/*
 * MVKCommandBuffer.mm
 *
 * Copyright (c) 2015-2020 The Brenwill Workshop Ltd. (http://www.brenwill.com)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "MVKCommandBuffer.h"
#include "MVKCommandPool.h"
#include "MVKQueue.h"
#include "MVKPipeline.h"
#include "MVKFramebuffer.h"
#include "MVKQueryPool.h"
#include "MVKFoundation.h"
#include "MVKLogging.h"
#include "MTLRenderPassDescriptor+MoltenVK.h"
#include "MVKCmdDraw.h"

using namespace std;


#pragma mark -
#pragma mark MVKCommandBuffer

VkResult MVKCommandBuffer::begin(const VkCommandBufferBeginInfo* pBeginInfo) {

	reset(0);

	clearConfigurationResult();
	_canAcceptCommands = true;

	VkCommandBufferUsageFlags usage = pBeginInfo->flags;
	_isReusable = !mvkAreAllFlagsEnabled(usage, VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT);
	_supportsConcurrentExecution = mvkAreAllFlagsEnabled(usage, VK_COMMAND_BUFFER_USAGE_SIMULTANEOUS_USE_BIT);

	// If this is a secondary command buffer, and contains inheritance info, set the inheritance info and determine
	// whether it contains render pass continuation info. Otherwise, clear the inheritance info, and ignore it.
	const VkCommandBufferInheritanceInfo* pInheritInfo = (_isSecondary ? pBeginInfo->pInheritanceInfo : NULL);
	bool hasInheritInfo = mvkSetOrClear(&_secondaryInheritanceInfo, pInheritInfo);
	_doesContinueRenderPass = mvkAreAllFlagsEnabled(usage, VK_COMMAND_BUFFER_USAGE_RENDER_PASS_CONTINUE_BIT) && hasInheritInfo;

	return getConfigurationResult();
}

void MVKCommandBuffer::releaseCommands() {
	MVKCommand* cmd = _head;
	while (cmd) {
		MVKCommand* nextCmd = cmd->_next;	// Establish next before returning current to pool.
		(cmd->getTypePool(getCommandPool()))->returnObject(cmd);
		cmd = nextCmd;
	}
	_head = nullptr;
	_tail = nullptr;
}

VkResult MVKCommandBuffer::reset(VkCommandBufferResetFlags flags) {
	clearPrefilledMTLCommandBuffer();
	releaseCommands();
	_doesContinueRenderPass = false;
	_canAcceptCommands = false;
	_isReusable = false;
	_supportsConcurrentExecution = false;
	_wasExecuted = false;
	_isExecutingNonConcurrently.clear();
	_commandCount = 0;
	_initialVisibilityResultMTLBuffer = nil;		// not retained
	setConfigurationResult(VK_NOT_READY);

	if (mvkAreAllFlagsEnabled(flags, VK_COMMAND_BUFFER_RESET_RELEASE_RESOURCES_BIT)) {
		// TODO: what are we releasing or returning here?
	}

	return VK_SUCCESS;
}

VkResult MVKCommandBuffer::end() {
	_canAcceptCommands = false;
	prefill();
	return getConfigurationResult();
}

void MVKCommandBuffer::addCommand(MVKCommand* command) {
	if ( !_canAcceptCommands ) {
		setConfigurationResult(reportError(VK_NOT_READY, "Command buffer cannot accept commands before vkBeginCommandBuffer() is called."));
		return;
	}

    if (_tail) { _tail->_next = command; }
    command->_next = nullptr;
    _tail = command;
    if ( !_head ) { _head = command; }
    _commandCount++;
}

void MVKCommandBuffer::submit(MVKQueueCommandBufferSubmission* cmdBuffSubmit) {
	if ( !canExecute() ) { return; }

	if (_prefilledMTLCmdBuffer) {
		cmdBuffSubmit->setActiveMTLCommandBuffer(_prefilledMTLCmdBuffer);
		clearPrefilledMTLCommandBuffer();
	} else {
		MVKCommandEncoder encoder(this);
		encoder.encode(cmdBuffSubmit->getActiveMTLCommandBuffer());
	}

	if ( !_supportsConcurrentExecution ) { _isExecutingNonConcurrently.clear(); }
}

bool MVKCommandBuffer::canExecute() {
	if (_isSecondary) {
		setConfigurationResult(reportError(VK_NOT_READY, "Secondary command buffers may not be submitted directly to a queue."));
		return false;
	}
	if ( !_isReusable && _wasExecuted ) {
		setConfigurationResult(reportError(VK_NOT_READY, "Command buffer does not support execution more that once."));
		return false;
	}

