDevicePtr index_ptr = nullptr; CHECK_RR_CALL(rrGetDevicePtrFromMTLResource(context, vertices_buf, 0, &vertex_ptr)); CHECK_RR_CALL(rrGetDevicePtrFromMTLResource(context, indices_buf, 0, &index_ptr));
Set geometry build info.
RRGeometryBuildInput geometry_build_input = {}; RRTriangleMeshPrimitive mesh = {}; geometry_build_input.triangle_mesh_primitives = &mesh; geometry_build_input.primitive_type = RR_PRIMITIVE_TYPE_TRIANGLE_MESH; geometry_build_input.triangle_mesh_primitives->vertices = vertex_ptr; geometry_build_input.triangle_mesh_primitives->vertex_count = mesh_data.positions.size() / 3; geometry_build_input.triangle_mesh_primitives->vertex_stride = 3 * sizeof(float); geometry_build_input.triangle_mesh_primitives->triangle_indices = index_ptr; geometry_build_input.triangle_mesh_primitives->triangle_count = mesh_data.indices.size() / 3; geometry_build_input.triangle_mesh_primitives->index_type = RR_INDEX_TYPE_UINT32; geometry_build_input.primitive_count = 1;
Create Metal performance shaders specific for a group acceleration structure to combine geometries and scenes.
RRDevicePtr group_ptr = nullptr; CHECK_RR_CALL(rrCreateGroupMPS(context, &group_ptr));
Group goes to backend-specific info.
RRBuildOptions options; options.build_flags = RR_BUILD_FLAG_BITS_ALLOW_UPDATE; options.backend_specific_info = group_ptr; RRDevicePtr geometry_ptr = nullptr; CHECK_RR_CALL(rrGetDevicePtrFromMTLResource(context, nullptr, 0, &geometry_ptr));
Create a command stream to build an acceleration structure.
RRCommandStream build_geom_command_stream = nullptr; CHECK_RR_CALL(rrAllocateCommandStream(context, &build_geom_command_stream));
Register a build command.
CHECK_RR_CALL(rrCmdBuildGeometry( context, RR_BUILD_OPERATION_BUILD, &geometry_build_input, &options, nullptr, geometry_ptr, build_geom_command_stream)); RREvent wait_event = nullptr; CHECK_RR_CALL(rrSumbitCommandStream(context, build_geom_command_stream, nullptr, &wait_event));
Wait until completed.
CHECK_RR_CALL(rrWaitEvent(context, wait_event)); CHECK_RR_CALL(rrReleaseEvent(context, wait_event)); CHECK_RR_CALL(rrReleaseCommandStream(context, build_geom_command_stream));
Allocate another command stream to build a 2 level acceleration structure.
RRCommandStream build_scene_command_stream = nullptr; CHECK_RR_CALL(rrAllocateCommandStream(context, &build_scene_command_stream)); RREvent wait_scene_event = nullptr; RRDevicePtr scene_ptr = nullptr; CHECK_RR_CALL(rrGetDevicePtrFromMTLResource(context, nullptr, 0, &scene_ptr));
It is a simple example so we are using just one instance and unit transform.
RRInstance instance = {geometry_ptr, {1.f, 0.f, 0.f, 0.f, 0.f, 1.f, 0.f, 0.f, 0.f, 0.f, 1.f, 0.f}}; RRSceneBuildInput scene_build_input = {&instance, 1};
Register a build command in the command stream.
CHECK_RR_CALL(rrCmdBuildScene( context, &scene_build_input, &options, nullptr, scene_ptr, build_scene_command_stream)); CHECK_RR_CALL(rrSumbitCommandStream(context, build_scene_command_stream, nullptr, &wait_scene_event));
Wait until completed.
CHECK_RR_CALL(rrWaitEvent(context, wait_scene_event)); CHECK_RR_CALL(rrReleaseEvent(context, wait_scene_event)); CHECK_RR_CALL(rrReleaseCommandStream(context, build_scene_command_stream));
Now we can trace.
using Ray = MPSRayOriginMinDistanceDirectionMaxDistance; using Hit = MPSIntersectionDistancePrimitiveIndexInstanceIndexCoordinates; RRCommandStream trace_command_stream = nullptr; CHECK_RR_CALL(rrAllocateCommandStream(context, &trace_command_stream)); constexpr uint32_t kResolution = 640;
Generate rays.
std::vector<Ray> rays(kResolution * kResolution); std::vector<Hit> hits(kResolution * kResolution); for (int x = 0; x < kResolution; ++x) { for (int y = 0; y < kResolution; ++y) { auto i = kResolution * y + x; rays[i].origin[0] = 0.f; rays[i].origin[1] = 15.f; rays[i].origin[2] = 0.f; rays[i].direction[0] = -1.f; rays[i].direction[1] = -1.f + (2.f / kResolution) * y; rays[i].direction[2] = -1.f + (2.f / kResolution) * x; rays[i].minDistance = 0.001f; rays[i].maxDistance = 100000.f; hits[i].distance = 1.0f; } } size_t rays_size = sizeof(Ray) * rays.size(); size_t hits_size = sizeof(Hit) * hits.size();
Create MTL buffers for trace.
id<MTLBuffer> rays_buf = [device newBufferWithLength:rays_size options:MTLResourceStorageModeManaged]; memcpy(rays_buf.contents, rays.data(), rays_buf.length); [rays_buf didModifyRange:NSMakeRange(0, rays_buf.length)]; id<MTLBuffer> hits_buf = [device newBufferWithLength:hits_size options:MTLResourceStorageModeShared]; RRDevicePtr rays_ptr = nullptr; RRDevicePtr hits_ptr = nullptr; CHECK_RR_CALL(rrGetDevicePtrFromMTLResource(context, rays_buf, 0, &rays_ptr)); CHECK_RR_CALL(rrGetDevicePtrFromMTLResource(context, hits_buf, 0, &hits_ptr));
Encode trace command.
CHECK_RR_CALL(rrCmdIntersect(context, scene_ptr, RR_INTERSECT_QUERY_CLOSEST, rays_ptr, kResolution * kResolution, nullptr, RR_INTERSECT_QUERY_OUTPUT_FULL_HIT, hits_ptr, trace_command_stream)); RREvent trace_wait_event = nullptr; CHECK_RR_CALL(rrSumbitCommandStream(context, trace_command_stream, nullptr, &trace_wait_event)); CHECK_RR_CALL(rrWaitEvent(context, trace_wait_event)); CHECK_RR_CALL(rrReleaseEvent(context, trace_wait_event)); CHECK_RR_CALL(rrReleaseCommandStream(context, trace_command_stream));
Update buffer.
memcpy(hits.data(), hits_buf.contents, hits_buf.length); std::vector<uint32_t> data(kResolution * kResolution);
Prepare output.
for (int y = 0; y < kResolution; ++y) { for (int x = 0; x < kResolution; ++x) { int wi = kResolution * (kResolution - 1 - y) + x; int i = kResolution * y + x; if (hits[i].distance >= 0.f) { data[wi] = 0xff000000 | (uint32_t(hits[i].coordinates[0] * 255) << 8) | (uint32_t(hits[i].coordinates[1] * 255) << 16); } else { data[wi] = 0xff101010; } } } stbi_write_jpg("example_mtl_scene.jpg", kResolution, kResolution, 4, data.data(), 120);
Release resources.
CHECK_RR_CALL(rrDestroyContext(context)); }