HP b2600 Reference Manual page 440

T
glTexImage2D
format
type
pixels
Description
Texturing maps a portion of a specified texture image onto each graphical primitive for
which texturing is enabled. To enable and disable two-dimensional texturing, call
glEnable and glDisable with argument GL_TEXTURE_2D.
To define texture images, call glTexImage2D. The arguments describe the parameters of
the texture image, such as height, width, width of the border, level-of-detail number (see
glTexParameter), and number of color components provided. The last three arguments
describe how the image is represented in memory; they are identical to the pixel formats
used for glDrawPixels.
If target is GL_PROXY_TEXTURE_2D, no data is read from pixels, but all of the texture
image state is recalculated, checked for consistency, and checked against the
implementation's capabilities. If the implementation cannot handle a texture of the
requested texture size, it sets all of the image state to 0, but does not generate an error
(see glGetError). To query for an entire mipmap array, use an image array level greater
than or equal to 1.
If target is GL_TEXTURE_2D, data is read from pixels as a sequence of signed or
unsigned bytes, shorts, or longs, or single-precision floating-point values, depending on
type. These values are grouped into sets of one, two, three, or four values, depending on
format, to form elements. If type is GL_BITMAP, the data is considered as a string of
unsigned bytes (and format must be GL_COLOR_INDEX). Each data byte is treated as
eight 1-bit elements, with bit ordering determined by GL_UNPACK_LSB_FIRST (see
glPixelStore).
The first element corresponds to the lower left corner of the texture image. Subsequent
elements progress left-to-right through the remaining texels in the lowest row of the
texture image, and then in successively higher rows of the texture image. The final
element corresponds to the upper right corner of the texture image.
format determines the composition of each element in pixels. It can assume one of nine
symbolic values:
GL_COLOR_INDEX
Each element is a single value, a color index. The GL converts it to fixed point (with an
unspecified number of zero bits to the right of the binary point), shifted left or right
depending on the value and sign of GL_INDEX_SHIFT, and added to
GL_INDEX_OFFSET (see glPixelTransfer). The resulting index is converted to a set of
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Specifies the format of the pixel data. The following symbolic values
are accepted: GL_COLOR_INDEX, GL_RED, GL_GREEN, GL_BLUE,
GL_ALPHA, GL_RGB, GL_RGBA, GL_LUMINANCE, and
GL_LUMINANCE_ALPHA. If the extension GL_EXT_shadow is
supported, the symbolic value GL_DEPTH_COMPONENT is also
accepted.
Specifies the data type of the pixel data. The following symbolic values
are accepted: GL_UNSIGNED_BYTE, GL_BYTE, GL_BITMAP,
GL_UNSIGNED_SHORT, GL_SHORT, GL_UNSIGNED_INT,
GL_INT, and GL_FLOAT.
Specifies a pointer to the image data in memory.
Chapter 18