OpenGL: Draw lines with VBO

Question

How to draw several separate lines using a single VBO?

score 19 · Accepted Answer · answered Apr 28 '11 at 15:37

19

glDrawElements(GL_LINES, ..., ..., ...);

answered Apr 28 '11 at 15:37

genpfault

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Yup. There really is nothing else to it. This is the right answer. Each pair of points form one line. So, you can store unlimited lines in one huge VBO. – TheBuzzSaw Apr 28 '11 at 16:12

score 8 · Answer 2 · answered Apr 28 '11 at 16:25

In OpenGL-3.1 and later there's a functionality called primitive restart. It works by specifying a special vertex array element index that causes the current primitive to be restarted. That way a single element array allows to draw several GL_LINE_STRIP, GL_LINE_LOOP, GL_TRIANGLE_FAN, GL_TRIANGLE_STRIP, GL_QUAD_STRIP.

http://www.opengl.org/sdk/docs/man4/xhtml/glPrimitiveRestartIndex.xml

This is largely based on the NV_primitive_restart extension: http://www.opengl.org/registry/specs/NV/primitive_restart.txt

Apart from that you can use a primitive type in which vertices are not shared and blow up the element index array a bit.

glDrawElements should be enough - plus as you say primative restart is not available in all versions. — paulm, Feb 10 '14 at 13:27

OpenGL: Draw lines with VBO

2 Answers2