[DX12] Create texture from dds files.

dx12_create_texture_from_dds.cpp

struct DDSHeader {
	uint32_t h3[3];
	int h, w;
	uint32_t h2[2];
	int mipCnt;
	uint32_t h13[13];
	uint32_t fourcc, bitsPerPixel, rMask, gMask, bMask, aMask, caps1, caps2;
	bool IsCubeMap() const { return caps2 == 0xFE00; }
	int GetArraySize() const { return IsCubeMap() ? 6 : 1; }
	int GetMipCnt() const { return std::max(mipCnt, 1); }
};

struct TexDesc {
	IVec2 size;
	int arraySize = 1;
	bool isCubeMap = false;
};

struct AFTexSubresourceData
{
	const void* ptr;
	uint32_t pitch;
	uint32_t pitchSlice;
};

static ComPtr<ID3D12Resource> LoadDDSTexture(const char* name, TexDesc& texDesc)
{
	int size;
	void* img = LoadFile(name, &size);
	if (!img) {
		aflog("LoadDDSTexture failed! %s", name);
		return nullptr;
	}
	const DDSHeader* hdr = (DDSHeader*)img;

	AFDTFormat format = AFDT_INVALID;
	int(*pitchCalcurator)(int, int) = nullptr;
	switch (hdr->fourcc) {
	case 0x31545844: //'1TXD':
		format = AFDT_BC1_UNORM;
		pitchCalcurator = [](int w, int h) { return ((w + 3) / 4) * ((h + 3) / 4) * 8; };
		break;
	case 0x33545844: //'3TXD':
		format = AFDT_BC2_UNORM;
		pitchCalcurator = [](int w, int h) { return ((w + 3) / 4) * ((h + 3) / 4) * 16; };
		break;
	case 0x35545844: //'5TXD':
		format = AFDT_BC3_UNORM;
		pitchCalcurator = [](int w, int h) { return ((w + 3) / 4) * ((h + 3) / 4) * 16; };
		break;
	default:
		ArrangeRawDDS(img, size);
		format = AFDT_R8G8B8A8_UNORM;
		pitchCalcurator = [](int w, int h) { return w * h * 4; };
		break;
	}
	texDesc.size.x = hdr->w;
	texDesc.size.y = hdr->h;
	texDesc.arraySize = hdr->GetArraySize();
	texDesc.isCubeMap = hdr->IsCubeMap();

	int arraySize = hdr->GetArraySize();
	int mipCnt = hdr->GetMipCnt();
	std::vector<AFTexSubresourceData> r;
	int offset = 128;
	for (int a = 0; a < arraySize; a++) {
		for (int m = 0; m < mipCnt; m++) {
			int w = std::max(1, hdr->w >> m);
			int h = std::max(1, hdr->h >> m);
			int size = pitchCalcurator(w, h);
			r.push_back({ (char*)img + offset, (uint32_t)pitchCalcurator(w, 1), (uint32_t)size });
			offset += size;
		}
	}

	ComPtr<ID3D12Resource> tex = afCreateTexture2D(format, texDesc, mipCnt, &r[0]);
	assert(tex);
	free(img);
	return tex;
}

static const D3D12_HEAP_PROPERTIES defaultHeapProperties = { D3D12_HEAP_TYPE_DEFAULT, D3D12_CPU_PAGE_PROPERTY_UNKNOWN, D3D12_MEMORY_POOL_UNKNOWN, 1, 1 };

ComPtr<ID3D12Resource> afCreateTexture2D(AFDTFormat format, const struct TexDesc& desc, int mipCount, const AFTexSubresourceData datas[])
{
	D3D12_RESOURCE_DESC resourceDesc = { D3D12_RESOURCE_DIMENSION_TEXTURE2D, 0, (UINT64)desc.size.x, (UINT)desc.size.y, (UINT16)desc.arraySize, (UINT16)mipCount, format, {1, 0} };
	ComPtr<ID3D12Resource> tex;
	HRESULT hr = deviceMan.GetDevice()->CreateCommittedResource(&defaultHeapProperties, D3D12_HEAP_FLAG_NONE, &resourceDesc, D3D12_RESOURCE_STATE_PIXEL_SHADER_RESOURCE, nullptr, IID_PPV_ARGS(&tex));
	afWriteTexture(tex, desc, mipCount, datas);
	return tex;
}