C++ TCacheEntryBase::Load方法代码示例

TextureCache::TCacheEntryBase* TextureCache::Load(const u32 stage)
{
	const FourTexUnits &tex = bpmem.tex[stage >> 2];
	const u32 id = stage & 3;
	const u32 address = (tex.texImage3[id].image_base/* & 0x1FFFFF*/) << 5;
	u32 width = tex.texImage0[id].width + 1;
	u32 height = tex.texImage0[id].height + 1;
	const int texformat = tex.texImage0[id].format;
	const u32 tlutaddr = tex.texTlut[id].tmem_offset << 9;
	const u32 tlutfmt = tex.texTlut[id].tlut_format;
	const bool use_mipmaps = (tex.texMode0[id].min_filter & 3) != 0;
	u32 tex_levels = use_mipmaps ? ((tex.texMode1[id].max_lod + 0xf) / 0x10 + 1) : 1;
	const bool from_tmem = tex.texImage1[id].image_type != 0;

	if (0 == address)
		return nullptr;

	// TexelSizeInNibbles(format) * width * height / 16;
	const unsigned int bsw = TexDecoder_GetBlockWidthInTexels(texformat);
	const unsigned int bsh = TexDecoder_GetBlockHeightInTexels(texformat);

	unsigned int expandedWidth = ROUND_UP(width, bsw);
	unsigned int expandedHeight = ROUND_UP(height, bsh);
	const unsigned int nativeW = width;
	const unsigned int nativeH = height;

	// Hash assigned to texcache entry (also used to generate filenames used for texture dumping and custom texture lookup)
	u64 base_hash = TEXHASH_INVALID;
	u64 full_hash = TEXHASH_INVALID;

	u32 full_format = texformat;

	const bool isPaletteTexture = (texformat == GX_TF_C4 || texformat == GX_TF_C8 || texformat == GX_TF_C14X2);

	// Reject invalid tlut format.
	if (isPaletteTexture && tlutfmt > GX_TL_RGB5A3)
		return nullptr;

	if (isPaletteTexture)
		full_format = texformat | (tlutfmt << 16);

	const u32 texture_size = TexDecoder_GetTextureSizeInBytes(expandedWidth, expandedHeight, texformat);
	u32 additional_mips_size = 0; // not including level 0, which is texture_size

	// GPUs don't like when the specified mipmap count would require more than one 1x1-sized LOD in the mipmap chain
	// e.g. 64x64 with 7 LODs would have the mipmap chain 64x64,32x32,16x16,8x8,4x4,2x2,1x1,0x0, so we limit the mipmap count to 6 there
	tex_levels = std::min<u32>(IntLog2(std::max(width, height)) + 1, tex_levels);

	for (u32 level = 1; level != tex_levels; ++level)
	{
		// We still need to calculate the original size of the mips
		const u32 expanded_mip_width = ROUND_UP(CalculateLevelSize(width, level), bsw);
		const u32 expanded_mip_height = ROUND_UP(CalculateLevelSize(height, level), bsh);

		additional_mips_size += TexDecoder_GetTextureSizeInBytes(expanded_mip_width, expanded_mip_height, texformat);
	}

	// If we are recording a FifoLog, keep track of what memory we read.
	// FifiRecorder does it's own memory modification tracking independant of the texture hashing below.
	if (g_bRecordFifoData && !from_tmem)
		FifoRecorder::GetInstance().UseMemory(address, texture_size + additional_mips_size, MemoryUpdate::TEXTURE_MAP);

	const u8* src_data;
	if (from_tmem)
		src_data = &texMem[bpmem.tex[stage / 4].texImage1[stage % 4].tmem_even * TMEM_LINE_SIZE];
	else
		src_data = Memory::GetPointer(address);

	// TODO: This doesn't hash GB tiles for preloaded RGBA8 textures (instead, it's hashing more data from the low tmem bank than it should)
	base_hash = GetHash64(src_data, texture_size, g_ActiveConfig.iSafeTextureCache_ColorSamples);
	u32 palette_size = 0;
	if (isPaletteTexture)
	{
		palette_size = TexDecoder_GetPaletteSize(texformat);
		full_hash = base_hash ^ GetHash64(&texMem[tlutaddr], palette_size, g_ActiveConfig.iSafeTextureCache_ColorSamples);
	}
	else
	{
		full_hash = base_hash;
	}

	// Search the texture cache for textures by address
	//
	// Find all texture cache entries for the current texture address, and decide whether to use one of
	// them, or to create a new one
	//
	// In most cases, the fastest way is to use only one texture cache entry for the same address. Usually,
	// when a texture changes, the old version of the texture is unlikely to be used again. If there were
	// new cache entries created for normal texture updates, there would be a slowdown due to a huge amount
	// of unused cache entries. Also thanks to texture pooling, overwriting an existing cache entry is
	// faster than creating a new one from scratch.
	//
	// Some games use the same address for different textures though. If the same cache entry was used in
	// this case, it would be constantly overwritten, and effectively there wouldn't be any caching for
	// those textures. Examples for this are Metroid Prime and Castlevania 3. Metroid Prime has multiple
	// sets of fonts on each other stored in a single texture and uses the palette to make different
	// characters visible or invisible. In Castlevania 3 some textures are used for 2 different things or
	// at least in 2 different ways(size 1024x1024 vs 1024x256).
	//
	// To determine whether to use multiple cache entries or a single entry, use the following heuristic:
//.........这里部分代码省略.........