glColorPointer(): specify pointer to RGB color array.

glNormalPointer(): specify pointer to normal array.glVertexPointer(): specify pointer to vertex coords array.Plus, there are 6 functions to specify the exact positions(addresses) of arrays, so, OpenGL can access the arrays in your application. OpenGL provides glEnableClientState() and glDisableClientState() functions to activate and deactivate 6 different types of arrays. Although, better approach is using vertex buffer objects (VBO) or display lists. Here, 3 different OpenGL functions are explained to use vertex arrays glDrawArrays(), glDrawElements() and glDrawRangeElements(). Therefore, you may increase the performance of rendering. Using vertex arrays reduces the number of function calls and redundant usage of shared vertices. GlBegin(GL_TRIANGLES) // draw a cube with 12 triangles // front face =

In immediate mode, you have to provide this shared vertex 6 times, twice for each side as shown in the code. The other thing that you should notice is the vertex 'v0' is shared with 3 adjacent faces front, right and top face. If you also specify normals, texture coordinates and colors to the corresponding vertices, it increases the number of OpenGL function calls.

A cube has 6 faces, so the total number of glVertex*() calls is 36. Take a look the following code to draw a cube with immediate mode.Įach face needs 6 times of glVertex*() calls to make 2 triangles, for example, the front face has v0-v1-v2 and v2-v3-v0 triangles.

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