	// Do this test last so that _isExecutingNonConcurrently is only set if everything else passes
	if ( !_supportsConcurrentExecution && _isExecutingNonConcurrently.test_and_set()) {
		setConfigurationResult(reportError(VK_NOT_READY, "Command buffer does not support concurrent execution."));
		return false;
	}

	_wasExecuted = true;
	return true;
}

// If we can, prefill a MTLCommandBuffer with the commands in this command buffer.
// Wrap in autorelease pool to capture autoreleased Metal encoding activity.
void MVKCommandBuffer::prefill() {
	@autoreleasepool {
		clearPrefilledMTLCommandBuffer();

		if ( !canPrefill() ) { return; }

		uint32_t qIdx = 0;
		_prefilledMTLCmdBuffer = _commandPool->newMTLCommandBuffer(qIdx);	// retain

		MVKCommandEncoder encoder(this);
		encoder.encode(_prefilledMTLCmdBuffer);

		// Once encoded onto Metal, if this command buffer is not reusable, we don't need the
		// MVKCommand instances anymore, so release them in order to reduce memory pressure.
		if ( !_isReusable ) { releaseCommands(); }
	}
}

bool MVKCommandBuffer::canPrefill() {
	bool wantPrefill = _device->_pMVKConfig->prefillMetalCommandBuffers;
	return wantPrefill && !(_isSecondary || _supportsConcurrentExecution);
}

void MVKCommandBuffer::clearPrefilledMTLCommandBuffer() {

	// Metal command buffers do not return to their pool on release, nor do they support the
	// concept of a reset. In order to become available again in their pool, they must pass
	// through the commit step. This is unfortunate because if the app adds commands to this
	// command buffer and then chooses to reset it instead of submit it, we risk committing
	// a prefilled Metal command buffer that the app did not intend to submit, potentially
	// causing unexpected side effects. But unfortunately there is nothing else we can do.
	if (_prefilledMTLCmdBuffer && _prefilledMTLCmdBuffer.status == MTLCommandBufferStatusNotEnqueued) {
		[_prefilledMTLCmdBuffer commit];
	}

	[_prefilledMTLCmdBuffer release];
	_prefilledMTLCmdBuffer = nil;
}

#pragma mark Construction

// Initializes this instance after it has been created or retrieved from a pool.
void MVKCommandBuffer::init(const VkCommandBufferAllocateInfo* pAllocateInfo) {
	_commandPool = (MVKCommandPool*)pAllocateInfo->commandPool;
	_isSecondary = (pAllocateInfo->level == VK_COMMAND_BUFFER_LEVEL_SECONDARY);

	reset(0);
}

MVKCommandBuffer::~MVKCommandBuffer() {
	reset(0);
}


#pragma mark -
#pragma mark Tessellation constituent command management

void MVKCommandBuffer::recordBeginRenderPass(MVKLoadStoreOverrideMixin* mvkBeginRenderPass) {
	_lastBeginRenderPass = mvkBeginRenderPass;
	_lastTessellationPipeline = nullptr;
	_lastTessellationDraw = nullptr;
}

void MVKCommandBuffer::recordEndRenderPass() {
	// Unset the store override for the last draw call
	if (_lastTessellationDraw != nullptr)
	{
		_lastTessellationDraw->setStoreOverride(false);
		_lastBeginRenderPass->setStoreOverride(true);
	}
	_lastBeginRenderPass = nullptr;
	_lastTessellationPipeline = nullptr;
	_lastTessellationDraw = nullptr;
}

