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# docs.GL

OpenGL 4
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# glDrawArrays

## Name

glDrawArrays — render primitives from array data

## C Specification

`void glDrawArrays(` | GLenum mode,
| GLint first,
| GLsizei count`)`;

## 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`, and `GL_TRIANGLES` 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 attribute, you can use glVertexAttribPointer to 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.

To enable and disable a generic vertex attribute array, call glEnableVertexAttribArray and glDisableVertexAttribArray.

## Notes

If the current program object, as set by glUseProgram, is invalid, rendering results are undefined. However, no error is generated for this case.

## Errors

`GL_INVALID_ENUM` is generated if `mode` is not an accepted value.

`GL_INVALID_VALUE` is generated if `count` is negative.

`GL_INVALID_FRAMEBUFFER_OPERATION` is generated if the currently bound framebuffer is not framebuffer complete (i.e. the return value from glCheckFramebufferStatus is not `GL_FRAMEBUFFER_COMPLETE`).

## Examples

Render a vertex array (not loaded into OpenGL) using texture UV, color, and normal vertex attributes.

    glEnableVertexAttribArray(texcoord_attrib_index); // Attribute indexes were received from calls to glGetAttribLocation, or passed into glBindAttribLocation.
    glEnableVertexAttribArray(normal_attrib_index);
    glEnableVertexAttribArray(color_attrib_index);
    glEnableVertexAttribArray(position_attrib_index);

    glVertexAttribPointer(texcoord_attrib_index, 2, GL_FLOAT, false, 0, texcoords_data); // texcoords_data is a float*, 2 per vertex, representing UV coordinates.
    glVertexAttribPointer(normal_attrib_index, 3, GL_FLOAT, false, 0, normals_data); // normals_data is a float*, 3 per vertex, representing normal vectors.
    glVertexAttribPointer(color_attrib_index, 3, GL_UNSIGNED_BYTE, true, sizeof(unsigned char)*3, colors_data); // colors_data is a unsigned char*, 3 per vertex, representing the color of each vertex.
    glVertexAttribPointer(position_attrib_index, 3, GL_FLOAT, false, 0, vertex_data); // vertex_data is a float*, 3 per vertex, representing the position of each vertex

    glDrawArrays(GL_TRIANGLES, 0, vertex_count); // vertex_count is an integer containing the number of indices to be rendered

    glDisableVertexAttribArray(position_attrib_index);
    glDisableVertexAttribArray(texcoord_attrib_index);
    glDisableVertexAttribArray(normal_attrib_index);
    glDisableVertexAttribArray(color_attrib_index);

## Tutorials

nehe.gamedev.net - iOS Lesson 02 - First Triangle
open.gl - Depth and Stencil Buffers
open.gl - Geometry Shaders
open.gl - The Graphics Pipeline
open.gl - Transform Feedback
opengl-tutorial.org - Tutorial 2 : The first triangle
opengl-tutorial.org - Tutorial 4 : A Colored Cube

## See Also

glCheckFramebufferStatus, glDisableVertexAttribArray, glDrawElements, glEnableVertexAttribArray, glUseProgram, glVertexAttribPointer

## Copyright

Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see https://web.archive.org/web/20171022161616/http://oss.sgi.com/projects/FreeB/.

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