diff --git a/src/global-ibo.h b/src/global-ibo.h
index 2e2d5f2..e1d6e1f 100644
--- a/src/global-ibo.h
+++ b/src/global-ibo.h
@@ -25,11 +25,18 @@
 #include "gl-util.h"
 
 #include <vector>
+#include <limits>
+#include <assert.h>
+#include <stdint.h>
+
+typedef uint32_t index_t;
+#define INDEX_T_MAX std::numeric_limits<index_t>::max()
+#define _GL_INDEX_TYPE GL_UNSIGNED_INT
 
 struct GlobalIBO
 {
 	IBO::ID ibo;
-	std::vector<uint32_t> buffer;
+	std::vector<index_t> buffer;
 
 	GlobalIBO()
 	{
@@ -43,6 +50,8 @@ struct GlobalIBO
 
 	void ensureSize(size_t quadCount)
 	{
+		assert(quadCount*6 < INDEX_T_MAX);
+
 		if (buffer.size() >= quadCount*6)
 			return;
 
@@ -51,14 +60,14 @@ struct GlobalIBO
 
 		for (size_t i = startInd; i < quadCount; ++i)
 		{
-			static const uint32_t indTemp[] = { 0, 1, 2, 2, 3, 0 };
+			static const index_t indTemp[] = { 0, 1, 2, 2, 3, 0 };
 
 			for (size_t j = 0; j < 6; ++j)
 				buffer.push_back(i * 4 + indTemp[j]);
 		}
 
 		IBO::bind(ibo);
-		IBO::uploadData(buffer.size() * sizeof(uint32_t), &buffer[0]);
+		IBO::uploadData(buffer.size() * sizeof(index_t), &buffer[0]);
 		IBO::unbind();
 	}
 };
diff --git a/src/quad.h b/src/quad.h
index bb89640..c7a784d 100644
--- a/src/quad.h
+++ b/src/quad.h
@@ -176,7 +176,7 @@ struct Quad
 		}
 
 		VAO::bind(vao);
-		gl.DrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
+		gl.DrawElements(GL_TRIANGLES, 6, _GL_INDEX_TYPE, 0);
 		VAO::unbind();
 	}
 };
diff --git a/src/quadarray.h b/src/quadarray.h
index 1f25755..635bfd7 100644
--- a/src/quadarray.h
+++ b/src/quadarray.h
@@ -31,9 +31,6 @@
 
 #include <stdint.h>
 
-typedef uint32_t index_t;
-#define _GL_INDEX_TYPE GL_UNSIGNED_INT
-
 /* A small hack to get mutable QuadArray constructors */
 inline void initBufferBindings(Vertex *)
 {
diff --git a/src/tilemap.cpp b/src/tilemap.cpp
index 0872f8a..634ac78 100644
--- a/src/tilemap.cpp
+++ b/src/tilemap.cpp
@@ -28,6 +28,7 @@
 #include "sharedstate.h"
 #include "glstate.h"
 #include "gl-util.h"
+#include "global-ibo.h"
 #include "etc-internal.h"
 #include "quadarray.h"
 #include "texpool.h"
@@ -1124,12 +1125,12 @@ void GroundLayer::draw()
 
 void GroundLayer::drawInt()
 {
-	gl.DrawElements(GL_TRIANGLES, vboCount, GL_UNSIGNED_INT, (GLvoid*) 0);
+	gl.DrawElements(GL_TRIANGLES, vboCount, _GL_INDEX_TYPE, (GLvoid*) 0);
 }
 
 void GroundLayer::drawFlashInt()
 {
-	gl.DrawElements(GL_TRIANGLES, p->flash.quadCount * 6, GL_UNSIGNED_INT, 0);
+	gl.DrawElements(GL_TRIANGLES, p->flash.quadCount * 6, _GL_INDEX_TYPE, 0);
 }
 
 void GroundLayer::onGeometryChange(const Scene::Geometry &geo)
@@ -1154,7 +1155,7 @@ void ScanRow::setIndex(int value)
 	z = calculateZ(p, index);
 	scene->reinsert(*this);
 
-	vboOffset = p->scanrowBases[index] * sizeof(uint32_t) * 6;
+	vboOffset = p->scanrowBases[index] * sizeof(index_t) * 6;
 	vboCount = p->scanrowSize(index) * 6;
 }
 
@@ -1178,7 +1179,7 @@ void ScanRow::draw()
 
 void ScanRow::drawInt()
 {
-	gl.DrawElements(GL_TRIANGLES, vboBatchCount, GL_UNSIGNED_INT, (GLvoid*) vboOffset);
+	gl.DrawElements(GL_TRIANGLES, vboBatchCount, _GL_INDEX_TYPE, (GLvoid*) vboOffset);
 }
 
 int ScanRow::calculateZ(TilemapPrivate *p, int index)