void MVKCommandBuffer::recordBindPipeline(MVKCmdBindPipeline* mvkBindPipeline) {
	if (mvkBindPipeline->isTessellationPipeline())
		_lastTessellationPipeline = mvkBindPipeline;
	else
		_lastTessellationPipeline = nullptr;
}

void MVKCommandBuffer::recordDraw(MVKLoadStoreOverrideMixin* mvkDraw) {
	if (_lastTessellationPipeline != nullptr) {
		// If a multi-pass pipeline is bound and we've already drawn something, need to override load actions
		mvkDraw->setLoadOverride(true);
		mvkDraw->setStoreOverride(true);
		_lastTessellationDraw = mvkDraw;
	}
}


#pragma mark -
#pragma mark MVKCommandEncoder

void MVKCommandEncoder::encode(id<MTLCommandBuffer> mtlCmdBuff) {
	_subpassContents = VK_SUBPASS_CONTENTS_INLINE;
	_renderSubpassIndex = 0;
	_isUsingLayeredRendering = false;

	_mtlCmdBuffer = mtlCmdBuff;		// not retained

	setLabelIfNotNil(_mtlCmdBuffer, _cmdBuffer->_debugName);

	MVKCommand* cmd = _cmdBuffer->_head;
	while (cmd) {
		cmd->encode(this);
		cmd = cmd->_next;
	}

	endCurrentMetalEncoding();
	finishQueries();
}

void MVKCommandEncoder::encodeSecondary(MVKCommandBuffer* secondaryCmdBuffer) {
	MVKCommand* cmd = secondaryCmdBuffer->_head;
	while (cmd) {
		cmd->encode(this);
		cmd = cmd->_next;
	}
}

void MVKCommandEncoder::beginRenderpass(VkSubpassContents subpassContents,
										MVKRenderPass* renderPass,
										MVKFramebuffer* framebuffer,
										VkRect2D& renderArea,
										MVKArrayRef<VkClearValue> clearValues,
										bool loadOverride,
										bool storeOverride) {
	_renderPass = renderPass;
	_framebuffer = framebuffer;
	_renderArea = renderArea;
	_isRenderingEntireAttachment = (mvkVkOffset2DsAreEqual(_renderArea.offset, {0,0}) &&
									mvkVkExtent2DsAreEqual(_renderArea.extent, _framebuffer->getExtent2D()));
	_clearValues.assign(clearValues.begin(), clearValues.end());
	setSubpass(subpassContents, 0, loadOverride, storeOverride);
}

void MVKCommandEncoder::beginNextSubpass(VkSubpassContents contents) {
	setSubpass(contents, _renderSubpassIndex + 1);
}

// Sets the current render subpass to the subpass with the specified index.
void MVKCommandEncoder::setSubpass(VkSubpassContents subpassContents, uint32_t subpassIndex, bool loadOverride, bool storeOverride) {
	_subpassContents = subpassContents;
	_renderSubpassIndex = subpassIndex;

	_isUsingLayeredRendering = ((_framebuffer->getLayerCount() > 1) &&
								_device->_pMetalFeatures->layeredRendering &&
								(_device->_pMetalFeatures->multisampleLayeredRendering ||
								 (getSubpass()->getSampleCount() == VK_SAMPLE_COUNT_1_BIT)));

	beginMetalRenderPass(loadOverride, storeOverride);
}

// Creates _mtlRenderEncoder and marks cached render state as dirty so it will be set into the _mtlRenderEncoder.
void MVKCommandEncoder::beginMetalRenderPass(bool loadOverride, bool storeOverride) {

    endCurrentMetalEncoding();

    MTLRenderPassDescriptor* mtlRPDesc = [MTLRenderPassDescriptor renderPassDescriptor];
    getSubpass()->populateMTLRenderPassDescriptor(mtlRPDesc, _framebuffer, _clearValues.contents(), _isRenderingEntireAttachment, loadOverride, storeOverride);
    mtlRPDesc.visibilityResultBuffer = _occlusionQueryState.getVisibilityResultMTLBuffer();

