/*
 * MVKRenderPass.mm
 *
 * Copyright (c) 2014-2018 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 "MVKRenderPass.h"
#include "MVKFramebuffer.h"
#include "MVKCommandBuffer.h"
#include "MVKFoundation.h"
#include "mvk_datatypes.h"

using namespace std;


#pragma mark -
#pragma mark MVKRenderSubpass

VkFormat MVKRenderSubpass::getColorAttachmentFormat(uint32_t colorAttIdx) {
	if (colorAttIdx < _colorAttachments.size()) {
		uint32_t rpAttIdx = _colorAttachments[colorAttIdx].attachment;
		if (rpAttIdx == VK_ATTACHMENT_UNUSED) { return VK_FORMAT_UNDEFINED; }
		return _renderPass->_attachments[rpAttIdx].getFormat();
	}
	return VK_FORMAT_UNDEFINED;
}

VkFormat MVKRenderSubpass::getDepthStencilFormat() {
	uint32_t rpAttIdx = _depthStencilAttachment.attachment;
	if (rpAttIdx == VK_ATTACHMENT_UNUSED) { return VK_FORMAT_UNDEFINED; }
	return _renderPass->_attachments[rpAttIdx].getFormat();
}

void MVKRenderSubpass::populateMTLRenderPassDescriptor(MTLRenderPassDescriptor* mtlRPDesc,
													   MVKFramebuffer* framebuffer,
													   vector<VkClearValue>& clearValues,
													   bool isRenderingEntireAttachment) {
	// Populate the Metal color attachments
	uint32_t caCnt = getColorAttachmentCount();
	for (uint32_t caIdx = 0; caIdx < caCnt; caIdx++) {
		uint32_t clrRPAttIdx = _colorAttachments[caIdx].attachment;
        if (clrRPAttIdx != VK_ATTACHMENT_UNUSED) {
            MTLRenderPassColorAttachmentDescriptor* mtlColorAttDesc = mtlRPDesc.colorAttachments[caIdx];

            // If it exists, configure the resolve attachment first,
            // as it affects how the store action of the color attachment.
            uint32_t rslvRPAttIdx = _resolveAttachments.empty() ? VK_ATTACHMENT_UNUSED : _resolveAttachments[caIdx].attachment;
            bool hasResolveAttachment = (rslvRPAttIdx != VK_ATTACHMENT_UNUSED);
            if (hasResolveAttachment) {
                framebuffer->getAttachment(rslvRPAttIdx)->populateMTLRenderPassAttachmentDescriptorResolve(mtlColorAttDesc);
            }

            // Configure the color attachment
            MVKRenderPassAttachment* clrMVKRPAtt = &_renderPass->_attachments[clrRPAttIdx];
			framebuffer->getAttachment(clrRPAttIdx)->populateMTLRenderPassAttachmentDescriptor(mtlColorAttDesc);
			if (clrMVKRPAtt->populateMTLRenderPassAttachmentDescriptor(mtlColorAttDesc, this,
                                                                       isRenderingEntireAttachment,
                                                                       hasResolveAttachment, false)) {
				mtlColorAttDesc.clearColor = mvkMTLClearColorFromVkClearValue(clearValues[clrRPAttIdx], clrMVKRPAtt->getFormat());
			}

		}
	}

	// Populate the Metal depth and stencil attachments
	uint32_t dsRPAttIdx = _depthStencilAttachment.attachment;
	if (dsRPAttIdx != VK_ATTACHMENT_UNUSED) {
		MVKRenderPassAttachment* dsMVKRPAtt = &_renderPass->_attachments[dsRPAttIdx];
		MVKImageView* dsImage = framebuffer->getAttachment(dsRPAttIdx);
		MTLPixelFormat mtlDSFormat = dsImage->getMTLPixelFormat();

		if (mvkMTLPixelFormatIsDepthFormat(mtlDSFormat)) {
			MTLRenderPassDepthAttachmentDescriptor* mtlDepthAttDesc = mtlRPDesc.depthAttachment;
			dsImage->populateMTLRenderPassAttachmentDescriptor(mtlDepthAttDesc);
			if (dsMVKRPAtt->populateMTLRenderPassAttachmentDescriptor(mtlDepthAttDesc, this,
                                                                      isRenderingEntireAttachment,
                                                                      false, false)) {
				mtlDepthAttDesc.clearDepth = mvkMTLClearDepthFromVkClearValue(clearValues[dsRPAttIdx]);
			}
		}
		if (mvkMTLPixelFormatIsStencilFormat(mtlDSFormat)) {
			MTLRenderPassStencilAttachmentDescriptor* mtlStencilAttDesc = mtlRPDesc.stencilAttachment;
			dsImage->populateMTLRenderPassAttachmentDescriptor(mtlStencilAttDesc);
			if (dsMVKRPAtt->populateMTLRenderPassAttachmentDescriptor(mtlStencilAttDesc, this,
                                                                      isRenderingEntireAttachment,
                                                                      false, true)) {
				mtlStencilAttDesc.clearStencil = mvkMTLClearStencilFromVkClearValue(clearValues[dsRPAttIdx]);
			}
		}
	}
}

