1GLGETTEXLEVELPARAMET(3G)        [FIXME: manual]       GLGETTEXLEVELPARAMET(3G)
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4

NAME

6       glGetTexLevelParameter - return texture parameter values for a specific
7       level of detail
8

C SPECIFICATION

10       void glGetTexLevelParameterfv(GLenum target, GLint level, GLenum pname,
11                                     GLfloat * params);
12
13       void glGetTexLevelParameteriv(GLenum target, GLint level, GLenum pname,
14                                     GLint * params);
15
16       void glGetTextureLevelParameterfv(GLuint texture, GLint level,
17                                         GLenum pname, GLfloat *params);
18
19       void glGetTextureLevelParameteriv(GLuint texture, GLint level,
20                                         GLenum pname, GLint *params);
21

PARAMETERS

23       target
24           Specifies the target to which the texture is bound for
25           glGetTexLevelParameterfv and glGetTexLevelParameteriv functions.
26           Must be one of the following values: GL_TEXTURE_1D, GL_TEXTURE_2D,
27           GL_TEXTURE_3D, GL_TEXTURE_1D_ARRAY, GL_TEXTURE_2D_ARRAY,
28           GL_TEXTURE_RECTANGLE, GL_TEXTURE_2D_MULTISAMPLE,
29           GL_TEXTURE_2D_MULTISAMPLE_ARRAY, GL_TEXTURE_CUBE_MAP_POSITIVE_X,
30           GL_TEXTURE_CUBE_MAP_NEGATIVE_X, GL_TEXTURE_CUBE_MAP_POSITIVE_Y,
31           GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, GL_TEXTURE_CUBE_MAP_POSITIVE_Z,
32           GL_TEXTURE_CUBE_MAP_NEGATIVE_Z, GL_PROXY_TEXTURE_1D,
33           GL_PROXY_TEXTURE_2D, GL_PROXY_TEXTURE_3D,
34           GL_PROXY_TEXTURE_1D_ARRAY, GL_PROXY_TEXTURE_2D_ARRAY,
35           GL_PROXY_TEXTURE_RECTANGLE, GL_PROXY_TEXTURE_2D_MULTISAMPLE,
36           GL_PROXY_TEXTURE_2D_MULTISAMPLE_ARRAY, GL_PROXY_TEXTURE_CUBE_MAP,
37           or GL_TEXTURE_BUFFER.
38
39       texture
40           Specifies the texture object name for glGetTextureLevelParameterfv
41           and glGetTextureLevelParameteriv functions.
42
43       level
44           Specifies the level-of-detail number of the desired image. Level 0
45           is the base image level. Level n is the nth mipmap reduction image.
46
47       pname
48           Specifies the symbolic name of a texture parameter.
49           GL_TEXTURE_WIDTH, GL_TEXTURE_HEIGHT, GL_TEXTURE_DEPTH,
50           GL_TEXTURE_INTERNAL_FORMAT, GL_TEXTURE_RED_SIZE,
51           GL_TEXTURE_GREEN_SIZE, GL_TEXTURE_BLUE_SIZE, GL_TEXTURE_ALPHA_SIZE,
52           GL_TEXTURE_DEPTH_SIZE, GL_TEXTURE_COMPRESSED,
53           GL_TEXTURE_COMPRESSED_IMAGE_SIZE, and GL_TEXTURE_BUFFER_OFFSET are
54           accepted.
55
56       params
57           Returns the requested data.
58