	// Only set the layered rendering properties if layered rendering is supported and the framebuffer really has multiple layers
	if (_isUsingLayeredRendering) {
		VkExtent2D fbExtent = _framebuffer->getExtent2D();
		mtlRPDesc.renderTargetWidthMVK = min(_renderArea.offset.x + _renderArea.extent.width, fbExtent.width);
		mtlRPDesc.renderTargetHeightMVK = min(_renderArea.offset.y + _renderArea.extent.height, fbExtent.height);
		mtlRPDesc.renderTargetArrayLengthMVK = _framebuffer->getLayerCount();
	}

    _mtlRenderEncoder = [_mtlCmdBuffer renderCommandEncoderWithDescriptor: mtlRPDesc];     // not retained
	setLabelIfNotNil(_mtlRenderEncoder, getMTLRenderCommandEncoderName());

    if ( !_isRenderingEntireAttachment ) { clearRenderArea(); }

    _graphicsPipelineState.beginMetalRenderPass();
    _graphicsResourcesState.beginMetalRenderPass();
    _viewportState.beginMetalRenderPass();
    _scissorState.beginMetalRenderPass();
    _depthBiasState.beginMetalRenderPass();
    _blendColorState.beginMetalRenderPass();
    _vertexPushConstants.beginMetalRenderPass();
    _tessCtlPushConstants.beginMetalRenderPass();
    _tessEvalPushConstants.beginMetalRenderPass();
    _fragmentPushConstants.beginMetalRenderPass();
    _depthStencilState.beginMetalRenderPass();
    _stencilReferenceValueState.beginMetalRenderPass();
    _occlusionQueryState.beginMetalRenderPass();
}

MVKRenderSubpass* MVKCommandEncoder::getSubpass() { return _renderPass->getSubpass(_renderSubpassIndex); }

// Returns a name for use as a MTLRenderCommandEncoder label
NSString* MVKCommandEncoder::getMTLRenderCommandEncoderName() {
	NSString* rpName;

	rpName = _renderPass->getDebugName();
	if (rpName) { return rpName; }

	rpName = _cmdBuffer->getDebugName();
	if (rpName) { return rpName; }

	MVKCommandUse cmdUse = (_renderSubpassIndex == 0) ? kMVKCommandUseBeginRenderPass : kMVKCommandUseNextSubpass;
	return mvkMTLRenderCommandEncoderLabel(cmdUse);
}

void MVKCommandEncoder::bindPipeline(VkPipelineBindPoint pipelineBindPoint, MVKPipeline* pipeline) {
    switch (pipelineBindPoint) {
        case VK_PIPELINE_BIND_POINT_GRAPHICS:
            _graphicsPipelineState.setPipeline(pipeline);
            break;

        case VK_PIPELINE_BIND_POINT_COMPUTE:
            _computePipelineState.setPipeline(pipeline);
            break;

        default:
            break;
    }
}

void MVKCommandEncoder::signalEvent(MVKEvent* mvkEvent, bool status) {
	endCurrentMetalEncoding();
	mvkEvent->encodeSignal(_mtlCmdBuffer, status);
}

bool MVKCommandEncoder::supportsDynamicState(VkDynamicState state) {
    MVKGraphicsPipeline* gpl = (MVKGraphicsPipeline*)_graphicsPipelineState.getPipeline();
    return !gpl || gpl->supportsDynamicState(state);
}

