308 lines
10 KiB
Groff
308 lines
10 KiB
Groff
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Mesa 4.1 release notes
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October 29, 2002
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PLEASE READ!!!!
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Introduction
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------------
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Mesa uses an even/odd version number scheme like the Linux kernel.
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Even numbered versions (such as 4.0) designate stable releases.
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Odd numbered versions (such as 4.1) designate new developmental releases.
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New Features in Mesa 4.1
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------------------------
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New extensions. Docs at http://oss.sgi.com/projects/ogl-sample/registry/
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GL_NV_vertex_program
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NVIDIA's vertex programming extension
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GL_NV_vertex_program1_1
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A few features built on top of GL_NV_vertex_program
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GL_ARB_window_pos
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This is the ARB-approved version of GL_MESA_window_pos
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GL_ARB_depth_texture
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This is the ARB-approved version of GL_SGIX_depth_texture.
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It allows depth (Z buffer) data to be stored in textures.
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This is used by GL_ARB_shadow
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GL_ARB_shadow
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Shadow mapping with depth textures.
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This is the ARB-approved version of GL_SGIX_shadow.
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GL_ARB_shadow_ambient
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Allows one to specify the luminance of shadowed pixels.
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This is the ARB-approved version of GL_SGIX_shadow_ambient.
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GL_EXT_shadow_funcs
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Extends the set of GL_ARB_shadow texture comparision functions to
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include all eight of standard OpenGL dept-test functions.
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GL_ARB_point_parameters
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This is basically the same as GL_EXT_point_parameters.
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GL_ARB_texture_env_crossbar
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Allows any texture combine stage to reference any texture source unit.
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GL_NV_point_sprite
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For rendering points as textured quads. Useful for particle effects.
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GL_NV_texture_rectangle (new in 4.0.4 actually)
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Allows one to use textures with sizes that are not powers of two.
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Note that mipmapping and several texture wrap modes are not allowed.
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GL_EXT_multi_draw_arrays
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Allows arrays of vertex arrays to be rendered with one call.
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GL_EXT_stencil_two_side
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Separate stencil modes for front and back-facing polygons.
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GLX_SGIX_fbconfig & GLX_SGIX_pbuffer
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Off-screen rendering support.
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GL_ATI_texture_mirror_once
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Adds two new texture wrap modes: GL_MIRROR_CLAMP_ATI and
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GL_MIRROR_CLAMP_TO_EDGE_ATI.
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Device Driver Status
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--------------------
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A number of Mesa's software drivers haven't been actively maintained for
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some time. We rely on volunteers to maintain many of these drivers.
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Here's the current status of all included drivers:
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Driver Status
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---------------------- ---------------------
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XMesa (Xlib) implements OpenGL 1.3
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OSMesa (off-screen) implements OpenGL 1.3
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FX (3dfx Voodoo1/2) implements OpenGL 1.3
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SVGA implements OpenGL 1.3
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Wind River UGL implements OpenGL 1.3
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Windows/Win32 implements OpenGL 1.3
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DOS/DJGPP implements OpenGL 1.3
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GGI implements OpenGL 1.3
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BeOS needs updating (underway)
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Allegro needs updating
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D3D needs updating
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DOS needs updating
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New features in GLUT
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--------------------
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1. Frames per second printing
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GLUT now looks for an environment variable called "GLUT_FPS". If it's
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set, GLUT will print out a frames/second statistic to stderr when
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glutSwapBuffers() is called. By default, frames/second is computed
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and displayed once every 5 seconds. You can specify a different
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interval (in milliseconds) when you set the env var. For example
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'export GLUT_FPS=1000' or 'setenv GLUT_FPS 1000' will set the interval
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to one second.
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NOTE: the demo or application must call the glutInit() function for
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this to work. Otherwise, the env var will be ignored.
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Finally, this feature may not be reliable in multi-window programs.
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2. glutGetProcAddress() function
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The new function:
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void *glutGetProcAddress(const char *procName)
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is a wrapper for glXGetProcAddressARB() and wglGetProcAddress(). It
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lets you dynamically get the address of an OpenGL function at runtime.
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The GLUT_API_VERSION has been bumped to 5, but I haven't bumped the
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GLUT version number from 3.7 since that's probably Mark Kilgard's role.
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This function should probably also be able to return the address of
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GLUT functions themselves, but it doesn't do that yet.
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XXX Things To Do Yet XXXX
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-------------------------
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isosurf with vertex program exhibits some missing triangles (probably
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when recycling the vertex buffer for long prims).
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Porting Info
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------------
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If you're porting a DRI or other driver from Mesa 4.0.x to Mesa 4.1 here
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are some things to change:
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1. ctx->Texture._ReallyEnabled is obsolete.
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Since there are now 5 texture targets (1D, 2D, 3D, cube and rect) that
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left room for only 6 units (6*5 < 32) in this field.
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This field is being replaced by ctx->Texture._EnabledUnits which has one
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bit per texture unit. If the bit k of _EnabledUnits is set, that means
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ctx->Texture.Unit[k]._ReallyEnabled is non-zero. You'll have to look at
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ctx->Texture.Unit[k]._ReallyEnabled to learn if the 1D, 2D, 3D, cube or
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rect texture is enabled for unit k.
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This also means that the constants TEXTURE1_*, TEXTURE2_*, etc are
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obsolete.
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The tokens TEXTURE0_* have been replaced as well (since there's no
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significance to the "0" part:
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old token new token
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TEXTURE0_1D TEXTURE_1D_BIT
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TEXTURE0_2D TEXTURE_2D_BIT
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TEXTURE0_3D TEXTURE_3D_BIT
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TEXTURE0_CUBE TEXTURE_CUBE_BIT
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<none> TEXTURE_RECT_BIT
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These tokens are only used for the ctx->Texture.Unit[i].Enabled and
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ctx->Texture.Unit[i]._ReallyEnabled fields. Exactly 0 or 1 bits will
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be set in _ReallyEnabled at any time!
