Package org.lwjgl.opengles

Class OESDrawElementsBaseVertex

java.lang.Object
org.lwjgl.opengles.OESDrawElementsBaseVertex
public class OESDrawElementsBaseVertex extends Object
Native bindings to the OES_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:


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

Requires GLES 2.0.

  • Method Details

    • nglDrawElementsBaseVertexOES

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

    • glDrawElementsBaseVertexOES

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

    • glDrawElementsBaseVertexOES

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

    • glDrawElementsBaseVertexOES

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

    • glDrawElementsBaseVertexOES

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

    • glDrawElementsBaseVertexOES

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

    • nglDrawRangeElementsBaseVertexOES

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

    • glDrawRangeElementsBaseVertexOES

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

    • glDrawRangeElementsBaseVertexOES

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

    • glDrawRangeElementsBaseVertexOES

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

    • glDrawRangeElementsBaseVertexOES

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

    • glDrawRangeElementsBaseVertexOES

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

    • nglDrawElementsInstancedBaseVertexOES

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

    • glDrawElementsInstancedBaseVertexOES

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

    • glDrawElementsInstancedBaseVertexOES

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

    • glDrawElementsInstancedBaseVertexOES

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

    • glDrawElementsInstancedBaseVertexOES

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

    • glDrawElementsInstancedBaseVertexOES

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

    • nglMultiDrawElementsBaseVertexOES

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

    • glMultiDrawElementsBaseVertexOES

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

    • glMultiDrawElementsBaseVertexOES

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