﻿// Copyright 2018 The SwiftShader Authors. All Rights Reserved.
//
// 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 "VkImageView.hpp"
#include "VkImage.hpp"

namespace
{
	VkComponentMapping ResolveComponentMapping(VkComponentMapping m, vk::Format format)
	{
		if (m.r == VK_COMPONENT_SWIZZLE_IDENTITY) m.r = VK_COMPONENT_SWIZZLE_R;
		if (m.g == VK_COMPONENT_SWIZZLE_IDENTITY) m.g = VK_COMPONENT_SWIZZLE_G;
		if (m.b == VK_COMPONENT_SWIZZLE_IDENTITY) m.b = VK_COMPONENT_SWIZZLE_B;
		if (m.a == VK_COMPONENT_SWIZZLE_IDENTITY) m.a = VK_COMPONENT_SWIZZLE_A;

		// Replace non-present components with zero/one swizzles so that the sampler
		// will give us correct interactions between channel replacement and texel replacement,
		// where we've had to invent new channels behind the app's back (eg transparent decompression
		// of ETC2 RGB -> BGRA8)
		VkComponentSwizzle table[] = {
			VK_COMPONENT_SWIZZLE_IDENTITY,
			VK_COMPONENT_SWIZZLE_ZERO,
			VK_COMPONENT_SWIZZLE_ONE,
			VK_COMPONENT_SWIZZLE_R,
			format.componentCount() < 2 ? VK_COMPONENT_SWIZZLE_ZERO : VK_COMPONENT_SWIZZLE_G,
			format.componentCount() < 3 ? VK_COMPONENT_SWIZZLE_ZERO : VK_COMPONENT_SWIZZLE_B,
			format.componentCount() < 4 ? VK_COMPONENT_SWIZZLE_ONE : VK_COMPONENT_SWIZZLE_A,
		};

		return {table[m.r], table[m.g], table[m.b], table[m.a]};
	}

	VkImageSubresourceRange ResolveRemainingLevelsLayers(VkImageSubresourceRange range, const vk::Image *image)
	{
		return {
			range.aspectMask,
			range.baseMipLevel,
			(range.levelCount == VK_REMAINING_MIP_LEVELS) ? (image->getMipLevels() - range.baseMipLevel) : range.levelCount,
			range.baseArrayLayer,
			(range.layerCount == VK_REMAINING_ARRAY_LAYERS) ? (image->getArrayLayers() - range.baseArrayLayer) : range.layerCount,
		};
	}
}

namespace vk
{

std::atomic<uint32_t> ImageView::nextID(1);

ImageView::ImageView(const VkImageViewCreateInfo* pCreateInfo, void* mem) :
	image(Cast(pCreateInfo->image)), viewType(pCreateInfo->viewType), format(pCreateInfo->format),
	components(ResolveComponentMapping(pCreateInfo->components, format)),
	subresourceRange(ResolveRemainingLevelsLayers(pCreateInfo->subresourceRange, image))
{
}

size_t ImageView::ComputeRequiredAllocationSize(const VkImageViewCreateInfo* pCreateInfo)
{
	return 0;
}

void ImageView::destroy(const VkAllocationCallbacks* pAllocator)
{
}

bool ImageView::imageTypesMatch(VkImageType imageType) const
{
	uint32_t imageArrayLayers = image->getArrayLayers();

	switch(viewType)
	{
	case VK_IMAGE_VIEW_TYPE_1D:
		return (imageType == VK_IMAGE_TYPE_1D) &&
		       (subresourceRange.layerCount == 1);
	case VK_IMAGE_VIEW_TYPE_1D_ARRAY:
		return imageType == VK_IMAGE_TYPE_1D;
	case VK_IMAGE_VIEW_TYPE_2D:
		return ((imageType == VK_IMAGE_TYPE_2D) ||
		        ((imageType == VK_IMAGE_TYPE_3D) &&
		         (imageArrayLayers == 1))) &&
		       (subresourceRange.layerCount == 1);
	case VK_IMAGE_VIEW_TYPE_2D_ARRAY:
		return (imageType == VK_IMAGE_TYPE_2D) ||
		       ((imageType == VK_IMAGE_TYPE_3D) &&
		        (imageArrayLayers == 1));
	case VK_IMAGE_VIEW_TYPE_CUBE:
		return image->isCube() &&
		       (imageArrayLayers >= subresourceRange.layerCount) &&
		       (subresourceRange.layerCount == 6);
	case VK_IMAGE_VIEW_TYPE_CUBE_ARRAY:
		return image->isCube() &&
		       (imageArrayLayers >= subresourceRange.layerCount) &&
		       (subresourceRange.layerCount >= 6);
	case VK_IMAGE_VIEW_TYPE_3D:
		return (imageType == VK_IMAGE_TYPE_3D) &&
		       (imageArrayLayers == 1) &&
		       (subresourceRange.layerCount == 1);
	default:
		UNREACHABLE("Unexpected viewType %d", (int)viewType);
	}

	return false;
}

void ImageView::clear(const VkClearValue& clearValue, const VkImageAspectFlags aspectMask, const VkRect2D& renderArea)
{
	// Note: clearing ignores swizzling, so components is ignored.

