oracular (3) glDrawArraysInstancedBaseInstance.3G.gz

Provided by: opengl-4-man-doc_1.0~svn33624-2_all bug

NAME
       glDrawArraysInstancedBaseInstance - draw multiple instances of a range of elements with offset applied to
       instanced attributes


C SPECIFICATION
       void glDrawArraysInstancedBaseInstance(GLenum mode, GLint first, GLsizei count, GLsizei primcount,
                                              GLuint baseinstance);


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_LINES_ADJACENCY,
           GL_LINE_STRIP_ADJACENCY, GL_TRIANGLES_ADJACENCY, GL_TRIANGLE_STRIP_ADJACENCY and GL_PATCHES are
           accepted.

       first
           Specifies the starting index in the enabled arrays.

       count
           Specifies the number of indices to be rendered.

       primcount
           Specifies the number of instances of the specified range of indices to be rendered.

       baseinstance
           Specifies the base instance for use in fetching instanced vertex attributes.


DESCRIPTION
       glDrawArraysInstancedBaseInstance behaves identically to glDrawArrays() except that primcount instances
       of the range of elements are executed and the value of the internal counter instanceID advances for each
       iteration.  instanceID is an internal 32-bit integer counter that may be read by a vertex shader as
       gl_InstanceID.

       glDrawArraysInstancedBaseInstance has the same effect as:

               if ( mode or count is invalid )
                   generate appropriate error
               else {
                   for (int i = 0; i < primcount ; i++) {
                       instanceID = i;
                       glDrawArrays(mode, first, count);
                   }
                   instanceID = 0;
               }

       Specific vertex attributes may be classified as instanced through the use of glVertexAttribDivisor().
       Instanced vertex attributes supply per-instance vertex data to the vertex shader. The index of the vertex
       fetched from the enabled instanced vertex attribute arrays is calculated as: gl _ InstanceID divisor +
       baseInstance. Note that baseinstance does not affect the shader-visible value of gl_InstanceID.


ERRORS
       GL_INVALID_ENUM is generated if mode is not one of the accepted values.

       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_VALUE is generated if count or primcount are 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.


VERSION SUPPORT
       ┌──────────────────────────────────┬───────────────────────────────────────────────────────────────────────┐
       │                                  │                OpenGL Version                                         │
       ├──────────────────────────────────┼─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┤
       │Function                          │ 2.0 │ 2.1 │ 3.0 │ 3.1 │ 3.2 │ 3.3 │ 4.0 │ 4.1 │ 4.2 │ 4.3 │ 4.4 │ 4.5 │
       │/                                 │     │     │     │     │     │     │     │     │     │     │     │     │
       │Feature                           │     │     │     │     │     │     │     │     │     │     │     │     │
       │Name                              │     │     │     │     │     │     │     │     │     │     │     │     │
       ├──────────────────────────────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
       │glDrawArraysInstancedBaseInstance │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  ✔  │  ✔  │  ✔  │  ✔  │
       └──────────────────────────────────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┘


SEE ALSO
       glDrawArrays(), glDrawElementsInstanced()


       Copyright © 2011-2014 Khronos Group. This material may be distributed subject to the terms and conditions
       set forth in the Open Publication License, v 1.0, 8 June 1999.  http://opencontent.org/openpub/.


       Copyright © 2011-2014 Khronos Group

[FIXME: source]                                    04/26/2024                           GLDRAWARRAYSINSTANCE(3G)