docs/RELNOTES-4.1

   1
   2                             Mesa 4.1 release notes
   3
   4                             October, <day>, 2002
   5
   6                                PLEASE READ!!!!
   7
   8
   9
  10 Introduction
  11 ------------
  12
  13 Mesa uses an even/odd version number scheme like the Linux kernel.
  14 Even numbered versions (such as 4.0) designate stable releases.
  15 Odd numbered versions (such as 4.1) designate new developmental releases.
  16
  17
  18 New Features in Mesa 4.1
  19 ------------------------
  20
  21 New extensions.  Docs at http://oss.sgi.com/projects/ogl-sample/registry/
  22
  23 GL_NV_vertex_program
  24
  25     NVIDIA's vertex programming extension
  26
  27 GL_NV_vertex_program1_1
  28
  29     A few features built on top of GL_NV_vertex_program
  30
  31 GL_ARB_window_pos
  32
  33     This is the ARB-approved version of GL_MESA_window_pos
  34
  35 GL_ARB_depth_texture
  36
  37     This is the ARB-approved version of GL_SGIX_depth_texture.
  38     It allows depth (Z buffer) data to be stored in textures.
  39     This is used by GL_ARB_shadow
  40
  41 GL_ARB_shadow
  42
  43     Shadow mapping with depth textures.
  44     This is the ARB-approved version of GL_SGIX_shadow.
  45
  46 GL_ARB_shadow_ambient
  47
  48     Allows one to specify the luminance of shadowed pixels.
  49     This is the ARB-approved version of GL_SGIX_shadow_ambient.
  50
  51 GL_EXT_shadow_funcs
  52
  53     Extends the set of GL_ARB_shadow texture comparision functions to
  54     include all eight of standard OpenGL dept-test functions.
  55
  56 GL_ARB_point_parameters
  57
  58     This is basically the same as GL_EXT_point_parameters.
  59
  60 GL_ARB_texture_env_crossbar
  61
  62     Allows any texture combine stage to reference any texture source unit.
  63
  64 GL_NV_point_sprite
  65
  66     For rendering points as textured quads.  Useful for particle effects.
  67
  68 GL_NV_texture_rectangle  (new in 4.0.4 actually)
  69
  70     Allows one to use textures with sizes that are not powers of two.
  71     Note that mipmapping and several texture wrap modes are not allowed.
  72
  73 GL_EXT_multi_draw_arrays
  74
  75     Allows arrays of vertex arrays to be rendered with one call.
  76
  77 GL_EXT_stencil_two_side
  78
  79    Separate stencil modes for front and back-facing polygons.
  80
  81 GLX_SGIX_fbconfig & GLX_SGIX_pbuffer
  82
  83    Off-screen rendering support.
  84
  85
  86
  87 Device Driver Status
  88 --------------------
  89
  90 A number of Mesa's software drivers haven't been actively maintained for
  91 some time.  We rely on volunteers to maintain many of these drivers.
  92 Here's the current status of all included drivers:
  93
  94
  95 Driver                  Status
  96 ----------------------  ---------------------
  97 XMesa (Xlib)            implements OpenGL 1.3
  98 OSMesa (off-screen)     implements OpenGL 1.3
  99 FX (3dfx Voodoo1/2)     implements OpenGL 1.3
 100 SVGA                    implements OpenGL 1.3
 101 Wind River UGL          implements OpenGL 1.3
 102 Windows/Win32           implements OpenGL 1.3
 103 DOS/DJGPP               implements OpenGL 1.3
 104 GGI                     implements OpenGL 1.3
 105 BeOS                    needs updating (underway)
 106 Allegro                 needs updating
 107 D3D                     needs updating
 108 DOS                     needs updating
 109
 110
 111
 112 New features in GLUT
 113 --------------------
 114
 115 1. Frames per second printing
 116
 117    GLUT now looks for an environment variable called "GLUT_FPS".  If it's
 118    set, GLUT will print out a frames/second statistic to stderr when
 119    glutSwapBuffers() is called.  By default, frames/second is computed
 120    and displayed once every 5 seconds.  You can specify a different
 121    interval (in milliseconds) when you set the env var.  For example
 122    'export GLUT_FPS=1000' or 'setenv GLUT_FPS 1000' will set the interval
 123    to one second.
