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1Name
2
3	SGIX_shadow_ambient
4
5Name Strings
6
7	GL_SGIX_shadow_ambient
8
9Version
10
11	$Date: 1997/02/26 03:36:32 $ $Revision: 1.3 $
12
13Number
14
15	90
16
17Dependencies
18
19	None.
20
21Overview
22
23	This extension allows a value other than 0.0 to be returned by the
24	SGIX_shadow operation in the case when the shadow test passes.
25	With this extension any floating point value in the range [0.0,
26	1.0] can be returned as the texture value when an object is in
27	shadow.  This allows the (untextured) ambient lighting and direct
28	shadowed lighting from a single light source to be computed in a
29	single pass.
30
31New Procedures and Functions
32
33	None
34
35New Tokens
36
37	Accepted by the <pname> parameter of TexParameterf, TexParameteri,
38	TexParameterfv, TexParameteriv, GetTexParameterfv, and
39	GetTexParameteriv:
40
41	SHADOW_AMBIENT_SGIX		0x80BF
42
43Additions to Chapter 2 of the 1.0 Specification (OpenGL Operation)
44
45	None
46
47Additions to Chapter 3 of the 1.0 Specification (Rasterization)
48
49	GL Specification Table 3.8 is updated as follows:
50
51	Name				Type		Legal Values
52	----				----		------------
53	TEXTURE_WRAP_S			integer		CLAMP, REPEAT
54	TEXTURE_WRAP_T			integer		CLAMP, REPEAT
55	TEXTURE_WRAP_R_EXT		integer		CLAMP, REPEAT
56	TEXTURE_MIN_FILTER		integer		NEAREST, LINEAR,
57							NEAREST_MIPMAP_NEAREST,
58							NEAREST_MIPMAP_LINEAR,
59							LINEAR_MIPMAP_NEAREST,
60							LINEAR_MIPMAP_LINEAR,
61							FILTER4_SGIS,
62							LINEAR_CLIPMAP_LINEAR_SGIX
63	TEXTURE_MAG_FILTER		integer		NEAREST, LINEAR,
64							FILTER4_SGIS,
65							LINEAR_DETAIL_SGIS,
66							LINEAR_DETAIL_ALPHA_SGIS,
67							LINEAR_DETAIL_COLOR_SGIS,
68							LINEAR_SHARPEN_SGIS,
69							LINEAR_SHARPEN_ALPHA_SGIS,
70							LINEAR_SHARPEN_COLOR_SGIS,
71	TEXTURE_BORDER_COLOR		4 floats	any 4 values in [0,1]
72	DETAIL_TEXTURE_LEVEL_SGIS	integer		any non-negative integer
73	DETAIL_TEXTURE_MODE_SGIS	integer		ADD, MODULATE
74	TEXTURE_MIN_LOD_SGIS		float		any value
75	TEXTURE_MAX_LOD_SGIS		float		any value
76	TEXTURE_BASE_LEVEL_SGIS		integer		any non-negative integer
77	TEXTURE_MAX_LEVEL_SGIS		integer		any non-negative integer
78	GENERATE_MIPMAP_SGIS		boolean		TRUE or FALSE
79	TEXTURE_CLIPMAP_OFFSET_SGIX	2 floats	any 2 values
80	SHADOW_AMBIENT_SGIX		float		any value
81
82	Table 3.8: Texture parameters and their values.
83
84	Notes:
85
86	* A new texture parameter is defined which changes the sampled
87	texture value when SGIX_shadow is used, and a pixel is determined
88	to be in shadow.  In this case, the value of the
89	SHADOW_AMBIENT_SGIX parameter is returned, instead of 0.0 .  When
90	SHADOW_AMBIENT_SGIX is set, the <param> value is clamped to the
91	range [0.0, 1.0].
92
93Additions to Chapter 4 of the 1.0 Specification (Per-Fragment Operations
94and the Frame Buffer)
95
96	None
97
98Additions to Chapter 5 of the 1.0 Specification (Special Functions)
99
100	None
101
102Additions to Chapter 6 of the 1.0 Specification (State and State Requests)
103
104	The shadow ambient value is queried by calling GetTexParameterfv
105	with <pname> set to SHADOW_AMBIENT_SGIX.
106
107Additions to the GLX Specification
108
109	None
110
111Errors
112
113	None
114
115New State
116
117Get Value			Get Command		Type	Initial Value		Attribute
118---------			-----------		----	-------------		---------
119SHADOW_AMBIENT_SGIX		GetTexParameter[if]v	F	0.0			texture
120
121New Implementation Dependent State
122
123	None
124