GlDrawArrays
_glDrawArrays: render primitives from array data
Contents
Syntax
- SUB _glDrawArrays (BYVAL mode AS _UNSIGNED LONG, BYVAL first AS LONG, BYVAL count AS LONG)
- void _glDrawArrays(GLenum mode, GLint first, GLsizei count);
- 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.
- 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 prespecify separate arrays of vertices, 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.
Vertex attributes that are modified by _glDrawArrays have an unspecified value after _glDrawArrays returns. Attributes that aren't modified remain well defined.
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
_GL_INVALID_ENUM is generated if mode is not an accepted value.
_GL_INVALID_VALUE is generated if count is negative.
_GL_INVALID_OPERATION is generated if a non-zero buffer object name is bound to an enabled array and the buffer object's data store is currently mapped.
_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.
See also
SUB _GL _glBindVertexArray, _glDrawArraysIndirect, _glDrawArraysInstanced, _glDrawArraysInstancedBaseInstance, _glMultiDrawArrays, _glMultiDrawArraysIndirect