void MVKRenderSubpass::populateClearAttachments(vector<VkClearAttachment>& clearAtts,
												vector<VkClearValue>& clearValues) {
	VkClearAttachment cAtt;

	uint32_t attIdx;
	uint32_t caCnt = getColorAttachmentCount();
	for (uint32_t caIdx = 0; caIdx < caCnt; caIdx++) {
		attIdx = _colorAttachments[caIdx].attachment;
		if ((attIdx != VK_ATTACHMENT_UNUSED) && _renderPass->_attachments[attIdx].shouldUseClearAttachment(this)) {
			cAtt.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
			cAtt.colorAttachment = caIdx;
			cAtt.clearValue = clearValues[attIdx];
			clearAtts.push_back(cAtt);
		}
	}

	attIdx = _depthStencilAttachment.attachment;
	if ((attIdx != VK_ATTACHMENT_UNUSED) && _renderPass->_attachments[attIdx].shouldUseClearAttachment(this)) {
		cAtt.aspectMask = 0;
		cAtt.colorAttachment = 0;
		cAtt.clearValue = clearValues[attIdx];

		MTLPixelFormat mtlDSFmt = _renderPass->mtlPixelFormatFromVkFormat(getDepthStencilFormat());
		if (mvkMTLPixelFormatIsDepthFormat(mtlDSFmt)) { cAtt.aspectMask |= VK_IMAGE_ASPECT_DEPTH_BIT; }
		if (mvkMTLPixelFormatIsStencilFormat(mtlDSFmt)) { cAtt.aspectMask |= VK_IMAGE_ASPECT_STENCIL_BIT; }
		if (cAtt.aspectMask) { clearAtts.push_back(cAtt); }
	}
}

/**
 * Returns whether this subpass uses the attachment at the specified index within the
 * parent renderpass, as any of input, color, resolve, or depth/stencil attachment type.
 */
bool MVKRenderSubpass::isUsingAttachmentAt(uint32_t rpAttIdx) {

	for (auto& att : _inputAttachments) {
		if (att.attachment == rpAttIdx) { return true; }
	}
	for (auto& att : _colorAttachments) {
		if (att.attachment == rpAttIdx) { return true; }
	}
	for (auto& att : _resolveAttachments) {
		if (att.attachment == rpAttIdx) { return true; }
	}
	if (_depthStencilAttachment.attachment == rpAttIdx) { return true; }

	return false;
}

MVKRenderSubpass::MVKRenderSubpass(MVKRenderPass* renderPass,
								   const VkSubpassDescription* pCreateInfo) : MVKBaseObject() {
	_renderPass = renderPass;
	_subpassIndex = (uint32_t)_renderPass->_subpasses.size();

	// Add attachments
	_inputAttachments.reserve(pCreateInfo->inputAttachmentCount);
	for (uint32_t i = 0; i < pCreateInfo->inputAttachmentCount; i++) {
		_inputAttachments.push_back(pCreateInfo->pInputAttachments[i]);
	}

	_colorAttachments.reserve(pCreateInfo->colorAttachmentCount);
	for (uint32_t i = 0; i < pCreateInfo->colorAttachmentCount; i++) {
		_colorAttachments.push_back(pCreateInfo->pColorAttachments[i]);
	}

	if (pCreateInfo->pResolveAttachments) {
		_resolveAttachments.reserve(pCreateInfo->colorAttachmentCount);
		for (uint32_t i = 0; i < pCreateInfo->colorAttachmentCount; i++) {
			_resolveAttachments.push_back(pCreateInfo->pResolveAttachments[i]);
		}
	}

	if (pCreateInfo->pDepthStencilAttachment) {
		_depthStencilAttachment = *pCreateInfo->pDepthStencilAttachment;
	} else {
		_depthStencilAttachment.attachment = VK_ATTACHMENT_UNUSED;
	}

	_preserveAttachments.reserve(pCreateInfo->preserveAttachmentCount);
	for (uint32_t i = 0; i < pCreateInfo->preserveAttachmentCount; i++) {
		_preserveAttachments.push_back(pCreateInfo->pPreserveAttachments[i]);
	}
}