 124
 125    NOTE: the demo or application must call the glutInit() function for
 126    this to work.  Otherwise, the env var will be ignored.
 127
 128    Finally, this feature may not be reliable in multi-window programs.
 129
 130
 131 2. glutGetProcAddress() function
 132
 133    The new function:
 134
 135         void *glutGetProcAddress(const char *procName)
 136
 137    is a wrapper for glXGetProcAddressARB() and wglGetProcAddress().  It
 138    lets you dynamically get the address of an OpenGL function at runtime.
 139    The GLUT_API_VERSION has been bumped to 5, but I haven't bumped the
 140    GLUT version number from 3.7 since that's probably Mark Kilgard's role.
 141
 142    This function should probably also be able to return the address of
 143    GLUT functions themselves, but it doesn't do that yet.
 144
 145
 146
 147 XXX Things To Do Yet XXXX
 148 -------------------------
 149
 150 isosurf with vertex program exhibits some missing triangles (probably
 151 when recycling the vertex buffer for long prims).
 152
 153
 154
 155 Porting Info
 156 ------------
 157
 158 If you're porting a DRI or other driver from Mesa 4.0.x to Mesa 4.1 here
 159 are some things to change:
 160
 161 1. ctx->Texture._ReallyEnabled is obsolete.
 162
 163    Since there are now 5 texture targets (1D, 2D, 3D, cube and rect) that
 164    left room for only 6 units (6*5 < 32) in this field.
 165    This field is being replaced by ctx->Texture._EnabledUnits which has one
 166    bit per texture unit.  If the bit k of _EnabledUnits is set, that means
 167    ctx->Texture.Unit[k]._ReallyEnabled is non-zero.  You'll have to look at
 168    ctx->Texture.Unit[k]._ReallyEnabled to learn if the 1D, 2D, 3D, cube or
 169    rect texture is enabled for unit k.
 170
 171    This also means that the constants TEXTURE1_*, TEXTURE2_*, etc are
 172    obsolete.
 173
 174    The tokens TEXTURE0_* have been replaced as well (since there's no
 175    significance to the "0" part:
 176
 177    old token           new token
 178    TEXTURE0_1D         TEXTURE_1D_BIT
 179    TEXTURE0_2D         TEXTURE_2D_BIT
 180    TEXTURE0_3D         TEXTURE_3D_BIT
 181    TEXTURE0_CUBE       TEXTURE_CUBE_BIT
 182    <none>              TEXTURE_RECT_BIT
 183
 184    These tokens are only used for the ctx->Texture.Unit[i].Enabled and
 185    ctx->Texture.Unit[i]._ReallyEnabled fields.  Exactly 0 or 1 bits will
 186    be set in _ReallyEnabled at any time!
 187
 188    Q: "What's the purpose of Unit[i].Enabled vs Unit[i]._ReallyEnabled?"
 189    A: The user can enable GL_TEXTURE_1D, GL_TEXTURE_2D, etc for any
 190       texure unit all at once (an unusual thing to do).
 191       OpenGL defines priorities that basically say GL_TEXTURE_2D has
 192       higher priority than GL_TEXTURE_1D, etc.  Also, just because a
 193       texture target is enabled by the user doesn't mean we'll actually
 194       use that texture!  If a texture object is incomplete (missing mip-
 195       map levels, etc) it's as if texturing is disabled for that target.
 196       The _ReallyEnabled field will have a bit set ONLY if the texture
 197       target is enabled and complete.  This spares the driver writer from
 198       examining a _lot_ of GL state to determine which texture target is
 199       to be used.
