/*
	Copyright 2021 flyinghead

	This file is part of Flycast.

    Flycast is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 2 of the License, or
    (at your option) any later version.

    Flycast is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with Flycast.  If not, see <https://www.gnu.org/licenses/>.
*/
#include "dx11_texture.h"
#include "dx11context.h"
#include <versionhelpers.h>

void DX11Texture::UploadToGPU(int width, int height, const u8* temp_tex_buffer, bool mipmapped, bool mipmapsIncluded)
{
	D3D11_TEXTURE2D_DESC desc{};
	desc.Width = width;
	desc.Height = height;
	desc.ArraySize = 1;
	desc.SampleDesc.Count = 1;
	desc.Usage = D3D11_USAGE_DEFAULT;
	desc.BindFlags = D3D11_BIND_SHADER_RESOURCE;

	u32 bpp = 2;
	switch (tex_type)
	{
	case TextureType::_5551:
		desc.Format = DXGI_FORMAT_B5G5R5A1_UNORM;
		break;
	case TextureType::_4444:
		desc.Format = DXGI_FORMAT_B4G4R4A4_UNORM;
		break;
	case TextureType::_565:
		desc.Format = DXGI_FORMAT_B5G6R5_UNORM;
		break;
	case TextureType::_8888:
		bpp = 4;
		desc.Format = DXGI_FORMAT_B8G8R8A8_UNORM;
		break;
	case TextureType::_8:
		bpp = 1;
		desc.Format = DXGI_FORMAT_A8_UNORM;
		break;
	default:
		return;
	}
	int mipmapLevels = 1;
	if (mipmapsIncluded)
	{
		mipmapLevels = 0;
		int dim = width;
		while (dim != 0)
		{
			mipmapLevels++;
			dim >>= 1;
		}
	}
	desc.MipLevels = mipmapLevels;

	if (texture != nullptr)
	{
		// Recreate the texture if its dimensions or format have changed
		D3D11_TEXTURE2D_DESC curDesc;
		texture->GetDesc(&curDesc);
		if (desc.Width != curDesc.Width || desc.Height != curDesc.Height || desc.Format != curDesc.Format || desc.MipLevels != curDesc.MipLevels)
		{
			textureView.reset();
			texture.reset();
		}
	}
	if (texture == nullptr)
	{
		if (mipmapped && !mipmapsIncluded)
		{
			desc.MipLevels = 0;
			desc.MiscFlags = D3D11_RESOURCE_MISC_GENERATE_MIPS;
			desc.BindFlags |= D3D11_BIND_RENDER_TARGET;
			mipmapLevels = 1;
		}
		if (SUCCEEDED(theDX11Context.getDevice()->CreateTexture2D(&desc, nullptr, &texture.get())))
		{
			D3D11_SHADER_RESOURCE_VIEW_DESC viewDesc{};
			viewDesc.Format = desc.Format;
			viewDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE2D;
			viewDesc.Texture2D.MipLevels = desc.MipLevels == 0 ? -1 : desc.MipLevels;
			theDX11Context.getDevice()->CreateShaderResourceView(texture, &viewDesc, &textureView.get());
		}
		verify(texture != nullptr);
		verify(textureView != nullptr);
	}

	for (int i = 0; i < mipmapLevels; i++)
	{
		u32 w = mipmapLevels == 1 ? width : 1 << i;
		u32 h = mipmapLevels == 1 ? height : 1 << i;
		theDX11Context.getDeviceContext()->UpdateSubresource(texture, mipmapLevels - i - 1, nullptr, temp_tex_buffer, w * bpp, w * bpp * h);
		temp_tex_buffer += (1 << (2 * i)) * bpp;
	}
	if (mipmapped && !mipmapsIncluded)
		theDX11Context.getDeviceContext()->GenerateMips(textureView);
}

#ifndef TARGET_UWP
bool DX11Texture::Force32BitTexture(TextureType type) const
{
	if (IsWindows8OrGreater())
		return false;
	// DXGI_FORMAT_B5G5R5A1_UNORM, DXGI_FORMAT_B4G4R4A4_UNORM and DXGI_FORMAT_B5G6R5_UNORM
	// are not supported on Windows 7
	return type == TextureType::_565 || type == TextureType::_5551 || type == TextureType::_4444;
}
#endif

bool DX11Texture::Delete()
{
	if (!BaseTextureCacheData::Delete())
		return false;

	textureView.reset();
	texture.reset();
	return true;
}

void DX11Texture::loadCustomTexture()
{
	u32 size = custom_width * custom_height;
	u8 *p = custom_image_data;
	while (size--)
	{
		// RGBA -> BGRA
		std::swap(p[0], p[2]);
		p += 4;
	}
	CheckCustomTexture();
}

HRESULT Samplers::createSampler(const D3D11_SAMPLER_DESC *desc, ID3D11SamplerState **sampler)
{
	return theDX11Context.getDevice()->CreateSamplerState(desc, sampler);
}