VkRect2D MVKCommandEncoder::clipToRenderArea(VkRect2D scissor) {

	int32_t raLeft = _renderArea.offset.x;
	int32_t raRight = raLeft + _renderArea.extent.width;
	int32_t raBottom = _renderArea.offset.y;
	int32_t raTop = raBottom + _renderArea.extent.height;

	scissor.offset.x		= mvkClamp(scissor.offset.x, raLeft, max(raRight - 1, raLeft));
	scissor.offset.y		= mvkClamp(scissor.offset.y, raBottom, max(raTop - 1, raBottom));
	scissor.extent.width	= min<int32_t>(scissor.extent.width, raRight - scissor.offset.x);
	scissor.extent.height	= min<int32_t>(scissor.extent.height, raTop - scissor.offset.y);

	return scissor;
}

void MVKCommandEncoder::finalizeDrawState(MVKGraphicsStage stage) {
    _graphicsPipelineState.encode(stage);    // Must do first..it sets others
    _graphicsResourcesState.encode(stage);
    _viewportState.encode(stage);
    _scissorState.encode(stage);
    _depthBiasState.encode(stage);
    _blendColorState.encode(stage);
    _vertexPushConstants.encode(stage);
    _tessCtlPushConstants.encode(stage);
    _tessEvalPushConstants.encode(stage);
    _fragmentPushConstants.encode(stage);
    _depthStencilState.encode(stage);
    _stencilReferenceValueState.encode(stage);
    _occlusionQueryState.encode(stage);
}

// Clears the render area of the framebuffer attachments.
void MVKCommandEncoder::clearRenderArea() {

	MVKClearAttachments clearAtts;
	getSubpass()->populateClearAttachments(clearAtts, _clearValues.contents());

	uint32_t clearAttCnt = (uint32_t)clearAtts.size();

	if (clearAttCnt == 0) { return; }

	VkClearRect clearRect;
	clearRect.rect = _renderArea;
	clearRect.baseArrayLayer = 0;
	clearRect.layerCount = _framebuffer->getLayerCount();

    // Create and execute a temporary clear attachments command.
    // To be threadsafe...do NOT acquire and return the command from the pool.
    MVKCmdClearMultiAttachments<1> cmd;
    cmd.setContent(_cmdBuffer, clearAttCnt, clearAtts.data(), 1, &clearRect);
    cmd.encode(this);
}

void MVKCommandEncoder::finalizeDispatchState() {
    _computePipelineState.encode();    // Must do first..it sets others
    _computeResourcesState.encode();
    _computePushConstants.encode();
}

void MVKCommandEncoder::endRenderpass() {
	endMetalRenderEncoding();

	_renderPass = nullptr;
	_framebuffer = nullptr;
	_renderSubpassIndex = 0;
}

void MVKCommandEncoder::endMetalRenderEncoding() {
//    MVKLogDebugIf(_mtlRenderEncoder, "Render subpass end MTLRenderCommandEncoder.");
    [_mtlRenderEncoder endEncoding];
	_mtlRenderEncoder = nil;    // not retained
}

void MVKCommandEncoder::endCurrentMetalEncoding() {
	endMetalRenderEncoding();

	_computePipelineState.markDirty();
	_computeResourcesState.markDirty();
	_computePushConstants.markDirty();

	[_mtlComputeEncoder endEncoding];
	_mtlComputeEncoder = nil;       // not retained
	_mtlComputeEncoderUse = kMVKCommandUseNone;

	[_mtlBlitEncoder endEncoding];
	_mtlBlitEncoder = nil;          // not retained
    _mtlBlitEncoderUse = kMVKCommandUseNone;
}

id<MTLComputeCommandEncoder> MVKCommandEncoder::getMTLComputeEncoder(MVKCommandUse cmdUse) {
	if ( !_mtlComputeEncoder ) {
		endCurrentMetalEncoding();
		_mtlComputeEncoder = [_mtlCmdBuffer computeCommandEncoder];		// not retained
	}
	if (_mtlComputeEncoderUse != cmdUse) {
		_mtlComputeEncoderUse = cmdUse;
		setLabelIfNotNil(_mtlComputeEncoder, mvkMTLComputeCommandEncoderLabel(cmdUse));
	}
	return _mtlComputeEncoder;
}

id<MTLBlitCommandEncoder> MVKCommandEncoder::getMTLBlitEncoder(MVKCommandUse cmdUse) {
	if ( !_mtlBlitEncoder ) {
		endCurrentMetalEncoding();
		_mtlBlitEncoder = [_mtlCmdBuffer blitCommandEncoder];   // not retained
	}
    if (_mtlBlitEncoderUse != cmdUse) {
        _mtlBlitEncoderUse = cmdUse;
		setLabelIfNotNil(_mtlBlitEncoder, mvkMTLBlitCommandEncoderLabel(cmdUse));
    }
	return _mtlBlitEncoder;
}

