Effecient Texture MipMap Offset

Howdy, So ive nearly finished my image libary for loading and convertign textures, but im wonderign about a more effecient way to get surface data. These are the 2 storage methods that come to mind: std::vector<std::vector<Byte> > mData; Byte* mData; Vector Pros: -Can access any surface/mip easily: Uint32 Image::GetSurfaceIndex(Uint32 face, Uint32 mipLevel)const { return (face * (mFileInfo.mArraySize - 1)) + mipLevel; } -No manually memory clean up etc. Cons: -Cannot load Blob data in single call, must run loop such as: for (size_t f = 0; f < mFileInfo.mArraySize; f++) { Uint32 w = mFileInfo.mWidth; Uint32 h = mFileInfo.mHeight; for (size_t i = 0; i < mFileInfo.mMipCount; i++) { numBytes = GetSurfaceByteCount(w, h, mFileInfo.mSurfaceFormat); std::vector<Byte> cpyData = std::vector<Byte>(data, data + numBytes); mData[GetSurfaceIndex(f, i)] = cpyData; } if (src + numBytes > end) { Reset(); return; } src += numBytes; w = SF::Max(w >> 1, 1); h = SF::Max(h >> 1, 1); } Byte array Pros: -Loading is simple: mData = new Byte[mFileInfo.mByteCount]; memcpy(mData, ptr, mFileInfo.mByteCount); Cons: -Getting ptr to start of a surface becomes ineffecinet, especilaly with mips as it reuqires a loop. Byte* Image::GetPixelPtr(Uint32 face, Uint32 mipLevel, Uint32 x, Uint32 y) { if (mData.size() == 0) { return nullptr; } if (face > mFileInfo.mArraySize) { return nullptr; } if (mipLevel > mFileInfo.mMipCount) { return nullptr; } int w = mFileInfo.mWidth; int h = mFileInfo.mHeight; int mipBytes = 0; for(int i = 1; i < mipLevel, i++) { w = SF::Max(w >> 1,1 ); h = SF::Max(h >> 1, 1); mipBytes += GetSurfacebytes(w, h, mFileInfo.mSurfaceFormat); } return &mData[GetSurfaceOffset(face) + mipBytes + ((y * w) + x) * mPixelByteSize]; } Note that GetSurfaceOffset() calculates the offset to the start of a surface, includeing the offset of the previous surfaces mips. Does anyone know of a better way to store surface arrays with there mips in a single blob thats effecient to access? Thanks

from GameDev.net http://bit.ly/2WX7zc9
Howdy, So ive nearly finished my image libary for loading and convertign textures, but im wonderign about a more effecient way to get surface data. These are the 2 storage methods that come to mind: std::vector<std::vector<Byte> > mData; Byte* mData; Vector Pros: -Can access any surface/mip easily: Uint32 Image::GetSurfaceIndex(Uint32 face, Uint32 mipLevel)const { return (face * (mFileInfo.mArraySize - 1)) + mipLevel; } -No manually memory clean up etc. Cons: -Cannot load Blob data in single call, must run loop such as: for (size_t f = 0; f < mFileInfo.mArraySize; f++) { Uint32 w = mFileInfo.mWidth; Uint32 h = mFileInfo.mHeight; for (size_t i = 0; i < mFileInfo.mMipCount; i++) { numBytes = GetSurfaceByteCount(w, h, mFileInfo.mSurfaceFormat); std::vector<Byte> cpyData = std::vector<Byte>(data, data + numBytes); mData[GetSurfaceIndex(f, i)] = cpyData; } if (src + numBytes > end) { Reset(); return; } src += numBytes; w = SF::Max(w >> 1, 1); h = SF::Max(h >> 1, 1); } Byte array Pros: -Loading is simple: mData = new Byte[mFileInfo.mByteCount]; memcpy(mData, ptr, mFileInfo.mByteCount); Cons: -Getting ptr to start of a surface becomes ineffecinet, especilaly with mips as it reuqires a loop. Byte* Image::GetPixelPtr(Uint32 face, Uint32 mipLevel, Uint32 x, Uint32 y) { if (mData.size() == 0) { return nullptr; } if (face > mFileInfo.mArraySize) { return nullptr; } if (mipLevel > mFileInfo.mMipCount) { return nullptr; } int w = mFileInfo.mWidth; int h = mFileInfo.mHeight; int mipBytes = 0; for(int i = 1; i < mipLevel, i++) { w = SF::Max(w >> 1,1 ); h = SF::Max(h >> 1, 1); mipBytes += GetSurfacebytes(w, h, mFileInfo.mSurfaceFormat); } return &mData[GetSurfaceOffset(face) + mipBytes + ((y * w) + x) * mPixelByteSize]; } Note that GetSurfaceOffset() calculates the offset to the start of a surface, includeing the offset of the previous surfaces mips. Does anyone know of a better way to store surface arrays with there mips in a single blob thats effecient to access? Thanks https://ift.tt/eA8V8J June 24, 2019 at 03:05PM