+ fun gl_texture: Int do return root.gl_texture
+
+ # Prepare a subtexture from this texture, from the given pixel offsets
+ fun subtexture(left, top, width, height: Numeric): Subtexture
+ do
+ return new AbsoluteSubtexture(self, left.to_f, top.to_f, width.to_f, height.to_f)
+ end
+
+ # Offset of the left border on `root` from 0.0 to 1.0
+ fun offset_left: Float do return 0.0
+
+ # Offset of the top border on `root` from 0.0 to 1.0
+ fun offset_top: Float do return 0.0
+
+ # Offset of the right border on `root` from 0.0 to 1.0
+ fun offset_right: Float do return 1.0
+
+ # Offset of the bottom border on `root` from 0.0 to 1.0
+ fun offset_bottom: Float do return 1.0
+
+ # Should this texture be drawn pixelated when magnified? otherwise it is interpolated
+ #
+ # This setting affects all the textures based on the same pixel data, or `root`.
+ #
+ # Must be set after a successful call to `load`.
+ fun pixelated=(pixelated: Bool)
+ do
+ if root.gl_texture == -1 then return
+
+ # TODO do not modify `root` by using *sampler objects* in glesv3
+ glBindTexture(gl_TEXTURE_2D, root.gl_texture)
+
+ var param = if pixelated then gl_NEAREST else gl_LINEAR
+ glTexParameteri(gl_TEXTURE_2D, gl_TEXTURE_MAG_FILTER, param)
+ end
+end
+
+# Colorful small texture of 32x32 pixels by default
+class CheckerTexture
+ super RootTexture
+
+ # Width and height in pixels, defaults to 32
+ var size = 32 is optional
+
+ redef fun load(force)
+ do
+ if gl_texture != -1 then return
+ load_checker size
+ loaded = true
+ end
+end
+
+# Custom texture with pixel values filled programmatically
+#
+# At creation, the texture is composed of `width` by `height` (rounded down)
+# transparent pixels. The pixels value can be set using `[]=`.
+#
+# ~~~
+# # Build a texture with 4 colors
+# var tex = new CustomTexture(2.0, 2.0)
+# tex[0, 0] = [1.0, 0.0, 0.0] # Red
+# tex[0, 1] = [0.0, 1.0, 0.0] # Green
+# tex[1, 0] = [0.0, 0.0, 1.0] # Blue
+# tex[1, 1] = [1.0, 1.0, 1.0, 0.5] # Transparent white
+# tex.load
+# ~~~
+class CustomTexture
+ super RootTexture
+
+ redef var width
+ redef var height
+
+ private var cpixels = new CByteArray(4*width.to_i*height.to_i) is lazy
+
+ # Set the `color` of the pixel at `x`, `y` (from the top-left corner)
+ #
+ # The argument `color` should be an array of up to 4 floats (RGBA).
+ # If `color` has less than 4 items, the missing items are replaced by 1.0.
+ #
+ # Require: `x < width.to_i and y < height.to_i`
+ fun []=(x, y: Int, color: Array[Float])
+ do
+ assert x < width.to_i and y < height.to_i else print_error "{class_name}::[] out of bounds"
+
+ # Simple conversion from [0.0..1.0] to [0..255]
+ var bytes = [for c in color do (c*255.0).round.to_i.clamp(0, 255).to_bytes.last]
+ while bytes.length < 4 do bytes.add 255
+
+ var offset = 4*(x + y*width.to_i)
+ for i in [0..4[ do cpixels[offset+i] = bytes[i].to_b