Celestia started up and automatically went to Io. Io at the time was in the shadow of Jupiter. However, one half was lighted more than the other half. The division between light and dark was the terminator line (I think that's the term). Basically, the side that would otherwise be lighted by the sun was darker than the side facing away from the sun. Ambient light was set on low.
I have confirmed that the same effect occurs on other moon eclipses on my system. This may be due to ambient light only thinking to light the side facing away from the sun, which leads to the visual discrepancy during a lunar eclipse.
I was running 1.3.0 pre4
System Config:
1Gz PIII
Nvidia Geforce 2MX running 40.72 dets
256 Megs RAM
OpenGL driver info:
Vendor: NVIDIA Corporation
Renderer: GeForce2 MX/AGP/SSE
Version: 1.4.0
Max simultaneous textures: 2
Max texture size: 2048
Supported Extensions:
GL_ARB_imaging
GL_ARB_multitexture
GL_ARB_point_parameters
GL_ARB_texture_compression
GL_ARB_texture_cube_map
GL_ARB_texture_env_add
GL_ARB_texture_env_combine
GL_ARB_texture_env_dot3
GL_ARB_texture_mirrored_repeat
GL_ARB_transpose_matrix
GL_ARB_vertex_program
GL_ARB_window_pos
GL_S3_s3tc
GL_EXT_abgr
GL_EXT_bgra
GL_EXT_blend_color
GL_EXT_blend_minmax
GL_EXT_blend_subtract
GL_EXT_clip_volume_hint
GL_EXT_compiled_vertex_array
GL_EXT_draw_range_elements
GL_EXT_fog_coord
GL_EXT_multi_draw_arrays
GL_EXT_packed_pixels
GL_EXT_paletted_texture
GL_EXT_point_parameters
GL_EXT_rescale_normal
GL_EXT_secondary_color
GL_EXT_separate_specular_color
GL_EXT_shared_texture_palette
GL_EXT_stencil_wrap
GL_EXT_texture_compression_s3tc
GL_EXT_texture_cube_map
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
GL_EXT_texture_lod_bias
GL_EXT_texture_object
GL_EXT_vertex_array
GL_EXT_vertex_weighting
GL_IBM_texture_mirrored_repeat
GL_KTX_buffer_region
GL_NV_blend_square
GL_NV_fence
GL_NV_fog_distance
GL_NV_light_max_exponent
GL_NV_packed_depth_stencil
GL_NV_pixel_data_range
GL_NV_point_sprite
GL_NV_register_combiners
GL_NV_texgen_emboss
GL_NV_texgen_reflection
GL_NV_texture_env_combine4
GL_NV_texture_rectangle
GL_NV_vertex_array_range
GL_NV_vertex_array_range2
GL_NV_vertex_program
GL_NV_vertex_program1_1
GL_SGIS_generate_mipmap
GL_SGIS_multitexture
GL_SGIS_texture_lod
GL_WIN_swap_hint
WGL_EXT_swap_control
Hoping to get this bug fixed before 1.3.0 final.
Lighting issue with moon eclipses
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granthutchison
- Developer
- Posts: 1863
- Joined: 21.11.2002
- With us: 22 years 2 months
This is, I think, a consequence of a previous bug fix.
Celestia used to cast eclipse shadows right through a body, so that the shadow would be generated on both the sun-facing side and the dark side (it still does this with ring shadows, I notice, at least on my system). This was annoying for those who kept ambient light switched on, because they'd see a shadow disc suddenly flitting across the night side of Jupiter, for instance. So the night-side eclipse shadow has been suppressed, and you're seeing the consequence of that, when a body is totally immersed in an eclipse shadow - the shadow paints the entire daylight side, and ambient light illuminates the night side.
Maybe if ambient light also filled eclipse shadows? But that'd make them harder to see, and would (I imagine) generate even odder effects in the penumbral part of an eclipse, where "real" and ambient light would fight each other.
The problem is really that ambient light is an entirely non-physical effect, so you must expect odd appearances from it.
Grant
Celestia used to cast eclipse shadows right through a body, so that the shadow would be generated on both the sun-facing side and the dark side (it still does this with ring shadows, I notice, at least on my system). This was annoying for those who kept ambient light switched on, because they'd see a shadow disc suddenly flitting across the night side of Jupiter, for instance. So the night-side eclipse shadow has been suppressed, and you're seeing the consequence of that, when a body is totally immersed in an eclipse shadow - the shadow paints the entire daylight side, and ambient light illuminates the night side.
Maybe if ambient light also filled eclipse shadows? But that'd make them harder to see, and would (I imagine) generate even odder effects in the penumbral part of an eclipse, where "real" and ambient light would fight each other.
The problem is really that ambient light is an entirely non-physical effect, so you must expect odd appearances from it.
Grant