glEnableVertexAttribArray — Enable or disable a generic vertex attribute array
void glEnableVertexAttribArray( | GLuint | index); |
void glDisableVertexAttribArray( | GLuint | index); |
glEnableVertexAttribArray enables the
generic vertex attribute array specified by
index.
glDisableVertexAttribArray disables the
generic vertex attribute array specified by
index. By default, all client-side
capabilities are disabled, including all generic vertex
attribute arrays. If enabled, the values in the generic vertex
attribute array will be accessed and used for rendering when
calls are made to vertex array commands such as
glDrawArrays,
glDrawElements,
glDrawRangeElements,
glArrayElement,
glMultiDrawElements,
or
glMultiDrawArrays.
glEnableVertexAttribArray and
glDisableVertexAttribArray are available
only if the GL version is 2.0 or greater.
GL_INVALID_VALUE is generated if
index is greater than or equal to
GL_MAX_VERTEX_ATTRIBS.
GL_INVALID_OPERATION is generated if either
glEnableVertexAttribArray or
glDisableVertexAttribArray is executed
between the execution of
glBegin
and the corresponding execution of
glEnd.
glGet
with argument GL_MAX_VERTEX_ATTRIBS
glGetVertexAttrib
with arguments index and
GL_VERTEX_ATTRIB_ARRAY_ENABLED
glGetVertexAttribPointerv
with arguments index and
GL_VERTEX_ATTRIB_ARRAY_POINTER
glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer); // vertex_buffer is retrieved from glGenBuffers glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, index_buffer); // index_buffer is retrieved from glGenBuffers glEnableVertexAttribArray(texcoord_attrib_index); // Attribute indexes were received from calls to glGetAttribLocation, or passed into glBindAttribLocation. glEnableVertexAttribArray(normal_attrib_index); glEnableVertexAttribArray(position_attrib_index); // vertex_stride is the size of bytes of each vertex in the buffer object // vertex_position_offset and kin are the offset in bytes of the position data // in each vertex. For example if your vertex structure is // [ position, texcoord, normal ] then position vertex_position_offset will // have offset 0, vertex_texcoord_offset is 12 (position is 3 * sizeof(float) // bytes large, and texcoord comes just after) and vertex_normal_offset is // 20 = 5 * sizeof(float). GLintptr vertex_texcoord_offset = 3 * sizeof(float); GLintptr vertex_normal_offset = 5 * sizeof(float); GLintptr vertex_position_offset = 0 * sizeof(float); glVertexAttribPointer(texcoord_attrib_index, 2, GL_FLOAT, false, vertex_stride, (GLvoid*)vertex_texcoord_offset); glVertexAttribPointer(normal_attrib_index, 3, GL_FLOAT, false, vertex_stride, (GLvoid*)vertex_normal_offset); glVertexAttribPointer(position_attrib_index, 3, GL_FLOAT, false, vertex_stride, (GLvoid*)vertex_position_offset); // num_vertices is the number of verts in your vertex_data. // index_data is an array of unsigned int offsets into vertex_data. glDrawElements(GL_TRIANGLES, num_vertices, GL_UNSIGNED_INT, NULL); glDisableVertexAttribArray(position_attrib_index); glDisableVertexAttribArray(texcoord_attrib_index); glDisableVertexAttribArray(normal_attrib_index);
glArrayElement, glBindAttribLocation, glDrawArrays, glDrawElements, glDrawRangeElements, glMultiDrawElements, glPopClientAttrib, glPushClientAttrib, glVertexAttrib, glVertexAttribPointer
Copyright © 2003-2005 3Dlabs Inc. Ltd. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. https://opencontent.org/openpub/.