Bug#390405: libgl1-mesa-dri: fog modes LINEAR and EXP broken on
Rage Mobility 7500 (w/ trivial fix)
Christopher Lane Hinson
lane at downstairspeople.org
Sun Oct 1 01:38:56 UTC 2006
Package: libgl1-mesa-dri
Version: 6.5.1-0.1
Severity: normal
Since upgrading from sarge to etch, I noticed that fog does not render at all in several
OpenGL applications if the fog mode is LINEAR or EXP, but does render correctly when the
fog mode is set to EXP2. Using grep I discovered the following suspicious snippet of
code:
mesa-6.5.0.cvs.20060524/src/mesa/drivers/dri/radeon/radeon_state.c starting on line 362
case GL_EXP:
c.f = 0.0;
/* While this is the opposite sign from the DDK, it makes the fog test
* pass, and matches r200.
*/
d.f = -ctx->Fog.Density;
break;
case GL_EXP2:
c.f = 0.0;
d.f = -(ctx->Fog.Density * ctx->Fog.Density);
break;
case GL_LINEAR:
if (ctx->Fog.Start == ctx->Fog.End) {
c.f = 1.0F;
d.f = 1.0F;
} else {
c.f = ctx->Fog.End/(ctx->Fog.End-ctx->Fog.Start);
/* While this is the opposite sign from the DDK, it makes the fog
* test pass, and matches r200.
*/
d.f = -1.0/(ctx->Fog.End-ctx->Fog.Start);
}
break;
Indeed, removing the two unary minus operators fixes the problem. I didn't include a
patch because I figure such a simple correction would just break fog on the system of the
developer who inserted the comments in the first place.
I checked the source in unstable (mesa 6.5.1) and did not see any correction to the source
code, and so I'm assuming that it hasn't been noticed of fixed.
glxinfo after applying my correction:
$ glxinfo
name of display: :0.0
display: :0 screen: 0
direct rendering: Yes
server glx vendor string: SGI
server glx version string: 1.2
server glx extensions:
GLX_ARB_multisample, GLX_EXT_visual_info, GLX_EXT_visual_rating,
GLX_EXT_import_context, GLX_OML_swap_method, GLX_SGI_make_current_read,
GLX_SGIS_multisample, GLX_SGIX_hyperpipe, GLX_SGIX_swap_barrier,
GLX_SGIX_fbconfig
client glx vendor string: SGI
client glx version string: 1.4
client glx extensions:
GLX_ARB_get_proc_address, GLX_ARB_multisample, GLX_EXT_import_context,
GLX_EXT_visual_info, GLX_EXT_visual_rating, GLX_MESA_allocate_memory,
GLX_MESA_copy_sub_buffer, GLX_MESA_swap_control,
GLX_MESA_swap_frame_usage, GLX_OML_swap_method, GLX_OML_sync_control,
GLX_SGI_make_current_read, GLX_SGI_swap_control, GLX_SGI_video_sync,
GLX_SGIS_multisample, GLX_SGIX_fbconfig, GLX_SGIX_pbuffer,
GLX_SGIX_visual_select_group, GLX_EXT_texture_from_pixmap
GLX version: 1.2
GLX extensions:
GLX_ARB_get_proc_address, GLX_ARB_multisample, GLX_EXT_import_context,
GLX_EXT_visual_info, GLX_EXT_visual_rating, GLX_MESA_swap_control,
GLX_MESA_swap_frame_usage, GLX_OML_swap_method, GLX_SGI_video_sync,
GLX_SGIS_multisample, GLX_SGIX_fbconfig
OpenGL vendor string: Tungsten Graphics, Inc.
