| Name |
| |
| NV_3dvision_settings |
| |
| Name Strings |
| |
| GL_NV_3dvision_settings |
| |
| Contributors |
| |
| Mathias Heyer, NVIDIA |
| Swaminathan Narayanan, NVIDIA |
| Greg Roth, NVIDIA |
| |
| Contact |
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| Greg Roth, NVIDIA (groth 'at' nvidia.com) |
| |
| Status |
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| Complete |
| |
| Version |
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| Last Modified Date: 05 Oct 2012 |
| Revision: 5 |
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| Number |
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| OpenGL ES Extension #129 |
| |
| Dependencies |
| |
| Written based on the wording of the OpenGL ES 2.0.25 specification |
| |
| OpenGL ES 2.0 is required. |
| |
| EGL_NV_3dvision_surface is used to specify a surface |
| with support for these features explicitly enabled. |
| |
| Overview |
| |
| NVIDIA 3D Vision provides stereoscopic 3d rendering without |
| requiring applications to change their rendering methods. However |
| there are cases where applications can benefit from adjusting 3D |
| vision parameters directly to experiment with this functionality in |
| applications not yet known to 3D Vision, to assist 3D Vision in |
| setting parameters correctly for unusual situations, or to present |
| application-specific user-accessible controls for 3D Vision |
| parameters. |
| |
| This extension provides the ability to query the current stereo |
| settings and adjust them as necessary. |
| |
| IP Status |
| |
| NVIDIA Proprietary |
| |
| New Procedures and Functions |
| |
| void StereoParameterfNV(enum pname, float param); |
| void StereoParameteriNV(enum pname, int param); |
| |
| New Tokens |
| |
| Accepted by the <value> parameter of GetBooleanv, GetIntegerv, |
| and GetFloatv, and the <cap> parameter of isEnabled, Enable, and |
| Disable: |
| |
| 3DVISION_STEREO_NV 0x90F4 |
| |
| Accepted by the <value> parameter of GetBooleanv, GetIntegerv, |
| and GetFloatv and the <param> parameter of StereoParameterfNV, |
| and StereoParameteriNV: |
| |
| STEREO_SEPARATION_NV 0x90F5 |
| STEREO_CONVERGENCE_NV 0x90F6 |
| STEREO_CUTOFF_NV 0x90F7 |
| STEREO_PROJECTION_NV 0x90F8 |
| |
| Accepted by the <param> parameter of StereoParameterfNV and |
| StereoParameteriNV and returned by GetBooleanv, GetIntegerv, and |
| GetFloatv when <value> is STEREO_PROJECTION_NV. |
| |
| STEREO_PROJECTION_PERSPECTIVE_NV 0x90F9 |
| STEREO_PROJECTION_ORTHO_NV 0x90FA |
| |
| Changes to Chapter 4 of the OpenGL ES 2.0.25 Specification (Per-Fragment |
| Operations and the Frame Buffer) |
| |
| Add to section 4.2.1, "Selecting a Buffer for Writing": |
| |
| If the bound draw surface is auto stereo enabled and 3d Vision |
| rendering is enabled in the GL, color values are written to left and |
| right buffers with adjustments according to current separation and |
| convergence values. |
| |
| Add subsection 4.2.x, "Stereo Parameters": |
| |
| 3D Vision stereo capability may be enabled at surface creation. If |
| the bound draw surface is auto stereo capable, 3D Vision rendering |
| can be enabled and disabled by calling Enable or Disable with the |
| symbolic constant 3DVISION_STEREO_NV. If the current draw surface is |
| not auto stereo capable, enabling 3D Vision rendering has no |
| effect. The current state of 3D Vision rendering may be queried |
| using isEnabled with <cap> set to 3DVISION_STEREO_NV. |
| |
| Various parameters control how 3D Vision stereo rendering is |
| performed. Each parameter is set by calling |
| |
| void StereoParameter{if}NV(enum pname, T param); |
| |
| <pname> is a symbolic constant indicating the parameter to be set. |
| |
| If <pname> is STEREO_PROJECTION_NV, then <param> specifies the |
| method of rendering 3D Vision will use. <param> must be |
| STEREO_PROJECTION_PERSPECTIVE_NV or STEREO_PROJECTION_ORTHO_NV |
| identifying the projection type used. If <param> has any other |
| value, an INVALID_ENUM error is generated. The current 3D Vision |
| stereo method is queried by calling GetIntegerv with <pname> set to |
| STEREO_PROJECTION_NV. The initial value of STEREO_PROJECTION_NV is |
| STEREO_PROJECTION_PERSPECTIVE_NV, but may differ for contexts |
| created with a 3D Vision profile in effect. |
| |
| If <pname> is STEREO_SEPARATION_NV, then <param> specifies the |
| separation value used in 3D Vision stereo rendering. The current |
| separation value is queried by calling GetFloatv with <pname> set |
| to STEREO_SEPARATION_NV. The initial value of STEREO_PROJECTION_NV |
| depends on 3D Vision system settings at the time the context was |
| created. The separation value indicates a percentage. If <param> is |
| less than zero or greater than 100, an INVALID_VALUE error is |
| generated. |
| |
| If <pname> is STEREO_CONVERGENCE_NV, then <param> specifies the |
| convergence value used in 3D Vision stereo rendering. The current |
| convergence value is queried by calling GetFloatv with <pname> set |
| to STEREO_CONVERGENCE_NV. The initial value of STEREO_CONVERGENCE- |
| _NV is zero, but may differ for contexts created with a 3D Vision |
| profile in effect. |
| |
| If <pname> is STEREO_CUTOFF_NV, then <param> specifies the |
