Implement automatic batching for points, lines, shapes, and images/quads.

The above are batched together into a single draw call when called without other drawing calls in between, as long as the following criteria are met:

- The texture is the same.
- The primitive type is the same (points cannot be batched with non-points).
- The love.graphics state is the same (aside from the current color - i.e. setColor - and the transform state).
- The active shader’s uniform values are the same.

You can examine the ‘drawcalls’ field of love.graphics.getStats() to help determine if your code is allowing for optimum batching.

--HG--
branch : minor

src/modules/graphics/StreamBuffer.cpp

@@ -0,0 +1,80 @@
+/**
+ * Copyright (c) 2006-2016 LOVE Development Team
+ *
+ * This software is provided 'as-is', without any express or implied
+ * warranty.  In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ *    claim that you wrote the original software. If you use this software
+ *    in a product, an acknowledgment in the product documentation would be
+ *    appreciated but is not required.
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ *    misrepresented as being the original software.
+ * 3. This notice may not be removed or altered from any source distribution.
+ **/
+
+#include "StreamBuffer.h"
+#include "common/Exception.h"
+
+namespace love
+{
+namespace graphics
+{
+
+StreamBuffer::StreamBuffer(Mode mode, size_t size)
+	: data(nullptr)
+	, offset(0)
+	, totalSize(size)
+	, mode(mode)
+{
+	setSize(size);
+}
+
+StreamBuffer::~StreamBuffer()
+{
+		delete[] data;
+}
+
+void *StreamBuffer::getData() const
+{
+	return data;
+}
+
+void *StreamBuffer::getOffsetData() const
+{
+	return data + offset;
+}
+
+void StreamBuffer::incrementOffset(size_t amount)
+{
+	offset += amount;
+}
+
+void StreamBuffer::resetOffset()
+{
+	offset = 0;
+}
+
+void StreamBuffer::setSize(size_t size)
+{
+	delete[] data;
+
+	try
+	{
+		data = new uint8[size];
+	}
+	catch (std::exception &)
+	{
+		throw love::Exception("Out of memory.");
+	}
+
+	this->totalSize = size;
+}
+
+} // graphics
+} // love