docs/RELNOTES-4.1

   1
   2                             Mesa 4.1 release notes
   3
   4                             <month>, <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
  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
  78
  79 Device Driver Status
  80 --------------------
  81
  82 A number of Mesa's software drivers haven't been actively maintained for
  83 some time.  We rely on volunteers to maintain many of these drivers.
  84 Here's the current status of all included drivers:
  85
  86
  87 Driver                  Status
  88 ----------------------  ---------------------
  89 XMesa (Xlib)            implements OpenGL 1.3
  90 OSMesa (off-screen)     implements OpenGL 1.3
  91 FX (3dfx Voodoo1/2)     implements OpenGL 1.3
  92 SVGA                    implements OpenGL 1.3
  93 Wind River UGL          implements OpenGL 1.3
  94 Windows/Win32           implements OpenGL 1.3
  95 DOS/DJGPP               implements OpenGL 1.3
  96 GGI                     implements OpenGL 1.3
  97 BeOS                    needs updating (underway)
  98 Allegro                 needs updating
  99 D3D                     needs updating
 100 DOS                     needs updating
 101
 102
 103
 104 New features in GLUT
 105 --------------------
 106
 107 1. Frames per second printing
 108
 109    GLUT now looks for an environment variable called "GLUT_FPS".  If it's
 110    set, GLUT will print out a frames/second statistic to stderr when
 111    glutSwapBuffers() is called.  By default, frames/second is computed
 112    and displayed once every 5 seconds.  You can specify a different
 113    interval (in milliseconds) when you set the env var.  For example
 114    'export GLUT_FPS=1000' or 'setenv GLUT_FPS 1000' will set the interval
 115    to one second.
 116
 117    NOTE: the demo or application must call the glutInit() function for
 118    this to work.  Otherwise, the env var will be ignored.
 119
 120    Finally, this feature may not be reliable in multi-window programs.
 121
 122
 123 2. glutGetProcAddress() function
 124
 125    The new function:
 126
 127         void *glutGetProcAddress(const char *procName)
 128
 129    is a wrapper for glXGetProcAddressARB() and wglGetProcAddress().  It
 130    lets you dynamically get the address of an OpenGL function at runtime.
 131    The GLUT_API_VERSION has been bumped to 5, but I haven't bumped the
 132    GLUT version number from 3.7 since that's probably Mark Kilgard's role.
 133
 134    This function should probably also be able to return the address of
 135    GLUT functions themselves, but it doesn't do that yet.
 136
 137
 138
 139 XXX Things To Do Yet XXXX
 140 -------------------------
 141
 142 Verify x86 code for normal transformation works with new 4-element normal
 143 vector arrays.  Pretty sure the SSE code is wrong.
 144
 145 Allow multiple points to be rendered into one sw_span.
 146
 147 improve point/line rendering speed.
 148
 149 glVertexAttrib*NV(index>15) should cause an error.
 150
 151 isosurf with vertex program exhibits some missing triangles (probably
 152 when recycling the vertex buffer for long prims).
 153
 154
 155
 156 Porting Info
 157 ------------
 158
 159 If you're porting a DRI or other driver from Mesa 4.0.x to Mesa 4.1 here
 160 are some things to change:
 161
 162 1. ctx->Texture._ReallyEnabled is obsolete.
 163
 164    Since there are now 5 texture targets (1D, 2D, 3D, cube and rect) that
 165    left room for only 6 units (6*5 < 32) in this field.
 166    This field is being replaced by ctx->Texture._EnabledUnits which has one
 167    bit per texture unit.  If the bit k of _EnabledUnits is set, that means
 168    ctx->Texture.Unit[k]._ReallyEnabled is non-zero.  You'll have to look at
 169    ctx->Texture.Unit[k]._ReallyEnabled to learn if the 1D, 2D, 3D, cube or
 170    rect texture is enabled for unit k.
 171
 172    This also means that the constants TEXTURE1_*, TEXTURE2_*, etc are
 173    obsolete.