| separation cutoff value used in 3D Vision stereo rendering. The |
| current separation cutoff value is queried by calling GetFloatv |
| with <pname> set to STEREO_CUTOFF_NV. The initial value of |
| STEREO_CUTOFF_NV is zero, but may differ for contexts created with a |
| 3D Vision profile in effect. |
| |
| Otherwise, INVALID_ENUM is generated. |
| |
| Setting stereo parameters on a context that does not support 3D |
| Vision rendering has no effect on rendering. |
| |
| The state required to implement these stereo parameters is three |
| floats and one integer. |
| |
| Errors |
| |
| The error INVALID_ENUM is generated if StereoParameter{if} is |
| called where <pname> is an unsupported enum value. |
| |
| The error INVALID_ENUM is generated if StereoParameter{if} is |
| called where <pname> is STEREO_PROJECTION_NV and <param> is an |
| unsupported enum value. |
| |
| New State |
| |
| Add new table "Stereo State" |
| Get Value Type Get Command Initial Value Description Sec |
| --------- ---- ----------- ------------- ----------- ------ |
| 3DVISION_STEREO_NV B isEnabled see 4.2.x 3D Vision stereo enable 4.2.x |
| STEREO_SEPARATION_NV R GetFloatv see 4.2.x 3D Vision separation 4.2.x |
| STEREO_CONVERGENCE_NV R GetFloatv see 4.2.x 3D Vision convergence 4.2.x |
| STEREO_CUTOFF_NV R GetFloatv see 4.2.x 3D Vision separation cutoff 4.2.x |
| STEREO_PROJECTION_NV Z GetIntegerv see 4.2.x 3D Vision projection method 4.2.x |
| |
| Issues |
| |
| 1. What are the default values of 3D Vision stereo parameters? |
| |
| RESOLVED: The default values depend on the application being run and |
| current system 3D Vision settings. For all but separation, defaults |
| for an application with no 3D Vision profile. GL contexts created |
| for Applications with established stereo profiles will have |
| different default values for stereo parameters. |
| |
| 2. Should method settings be included? |
| |
| RESOLVED: Yes, but in a form that makes sense to the user. Internal |
| method settings have many forms, but all the user needs be concerned |
| with are orthographic and perspective settings. For Applications |
| controlled by application detection, changing this is inadvisable. |
| Applications that use context creation attributes to enable 3D |
| Vision may have to set the method explicitly. |
| |
| 3. Should descriptions of how these settings are used by 3D Vision |
| be included here? |
| |
| RESOLVED: No. This functionality is extensively documented in |
| existing 3D Vision documents such as "NVIDIA 3D Vision Automatic Best |
| Practices". Merging these explanations into the OpenGL document and |
| maintaining them won't add any additional clarity to the functionality |
| and may limit the underlying implementation. |
| |
| |
| 4. What is the behavior of GL calls that may use a 3D Vision surface |
| such as ReadPixels, CopyTex[Sub]Image, and BlitFramebuffer? |
| |
| RESOLVED: The current implementation makes calls that expect a |
| single surface by definition such as ReadPixels read from the left |
| buffer only. Calls that permit the number of surfaces to be |
| abstracted behind objects that have no direct interaction with the |
| user application such as CopyTexImage and BlitFramebuffer sample |
| from both surfaces of the source when available to copy to the |
| corresponding destination surfaces. |
| |
| The intent of this extension is to provide a 3D Vision support |
| that is as transparent to the developer as possible. Introducing the |
| ability to select which buffer is read from breaks the notion of the |
| application that what was developed as a single buffer is |
| represented as two surfaces when 3D Vision is enabled. Furthermore, |
| this matches behavior of 3D Vision enabled applications that do not |
| make use of this extension. |
| |
| It's possible that this approach may cause problems with particular |
| applications that make meaningful use of ReadPixels. Such |
| incidents are not expected to be common. Where they arise, the 3D |
| Vision implementation may change to accomodate them. It is in |
| keeping with one purpose of this extension to test new development |
| with 3D Vision to identify interaction problems before it becomes |
| publicly available. By keeping with the current implementation, |
| these conflicts can be identified and resolved beforehand. This is |
| one such conflict that may be identified and addressed either by the |
| application developer or through communication with the extension |
| implementor. |
| |
| Because the implementation may change according to future |
| requirements, this extension makes no changes to the corresponding |
| documentation in the specification to enable future implementation |
| changes that may do something different. Conceptually, the behavior |
| of this functionality does not change any more than that of the draw |
| calls. |
| |
| Revision History |
| |
| Rev. Date Author Changes |
| ---- ------------- --------- ---------------------------------------- |
| 5 05 Oct 2012 groth Add issue addressing ReadPixels. |
| 4 15 Dec 2011 groth Refine default values. Add invalid value errors |
| 3 02 Dec 2011 groth Restore method settings in limited form |
| 2 11 Nov 2011 groth Remove method query and settings |
| 1 08 Nov 2011 groth Initial version |
| |
