glCopyImageSubData

glCopyImageSubData: man4/glCopyImageSubData.xml

glCopyImageSubData may be used to copy data from one image (i.e. texture or renderbuffer) to another. glCopyImageSubData does not perform general-purpose conversions such as scaling, resizing, blending, color-space, or format conversions. It should be considered to operate in a manner similar to a CPU memcpy. CopyImageSubData can copy between images with different internal formats, provided the formats are compatible. glCopyImageSubData also allows copying between certain types of compressed and uncompressed internal formats. This copy does not perform on-the-fly compression or decompression. When copying from an uncompressed internal format to a compressed internal format, each texel of uncompressed data becomes a single block of compressed data. When copying from a compressed internal format to an uncompressed internal format, a block of compressed data becomes a single texel of uncompressed data. The texel size of the uncompressed format must be the same size the block size of the compressed formats. Thus it is permitted to copy between a 128-bit uncompressed format and a compressed format which uses 8-bit 4x4 blocks, or between a 64-bit uncompressed format and a compressed format which uses 4-bit 4x4 blocks. The source object is identified by srcName and srcTarget and the destination object is identified by dstName and dstTarget. The interpretation of the name depends on the value of the corresponding target parameter. If target is GL_RENDERBUFFER, the name is interpreted as the name of a renderbuffer object. If the target parameter is a texture target, the name is interpreted as a texture object. All non-proxy texture targets are accepted, with the exception of GL_TEXTURE_BUFFER and the cubemap face selectors. srcLevel and dstLevel identify the source and destination level of detail. For textures, this must be a valid level of detail in the texture object. For renderbuffers, this value must be zero. srcX, srcY, and srcZ specify the lower left texel coordinates of a srcWidth -wide by srcHeight -high by srcDepth -deep rectangular subregion of the source texel array. Similarly, dstX, dstY and dstZ specify the coordinates of a subregion of the destination texel array. The source and destination subregions must be contained entirely within the specified level of the corresponding image objects. The dimensions are always specified in texels, even for compressed texture formats. However, it should be noted that if only one of the source and destination textures is compressed then the number of texels touched in the compressed image will be a factor of the block size larger than in the uncompressed image. Slices of a GL_TEXTURE_1D_ARRAY, GL_TEXTURE_2D_ARRAY, GL_TEXTURE_CUBE_MAP_ARRAY GL_TEXTURE_3D and faces of GL_TEXTURE_CUBE_MAP are all compatible provided they share a compatible internal format, and multiple slices or faces may be copied between these objects with a single call by specifying the starting slice with srcZ and dstZ, and the number of slices to be copied with srcDepth. Cubemap textures always have six faces which are selected by a zero-based face index. For the purposes of CopyImageSubData, two internal formats are considered compatible if any of the following conditions are met:

1. the formats are the same,
2. the formats are considered compatible according to the compatibility rules used for texture views as defined in section 3.9.X. In particular, if both internal formats are listed in the same entry of Table 3.X.2, they are considered compatible, or
3. one format is compressed and the other is uncompressed and Table 4.X.1 lists the two formats in the same row.

If the formats are not compatible, an INVALID_OPERATION error is generated.<h3> Sized Internal Formats</h3> Texel / Block Size Uncompressed Internal Format Compressed Internal Format(s) 64-bit GL_RGBA32UI, GL_RGBA32I, GL_RGBA32F GL_COMPRESSED_RGBA_S3TC_DXT3_EXT, GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT, GL_COMPRESSED_RGBA_S3TC_DXT5_EXT, GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT, GL_COMPRESSED_RG_RGTC2, GL_COMPRESSED_SIGNED_RG_RGTC2, GL_COMPRESSED_RGBA_BPTC_UNORM, GL_COMPRESSED_SRGB_ALPHA_BPTC_UNORM, GL_COMPRESSED_RGB_BPTC_SIGNED_FLOAT, GL_COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT 128-bit GL_RGBA16UI, GL_RGBA16I, GL_RGBA16F, GL_RG32F, GL_RG32UI, GL_RG32I, GL_RGBA16, GL_RGBA16_SNORM GL_COMPRESSED_RGB_S3TC_DXT1_EXT, GL_COMPRESSED_SRGB_S3TC_DXT1_EXT, GL_COMPRESSED_RGBA_S3TC_DXT1_EXT, GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT, GL_COMPRESSED_RED_RGTC1, GL_COMPRESSED_SIGNED_RED_RGTC1