 200
 201
 202 2. Tnl tokens changes
 203
 204    During the implementation of GL_NV_vertex_program some of the vertex
 205    buffer code was changed.  Specifically, the VERT_* bits defined in
 206    tnl/t_context.h have been renamed to better match the conventions of
 207    GL_NV_vertex_program.  The old names are still present but obsolete.
 208    Drivers should use the newer names.
 209
 210    For example:  VERT_RGBA is now VERT_BIT_COLOR0 and
 211    VERT_SPEC_RGB is now VERT_BIT_COLOR1.
 212
 213
 214
 215 3. Read/Draw Buffer changes
 216
 217    The business of setting the current read/draw buffers in Mesa 4.0.x
 218    was complicated.  It's much simpler now in Mesa 4.1.
 219
 220    Here are the changes:
 221
 222    - Rename ctx->Color.DrawDestMask to ctx->Color._DrawDestMask
 223    - Rename ctx->Color.DriverDrawBuffer to ctx->Color._DriverDrawBuffer
 224    - Rename ctx->Pixel.DriverReadBuffer to ctx->Pixel._DriverReadBuffer
 225    - Removed ctx->Color.MultiDrawBuffer
 226    - Removed ctx->Driver.SetDrawBuffer
 227    - Added ctx->Driver.DrawBuffer and ctx->Driver.ReadBuffer.  These functions
 228      exactly correspond to glDrawBuffer and glReadBuffer calls.
 229      Many drivers will set ctx->Driver.DrawBuffer = _swrast_DrawBuffer and
 230      leave ctx->Draw.ReadBuffer NULL.
 231      DRI drivers should implement their own function for ctx->Driver.DrawBuffer
 232      and use it to set the current hardware drawing buffer.  You'll probably
 233      also want to check for GL_FRONT_AND_BACK mode and fall back to software.
 234      Call _swrast_DrawBuffer() too, to update the swrast state.
 235    - Removed swrast->Driver.SetReadBuffer
 236    - Added swrast->Driver.SetBuffer.  This function should be implemented by
 237      _all_ device drivers.  Mesa will call it to specify the buffer to use
 238      for span reading AND writing and point/line/triangle rendering.  There
 239      should be no confusion between current read or draw buffer anymore.
 240
 241
 242 4. _mesa_create_context() changes.  This function now takes a pointer to
 243    a __GLimports object.  The __GLimports structure contains function
 244    pointers to system functions like fprintf(), malloc(), etc.
 245    The _mesa_init_default_imports() function can be used to initialize
 246    a __GLimports object.  Most device drivers (like the DRI drivers)
 247    should use this.
 248
 249
 250 5. In tnl's struct vertex_buffer, the field "ProjectedClipCoords"
 251    has been replaced by "NdcPtr" to better match the OpenGL spec's
 252    terminology.
 253
 254
 255 6. Since GL_EXT_stencil_two_side has been implemented, many of the
 256    ctx->Stencil fields are now 2-element arrays.  For example,
 257    "GLenum Ref" is now "GLenum Ref[2]"  The [0] elements are the front-face
 258    values and the [1] elements are the back-face values.
 259    ctx->Stencil.ActiveFace is 0 or 1 to indicate the current face for
 260    the glStencilOp/Func/Mask() functions.
 261    ctx->Stencil.TestTwoSide controls whether or not 1 or 2-sided stenciling
 262    is enabled.
 263
 264
 265 7. Removed ctx->Polygon._OffsetAny.  Removed ctx->Polygon.OffsetMRD.
 266
 267
 268 8. GLfloat / GLchan changes:
 269
 270      Changed ctx->Driver.ClearColor() to take GLfloat[4] instead of GLchan[4].
 271      ctx->Color.ClearColor is now GLfloat[4] too.
 272      Changed ctx->Driver.AlphaRef() to take GLfloat instead of GLchan.
 273      ctx->Color.AlphaRef is now GLfloat.
 274      texObj->BorderColor is now GLfloat[4].  texObj->_BorderChan is GLchan[4].
 275
 276    This is part of an effort to remove all GLchan types from core Mesa so
 277    that someday we can support 8, 16 and 32-bit color channels dynamically
 278    at runtime, instead of at compile-time.
 279
 280
 281 ----------------------------------------------------------------------
 282 $Id: RELNOTES-4.1,v 1.18 2002/10/05 18:32:38 brianp Exp $