OpenGL renderer string: Mesa DRI Radeon 20060327 AGP 4x TCL
OpenGL version string: 1.3 Mesa 6.5.1
OpenGL extensions:
GL_ARB_imaging, GL_ARB_multisample, GL_ARB_multitexture,
GL_ARB_texture_border_clamp, GL_ARB_texture_compression,
GL_ARB_texture_cube_map, GL_ARB_texture_env_add,
GL_ARB_texture_env_combine, GL_ARB_texture_env_crossbar,
GL_ARB_texture_env_dot3, GL_ARB_texture_mirrored_repeat,
GL_ARB_texture_rectangle, GL_ARB_transpose_matrix, GL_ARB_window_pos,
GL_EXT_abgr, GL_EXT_bgra, GL_EXT_blend_color, GL_EXT_blend_logic_op,
GL_EXT_blend_minmax, GL_EXT_blend_subtract, GL_EXT_clip_volume_hint,
GL_EXT_compiled_vertex_array, GL_EXT_convolution, GL_EXT_copy_texture,
GL_EXT_draw_range_elements, GL_EXT_fog_coord, GL_EXT_histogram,
GL_EXT_packed_pixels, GL_EXT_polygon_offset, GL_EXT_rescale_normal,
GL_EXT_secondary_color, GL_EXT_separate_specular_color,
GL_EXT_stencil_wrap, GL_EXT_subtexture, GL_EXT_texture, GL_EXT_texture3D,
GL_EXT_texture_edge_clamp, GL_EXT_texture_env_add,
GL_EXT_texture_env_combine, GL_EXT_texture_env_dot3,
GL_EXT_texture_filter_anisotropic, GL_EXT_texture_lod_bias,
GL_EXT_texture_mirror_clamp, GL_EXT_texture_object,
GL_EXT_texture_rectangle, GL_EXT_vertex_array, GL_APPLE_packed_pixels,
GL_ATI_texture_env_combine3, GL_ATI_texture_mirror_once,
GL_IBM_rasterpos_clip, GL_IBM_texture_mirrored_repeat,
GL_MESA_ycbcr_texture, GL_MESA_window_pos, GL_NV_blend_square,
GL_NV_light_max_exponent, GL_NV_texture_rectangle,
GL_NV_texgen_reflection, GL_OES_read_format, GL_SGI_color_matrix,
GL_SGI_color_table, GL_SGIS_generate_mipmap, GL_SGIS_texture_border_clamp,
GL_SGIS_texture_edge_clamp, GL_SGIS_texture_lod
glu version: 1.3
glu extensions:
GLU_EXT_nurbs_tessellator, GLU_EXT_object_space_tess
visual x bf lv rg d st colorbuffer ax dp st accumbuffer ms cav
id dep cl sp sz l ci b ro r g b a bf th cl r g b a ns b eat
----------------------------------------------------------------------
0x23 24 tc 0 32 0 r . . 8 8 8 8 0 24 0 0 0 0 0 0 0 None
0x24 24 tc 0 32 0 r . . 8 8 8 8 0 24 8 0 0 0 0 0 0 None
0x25 24 tc 0 32 0 r . . 8 8 8 8 0 24 0 16 16 16 16 0 0 Slow
0x26 24 tc 0 32 0 r . . 8 8 8 8 0 24 8 16 16 16 16 0 0 Slow
0x27 24 tc 0 32 0 r y . 8 8 8 8 0 24 0 0 0 0 0 0 0 None
0x28 24 tc 0 32 0 r y . 8 8 8 8 0 24 8 0 0 0 0 0 0 None
0x29 24 tc 0 32 0 r y . 8 8 8 8 0 24 0 16 16 16 16 0 0 Slow
0x2a 24 tc 0 32 0 r y . 8 8 8 8 0 24 8 16 16 16 16 0 0 Slow
0x2b 24 dc 0 32 0 r . . 8 8 8 8 0 24 0 0 0 0 0 0 0 None
0x2c 24 dc 0 32 0 r . . 8 8 8 8 0 24 8 0 0 0 0 0 0 None
0x2d 24 dc 0 32 0 r . . 8 8 8 8 0 24 0 16 16 16 16 0 0 Slow
0x2e 24 dc 0 32 0 r . . 8 8 8 8 0 24 8 16 16 16 16 0 0 Slow
0x2f 24 dc 0 32 0 r y . 8 8 8 8 0 24 0 0 0 0 0 0 0 None
0x30 24 dc 0 32 0 r y . 8 8 8 8 0 24 8 0 0 0 0 0 0 None
0x31 24 dc 0 32 0 r y . 8 8 8 8 0 24 0 16 16 16 16 0 0 Slow
0x32 24 dc 0 32 0 r y . 8 8 8 8 0 24 8 16 16 16 16 0 0 Slow
-- System Information:
Debian Release: testing/unstable
APT prefers testing
APT policy: (500, 'testing')
Architecture: i386 (i686)
Shell: /bin/sh linked to /bin/bash
Kernel: Linux 2.6.17-2-686
Locale: LANG=en_US, LC_CTYPE=en_US (charmap=ISO-8859-1)
Versions of packages libgl1-mesa-dri depends on:
ii libc6 2.3.6.ds1-4 GNU C Library: Shared libraries
ii libdrm2 2.0.1-1 Userspace interface to kernel DRM
ii libexpat1 1.95.8-3.3 XML parsing C library - runtime li
ii libgl1-mesa-glx 6.5.0.cvs.20060524-1.1 A free implementation of the OpenG
libgl1-mesa-dri recommends no packages.
-- no debconf information
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