| Name |
| |
| SGIX_shadow_ambient |
| |
| Name Strings |
| |
| GL_SGIX_shadow_ambient |
| |
| Version |
| |
| $Date: 1997/02/26 03:36:32 $ $Revision: 1.3 $ |
| |
| Number |
| |
| 90 |
| |
| Dependencies |
| |
| None. |
| |
| Overview |
| |
| This extension allows a value other than 0.0 to be returned by the |
| SGIX_shadow operation in the case when the shadow test passes. |
| With this extension any floating point value in the range [0.0, |
| 1.0] can be returned as the texture value when an object is in |
| shadow. This allows the (untextured) ambient lighting and direct |
| shadowed lighting from a single light source to be computed in a |
| single pass. |
| |
| New Procedures and Functions |
| |
| None |
| |
| New Tokens |
| |
| Accepted by the <pname> parameter of TexParameterf, TexParameteri, |
| TexParameterfv, TexParameteriv, GetTexParameterfv, and |
| GetTexParameteriv: |
| |
| SHADOW_AMBIENT_SGIX 0x80BF |
| |
| Additions to Chapter 2 of the 1.0 Specification (OpenGL Operation) |
| |
| None |
| |
| Additions to Chapter 3 of the 1.0 Specification (Rasterization) |
| |
| GL Specification Table 3.8 is updated as follows: |
| |
| Name Type Legal Values |
| ---- ---- ------------ |
| TEXTURE_WRAP_S integer CLAMP, REPEAT |
| TEXTURE_WRAP_T integer CLAMP, REPEAT |
| TEXTURE_WRAP_R_EXT integer CLAMP, REPEAT |
| TEXTURE_MIN_FILTER integer NEAREST, LINEAR, |
| NEAREST_MIPMAP_NEAREST, |
| NEAREST_MIPMAP_LINEAR, |
| LINEAR_MIPMAP_NEAREST, |
| LINEAR_MIPMAP_LINEAR, |
| FILTER4_SGIS, |
| LINEAR_CLIPMAP_LINEAR_SGIX |
| TEXTURE_MAG_FILTER integer NEAREST, LINEAR, |
| FILTER4_SGIS, |
| LINEAR_DETAIL_SGIS, |
| LINEAR_DETAIL_ALPHA_SGIS, |
| LINEAR_DETAIL_COLOR_SGIS, |
| LINEAR_SHARPEN_SGIS, |
| LINEAR_SHARPEN_ALPHA_SGIS, |
| LINEAR_SHARPEN_COLOR_SGIS, |
| TEXTURE_BORDER_COLOR 4 floats any 4 values in [0,1] |
| DETAIL_TEXTURE_LEVEL_SGIS integer any non-negative integer |
| DETAIL_TEXTURE_MODE_SGIS integer ADD, MODULATE |
| TEXTURE_MIN_LOD_SGIS float any value |
| TEXTURE_MAX_LOD_SGIS float any value |
| TEXTURE_BASE_LEVEL_SGIS integer any non-negative integer |
| TEXTURE_MAX_LEVEL_SGIS integer any non-negative integer |
| GENERATE_MIPMAP_SGIS boolean TRUE or FALSE |
| TEXTURE_CLIPMAP_OFFSET_SGIX 2 floats any 2 values |
| SHADOW_AMBIENT_SGIX float any value |
| |
| Table 3.8: Texture parameters and their values. |
| |
| Notes: |
| |
| * A new texture parameter is defined which changes the sampled |
| texture value when SGIX_shadow is used, and a pixel is determined |
| to be in shadow. In this case, the value of the |
| SHADOW_AMBIENT_SGIX parameter is returned, instead of 0.0 . When |
| SHADOW_AMBIENT_SGIX is set, the <param> value is clamped to the |
| range [0.0, 1.0]. |
| |
| Additions to Chapter 4 of the 1.0 Specification (Per-Fragment Operations |
| and the Frame Buffer) |
| |
| None |
| |
| Additions to Chapter 5 of the 1.0 Specification (Special Functions) |
| |
| None |
| |
| Additions to Chapter 6 of the 1.0 Specification (State and State Requests) |
| |
| The shadow ambient value is queried by calling GetTexParameterfv |
| with <pname> set to SHADOW_AMBIENT_SGIX. |
| |
| Additions to the GLX Specification |
| |
| None |
| |
| Errors |
| |
| None |
| |
| New State |
| |
| Get Value Get Command Type Initial Value Attribute |
| --------- ----------- ---- ------------- --------- |
| SHADOW_AMBIENT_SGIX GetTexParameter[if]v F 0.0 texture |
| |
| New Implementation Dependent State |
| |
| None |
