GLAPI/glDrawElementsBaseVertex
| Core in version | 4.5 | |
|---|---|---|
| Core since version | 3.2 | |
| Core ARB extension | ARB_draw_elements_base_vertex | |
glDrawElementsBaseVertex: render primitives from array data with a per-element offset
Function Definition
void glDrawElementsBaseVertex(GLenum mode, GLsizei count, GLenum type, GLvoid *indices, GLint basevertex);
- 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.
- 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 byte offset (cast to a pointer type) into the buffer bound to GL_ELEMENT_ARRAY_BUFFER to start reading indices from.
- basevertex
- Specifies a constant that should be added to each element of indices when chosing elements from the enabled vertex arrays.
Description
glDrawElementsBaseVertex behaves identically to glDrawElements except that each index fetched from GL_ELEMENT_ARRAY_BUFFER (starting from the byte offset indices in bytesbytes) will have basevertex added to it before fetching that index from the vertex arrays. If the resulting index is larger than the maximum value representable by type, it is as if the calculation were upconverted to 32-bit unsigned integers (with wrapping on overflow conditions). The operation is undefined if the sum would be negative.
The gl_VertexID passed to the Vertex Shader will be the index after being offset by basevertex, not the index fetched from the buffer.
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 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.
See Also
glBindVertexArray, glDrawElements, glDrawElementsIndirect, glDrawElementsInstanced, glDrawElementsInstancedBaseInstance, glDrawElementsInstancedBaseVertex, glDrawElementsInstancedBaseVertexBaseInstance, glDrawRangeElements, glDrawRangeElementsBaseVertex, glMultiDrawElements, glMultiDrawElementsBaseVertex, glMultiDrawElementsIndirect
Copyright
Copyright © 2010 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/.