 174
 175    The tokens TEXTURE0_* have been replaced as well (since there's no
 176    significance to the "0" part:
 177
 178    old token           new token
 179    TEXTURE0_1D         TEXTURE_1D_BIT
 180    TEXTURE0_2D         TEXTURE_2D_BIT
 181    TEXTURE0_3D         TEXTURE_3D_BIT
 182    TEXTURE0_CUBE       TEXTURE_CUBE_BIT
 183    <none>              TEXTURE_RECT_BIT
 184
 185    These tokens are only used for the ctx->Texture.Unit[i].Enabled and
 186    ctx->Texture.Unit[i]._ReallyEnabled fields.  Exactly 0 or 1 bits will
 187    be set in _ReallyEnabled at any time!
 188
 189    Q: "What's the purpose of Unit[i].Enabled vs Unit[i]._ReallyEnabled?"
 190    A: The user can enable GL_TEXTURE_1D, GL_TEXTURE_2D, etc for any
 191       texure unit all at once (an unusual thing to do).
 192       OpenGL defines priorities that basically say GL_TEXTURE_2D has
 193       higher priority than GL_TEXTURE_1D, etc.  Also, just because a
 194       texture target is enabled by the user doesn't mean we'll actually
 195       use that texture!  If a texture object is incomplete (missing mip-
 196       map levels, etc) it's as if texturing is disabled for that target.
 197       The _ReallyEnabled field will have a bit set ONLY if the texture
 198       target is enabled and complete.  This spares the driver writer from
 199       examining a _lot_ of GL state to determine which texture target is
 200       to be used.
 201
 202
 203 2. Tnl tokens changes
 204
 205    During the implementation of GL_NV_vertex_program some of the vertex
 206    buffer code was changed.  Specifically, the VERT_* bits defined in
 207    tnl/t_context.h have been renamed to better match the conventions of
 208    GL_NV_vertex_program.  The old names are still present but obsolete.
 209    Drivers should use the newer names.
 210
 211    For example:  VERT_RGBA is now VERT_BIT_COLOR0 and
 212    VERT_SPEC_RGB is now VERT_BIT_COLOR1.
 213
 214
 215
 216 3. Read/Draw Buffer changes
 217
 218    The business of setting the current read/draw buffers in Mesa 4.0.x
 219    was complicated.  It's much simpler now in Mesa 4.1.
 220
 221    Here are the changes:
 222
 223    - Rename ctx->Color.DrawDestMask to ctx->Color._DrawDestMask
 224    - Rename ctx->Color.DriverDrawBuffer to ctx->Color._DriverDrawBuffer
 225    - Rename ctx->Pixel.DriverReadBuffer to ctx->Pixel._DriverReadBuffer
 226    - Removed ctx->Color.MultiDrawBuffer
 227    - Removed ctx->Driver.SetDrawBuffer
 228    - Added ctx->Driver.DrawBuffer and ctx->Driver.ReadBuffer.  These functions
 229      exactly correspond to glDrawBuffer and glReadBuffer calls.
 230      Many drivers will set ctx->Driver.DrawBuffer = _swrast_DrawBuffer and
 231      leave ctx->Draw.ReadBuffer NULL.
 232      DRI drivers should implement their own function for ctx->Driver.DrawBuffer
 233      and use it to set the current hardware drawing buffer.  You'll probably
 234      also want to check for GL_FRONT_AND_BACK mode and fall back to software.
 235      Call _swrast_DrawBuffer() too, to update the swrast state.
 236    - Removed swrast->Driver.SetReadBuffer
 237    - Added swrast->Driver.SetBuffer.  This function should be implemented by
 238      _all_ device drivers.  Mesa will call it to specify the buffer to use
 239      for span reading AND writing and point/line/triangle rendering.  There
 240      should be no confusion between current read or draw buffer anymore.
 241
 242
 243 4. _mesa_create_context() changes.  This function now takes a pointer to
 244    a __GLimports object.  The __GLimports structure contains function
 245    pointers to system functions like fprintf(), malloc(), etc.
 246    The _mesa_init_default_imports() function can be used to initialize
 247    a __GLimports object.  Most device drivers (like the DRI drivers)
 248    should use this.
 249
 250
 251
 252 ----------------------------------------------------------------------
 253 $Id: RELNOTES-4.1,v 1.15 2002/08/17 00:23:19 brianp Exp $