'Assets', some refactor

src/graphics/Batch2D.cpp

@@ -0,0 +1,18 @@
+#include "Batch2D.h"
+#include "Mesh.h"
+
+Batch2D::Batch2D(size_t capacity) : capacity(capacity),
+									offset(0),
+									color(1.0f, 1.0f, 1.0f, 1.0f){
+	const int attrs[] = {
+			2, 2, 4, 0 //null terminator
+	};
+
+	buffer = new float[capacity];
+	mesh = new Mesh(nullptr, 0, attrs);
+}
+
+Batch2D::~Batch2D(){
+	delete buffer;
+	delete mesh;
+}

src/graphics/Batch2D.h

@@ -0,0 +1,27 @@
+#ifndef SRC_GRAPHICS_BATCH2D_H_
+#define SRC_GRAPHICS_BATCH2D_H_
+
+#include <stdlib.h>
+#include <glm/glm.hpp>
+
+class Mesh;
+
+class Batch2D {
+	float* buffer;
+	size_t capacity;
+	size_t offset;
+	glm::vec4 color;
+	Mesh* mesh;
+
+	void vertex(float x, float y,
+			float u, float v,
+			float r, float g, float b, float a);
+public:
+	Batch2D(size_t capacity);
+	~Batch2D();
+
+	void rect(float x, float y, float w, float h);
+	void render();
+};
+
+#endif /* SRC_GRAPHICS_BATCH2D_H_ */

src/graphics/Mesh.cpp

@@ -12,7 +12,12 @@ Mesh::Mesh(const float* buffer, size_t vertices, const int* attrs) : vertices(ve
 
 	glBindVertexArray(vao);
 	glBindBuffer(GL_ARRAY_BUFFER, vbo);
-	glBufferData(GL_ARRAY_BUFFER, sizeof(float) * vertexSize * vertices, buffer, GL_STATIC_DRAW);
+	if (buffer){
+		glBufferData(GL_ARRAY_BUFFER, sizeof(float) * vertexSize * vertices, buffer, GL_STATIC_DRAW);
+	} else {
+		glBufferData(GL_ARRAY_BUFFER, 0, {}, GL_STATIC_DRAW);
+	}
+
 
 	// attributes
 	int offset = 0;