GLDRAWRANGEELEMENTS(3UNIX Programmer's ManGLDRAWRANGEELEMENTS(3G)
NAME
glDrawRangeElements - render primitives from array data
C SPECIFICATION
void glDrawRangeElements( GLenum mode,
GLuint start,
GLuint end,
GLsizei count,
GLenum type,
const GLvoid *indices )
PARAMETERS
mode Specifies what kind of primitives to render. Sym-
bolic constants GL_POINTS, GL_LINE_STRIP,
GL_LINE_LOOP, GL_LINES, GL_TRIANGLE_STRIP,
GL_TRIANGLE_FAN, GL_TRIANGLES, GL_QUAD_STRIP,
GL_QUADS, and GL_POLYGON are accepted.
start Specifies the minimum array index contained in
indices.
end Specifies the maximum array index contained in
indices.
count Specifies the number of elements to be rendered.
type Specifies the type of the values in count. Must be
one of GL_UNSIGNED_BYTE, GL_UNSIGNED_SHORT, or
GL_UNSIGNED_INT.
indices Specifies a pointer to the location where the
indices are stored.
DESCRIPTION
glDrawRangeElements is a restricted form of glDrawElements.
mode, start, end, and count match the corresponding argu-
ments to glDrawElements, with the additional constraint that
all values in the arrays count must lie between start and
end, inclusive.
Implementations denote recommended maximum amounts of vertex
and
index data, which may be queried by calling glGet with argu-
ment GL_MAX_ELEMENTS_VERTICES and GL_MAX_ELEMENTS_INDICES.
If end - start + 1 is greater than the value of
GL_MAX_ELEMENTS_VERTICES, or if count is greater than the
value of GL_MAX_ELEMENTS_INDICES, then the call may operate
at reduced performance. There is no requirement that all
vertices in the range [start, end] be referenced. However,
the implementation may partially process unused vertices,
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reducing performance from what could be achieved with an
optimal index set.
When glDrawRangeElements is called, it uses start sequential
elements from an enabled array, starting at count to con-
struct a sequence of geometric primitives. mode specifies
what kind of primitives are constructed, and how the array
elements construct these primitives. If more than one array
is enabled, each is used. If GL_VERTEX_ARRAY is not enabled,
no geometric primitives are constructed.
Vertex attributes that are modified by glDrawRangeElements
have an unspecified value after glDrawRangeElements returns.
For example, if GL_COLOR_ARRAY is enabled, the value of the
current color is undefined after glDrawRangeElements exe-
cutes. Attributes that aren't modified maintain their previ-
ous values.
NOTES
glDrawRangeElements is available only if the GL version is
1.2 or greater.
glDrawRangeElements is included in display lists. If
glDrawRangeElements is entered into a display list, the
necessary array data (determined by the array pointers and
enables) is also entered into the display list. Because the
array pointers and enables are client-side state, their
values affect display lists when the lists are created, not
when the lists are executed.
ERRORS
It is an error for indices to lie outside the range
[start, end], but implementations may not check for this
situation. Such indices cause implementation-dependent
behavior.
GL_INVALID_ENUM is generated if mode is not an accepted
value.
GL_INVALID_VALUE is generated if count is negative.
GL_INVALID_VALUE is generated if end < start.
GL_INVALID_OPERATION is generated if glDrawRangeElements is
executed between the execution of glBegin and the
corresponding glEnd.
ASSOCIATED GETS
glGet with argument GL_MAX_ELEMENTS_VERTICES
glGet with argument GL_MAX_ELEMENTS_INDICES
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SEE ALSO
glArrayElement(3G), glColorPointer(3G), glDrawArrays(3G),
glDrawElements(3G), glEdgeFlagPointer(3G),
glGetPointerv(3G), glIndexPointer(3G),
glInterleavedArrays(3G), glNormalPointer(3G),
glTexCoordPointer(3G), glVertexPointer(3G)
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