From 8abc836ae48aabe8744c1874ab20d97148e85baf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vladim=C3=ADr=20Vondru=C5=A1?= <mosra@centrum.cz>
Date: Mon, 19 Nov 2012 12:10:51 +0100
Subject: [PATCH] Allow passing nullptr to IndexedMesh::setIndexBuffer().

Similar functionality should be in Mesh itself for unbinding vertex
buffers.
---
 src/IndexedMesh.cpp | 8 +++++---
 src/IndexedMesh.h   | 3 +++
 src/Mesh.h          | 2 ++
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/src/IndexedMesh.cpp b/src/IndexedMesh.cpp
index e91453f74..4ef22584d 100644
--- a/src/IndexedMesh.cpp
+++ b/src/IndexedMesh.cpp
@@ -42,7 +42,7 @@ void IndexedMesh::draw() {
 }
 
 void IndexedMesh::bind() {
-    CORRADE_ASSERT(_indexCount, "IndexedMesh: the mesh has zero index count!", );
+    CORRADE_ASSERT(!_indexCount || _indexBuffer, "IndexedMesh: index buffer must be added if index count is non-zero", );
 
     Mesh::bind();
     (this->*bindIndexedImplementation)();
@@ -66,11 +66,13 @@ void IndexedMesh::bindIndexBufferImplementationDefault() {}
 
 void IndexedMesh::bindIndexBufferImplementationVAO() {
     bindVAO(vao);
-    _indexBuffer->bind(Buffer::Target::ElementArray);
+    if(_indexBuffer) _indexBuffer->bind(Buffer::Target::ElementArray);
+    else Buffer::unbind(Buffer::Target::ElementArray);
 }
 
 void IndexedMesh::bindIndexedImplementationDefault() {
-    _indexBuffer->bind(Buffer::Target::ElementArray);
+    if(_indexBuffer) _indexBuffer->bind(Buffer::Target::ElementArray);
+    else Buffer::unbind(Buffer::Target::ElementArray);
 }
 
 void IndexedMesh::bindIndexedImplementationVAO() {}
diff --git a/src/IndexedMesh.h b/src/IndexedMesh.h
index 06af7e492..bac40636e 100644
--- a/src/IndexedMesh.h
+++ b/src/IndexedMesh.h
@@ -68,6 +68,9 @@ class MAGNUM_EXPORT IndexedMesh: public Mesh {
         /**
          * @brief Set index buffer
          *
+         * By default there is no index buffer. Parameter @p buffer can be
+         * `nullptr`, in that case current index buffer is unbound from the
+         * mesh.
          * @see MeshTools::compressIndices(), @fn_gl{BindVertexArray},
          *      @fn_gl{BindBuffer} (if @extension{APPLE,vertex_array_object}
          *      is available)
diff --git a/src/Mesh.h b/src/Mesh.h
index d33c94115..d90687956 100644
--- a/src/Mesh.h
+++ b/src/Mesh.h
@@ -112,6 +112,8 @@ more information.
 
 @todo Support for indirect draw buffer (OpenGL 4.0, @extension{ARB,draw_indirect})
 @todo Redo in a way that allows glMultiDrawArrays, glDrawArraysInstanced etc.
+@todo Allow unbinding all vertex buffers with some function (not as side effect),
+    similarly to unbinding index buffer in IndexedMesh
  */
 class MAGNUM_EXPORT Mesh {
     friend class IndexedMesh;