add IndexedRenderElement

vtm/src/org/oscim/renderer/elements/IndexedRenderElement.java

@@ -0,0 +1,48 @@
+package org.oscim.renderer.elements;
+
+import java.nio.ShortBuffer;
+
+import org.oscim.backend.GL20;
+import org.oscim.renderer.BufferObject;
+import org.oscim.renderer.MapRenderer;
+
+public abstract class IndexedRenderElement extends RenderElement {
+	BufferObject indicesVbo;
+	int numIndices;
+
+	VertexData indiceItems = new VertexData();
+
+	protected IndexedRenderElement(int type) {
+		super(type);
+	}
+
+	@Override
+	protected void compile(ShortBuffer sbuf) {
+		if (numIndices <= 0) {
+			indicesVbo = BufferObject.release(indicesVbo);
+			return;
+		}
+
+		/* add vertices to shared VBO */
+		compileVertexItems(sbuf);
+
+		/* add indices to indicesVbo */
+		ShortBuffer ibuf = MapRenderer.getShortBuffer(numIndices);
+		indiceItems.compile(ibuf);
+
+		if (indicesVbo == null)
+			indicesVbo = BufferObject.get(GL20.GL_ELEMENT_ARRAY_BUFFER, 0);
+
+		indicesVbo.loadBufferData(ibuf.flip(), ibuf.limit() * 2);
+	}
+
+	@Override
+	protected void clear() {
+		indicesVbo = BufferObject.release(indicesVbo);
+		vertexItems.dispose();
+		indiceItems.dispose();
+		numIndices = 0;
+		numVertices = 0;
+	}
+
+}