diff options
Diffstat (limited to 'source/blender/gpu/metal/mtl_index_buffer.mm')
| -rw-r--r-- | source/blender/gpu/metal/mtl_index_buffer.mm | 517 |
1 files changed, 517 insertions, 0 deletions
diff --git a/source/blender/gpu/metal/mtl_index_buffer.mm b/source/blender/gpu/metal/mtl_index_buffer.mm new file mode 100644 index 00000000000..9712dce7b40 --- /dev/null +++ b/source/blender/gpu/metal/mtl_index_buffer.mm @@ -0,0 +1,517 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +/** \file + * \ingroup gpu + */ + +#include "mtl_index_buffer.hh" +#include "mtl_context.hh" +#include "mtl_debug.hh" + +#include "BLI_span.hh" + +namespace blender::gpu { + +/* -------------------------------------------------------------------- */ +/** \name Core MTLIndexBuf implementation. + * \{ */ + +MTLIndexBuf::~MTLIndexBuf() +{ + if (ibo_ != nullptr && !this->is_subrange_) { + ibo_->free(); + } + this->free_optimized_buffer(); +} + +void MTLIndexBuf::free_optimized_buffer() +{ + if (optimized_ibo_) { + optimized_ibo_->free(); + optimized_ibo_ = nullptr; + } +} + +void MTLIndexBuf::bind_as_ssbo(uint32_t binding) +{ + /* Flag buffer as incompatible with optimized/patched buffers as contents + * can now have partial modifications from the GPU. */ + this->flag_can_optimize(false); + this->free_optimized_buffer(); + + /* Ensure we have a valid IBO. */ + BLI_assert(this->ibo_); + + /* TODO(Metal): Support index buffer SSBO's. Dependent on compute implementation. */ + MTL_LOG_WARNING("MTLIndexBuf::bind_as_ssbo not yet implemented!\n"); +} + +const uint32_t *MTLIndexBuf::read() const +{ + if (ibo_ != nullptr) { + + /* Return host pointer. */ + void *data = ibo_->get_host_ptr(); + return static_cast<uint32_t *>(data); + } + BLI_assert(false && "Index buffer not ready to be read."); + return nullptr; +} + +void MTLIndexBuf::upload_data() +{ + /* Handle sub-range upload. */ + if (is_subrange_) { + MTLIndexBuf *mtlsrc = static_cast<MTLIndexBuf *>(src_); + mtlsrc->upload_data(); + +#ifndef NDEBUG + BLI_assert_msg(!mtlsrc->point_restarts_stripped_, + "Cannot use sub-range on stripped point buffer."); +#endif + + /* If parent sub-range allocation has changed, + * update our index buffer. */ + if (alloc_size_ != mtlsrc->alloc_size_ || ibo_ != mtlsrc->ibo_) { + + /* Update index buffer and allocation from source. */ + alloc_size_ = mtlsrc->alloc_size_; + ibo_ = mtlsrc->ibo_; + + /* Reset any allocated patched or optimized index buffers. */ + this->free_optimized_buffer(); + } + return; + } + + /* If new data ready, and index buffer already exists, release current. */ + if ((ibo_ != nullptr) && (this->data_ != nullptr)) { + MTL_LOG_INFO("Re-creating index buffer with new data. IndexBuf %p\n", this); + ibo_->free(); + ibo_ = nullptr; + } + + /* Prepare Buffer and Upload Data. */ + if (ibo_ == nullptr && data_ != nullptr) { + alloc_size_ = this->size_get(); + if (alloc_size_ == 0) { + MTL_LOG_WARNING("[Metal] Warning! Trying to allocate index buffer with size=0 bytes\n"); + } + else { + ibo_ = MTLContext::get_global_memory_manager().allocate_with_data(alloc_size_, true, data_); + BLI_assert(ibo_); + ibo_->set_label(@"Index Buffer"); + } + + /* No need to keep copy of data_ in system memory. */ + MEM_SAFE_FREE(data_); + } +} + +void MTLIndexBuf::update_sub(uint32_t start, uint32_t len, const void *data) +{ + BLI_assert(!is_subrange_); + + /* If host-side data still exists, modify and upload as normal */ + if (data_ != nullptr) { + + /* Free index buffer if one exists. */ + if (ibo_ != nullptr && !this->is_subrange_) { + ibo_->free(); + ibo_ = nullptr; + } + + BLI_assert(start + len < this->size_get()); + + /* Apply start byte offset to data pointer. */ + void *modified_base_ptr = data_; + uint8_t *ptr = static_cast<uint8_t *>(modified_base_ptr); + ptr += start; + modified_base_ptr = static_cast<void *>(ptr); + + /* Modify host-side data. */ + memcpy(modified_base_ptr, data, len); + return; + } + + /* Verify buffer. */ + BLI_assert(ibo_ != nullptr); + + /* Otherwise, we will inject a data update, using staged data, into the command stream. + * Stage update contents in temporary buffer. */ + MTLContext *ctx = static_cast<MTLContext *>(unwrap(GPU_context_active_get())); + BLI_assert(ctx); + MTLTemporaryBuffer range = ctx->get_scratchbuffer_manager().scratch_buffer_allocate_range(len); + memcpy(range.data, data, len); + + /* Copy updated contents into primary buffer. + * These changes need to be uploaded via blit to ensure the data copies happen in-order. */ + id<MTLBuffer> dest_buffer = ibo_->get_metal_buffer(); + BLI_assert(dest_buffer != nil); + + id<MTLBlitCommandEncoder> enc = ctx->main_command_buffer.ensure_begin_blit_encoder(); + [enc copyFromBuffer:range.metal_buffer + sourceOffset:(uint32_t)range.buffer_offset + toBuffer:dest_buffer + destinationOffset:start + size:len]; + + /* Synchronize changes back to host to ensure CPU-side data is up-to-date for non + * Shared buffers. */ + if (dest_buffer.storageMode == MTLStorageModeManaged) { + [enc synchronizeResource:dest_buffer]; + } + + /* Invalidate patched/optimized buffers. */ + this->free_optimized_buffer(); + + /* Flag buffer as incompatible with optimized/patched buffers as contents + * have partial modifications. */ + this->flag_can_optimize(false); + + BLI_assert(false); +} + +void MTLIndexBuf::flag_can_optimize(bool can_optimize) +{ + can_optimize_ = can_optimize; +} + +/** \} */ + +/** \name Index buffer optimization and topology emulation + * + * Index buffer optimization and emulation. Optimize index buffers by + * eliminating restart-indices. + * Emulate unsupported index types e.g. Triangle Fan and Line Loop. + * \{ */ + +/* Returns total vertices in new buffer. */ +template<typename T> +static uint32_t populate_optimized_tri_strip_buf(Span<T> original_data, + MutableSpan<T> output_data, + uint32_t input_index_len) +{ + /* Generate #TriangleList from #TriangleStrip. */ + uint32_t current_vert_len = 0; + uint32_t current_output_ind = 0; + T indices[3]; + + for (int c_index = 0; c_index < input_index_len; c_index++) { + T current_index = original_data[c_index]; + if (current_index == T(-1)) { + /* Stop current primitive. Move onto next. */ + current_vert_len = 0; + } + else { + if (current_vert_len < 3) { + /* Prepare first triangle. + * Cache indices before generating a triangle, in case we have bad primitive-restarts. */ + indices[current_vert_len] = current_index; + } + + /* Emit triangle once we reach 3 input verts in current strip. */ + if (current_vert_len == 3) { + /* First triangle in strip. */ + output_data[current_output_ind++] = indices[0]; + output_data[current_output_ind++] = indices[1]; + output_data[current_output_ind++] = indices[2]; + } + else if (current_vert_len > 3) { + /* All other triangles in strip. + * These triangles are populated using data from previous 2 vertices + * and the latest index. */ + uint32_t tri_id = current_vert_len - 3; + uint32_t base_output_ind = current_output_ind; + if ((tri_id % 2) == 0) { + output_data[base_output_ind + 0] = output_data[base_output_ind - 2]; + output_data[base_output_ind + 1] = current_index; + output_data[base_output_ind + 2] = output_data[base_output_ind - 1]; + } + else { + output_data[base_output_ind + 0] = output_data[base_output_ind - 1]; + output_data[base_output_ind + 1] = output_data[base_output_ind - 2]; + output_data[base_output_ind + 2] = current_index; + } + current_output_ind += 3; + } + + /* Increment relative vertex index. */ + current_vert_len++; + } + } + return current_output_ind; +} + +/* Returns total vertices in new buffer. */ +template<typename T> +static uint32_t populate_emulated_tri_fan_buf(Span<T> original_data, + MutableSpan<T> output_data, + uint32_t input_index_len) +{ + /* Generate #TriangleList from #TriangleFan. */ + T base_prim_ind_val = 0; + uint32_t current_vert_len = 0; + uint32_t current_output_ind = 0; + T indices[3]; + + for (int c_index = 0; c_index < input_index_len; c_index++) { + T current_index = original_data[c_index]; + if (current_index == T(-1)) { + /* Stop current primitive. Move onto next. */ + current_vert_len = 0; + } + else { + if (current_vert_len < 3) { + /* Prepare first triangle. + * Cache indices before generating a triangle, in case we have bad primitive-restarts. */ + indices[current_vert_len] = current_index; + } + + /* emit triangle once we reach 3 