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/vertex.h

@@ -0,0 +1,105 @@
+/**
+ * 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.
+ **/
+
+#pragma once
+
+// LOVE
+#include "common/int.h"
+#include "Color.h"
+
+// C
+#include <stddef.h>
+
+namespace love
+{
+namespace graphics
+{
+
+enum BufferType
+{
+	BUFFER_VERTEX = 0,
+	BUFFER_INDEX,
+	BUFFER_MAX_ENUM
+};
+
+struct Vertex
+{
+	float x, y;
+	float s, t;
+	Color color;
+};
+
+namespace vertex
+{
+
+enum class PrimitiveMode
+{
+	TRIANGLES,
+	POINTS,
+};
+
+enum class TriangleIndexMode
+{
+	NONE,
+	STRIP,
+	FAN,
+	QUADS,
+};
+
+enum class CommonFormat
+{
+	NONE,
+	XYf,
+	RGBAub,
+	XYf_STf,
+	XYf_STf_RGBAub,
+	XYf_STus_RGBAub,
+};
+
+struct XYf_STf
+{
+	float x, y;
+	float s, t;
+};
+
+struct XYf_STf_RGBAub
+{
+	float x, y;
+	float s, t;
+	Color color;
+};
+
+struct XYf_STus_RGBAub
+{
+	float x, y;
+	uint16 s, t;
+	Color color;
+};
+
+size_t getFormatStride(CommonFormat format);
+
+int getIndexCount(TriangleIndexMode mode, int vertexCount);
+
+void fillIndices(TriangleIndexMode mode, uint16 vertexStart, uint16 vertexCount, uint16 *indices);
+void fillIndices(TriangleIndexMode mode, uint32 vertexStart, uint32 vertexCount, uint32 *indices);
+
+} // vertex
+} // graphics
+} // love