On Mon, 2010-02-22 at 06:34 -0800, José Fonseca wrote: > On Sun, 2010-02-21 at 06:40 -0800, Marek Olšák wrote: > > Hi José, > > > > the attached patch fixes incorrect swizzles in u_format.csv. There are > > basically just 2 drivers which depend on the swizzles in this table: > > llvmpipe and r300g. Since r300g started supporting pretty much every > > texture format except SCALED ones, a few regressions have showed up. > > This patch resolves all issues I had, especially with the SRGB formats > > but I decided to clean it up all. git log: > > > > util: fix swizzles in the format table for 8-bits-per-channel > > formats > > > > The 8-bits-per-channel formats having the same channel order had > > completely > > different swizzles, and at the same time, the same swizzles were > > used for > > completely different channel orders of 8bpc formats. > > > > This made the whole table self-contradicting, caused headaches, > > and last > > but not least, incorrent rendering for the drivers relying on > > these swizzles. > > > > I hope I got it right. I didn't make a special distinction between the > > array and arith layouts. All I did was to make sure that if I grep > > e.g. A8R8G8B8, I'll get the same swizzles and not entirely different > > ones. > > Hi Marek, > > I'll need a bit more time to investigate this. > > One problem is that the interpretation of the swizzle varies with array > vs arith. The ordering for array is the lowest significant word to the > highest significant word (where word for 8bit formats is a byte), where > for arith it goes from least significant bit to the highest significant > bit. This is the same difference as array indexation and bit shifts. > > There is also the problem of byte order which affects the bit shift > interpretation... > > I admit thet the current format description table is terribly > underdocumented/confusing and likely broken in several ways. I wrote it > to be able to code generate pixel format translation (which is wroking > reasonably) and never expected people to use it for hardware drivers as > well, although it is perfectly legitimate use. > > I have my own interpretation of these concepts, you and others hw driver > writers have their own different interpretation. Furthermore in > draw/translate/util modules there are some inconsistencies in these > interpretations too. So I need to read the GL and DX10 specs very well, > see how current drivers are using the descriptions, and come up with > something that makes sense for everybody. > > So please hold on to your patch for a couple of days. > > I'd appreciate if the interested parties could take a good look to > u_format.h comments, and summarize what they think the format semantics > should be. > > Jose
There are two inconsistencies in formats ATM: a) the notation used in PIPE_FORMAT_xxx, and b) the values in util_format_description::swizzles . There's a D3D9 <-> D3D10 format conversion table in http://msdn.microsoft.com/en-us/library/ee415668(VS.85).aspx#Porting_Content and D3D9 <-> GL format table in http://source.winehq.org/git/wine.git/?a=blob;f=dlls/wined3d/utils.c;hb=HEAD . D3D10 dropped all arithmetically encoded formats, and inverted the swizzle notation (e.g., D3DFMT_A2B10G10R10 and DXGI_FORMAT_R10G10B10A2 are equivalent). Gallium has to represent both kinds and mixes both notations (the MSB->LSB notation traditionally used for texture formats, the LSB->MSB for vertex declarations). So instead of the current inconsistencies, both on p_format.h and u_format.csv, I suggest we all normalize on one notation, lets say MSB->LSB for pixel/vertex formats. For example, the vertex format struct vertex { float x; float y; }; should be described the format PIPE_FORMAT_G32R32_FLOAT (not the current PIPE_FORMAT_R32G32_FLOAT), which is equivalent: - D3D9's D3DFMT_G32R32F texture format - D3D9's D3DDECLTYPE_FLOAT2 vertex declaration type - D3D10's DXGI_FORMAT_R32G32_FLOAT - OpenGL's GL_RG32F format - OpenGL's glVertexAttrib2f attribute - OpenGL's glVertexPointer(2, GL_FLOAT, 0, 0); - etc. For the util_format_description::swizzles I suggest we always refer the swizzles from LSB->MSB. Leaving the interface change aside for now (Keith is away this week), unless somebody has a better suggestion I'll update at least the meaning of util_format_description::swizzles and u_format.csv to be consistent with this. Does everybody agree this is a sensible thing to do? Jose ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Mesa3d-dev mailing list Mesa3d-dev@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mesa3d-dev
