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,
glMultiDrawElements,
or
glMultiDrawArrays.
GL_INVALID_VALUE
is generated if
index
is greater than or equal to
GL_MAX_VERTEX_ATTRIBS
.
GL_INVALID_OPERATION
is generated if
there is no current vertex array object.
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);
Learning Modern 3D Graphics Programming - Chapter 5. Objects in Depth [Vertex Array Objects, Indexed Drawing]
open.gl - Geometry Shaders
open.gl - Textures Objects and Parameters
open.gl - The Graphics Pipeline
open.gl - Transform Feedback
opengl-tutorial.org - Particles / Instancing
opengl-tutorial.org - Tutorial 13 : Normal Mapping
opengl-tutorial.org - Tutorial 2 : The first triangle
opengl-tutorial.org - Tutorial 4 : A Colored Cube
opengl-tutorial.org - Tutorial 8 : Basic shading
glBindAttribLocation, glDrawArrays, glDrawElements, glDrawRangeElements, glMultiDrawElements, 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/.