id<MTLCommandEncoder> MVKCommandEncoder::getMTLEncoder(){
	if (_mtlRenderEncoder) { return _mtlRenderEncoder; }
	if (_mtlComputeEncoder) { return _mtlComputeEncoder; }
	if (_mtlBlitEncoder) { return _mtlBlitEncoder; }
	return nil;
}

MVKPushConstantsCommandEncoderState* MVKCommandEncoder::getPushConstants(VkShaderStageFlagBits shaderStage) {
	switch (shaderStage) {
		case VK_SHADER_STAGE_VERTEX_BIT:					return &_vertexPushConstants;
		case VK_SHADER_STAGE_TESSELLATION_CONTROL_BIT:		return &_tessCtlPushConstants;
		case VK_SHADER_STAGE_TESSELLATION_EVALUATION_BIT:	return &_tessEvalPushConstants;
		case VK_SHADER_STAGE_FRAGMENT_BIT:					return &_fragmentPushConstants;
		case VK_SHADER_STAGE_COMPUTE_BIT:					return &_computePushConstants;
		default:
			MVKAssert(false, "Invalid shader stage: %u", shaderStage);
			return nullptr;
	}
}

void MVKCommandEncoder::setVertexBytes(id<MTLRenderCommandEncoder> mtlEncoder,
                                       const void* bytes,
                                       NSUInteger length,
                                       uint32_t mtlBuffIndex) {
    if (_pDeviceMetalFeatures->dynamicMTLBufferSize && length <= _pDeviceMetalFeatures->dynamicMTLBufferSize) {
        [mtlEncoder setVertexBytes: bytes length: length atIndex: mtlBuffIndex];
    } else {
        const MVKMTLBufferAllocation* mtlBuffAlloc = copyToTempMTLBufferAllocation(bytes, length);
        [mtlEncoder setVertexBuffer: mtlBuffAlloc->_mtlBuffer offset: mtlBuffAlloc->_offset atIndex: mtlBuffIndex];
    }
}

void MVKCommandEncoder::setFragmentBytes(id<MTLRenderCommandEncoder> mtlEncoder,
                                         const void* bytes,
                                         NSUInteger length,
                                         uint32_t mtlBuffIndex) {
    if (_pDeviceMetalFeatures->dynamicMTLBufferSize && length <= _pDeviceMetalFeatures->dynamicMTLBufferSize) {
        [mtlEncoder setFragmentBytes: bytes length: length atIndex: mtlBuffIndex];
    } else {
        const MVKMTLBufferAllocation* mtlBuffAlloc = copyToTempMTLBufferAllocation(bytes, length);
        [mtlEncoder setFragmentBuffer: mtlBuffAlloc->_mtlBuffer offset: mtlBuffAlloc->_offset atIndex: mtlBuffIndex];
    }
}

void MVKCommandEncoder::setComputeBytes(id<MTLComputeCommandEncoder> mtlEncoder,
                                        const void* bytes,
                                        NSUInteger length,
                                        uint32_t mtlBuffIndex) {
    if (_pDeviceMetalFeatures->dynamicMTLBufferSize && length <= _pDeviceMetalFeatures->dynamicMTLBufferSize) {
        [mtlEncoder setBytes: bytes length: length atIndex: mtlBuffIndex];
    } else {
        const MVKMTLBufferAllocation* mtlBuffAlloc = copyToTempMTLBufferAllocation(bytes, length);
        [mtlEncoder setBuffer: mtlBuffAlloc->_mtlBuffer offset: mtlBuffAlloc->_offset atIndex: mtlBuffIndex];
    }
}

const MVKMTLBufferAllocation* MVKCommandEncoder::getTempMTLBuffer(NSUInteger length) {
    const MVKMTLBufferAllocation* mtlBuffAlloc = getCommandEncodingPool()->acquireMTLBufferAllocation(length);
	MVKMTLBufferAllocationPool* pool = mtlBuffAlloc->getPool();

