Fixing wrapper.ElementBuffers() (#21)

Author: tonitch

src/wrapper.zig

@@ -1883,14 +1883,15 @@ pub fn Wrap(comptime bindings: anytype) type {
 
  pub fn drawElements(
  mode: PrimitiveType,
+ length: u32,
  index_type: enum(Enum) {
  unsigned_byte = UNSIGNED_BYTE,
  unsigned_short = UNSIGNED_SHORT,
  unsigned_int = UNSIGNED_INT,
  },
- indices: []const anyopaque,
+ indices: u32, //offset in buffer
  ) void {
- bindings.drawElements(@intFromEnum(mode), @intCast(indices.len), @intFromEnum(index_type), indices.ptr);
+ bindings.drawElements(@intFromEnum(mode), @intCast(length), @intFromEnum(index_type), @ptrFromInt(indices));
  }
 
  pub fn polygonOffset(factor: f32, units: f32) void {