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Q: "What's the purpose of Unit[i].Enabled vs Unit[i]._ReallyEnabled?"
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A: The user can enable GL_TEXTURE_1D, GL_TEXTURE_2D, etc for any
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texure unit all at once (an unusual thing to do).
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OpenGL defines priorities that basically say GL_TEXTURE_2D has
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higher priority than GL_TEXTURE_1D, etc. Also, just because a
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texture target is enabled by the user doesn't mean we'll actually
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use that texture! If a texture object is incomplete (missing mip-
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map levels, etc) it's as if texturing is disabled for that target.
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The _ReallyEnabled field will have a bit set ONLY if the texture
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target is enabled and complete. This spares the driver writer from
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examining a _lot_ of GL state to determine which texture target is
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to be used.
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2. Tnl tokens changes
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During the implementation of GL_NV_vertex_program some of the vertex
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buffer code was changed. Specifically, the VERT_* bits defined in
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tnl/t_context.h have been renamed to better match the conventions of
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GL_NV_vertex_program. The old names are still present but obsolete.
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Drivers should use the newer names.
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For example: VERT_RGBA is now VERT_BIT_COLOR0 and
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VERT_SPEC_RGB is now VERT_BIT_COLOR1.
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3. Read/Draw Buffer changes
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The business of setting the current read/draw buffers in Mesa 4.0.x
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was complicated. It's much simpler now in Mesa 4.1.
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Here are the changes:
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- Renamed ctx->Color.DrawDestMask to ctx->Color._DrawDestMask
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- Removed ctx->Color.DriverDrawBuffer
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- Removed ctx->Pixel.DriverReadBuffer
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- Removed ctx->Color.MultiDrawBuffer
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- Removed ctx->Driver.SetDrawBuffer()
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- Removed swrast->Driver.SetReadBuffer().
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- Added ctx->Color._DrawDestMask - a bitmask of FRONT/BACK_LEFT/RIGHT_BIT
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values to indicate the current draw buffers.
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- Added ctx->Pixel._ReadSrcMask to indicate the source for pixel reading.
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The value is _one_ of the FRONT/BACK_LEFT/RIGHT_BIT values.
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- Added ctx->Driver.DrawBuffer() and ctx->Driver.ReadBuffer().
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These functions exactly correspond to glDrawBuffer and glReadBuffer calls.
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Many drivers will set ctx->Driver.DrawBuffer = _swrast_DrawBuffer and
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leave ctx->Draw.ReadBuffer NULL.
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DRI drivers should implement their own function for ctx->Driver.DrawBuffer
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and use it to set the current hardware drawing buffer. You'll probably
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also want to check for GL_FRONT_AND_BACK mode and fall back to software.
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Call _swrast_DrawBuffer() too, to update the swrast state.
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- Added swrast->Driver.SetBuffer().
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This function should be implemented by all device drivers that use swrast.
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Mesa will call it to specify the buffer to use for span reading AND
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writing and point/line/triangle rendering.
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There should be no confusion between current read or draw buffer anymore.
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- Added swrast->CurrentBuffer to indicate which color buffer to read/draw.
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Will be FRONT_LEFT_BIT, BACK_LEFT_BIT, FRONT_RIGHT_BIT or BACK_RIGHT_BIT.
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This value is usually passed to swrast->Driver.SetBuffer().
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4. _mesa_create_context() changes. This function now takes a pointer to
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a __GLimports object. The __GLimports structure contains function
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pointers to system functions like fprintf(), malloc(), etc.
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The _mesa_init_default_imports() function can be used to initialize
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a __GLimports object. Most device drivers (like the DRI drivers)
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should use this.
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5. In tnl's struct vertex_buffer, the field "ProjectedClipCoords"
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has been replaced by "NdcPtr" to better match the OpenGL spec's
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terminology.
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6. Since GL_EXT_stencil_two_side has been implemented, many of the
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ctx->Stencil fields are now 2-element arrays. For example,
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"GLenum Ref" is now "GLenum Ref[2]" The [0] elements are the front-face
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values and the [1] elements are the back-face values.
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ctx->Stencil.ActiveFace is 0 or 1 to indicate the current face for
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the glStencilOp/Func/Mask() functions.
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ctx->Stencil.TestTwoSide controls whether or not 1 or 2-sided stenciling
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is enabled.
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7. Removed ctx->Polygon._OffsetAny. Removed ctx->Polygon.OffsetMRD.
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8. GLfloat / GLchan changes:
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- Changed ctx->Driver.ClearColor() to take GLfloat[4] instead of GLchan[4].
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ctx->Color.ClearColor is now GLfloat[4] too.
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- Changed ctx->Driver.AlphaRef() to take GLfloat instead of GLchan.
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- ctx->Color.AlphaRef is now GLfloat.
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- texObj->BorderColor is now GLfloat[4]. texObj->_BorderChan is GLchan[4].
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This is part of an effort to remove all GLchan types from core Mesa so
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that someday we can support 8, 16 and 32-bit color channels dynamically
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at runtime, instead of at compile-time.
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9. GLboolean ctx->Tranform.ClipEnabled[MAX_CLIP_PLANES] has been replaced
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by GLuint ctx->Transform.ClipPlanesEnabled. The later is a bitfield.
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10. There's a new matrix_stack type in mtypes.h used for the Modelview,
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Projection, Color and Texcoord matrix stacks.
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11. The ctx->Current.* fields have changed a lot. Now, there's a
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ctx->Current.Attrib[] array for all vertex attributes which matches
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the NV vertex program conventions.
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----------------------------------------------------------------------
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