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Mesa 3.5 release notes
June 21, 2001
Mesa uses an even/odd version number scheme like the Linux kernel.
Odd numbered versions (such as 3.5) designate new developmental releases.
Even numbered versions (such as 3.4) designate stable releases.
The biggest change in Mesa 3.5 is a complete overhaul of the source
code in order to make it more modular. This was driven by the DRI
hardware drivers. It simplifies the DRI drivers and opens the door
to hardware transform/clip/lighting (TCL). Keith Whitwell can take
the credit for that.
Driver Support
The device driver interface in Mesa 3.5 has changed a lot since Mesa 3.4
Not all of the older Mesa drivers have been updated. Here's the status:
Driver Status
---------------------- -----------
XMesa (Xlib) updated
OSMesa (off-screen) updated
FX (3dfx Voodoo1/2) updated
SVGA updated
GGI not updated
Windows/Win32 not updated
DOS/DJGPP not updated
BeOS not updated
Allegro not updated
D3D not updated
DOS not updated
We're looking for volunteers to update the remaining drivers. Please
post to the Mesa3d-dev mailing list if you can help.
GLU 1.3
Mesa 3.5 includes the SGI Sample Implementation (SI) GLU library.
This version of GLU supports the GLU 1.3 specification. The old
Mesa GLU library implemented the 1.1 specification. The SI GLU
library should work much better.
You'll need a C++ compiler to compile the SI GLU library. This may
be a problem on some systems.
New Extensions
Adds image convolution to glRead/Copy/DrawPixels/TexImage.
This is the optional imaging subset of OpenGL 1.2.
It's the GL_EXT_convolution, GL_HP_convolution_border_modes,
GL_EXT_histogram, GL_EXT_color_table, GL_EXT_color_subtable
GL_EXT_blend_color, GL_EXT_blend_minmax, GL_EXT_blend_subtract
and GL_SGI_color_matrix extensions all rolled together.
This is supported in all software renderers but not in all
hardware drivers (3dfx for example).
This is supported in Mesa but only used by the 3dfx DRI drivers
for Voodoo4 and later.
This is identical to GL_EXT_texture_env_add.
Adds extra blend source and dest factors which allow squaring
of color values.
Allows specification of a per-vertex fog coordinate instead of
having fog always computed from the eye distance.
Allows specifying the secondary (specular) color for each vertex
instead of getting it only from lighting in GL_SEPARATE_SPECULAR_COLOR
Basically the same as GL_EXT_texture_env_combine
GL_ARB_texture_env_add extension
Texture addition mode.
GL_ARB_texture_env_dot3 extension
Dot product texture environment.
Adds GL_CLAMP_TO_BORDER_ARB texture wrap mode
GL_SGIX_depth_texture, GL_SGIX_shadow and GL_SGIX_shadow_ambient
Implements a shadow casting algorithm based on depth map textures
Automatically generate lower mipmap images whenever the base mipmap
image is changed with glTexImage, glCopyTexImage, etc.
------------ is a new library which contains the OSMesa interface for
off-screen rendering. Apps which need the OSMesa interface should link
with both -lOSMesa and -lGL. This change was made so that stand-alone
Mesa works the same way as XFree86/DRI's libGL.
Device Driver Changes / Core Mesa Changes
The ctx->Driver.LogicOp() function has been removed. It used to
be called during state update in order to determine if the driver
could do glLogicOp() operations, and if not, set the SWLogicOpEnabled
flag. Drivers should instead examine the LogicOp state themselves
and choose specialized point, line, and triangle functions appropriately,
or fall back to software rendering. The Xlib driver was the only driver
to use this function. And since the Xlib driver no longer draws
points, lines or triangles using Xlib, the LogicOp function isn't needed.
The ctx->Driver.Dither() function has been removed. Drivers should
detect dither enable/disable via ctx->Driver.Enable() instead.
The ctx->Driver.IndexMask() and ctx->Driver.ColorMask() functions
are now just called from glIndexMask and glColorMask like the other
GL state-changing functions. They are no longer called from inside
gl_update_state(). Also, they now return void. The change was made
mostly for sake of uniformity.
The NEW_DRVSTATE[0123] flags have been removed. They weren't being used
and are obsolete w.r.t. the way state updates are done in DRI drivers.
Removed obsolete gl_create_visual() and gl_destroy_visual().
Renamed functions (new namespace):
old new
gl_create_framebuffer _mesa_create_framebuffer
gl_destroy_framebuffer _mesa_destroy_framebuffer
gl_create_context _mesa_create_context
gl_destroy_context _mesa_destroy_context
gl_context_initialize _mesa_context_initialize
gl_copy_context _mesa_copy_context
gl_make_current _mesa_make_current
gl_make_current2 _mesa_make_current2
gl_get_current_context _mesa_get_current_context
gl_flush_vb _mesa_flush_vb
gl_warning _mesa_warning
gl_compile_error _mesa_compile_error
All the drivers have been updated, but not all of them have been
tested since I can't test some platforms (DOS, Windows, Allegro, etc).
X/Mesa Driver
The source files for the X/Mesa driver in src/X have been renamed.
The xmesa[1234].c files are gone. The new files are xm_api.c,
xm_dd.c, xm_line.c, xm_span.c and xm_tri.c.
Eight texture units are now supported by default.
OpenGL SI related changes
In an effort to make Mesa's internal interfaces more like the OpenGL
SI interfaces, a number of changes have been made:
1. Importing the SI's glcore.h file which defines a number of
interface structures like __GLimports and __GLexports.
2. Renamed "struct gl_context" to "struct __GLcontextRec".
3. Added __glCoreCreateContext() and __glCoreNopDispatch() functions.
4. The GLcontext member Visual is no longer a pointer.
5. New file: imports.c to setup default import functions for Mesa.
16-bit color channels
There's experimental support for 16-bit color channels (64-bit pixels)
in Mesa 3.5. Only the OSMesa interface can be used for 16-bit rendering.
Type "make linux-osmesa16" in the top-level directory to build the
special library.
This hasn't been tested very thoroughly yet so please file bug reports
if you have trouble.
In the future I hope to implement support for 32-bit, floating point
color channels.