From: Mikko Rasa <tdb@tdb.fi>
Date: Fri, 17 Oct 2014 11:18:27 +0000 (+0300)
Subject: Fallback to glDrawElements if EXT_draw_range_elements is unavailable
X-Git-Url: http://git.tdb.fi/?p=libs%2Fgl.git;a=commitdiff_plain;h=b9844472a5ec8fad571809409f6ed4203531d825

Fallback to glDrawElements if EXT_draw_range_elements is unavailable
---

diff --git a/source/batch.cpp b/source/batch.cpp
index e097fd63..3cb0a6ce 100644
--- a/source/batch.cpp
+++ b/source/batch.cpp
@@ -59,9 +59,6 @@ Batch::Batch(PrimitiveType t):
 	max_index(0),
 	restart(false)
 {
-	/* XXX Should probably provide a fallback to glDrawElements since this class
-	is pretty much required to render anything. */
-	static Require _req(EXT_draw_range_elements);
 }
 
 Batch::~Batch()
@@ -242,16 +239,22 @@ void Batch::draw() const
 	}
 
 	Buffer *ibuf = get_buffer();
+	const void *data_ptr;
 	BindRestore _bind_ibuf(ibuf, ELEMENT_ARRAY_BUFFER);
 	if(ibuf)
 	{
 		if(dirty)
 			update_buffer();
 
-		glDrawRangeElements(prim_type, min_index, max_index, size(), data_type, reinterpret_cast<void *>(get_offset()));
+		data_ptr = reinterpret_cast<const void *>(get_offset());
 	}
 	else
-		glDrawRangeElements(prim_type, min_index, max_index, size(), data_type, &data[0]);
+		data_ptr = &data[0];
+
+	if(EXT_draw_range_elements)
+		glDrawRangeElements(prim_type, min_index, max_index, size(), data_type, data_ptr);
+	else
+		glDrawElements(prim_type, size(), data_type, data_ptr);
 }