    // Return the MTLBuffer allocation to the pool once the command buffer is done with it
    [_mtlCmdBuffer addCompletedHandler: ^(id<MTLCommandBuffer> mcb) {
        pool->returnObjectSafely((MVKMTLBufferAllocation*)mtlBuffAlloc);
    }];

    return mtlBuffAlloc;
}

MVKCommandEncodingPool* MVKCommandEncoder::getCommandEncodingPool() {
	return _cmdBuffer->getCommandPool()->getCommandEncodingPool();
}

// Copies the specified bytes into a temporary allocation within a pooled MTLBuffer, and returns the MTLBuffer allocation.
const MVKMTLBufferAllocation* MVKCommandEncoder::copyToTempMTLBufferAllocation(const void* bytes, NSUInteger length) {
    const MVKMTLBufferAllocation* mtlBuffAlloc = getTempMTLBuffer(length);
    void* pBuffData = mtlBuffAlloc->getContents();
    memcpy(pBuffData, bytes, length);

    return mtlBuffAlloc;
}


#pragma mark Queries

void MVKCommandEncoder::beginOcclusionQuery(MVKOcclusionQueryPool* pQueryPool, uint32_t query, VkQueryControlFlags flags) {
    _occlusionQueryState.beginOcclusionQuery(pQueryPool, query, flags);
    addActivatedQuery(pQueryPool, query);
}

void MVKCommandEncoder::endOcclusionQuery(MVKOcclusionQueryPool* pQueryPool, uint32_t query) {
    _occlusionQueryState.endOcclusionQuery(pQueryPool, query);
}

void MVKCommandEncoder::markTimestamp(MVKQueryPool* pQueryPool, uint32_t query) {
    addActivatedQuery(pQueryPool, query);
}

// Marks the specified query as activated
void MVKCommandEncoder::addActivatedQuery(MVKQueryPool* pQueryPool, uint32_t query) {
    if ( !_pActivatedQueries ) { _pActivatedQueries = new MVKActivatedQueries(); }
    (*_pActivatedQueries)[pQueryPool].push_back(query);
}

// Register a command buffer completion handler that finishes each activated query.
// Ownership of the collection of activated queries is passed to the handler.
void MVKCommandEncoder::finishQueries() {
    if ( !_pActivatedQueries ) { return; }

    MVKActivatedQueries* pAQs = _pActivatedQueries;
    [_mtlCmdBuffer addCompletedHandler: ^(id<MTLCommandBuffer> mtlCmdBuff) {
        for (auto& qryPair : *pAQs) {
            qryPair.first->finishQueries(qryPair.second.contents());
        }
        delete pAQs;
    }];
    _pActivatedQueries = nullptr;
}


#pragma mark Construction

MVKCommandEncoder::MVKCommandEncoder(MVKCommandBuffer* cmdBuffer) : MVKBaseDeviceObject(cmdBuffer->getDevice()),
        _cmdBuffer(cmdBuffer),
        _graphicsPipelineState(this),
        _computePipelineState(this),
        _viewportState(this),
        _scissorState(this),
        _depthBiasState(this),
        _blendColorState(this),
        _vertexPushConstants(this, VK_SHADER_STAGE_VERTEX_BIT),
        _tessCtlPushConstants(this, VK_SHADER_STAGE_TESSELLATION_CONTROL_BIT),
        _tessEvalPushConstants(this, VK_SHADER_STAGE_TESSELLATION_EVALUATION_BIT),
        _fragmentPushConstants(this, VK_SHADER_STAGE_FRAGMENT_BIT),
        _computePushConstants(this, VK_SHADER_STAGE_COMPUTE_BIT),
        _depthStencilState(this),
        _stencilReferenceValueState(this),
        _graphicsResourcesState(this),
        _computeResourcesState(this),
        _occlusionQueryState(this) {