input verts in current strip. */ + if (current_vert_len == 3) { + /* First triangle in strip. */ + output_data[current_output_ind++] = indices[0]; + output_data[current_output_ind++] = indices[1]; + output_data[current_output_ind++] = indices[2]; + base_prim_ind_val = indices[0]; + } + else if (current_vert_len > 3) { + /* All other triangles in strip. + * These triangles are populated using data from previous 2 vertices + * and the latest index. */ + uint32_t base_output_ind = current_output_ind; + + output_data[base_output_ind + 0] = base_prim_ind_val; + output_data[base_output_ind + 1] = output_data[base_output_ind - 1]; + output_data[base_output_ind + 2] = current_index; + current_output_ind += 3; + } + + /* Increment relative vertex index. */ + current_vert_len++; + } + } + return current_output_ind; +} + +id<MTLBuffer> MTLIndexBuf::get_index_buffer(GPUPrimType &in_out_primitive_type, + uint32_t &in_out_v_count) +{ + /* Determine whether to return the original index buffer, or whether we + * should emulate an unsupported primitive type, or optimize a restart- + * compatible type for faster performance. */ + bool should_optimize_or_emulate = (in_out_primitive_type == GPU_PRIM_TRI_FAN) || + (in_out_primitive_type == GPU_PRIM_TRI_STRIP); + if (!should_optimize_or_emulate || is_subrange_ || !can_optimize_) { + /* Ensure we are not optimized. */ + BLI_assert(this->optimized_ibo_ == nullptr); + + /* Return regular index buffer. */ + BLI_assert(this->ibo_ && this->ibo_->get_metal_buffer()); + return this->ibo_->get_metal_buffer(); + } + + /* Perform optimization on type. */ + GPUPrimType input_prim_type = in_out_primitive_type; + this->upload_data(); + if (!ibo_ && optimized_ibo_ == nullptr) { + /* Cannot optimize buffer if no source IBO exists. */ + return nil; + } + + /* Verify whether existing index buffer is valid. */ + if (optimized_ibo_ != nullptr && optimized_primitive_type_ != input_prim_type) { + BLI_assert_msg(false, + "Cannot change the optimized primitive format after generation, as source " + "index buffer data is discarded."); + return nil; + } + + /* Generate optimized index buffer. */ + if (optimized_ibo_ == nullptr) { + + /* Generate unwrapped index buffer. */ + switch (input_prim_type) { + case GPU_PRIM_TRI_FAN: { + + /* Calculate maximum size. */ + uint32_t max_possible_verts = (this->index_len_ - 2) * 3; + BLI_assert(max_possible_verts > 0); + + /* Allocate new buffer. */ + optimized_ibo_ = MTLContext::get_global_memory_manager().allocate( + max_possible_verts * + ((index_type_ == GPU_INDEX_U16) ? sizeof(uint16_t) : sizeof(uint32_t)), + true); + + /* Populate new index buffer. */ + if (index_type_ == GPU_INDEX_U16) { + Span<uint16_t> orig_data(static_cast<const uint16_t *>(ibo_->get_host_ptr()), + this->index_len_); + MutableSpan<uint16_t> output_data( + static_cast<uint16_t *>(optimized_ibo_->get_host_ptr()), this->index_len_); + emulated_v_count = populate_emulated_tri_fan_buf<uint16_t>( + orig_data, output_data, this->index_len_); + } + else { + Span<uint32_t> orig_data(static_cast<const uint32_t *>(ibo_->get_host_ptr()), + this->index_len_); + MutableSpan<uint32_t> output_data( + static_cast<uint32_t *>(optimized_ibo_->get_host_ptr()), this->index_len_); + emulated_v_count = populate_emulated_tri_fan_buf<uint32_t>( + orig_data, output_data, this->index_len_); + } + + BLI_assert(emulated_v_count <= max_possible_verts); + + /* Flush buffer and output. */ + optimized_ibo_->flush(); + optimized_primitive_type_ = input_prim_type; + in_out_v_count = emulated_v_count; + in_out_primitive_type = GPU_PRIM_TRIS; + } + + case GPU_PRIM_TRI_STRIP: { + + /* Calculate maximum size. */ + uint32_t max_possible_verts = (this->index_len_ - 2) * 3; + BLI_assert(max_possible_verts > 0); + + /* Allocate new buffer. */ + optimized_ibo_ = MTLContext::get_global_memory_manager().allocate( + max_possible_verts * + ((index_type_ == GPU_INDEX_U16) ? sizeof(uint16_t) : sizeof(uint32_t)), + true); + + /* Populate new index buffer. */ + if (index_type_ == GPU_INDEX_U16) { + Span<uint16_t> orig_data(static_cast<const uint16_t *>(ibo_->get_host_ptr()), + this->index_len_); + MutableSpan<uint16_t> output_data( + static_cast<uint16_t *>(optimized_ibo_->get_host_ptr()), this->index_len_); + emulated_v_count = populate_optimized_tri_strip_buf<uint16_t>( + orig_data, output_data, this->index_len_); + } + else { + Span<uint32_t> orig_data(static_cast<const uint32_t *>(ibo_->get_host_ptr()), + this->index_len_); + MutableSpan<uint32_t> output_data( + static_cast<uint32_t *>(optimized_ibo_->get_host_ptr()), this->index_len_); + emulated_v_count = populate_optimized_tri_strip_buf<uint32_t>( + orig_data, output_data, this->index_len_); + } + + BLI_assert(emulated_v_count <= max_possible_verts); + + /* Flush buffer and output. */ + optimized_ibo_->flush(); + optimized_primitive_type_ = input_prim_type; + in_out_v_count = emulated_v_count; + in_out_primitive_type = GPU_PRIM_TRIS; + } break; + + case GPU_PRIM_LINE_STRIP: { + /* TODO(Metal): Line strip topology types would benefit from optimization to remove + * primitive restarts, however, these do not occur frequently, nor with + * significant geometry counts. */ + MTL_LOG_INFO("TODO: Primitive topology: Optimize line strip topology types\n"); + } break; + + case GPU_PRIM_LINE_LOOP: { + /* TODO(Metal): Line Loop primitive type requires use of optimized index buffer for + * emulation, if used with indexed rendering. This path is currently not hit as #LineLoop + * does not currently appear to be used alongside an index buffer. */ + MTL_LOG_WARNING( + "TODO: Primitive topology: Line Loop Index buffer optimization required for " + "emulation.\n"); + } break; + + case GPU_PRIM_TRIS: + case GPU_PRIM_LINES: + case GPU_PRIM_POINTS: { + /* Should not get here - TRIS/LINES/POINTS do not require emulation or optimization. */ + BLI_assert_unreachable(); + return nil; + } + + default: + /* Should not get here - Invalid primitive type. */ + BLI_assert_unreachable(); + break; + } + } + + /* Return optimized buffer. */ + if (optimized_ibo_ != nullptr) { + + /* Delete original buffer if one still exists, as we do no need it. */ + if (ibo_ != nullptr) { + ibo_->free(); + ibo_ = nullptr; + } + + /* Output params. */ + in_out_v_count = emulated_v_count; + in_out_primitive_type = GPU_PRIM_TRIS; + return optimized_ibo_->get_metal_buffer(); + } + return nil; +} + +void MTLIndexBuf::strip_restart_indices() +{ + /* We remove point buffer primitive restart indices by swapping restart indices + * with the first valid index at the end of the index buffer and reducing the + * length. Primitive restarts are invalid in Metal for non-restart-compatible + * primitive types. We also cannot just use zero unlike for Lines and Triangles, + * as we cannot create de-generative point primitives to hide geometry, as each + * point is independent. + * Instead, we must remove these hidden indices from the index buffer. + * NOTE: This happens prior to index squeezing so operate on 32-bit indices. */ + MutableSpan<uint32_t> uint_idx(static_cast<uint32_t *>(data_), index_len_); + for (uint i = 0; i < index_len_; i++) { + if (uint_idx[i] == 0xFFFFFFFFu) { + + /* Find swap index at end of index buffer. */ + int swap_index = -1; + for (uint j = index_len_ - 1; j >= i; j--) { + /* If end index is restart, just reduce length. */ + if (uint_idx[j] == 0xFFFFFFFFu) { + index_len_--; + continue; + } + /* Otherwise assign swap index. */ + swap_index = j; + break; + } + + /* If swap index is not valid, then there were no valid non-restart indices + * to swap with. However, the above loop will have removed these indices by + * reducing the length of indices. Debug assertions verify that the restart + * index is no longer included. */ + if (swap_index == -1) { + BLI_assert(index_len_ <= i); + } + else { + /* If we have found an index we can swap with, flip the values. + * We also reduce the length. As per above loop, swap_index should + * now be outside the index length range. */ + uint32_t swap_index_value = uint_idx[swap_index]; + uint_idx[i] = swap_index_value; + uint_idx[swap_index] = 0xFFFFFFFFu; + index_len_--; + BLI_assert(index_len_ <= swap_index); + } + } + } + +#ifndef NDEBUG + /* Flag as having been stripped to ensure invalid usage is tracked. */ + point_restarts_stripped_ = true; +#endif +} + +/** \} */ + +} // blender::gpu |