Added init struct (resource loading helpers)

sunpy/canvas/gl/shaders/texture.fs

@@ -0,0 +1,9 @@
+precision mediump float;
+
+uniform sampler2D u_texture;
+
+varying vec2 v_texcoord;
+
+void main() {
+    gl_FragColor = texture2D(u_texture, v_texcoord);
+}

sunpy/canvas/gl/shaders/texture.vs

@@ -0,0 +1,11 @@
+attribute vec4 position;
+attribute vec2 texcoord;
+
+uniform mat4 u_matrix;
+
+varying vec2 v_texcoord;
+
+void main() {
+    gl_Position = u_matrix * position;
+    v_texcoord = texcoord;
+}