D
glDrawArrays
Chapter 4
113
glDrawArrays
glDrawArrays: render primitives from array data.
C Specification
void glDrawArrays(
GLenum mode,
GLint first,
GLsizei count)
Parameters
mode Specifies what kind of primitives to render. Symbolic 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.
first Specifies the starting index in the enabled arrays.
count Specifies the number of indices to be rendered.
Description
glDrawArrays specifies multiple geometric primitives with very few subroutine calls.
Instead of calling a GL procedure to pass each individual vertex, normal, texture
coordinate, edge flag, or color, you can pre-specify separate arrays of vertexes, normals,
and colors and use them to construct a sequence of primitives with a single call to
glDrawArrays.
When glDrawArrays is called, it uses count sequential elements from each enabled array
to construct a sequence of geometric primitives, beginning with element first. mode
specifies what kind of primitives are constructed, and how the array elements construct
those primitives. If GL_VERTEX_ARRAY is not enabled, no geometric primitives are
generated.
Vertex attributes that are modified by glDrawArrays have an unspecified value after
glDrawArrays returns. For example, if GL_COLOR_ARRAY is enabled, the value of the
current color is undefined after glDrawArrays executes. Attributes that aren’t modified
remain well defined.
Notes
glDrawArrays is available only if the GL version is 1.1 or greater.
glDrawArrays is included in display lists. If glDrawArrays 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.
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