Fix iOS compilation.

Author: DelinWorks

core/renderer/backend/metal/CommandBufferMTL.h

@@ -164,7 +164,25 @@ class CommandBufferMTL : public CommandBuffer
                               std::size_t count,
                               std::size_t offset,
                               bool wireframe) override;
-
+							  
+    /**
+     * Draw primitives with an index list instanced.
+     * @param primitiveType The type of primitives that elements are assembled into.
+     * @param indexType The type if indexes, either 16 bit integer or 32 bit integer.
+     * @param count The number of indexes to read from the index buffer for each instance.
+     * @param offset Byte offset within indexBuffer to start reading indexes from.
+     * @param instance Count of
+     * instances to draw at once.
+     * @see `setIndexBuffer(Buffer* buffer)`
+     * @see `drawArrays(PrimitiveType primitiveType, unsigned int start,  unsigned int count)`
+     */
+    virtual void drawElementsInstanced(PrimitiveType primitiveType,
+                                       IndexFormat indexType,
+                                       std::size_t count,
+                                       std::size_t offset,
+                                       int instance,
+                                       bool wireframe = false) override;
+									   
     /**
      * Do some resources release.
      */

core/renderer/backend/metal/CommandBufferMTL.mm

@@ -310,6 +310,22 @@ inline int clamp(int value, int min, int max)
                            indexBufferOffset:offset];
 }
 
+void CommandBufferMTL::drawElementsInstanced(PrimitiveType primitiveType,
+                                             IndexFormat indexType,
+                                             std::size_t count,
+                                             std::size_t offset,
+                                             int instanceCount,
+                                             bool /* wireframe */)
+{
+    prepareDrawing();
+    [_mtlRenderEncoder drawIndexedPrimitives:toMTLPrimitive(primitiveType)
+                                  indexCount:count
+                                   indexType:toMTLIndexType(indexType)
+                                 indexBuffer:_mtlIndexBuffer
+                           indexBufferOffset:offset
+                               instanceCount:instanceCount];
+}
+
 void CommandBufferMTL::endRenderPass()
 {
     afterDraw();

core/renderer/backend/opengl/CommandBufferGL.cpp

@@ -263,7 +263,7 @@ void CommandBufferGL::drawElementsInstanced(PrimitiveType primitiveType,
                                             IndexFormat indexType,
                                             std::size_t count,
                                             std::size_t offset,
-                                            int instance,
+                                            int instanceCount,
                                             bool wireframe)
 {
     prepareDrawing();
@@ -276,7 +276,7 @@ void CommandBufferGL::drawElementsInstanced(PrimitiveType primitiveType,
 #endif
     glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _indexBuffer->getHandler());
     glDrawElementsInstanced(UtilsGL::toGLPrimitiveType(primitiveType), count, UtilsGL::toGLIndexType(indexType),
-                            (GLvoid*)offset, instance);
+                            (GLvoid*)offset, instanceCount);
     CHECK_GL_ERROR_DEBUG();
 #ifndef AX_USE_GLES  // glPolygonMode is only supported in Desktop OpenGL
     if (wireframe)

core/renderer/backend/opengl/CommandBufferGL.h

@@ -177,7 +177,7 @@ class CommandBufferGL final : public CommandBuffer
                                        IndexFormat indexType,
                                        std::size_t count,
                                        std::size_t offset,
-                                       int instance,
+                                       int instanceCount,
                                        bool wireframe = false) override;
 
     /**