Package org.lwjgl.opengles

Class EXTDrawElementsBaseVertex

java.lang.Object
org.lwjgl.opengles.EXTDrawElementsBaseVertex
public class EXTDrawElementsBaseVertex extends Object
Native bindings to the EXT_draw_elements_base_vertex extension.

This extension provides a method to specify a "base vertex offset" value which is effectively added to every vertex index that is transferred through DrawElements.

This mechanism can be used to decouple a set of indices from the actual vertex array that it is referencing. This is useful if an application stores multiple indexed models in a single vertex array. The same index array can be used to draw the model no matter where it ends up in a larger vertex array simply by changing the base vertex value. Without this functionality, it would be necessary to rebind all the vertex attributes every time geometry is switched and this can have larger performance penalty.

For example consider the (very contrived and simple) example of drawing two triangles to form a quad. In the typical example you have the following setup:


     vertices         indices
    ----------        -----
 0 | (-1,  1) |    0 |  0  |
 1 | (-1, -1) |    1 |  1  |
 2 | ( 1, -1) |    2 |  2  |
 3 | ( 1,  1) |    3 |  3  |
    ----------     4 |  0  |
                   5 |  2  |
                      -----

which is normally rendered with the call


 DrawElements(TRIANGLES, 6, UNSIGNED_BYTE, &indices).

Now consider the case where the vertices you want to draw are not at the start of a vertex array but are instead located at offset 100 into a larger array:


      vertices2         indices2
      ----------        -----
         ....        0 | 100 |
 100 | (-1,  1) |    1 | 101 |
 101 | (-1, -1) |    2 | 102 |
 102 | ( 1, -1) |    3 | 103 |
 103 | ( 1,  1) |    4 | 100 |
         ....        5 | 102 |
      ----------        -----

The typical choices for rendering this are to rebind your vertex attributes with an additional offset of 100*stride, or to create an new array of indices (as indices2 in the example). However both rebinding vertex attributes and rebuilding index arrays can be quite costly activities.

With the new drawing commands introduced by this extension you can instead draw using vertices2 and the new draw call:


 DrawElementsBaseVertexEXT(TRIANGLES, 6, UNSIGNED_BYTE, &indices, 100)

Requires GLES 2.0.

  • Method Details

    • nglDrawElementsBaseVertexEXT

      public static void nglDrawElementsBaseVertexEXT(int mode, int count, int type, long indices, int basevertex)

    • glDrawElementsBaseVertexEXT

      public static void glDrawElementsBaseVertexEXT(int mode, int count, int type, long indices, int basevertex)

    • glDrawElementsBaseVertexEXT

      public static void glDrawElementsBaseVertexEXT(int mode, int type, ByteBuffer indices, int basevertex)

    • glDrawElementsBaseVertexEXT

      public static void glDrawElementsBaseVertexEXT(int mode, ByteBuffer indices, int basevertex)

    • glDrawElementsBaseVertexEXT

      public static void glDrawElementsBaseVertexEXT(int mode, ShortBuffer indices, int basevertex)

    • glDrawElementsBaseVertexEXT

      public static void glDrawElementsBaseVertexEXT(int mode, IntBuffer indices, int basevertex)

    • nglDrawRangeElementsBaseVertexEXT

      public static void nglDrawRangeElementsBaseVertexEXT(int mode, int start, int end, int count, int type, long indices, int basevertex)

    • glDrawRangeElementsBaseVertexEXT

      public static void glDrawRangeElementsBaseVertexEXT(int mode, int start, int end, int count, int type, long indices, int basevertex)

    • glDrawRangeElementsBaseVertexEXT

      public static void glDrawRangeElementsBaseVertexEXT(int mode, int start, int end, int type, ByteBuffer indices, int basevertex)

    • glDrawRangeElementsBaseVertexEXT

      public static void glDrawRangeElementsBaseVertexEXT(int mode, int start, int end, ByteBuffer indices, int basevertex)

    • glDrawRangeElementsBaseVertexEXT

      public static void glDrawRangeElementsBaseVertexEXT(int mode, int start, int end, ShortBuffer indices, int basevertex)

    • glDrawRangeElementsBaseVertexEXT

      public static void glDrawRangeElementsBaseVertexEXT(int mode, int start, int end, IntBuffer indices, int basevertex)

    • nglDrawElementsInstancedBaseVertexEXT

      public static void nglDrawElementsInstancedBaseVertexEXT(int mode, int count, int type, long indices, int instancecount, int basevertex)

    • glDrawElementsInstancedBaseVertexEXT

      public static void glDrawElementsInstancedBaseVertexEXT(int mode, int count, int type, long indices, int instancecount, int basevertex)

    • glDrawElementsInstancedBaseVertexEXT

      public static void glDrawElementsInstancedBaseVertexEXT(int mode, int type, ByteBuffer indices, int instancecount, int basevertex)

    • glDrawElementsInstancedBaseVertexEXT

      public static void glDrawElementsInstancedBaseVertexEXT(int mode, ByteBuffer indices, int instancecount, int basevertex)

    • glDrawElementsInstancedBaseVertexEXT

      public static void glDrawElementsInstancedBaseVertexEXT(int mode, ShortBuffer indices, int instancecount, int basevertex)

    • glDrawElementsInstancedBaseVertexEXT

      public static void glDrawElementsInstancedBaseVertexEXT(int mode, IntBuffer indices, int instancecount, int basevertex)

    • nglMultiDrawElementsBaseVertexEXT

      public static void nglMultiDrawElementsBaseVertexEXT(int mode, long count, int type, long indices, int drawcount, long basevertex)

    • glMultiDrawElementsBaseVertexEXT

      public static void glMultiDrawElementsBaseVertexEXT(int mode, IntBuffer count, int type, PointerBuffer indices, IntBuffer basevertex)

    • glMultiDrawElementsBaseVertexEXT

      public static void glMultiDrawElementsBaseVertexEXT(int mode, int[] count, int type, PointerBuffer indices, int[] basevertex)
      Array version of: MultiDrawElementsBaseVertexEXT