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IRIX Base Documentation 2001 May
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SGI IRIX Base Documentation 2001 May.iso
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relnotes
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sirius
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ch6.z
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ch6
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2001-04-17
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199 lines
- 1 -
6. _D_o_c_u_m_e_n_t_a_t_i_o_n__E_r_r_o_r_s
The _S_i_r_i_u_s _P_r_o_g_r_a_m_m_i_n_g _a_n_d _C_o_n_f_i_g_u_r_a_t_i_o_n _G_u_i_d_e does not
include the changes to the Sirius Video API for use with
_I_n_f_i_n_i_t_e_R_e_a_l_i_t_y grapics. An abbreviated version of this
information is included here.
The Sirius video option is supported on the Infinite Reality
Graphics Systems for video input to and out of the graphics
subsystem.
_S_i_r_i_u_s _t_o _G_r_a_p_h_i_c_s _I_n_t_e_r_f_a_c_e :
In VL terminology, this is the Graphics/Texture drain
interface. On the Infinite Reality system, only field mode
transfers are supported. However, packing mode controls are
supported on both graphics and texture drains.
Listed below are the supported packing modes and their
measured performance :
VL_PACKING PERFORMANCE(transfer time per field)
RGBA_6 5.25 msecs
RGB_8 2.625 msecs
RGBA_12 2.625 msecs
YYYY_12 1.5 msecs
The transfer times listed about are the approximate measured
numbers.
_V_L _N_o_t_e : VL_CAPTURE_INTERLEAVED is a no-op. VL_PACKING is
a supported control on VL_GFX node.
_P_r_o_g_r_a_m_m_i_n_g _N_o_t_e:
In order to facilitate easy integration with OpenGL, OpenGL
extensions have been developed. Refer to the OpenGL
documentation for the SGIX_interlace and SGIX_video_source
extensions. Sample programs(vidtogfx, videobub and
videowarp) are provided to illustrate usage of OpenGL with
VL. For performance reasons, it is strongly recommended that
textures be used as the video drain.
_N_o_t_e: Only OpenGL Graphics API is supported for Video on
Infinite Reality.
_G_r_a_p_h_i_c_s _t_o _S_i_r_i_u_s _I_n_t_e_r_f_a_c_e :
A new interface board for pixel transfers between graphics
and video was designed. Called the PAB2, it supports pixels
- 2 -
transfers at 8bits/component and 10bits/component precision
depending on the mode of operation. The interface to sirius
is always 10bit per component. With 8bits/component
precision, the upper 2 bits are replicated to the lower 2
bits. In VL terminology, this is Graphics source.
_S_l_a_v_e _m_o_d_e _a_n_d _R_e_q_u_e_s_t _m_o_d_e : Applications have the option
of specifying if the graphics source is a portion of the
displayed surface from one of the other hi-res channels
(slave mode) or can request seperate display area allocation
for sirius channel(request mode). At startup, the display
channels have to be configured using _i_r_c_o_m_b_i_n_e(_1_G). Please
refer to the _i_r_c_o_m_b_i_n_e(_1_G) for more details on how to setup
the hi-res channels and sirius.
Once the display channels have been properly configured,
applications can use the VL controls (VL_ORIGIN,
VL_SIR_GFX_SIZE) to pan and zoom over the hi-res display. If
the grab area(VL_SIR_GFX_SIZE) matches the size of the
output video timing, pixels are handled with
10bits/component precision. If the grab area is larger then
the size of the output video timing, pixels have
8bits/component precision and are filtered down to fit the
output timing size. Specifying a grab area less then the
size of the output timing size is not permitted.
_N_o_t_e: For the first release, requesting mode is not
supported on Sirius.
_N_o_t_e:
+o For systems with Infinite Reality Graphics, it is
recommended that a combination with sirius channel as a
slave to one of the hi-res channels be setup as the
default combination and saved to EEPROM.
+o If the alpha component is desired, the combination has
to be setup with a Pixel Format of RGBA10 for both the
hi-res channel and the sirius channel.
_G_e_n_l_o_c_k _a_n_d _F_r_a_m_e _l_o_c_k :
In order to Genlock video-out to the hi-res displays, four
specially created formats are provided :
+o 1280x1024_25f.vfo
+o 1280x1024_30f.vfo
+o 1280x1024_50f.vfo
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+o 1280x1024_60f.vfo
You have to use _i_r_c_o_m_b_i_n_e(_1_G) to specify the Sync Source and
Sync Format. These can be setup in ircombine using the _E_d_i_t
_g_l_o_b_a_l_s panel.