render: move render_world_helper, remove chunks drawn behind view

internal/render/drawtexture.vert

@@ -0,0 +1,17 @@
+#version 330
+
+uniform vec2 onScreenPos, onScreenSize;
+
+layout (location = 0) in vec2 vert;
+layout (location = 1) in vec2 texCoord;
+
+out vec2 fragVert;
+out vec2 fragTexCoord;
+
+
+void main() {
+	gl_Position = vec4(onScreenPos + onScreenSize * texCoord, 1, 0);
+	fragVert = texCoord * 2 - vec2(1, 1);
+	fragTexCoord = texCoord;
+}
+