#pragma mark -
#pragma mark MVKRenderPassAttachment

VkFormat MVKRenderPassAttachment::getFormat() { return _info.format; }

bool MVKRenderPassAttachment::populateMTLRenderPassAttachmentDescriptor(MTLRenderPassAttachmentDescriptor* mtlAttDesc,
                                                                        MVKRenderSubpass* subpass,
                                                                        bool isRenderingEntireAttachment,
                                                                        bool hasResolveAttachment,
                                                                        bool isStencil) {

    bool willClear = false;		// Assume the attachment won't be cleared

    // Only allow clearing of entire attachment if we're actually rendering to the entire
    // attachment AND we're in the first subpass.
    if ( isRenderingEntireAttachment && (subpass->_subpassIndex == _firstUseSubpassIdx) ) {
        VkAttachmentLoadOp loadOp = isStencil ? _info.stencilLoadOp : _info.loadOp;
        mtlAttDesc.loadAction = mvkMTLLoadActionFromVkAttachmentLoadOp(loadOp);
        willClear = (_info.loadOp == VK_ATTACHMENT_LOAD_OP_CLEAR);
    } else {
        mtlAttDesc.loadAction = MTLLoadActionLoad;
    }

    // If a resolve attachment exists, this attachment must resolve once complete.
    // Otherwise only allow the attachment to be discarded if we're actually rendering
    // to the entire attachment and we're in the last subpass.
    if (hasResolveAttachment) {
        mtlAttDesc.storeAction = MTLStoreActionMultisampleResolve;
    } else if ( isRenderingEntireAttachment && (subpass->_subpassIndex == _lastUseSubpassIdx) ) {
        VkAttachmentStoreOp storeOp = isStencil ? _info.stencilStoreOp : _info.storeOp;
        mtlAttDesc.storeAction = mvkMTLStoreActionFromVkAttachmentStoreOp(storeOp);
    } else {
        mtlAttDesc.storeAction = MTLStoreActionStore;
    }
    return willClear;
}

bool MVKRenderPassAttachment::shouldUseClearAttachment(MVKRenderSubpass* subpass) {

	// If the subpass is not the first subpass to use this attachment, don't clear this attachment
	if (subpass->_subpassIndex != _firstUseSubpassIdx) { return false; }

	return (_info.loadOp == VK_ATTACHMENT_LOAD_OP_CLEAR);
}

MVKRenderPassAttachment::MVKRenderPassAttachment(MVKRenderPass* renderPass,
												 const VkAttachmentDescription* pCreateInfo) : MVKBaseObject() {
	_renderPass = renderPass;
	_attachmentIndex = uint32_t(_renderPass->_attachments.size());

	// Determine the indices of the first and last render subpasses to use that attachment.
	_firstUseSubpassIdx = kMVKMaxUnsigned;
	_lastUseSubpassIdx = 0;
	for (auto& subPass : _renderPass->_subpasses) {
		if (subPass.isUsingAttachmentAt(_attachmentIndex)) {
			uint32_t spIdx = subPass._subpassIndex;
			_firstUseSubpassIdx = MIN(spIdx, _firstUseSubpassIdx);
			_lastUseSubpassIdx = MAX(spIdx, _lastUseSubpassIdx);
		}
	}

    _info = *pCreateInfo;
}


#pragma mark -
#pragma mark MVKRenderPass

VkExtent2D MVKRenderPass::getRenderAreaGranularity() { return { 1, 1 }; }

MVKRenderSubpass* MVKRenderPass::getSubpass(uint32_t subpassIndex) { return &_subpasses[subpassIndex]; }

MVKRenderPass::MVKRenderPass(MVKDevice* device,
							 const VkRenderPassCreateInfo* pCreateInfo) : MVKBaseDeviceObject(device) {

    // Add subpasses and dependencies first
	_subpasses.reserve(pCreateInfo->subpassCount);
	for (uint32_t i = 0; i < pCreateInfo->subpassCount; i++) {
		_subpasses.push_back(MVKRenderSubpass(this, &pCreateInfo->pSubpasses[i]));
	}
	_subpassDependencies.reserve(pCreateInfo->dependencyCount);
	for (uint32_t i = 0; i < pCreateInfo->dependencyCount; i++) {
		_subpassDependencies.push_back(pCreateInfo->pDependencies[i]);
	}

	// Add attachments after subpasses, so each attachment can link to subpasses
	_attachments.reserve(pCreateInfo->attachmentCount);
	for (uint32_t i = 0; i < pCreateInfo->attachmentCount; i++) {
		_attachments.push_back(MVKRenderPassAttachment(this, &pCreateInfo->pAttachments[i]));
	}
}