man glDrawRangeElements (3): 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. Symbolic constants GL_POINTS, GL_LINE_STRIP, GL_LINE_LOOP, GL_LINES, GL_LINE_STRIP_ADJACENCY, GL_LINES_ADJACENCY, GL_TRIANGLE_STRIP, GL_TRIANGLE_FAN, GL_TRIANGLES, GL_TRIANGLE_STRIP_ADJACENCY, GL_TRIANGLES_ADJACENCY and GL_PATCHES 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 indices. 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 arguments 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 argument 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, reducing performance from what could be achieved with an optimal index set.

When glDrawRangeElements is called, it uses count sequential elements from an enabled array, starting at start to construct 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.

Vertex attributes that are modified by glDrawRangeElements have an unspecified value after glDrawRangeElements returns. Attributes that aren't modified maintain their previous values.

NOTES

GL_LINE_STRIP_ADJACENCY, GL_LINES_ADJACENCY, GL_TRIANGLE_STRIP_ADJACENCY and GL_TRIANGLES_ADJACENCY are available only if the GL version is 3.2 or greater.

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 a geometry shader is active and mode is incompatible with the input primitive type of the geometry shader in the currently installed program object.

GL_INVALID_OPERATION is generated if a non-zero buffer object name is bound to an enabled array or the element array and the buffer object's data store is currently mapped.

ASSOCIATED GETS

glGet() with argument GL_MAX_ELEMENTS_VERTICES

glGet() with argument GL_MAX_ELEMENTS_INDICES