DESCRIPTION

60       glGetTexLevelParameterfv, glGetTexLevelParameteriv,
61       glGetTextureLevelParameterfv and glGetTextureLevelParameteriv return in
62       params texture parameter values for a specific level-of-detail value,
63       specified as level. For the first two functions, target defines the
64       target texture, either GL_TEXTURE_1D, GL_TEXTURE_2D, GL_TEXTURE_3D,
65       GL_PROXY_TEXTURE_1D, GL_PROXY_TEXTURE_2D, GL_PROXY_TEXTURE_3D,
66       GL_TEXTURE_CUBE_MAP_POSITIVE_X, GL_TEXTURE_CUBE_MAP_NEGATIVE_X,
67       GL_TEXTURE_CUBE_MAP_POSITIVE_Y, GL_TEXTURE_CUBE_MAP_NEGATIVE_Y,
68       GL_TEXTURE_CUBE_MAP_POSITIVE_Z, GL_TEXTURE_CUBE_MAP_NEGATIVE_Z, or
69       GL_PROXY_TEXTURE_CUBE_MAP. The remaining two take a texture argument
70       which specifies the name of the texture object.
71
72       GL_MAX_TEXTURE_SIZE, and GL_MAX_3D_TEXTURE_SIZE are not really
73       descriptive enough. It has to report the largest square texture image
74       that can be accommodated with mipmaps but a long skinny texture, or a
75       texture without mipmaps may easily fit in texture memory. The proxy
76       targets allow the user to more accurately query whether the GL can
77       accommodate a texture of a given configuration. If the texture cannot
78       be accommodated, the texture state variables, which may be queried with
79       glGetTexLevelParameter and glGetTextureLevelParameter, are set to 0. If
80       the texture can be accommodated, the texture state values will be set
81       as they would be set for a non-proxy target.
82
83       pname specifies the texture parameter whose value or values will be
84       returned.
85
86       The accepted parameter names are as follows:
87
88       GL_TEXTURE_WIDTH
89           params returns a single value, the width of the texture image. The
90           initial value is 0.
91
92       GL_TEXTURE_HEIGHT
93           params returns a single value, the height of the texture image. The
94           initial value is 0.
95
96       GL_TEXTURE_DEPTH
97           params returns a single value, the depth of the texture image. The
98           initial value is 0.
99
100       GL_TEXTURE_INTERNAL_FORMAT
101           params returns a single value, the internal format of the texture
102           image.
103
104       GL_TEXTURE_RED_TYPE, GL_TEXTURE_GREEN_TYPE, GL_TEXTURE_BLUE_TYPE,
105       GL_TEXTURE_ALPHA_TYPE, GL_TEXTURE_DEPTH_TYPE
106           The data type used to store the component. The types GL_NONE,
107           GL_SIGNED_NORMALIZED, GL_UNSIGNED_NORMALIZED, GL_FLOAT, GL_INT, and
108           GL_UNSIGNED_INT may be returned to indicate signed normalized
109           fixed-point, unsigned normalized fixed-point, floating-point,
110           integer unnormalized, and unsigned integer unnormalized components,
111           respectively.
112
113       GL_TEXTURE_RED_SIZE, GL_TEXTURE_GREEN_SIZE, GL_TEXTURE_BLUE_SIZE,
114       GL_TEXTURE_ALPHA_SIZE, GL_TEXTURE_DEPTH_SIZE
115
116           The internal storage resolution of an individual component. The
117           resolution chosen by the GL will be a close match for the
118           resolution requested by the user with the component argument of
119           glTexImage1D(), glTexImage2D(), glTexImage3D(), glCopyTexImage1D(),
120           and glCopyTexImage2D(). The initial value is 0.
121
122       GL_TEXTURE_COMPRESSED
123
124           params returns a single boolean value indicating if the texture
125           image is stored in a compressed internal format. The initiali value
126           is GL_FALSE.
127
128       GL_TEXTURE_COMPRESSED_IMAGE_SIZE
129
130           params returns a single integer value, the number of unsigned bytes
131           of the compressed texture image that would be returned from
132           glGetCompressedTexImage().
133
134       GL_TEXTURE_BUFFER_OFFSET
135
136           params returns a single integer value, the offset into the data
137           store of the buffer bound to a buffer texture.  glTexBufferRange().
138
139       GL_TEXTURE_BUFFER_SIZE
140
141           params returns a single integer value, the size of the range of a
142           data store of the buffer bound to a buffer texture.
143           glTexBufferRange().
144

NOTES

146       If an error is generated, no change is made to the contents of params.
147
148       glGetTexLevelParameter returns the texture level parameters for the
149       active texture unit.
150
151       GL_TEXTURE_BUFFER_OFFSET and GL_TEXTURE_BUFFER_SIZE are available only
152       if the GL version is 4.3 or greater.
153

ERRORS

155       GL_INVALID_OPERATION is generated by glGetTextureLevelParameterfv and
156       glGetTextureLevelParameteriv functions if texture is not the name of an
157       existing texture object.
158
159       GL_INVALID_ENUM is generated by glGetTexLevelParameterfv and
160       glGetTexLevelParameteriv functions if target or pname is not an
161       accepted value.
162
163       GL_INVALID_VALUE is generated if level is less than 0.
164
165       GL_INVALID_VALUE may be generated if level is greater than log 2 max,
166       where max is the returned value of GL_MAX_TEXTURE_SIZE.
167
168       GL_INVALID_VALUE is generated if target is GL_TEXTURE_BUFFER and level
169       is not zero.
170
171       GL_INVALID_OPERATION is generated if GL_TEXTURE_COMPRESSED_IMAGE_SIZE
172       is queried on texture images with an uncompressed internal format or on
173       proxy targets.
174

VERSION SUPPORT

176       ┌─────────────────────────────┬───────────────────────────────────────────────────────────────────────┐
177       │                             │                OpenGL Version                                         
178       ├─────────────────────────────┼─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┤
179Function                     2.0 2.1 3.0 3.1 3.2 3.3 4.0 4.1 4.2 4.3 4.4 4.5 
180/                            │     │     │     │     │     │     │     │     │     │     │     │     │
181Feature                      │     │     │     │     │     │     │     │     │     │     │     │     │
182Name                         │     │     │     │     │     │     │     │     │     │     │     │     │
183       ├─────────────────────────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
184glGetTexLevelParameterfv     │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │
185       ├─────────────────────────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
186glGetTexLevelParameteriv     │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │
187       ├─────────────────────────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
188glGetTextureLevelParameterfv │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  ✔  │
189       ├─────────────────────────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
190glGetTextureLevelParameteriv │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  ✔  │
191       └─────────────────────────────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┘
192

SEE ALSO

194       glActiveTexture(), glGetTexParameter(), glCopyTexImage1D(),
195       glCopyTexImage2D(), glCopyTexSubImage1D(), glCopyTexSubImage2D(),
196       glCopyTexSubImage3D(), glTexImage1D(), glTexImage2D(), glTexImage3D(),
197       glTexSubImage1D(), glTexSubImage2D(), glTexSubImage3D(),
198       glTexParameter()
199
201       Copyright © 1991-2006 Silicon Graphics, Inc. Copyright © 2010-2014
202       Khronos Group. This document is licensed under the SGI Free Software B
203       License. For details, see http://oss.sgi.com/projects/FreeB/.
204
206       Copyright © 2014 Khronos Group
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210[FIXME: source]                   07/13/2018          GLGETTEXLEVELPARAMET(3G)
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