glGetTexLevelParameterfv Function

GL_APICALL void GL_APIENTRY glGetTexLevelParameterfv(
     GLenum target,
     GLint level,
     GLenum pname,
     GLfloat * params
);

	Name	Description
in	target	Texture target to get
in	level	Mipmap level of parameter to get
in	pname	Parameter to get
out	params	Pointer to the location where the acquired parameter is stored.

No values are returned.

Gets the texture level parameter.

Set target to one the following values. Procedural textures are not supported.

GL_TEXTURE_2D	2D texture.
GL_TEXTURE_CUBE_MAP_NEGATIVE_X	Face of a cube-map texture in the negative x direction.
GL_TEXTURE_CUBE_MAP_POSITIVE_X	Face of a cube-map texture in the positive x direction.
GL_TEXTURE_CUBE_MAP_NEGATIVE_Y	Face of a cube-map texture in the negative y direction.
GL_TEXTURE_CUBE_MAP_POSITIVE_Y	Face of a cube-map texture in the positive y direction.
GL_TEXTURE_CUBE_MAP_NEGATIVE_Z	Face of a cube-map texture in the negative z direction.
GL_TEXTURE_CUBE_MAP_POSITIVE_Z	Face of a cube-map texture in the positive z direction.

The values that can be specified in pname and the paramter that can be retrieved in params are shown in the table below.

GL_TEXTURE_WIDTH	Width of texture (in pixels).
GL_TEXTURE_HEIGHT	Height of texture (in pixels).
GL_TEXTURE_INTERNAL_FORMAT	Internal format of texture.
GL_TEXTURE_RED_SIZE	Red component of each pixel (in bits).
GL_TEXTURE_GREEN_SIZE	Green component of each pixel (in bits).
GL_TEXTURE_BLUE_SIZE	Blue component of each pixel (in bits).
GL_TEXTURE_ALPHA	Alpha component of each pixel (in bits).
GL_TEXTURE_LUMINANCE_SIZE	Luminance component of each pixel (in bits).
GL_TEXTURE_INTENSITY_SIZE	Intensity component of each pixel (in bits). Only valid with GL_SHADOW_DMP format.
GL_TEXTURE_DEPTH_SIZE	Depth component of each pixel (in bits). Only valid with GL_SHADOW_DMP format.
GL_TEXTURE_DENSITY1_SIZE_DMP	Density info 1 of each pixel (only valid with GL_GAS_DMP format; density information that does not take into account intersection with gas texture density information).
GL_TEXTURE_DENSITY2_SIZE_DMP	Density info 2 of each pixel (only valid with GL_GAS_DMP format; density information that takes into account intersection with gas texture density information).
GL_TEXTURE_COMPRESSED	TRUE if the texture is a compressed format; FALSE if not compressed.
GL_TEXTURE_COMPRESSED_IMAGE_SIZE	If the texture is a compressed format, the byte size of the mipmap level specified by level.

The internal-format values obtained by GL_TEXTURE_INTERNAL_FORMAT and the corresponding bit counts of the component pixels are as follows.

Internal Formats	Red (255/0/0)	Green (0/255/0)	Blue (0/0/255)	Alpha	Brightness	Intensity	Depth	Density 1	Density 2
GL_RGBA4	4	4	4	4
GL_RGB5_A1	5	5	5	1
GL_RGBA	8	8	8	8
GL_RGB565	5	6	5
GL_RGB	8	8	8
GL_ALPHA				8
GL_ALPHA4_EXT				4
GL_LUMINANCE					8
GL_LUMINANCE4_EXT					4
GL_LUMINANCE_ALPHA				8	8
GL_LUMINANCE4_ALPHA4_EXT				4	4
GL_SHADOW_DMP						8	24
GL_GAS_DMP								16	16
GL_HILO8_DMP	8	8
GL_ETC1_RGB8_NATIVE_DMP	8	8	8
GL_ETC1_ALPHA_RGB8_A4_NATIVE_DMP	8	8	8	4

This function generates the following errors.

GL_INVALID_OPERATION	If TEXTURE_COMPRESSED_IMAGE_SIZE is specified for an uncompressed texture.
GL_INVALID_ENUM	The target or pname argument was set to an invalid value.
GL_INVALID_VALUE	If an unloaded mipmap level is specified in level.

2011/03/18

Initial version.