            _pDeviceFeatures = &_device->_enabledFeatures;
            _pDeviceMetalFeatures = _device->_pMetalFeatures;
            _pDeviceProperties = _device->_pProperties;
            _pDeviceMemoryProperties = _device->_pMemoryProperties;
            _pActivatedQueries = nullptr;
            _mtlCmdBuffer = nil;
            _mtlRenderEncoder = nil;
            _mtlComputeEncoder = nil;
			_mtlComputeEncoderUse = kMVKCommandUseNone;
            _mtlBlitEncoder = nil;
            _mtlBlitEncoderUse = kMVKCommandUseNone;
}


#pragma mark -
#pragma mark Support functions

NSString* mvkMTLRenderCommandEncoderLabel(MVKCommandUse cmdUse) {
    switch (cmdUse) {
        case kMVKCommandUseBeginRenderPass:         return @"vkCmdBeginRenderPass RenderEncoder";
        case kMVKCommandUseNextSubpass:             return @"vkCmdNextSubpass RenderEncoder";
        case kMVKCommandUseBlitImage:               return @"vkCmdBlitImage RenderEncoder";
        case kMVKCommandUseResolveImage:            return @"vkCmdResolveImage (resolve stage) RenderEncoder";
        case kMVKCommandUseResolveExpandImage:      return @"vkCmdResolveImage (expand stage) RenderEncoder";
        case kMVKCommandUseClearColorImage:         return @"vkCmdClearColorImage RenderEncoder";
        case kMVKCommandUseClearDepthStencilImage:  return @"vkCmdClearDepthStencilImage RenderEncoder";
        default:                                    return @"Unknown Use RenderEncoder";
    }
}

NSString* mvkMTLBlitCommandEncoderLabel(MVKCommandUse cmdUse) {
    switch (cmdUse) {
        case kMVKCommandUsePipelineBarrier:     return @"vkCmdPipelineBarrier BlitEncoder";
        case kMVKCommandUseCopyImage:           return @"vkCmdCopyImage BlitEncoder";
        case kMVKCommandUseResolveCopyImage:    return @"vkCmdResolveImage (copy stage) RenderEncoder";
        case kMVKCommandUseCopyBuffer:          return @"vkCmdCopyBuffer BlitEncoder";
        case kMVKCommandUseCopyBufferToImage:   return @"vkCmdCopyBufferToImage BlitEncoder";
        case kMVKCommandUseCopyImageToBuffer:   return @"vkCmdCopyImageToBuffer BlitEncoder";
        case kMVKCommandUseFillBuffer:          return @"vkCmdFillBuffer BlitEncoder";
        case kMVKCommandUseUpdateBuffer:        return @"vkCmdUpdateBuffer BlitEncoder";
        case kMVKCommandUseResetQueryPool:      return @"vkCmdResetQueryPool BlitEncoder";
        case kMVKCommandUseCopyQueryPoolResults:return @"vkCmdCopyQueryPoolResults BlitEncoder";
        default:                                return @"Unknown Use BlitEncoder";
    }
}

NSString* mvkMTLComputeCommandEncoderLabel(MVKCommandUse cmdUse) {
    switch (cmdUse) {
        case kMVKCommandUseDispatch:            return @"vkCmdDispatch ComputeEncoder";
        case kMVKCommandUseCopyBuffer:          return @"vkCmdCopyBuffer ComputeEncoder";
        case kMVKCommandUseCopyBufferToImage:   return @"vkCmdCopyBufferToImage ComputeEncoder";
        case kMVKCommandUseCopyImageToBuffer:   return @"vkCmdCopyImageToBuffer ComputeEncoder";
        case kMVKCommandUseFillBuffer:          return @"vkCmdFillBuffer ComputeEncoder";
        case kMVKCommandUseTessellationControl: return @"vkCmdDraw (tess control stage) ComputeEncoder";
        case kMVKCommandUseCopyQueryPoolResults:return @"vkCmdCopyQueryPoolResults ComputeEncoder";
        default:                                return @"Unknown Use ComputeEncoder";
    }
}