	if(!imageTypesMatch(image->getImageType()))
	{
		UNIMPLEMENTED("imageTypesMatch");
	}

	if(!format.isCompatible(image->getFormat()))
	{
		UNIMPLEMENTED("incompatible formats");
	}

	VkImageSubresourceRange sr = subresourceRange;
	sr.aspectMask = aspectMask;
	image->clear(clearValue, format, renderArea, sr);
}

void ImageView::clear(const VkClearValue& clearValue, const VkImageAspectFlags aspectMask, const VkClearRect& renderArea)
{
	// Note: clearing ignores swizzling, so components is ignored.

	if(!imageTypesMatch(image->getImageType()))
	{
		UNIMPLEMENTED("imageTypesMatch");
	}

	if(!format.isCompatible(image->getFormat()))
	{
		UNIMPLEMENTED("incompatible formats");
	}

	VkImageSubresourceRange sr;
	sr.aspectMask = aspectMask;
	sr.baseMipLevel = subresourceRange.baseMipLevel;
	sr.levelCount = subresourceRange.levelCount;
	sr.baseArrayLayer = renderArea.baseArrayLayer + subresourceRange.baseArrayLayer;
	sr.layerCount = renderArea.layerCount;

	image->clear(clearValue, format, renderArea.rect, sr);
}

void ImageView::resolve(ImageView* resolveAttachment)
{
	if((subresourceRange.levelCount != 1) || (resolveAttachment->subresourceRange.levelCount != 1))
	{
		UNIMPLEMENTED("levelCount");
	}

	VkImageCopy region;
	region.srcSubresource =
	{
		subresourceRange.aspectMask,
		subresourceRange.baseMipLevel,
		subresourceRange.baseArrayLayer,
		subresourceRange.layerCount
	};
	region.srcOffset = { 0, 0, 0 };
	region.dstSubresource =
	{
		resolveAttachment->subresourceRange.aspectMask,
		resolveAttachment->subresourceRange.baseMipLevel,
		resolveAttachment->subresourceRange.baseArrayLayer,
		resolveAttachment->subresourceRange.layerCount
	};
	region.dstOffset = { 0, 0, 0 };
	region.extent = image->getMipLevelExtent(subresourceRange.baseMipLevel);

	image->copyTo(*(resolveAttachment->image), region);
}

const Image* ImageView::getImage(Usage usage) const
{
	switch(usage)
	{
	case RAW:
		return image;
	case SAMPLING:
		return image->getSampledImage(format);
	default:
		UNIMPLEMENTED("usage %d", int(usage));
		return nullptr;
	}
}

Format ImageView::getFormat(Usage usage) const
{
	return ((usage == RAW) || (getImage(usage) == image)) ? format : getImage(usage)->getFormat();
}

int ImageView::rowPitchBytes(VkImageAspectFlagBits aspect, uint32_t mipLevel, Usage usage) const
{
	return getImage(usage)->rowPitchBytes(aspect, subresourceRange.baseMipLevel + mipLevel);
}

int ImageView::slicePitchBytes(VkImageAspectFlagBits aspect, uint32_t mipLevel, Usage usage) const
{
	return getImage(usage)->slicePitchBytes(aspect, subresourceRange.baseMipLevel + mipLevel);
}

int ImageView::layerPitchBytes(VkImageAspectFlagBits aspect, Usage usage) const
{
	return static_cast<int>(getImage(usage)->getLayerSize(aspect));
}

VkExtent3D ImageView::getMipLevelExtent(uint32_t mipLevel) const
{
	return image->getMipLevelExtent(subresourceRange.baseMipLevel + mipLevel);
}

void *ImageView::getOffsetPointer(const VkOffset3D& offset, VkImageAspectFlagBits aspect, uint32_t mipLevel, uint32_t layer, Usage usage) const
{
	ASSERT(mipLevel < subresourceRange.levelCount);

	VkImageSubresourceLayers imageSubresourceLayers =
	{
		static_cast<VkImageAspectFlags>(aspect),
		subresourceRange.baseMipLevel + mipLevel,
		subresourceRange.baseArrayLayer + layer,
		subresourceRange.layerCount
	};
	return getImage(usage)->getTexelPointer(offset, imageSubresourceLayers);
}

}