path: root/game/addons/zylann.hterrain/native/image_utils_generic.gd

@tool

# These functions are the same as the ones found in the GDNative library.
# They are used if the user's platform is not supported.

const HT_Util = preload("../util/util.gd")

var _blur_buffer : Image


func get_red_range(im: Image, rect: Rect2) -> Vector2:
   rect = rect.intersection(Rect2(0, 0, im.get_width(), im.get_height()))
   var min_x := int(rect.position.x)
   var min_y := int(rect.position.y)
   var max_x := min_x + int(rect.size.x)
   var max_y := min_y + int(rect.size.y)

   var min_height := im.get_pixel(min_x, min_y).r
   var max_height := min_height

   for y in range(min_y, max_y):
      for x in range(min_x, max_x):
         var h = im.get_pixel(x, y).r
         if h < min_height:
            min_height = h
         elif h > max_height:
            max_height = h

   return Vector2(min_height, max_height)


func get_red_sum(im: Image, rect: Rect2) -> float:
   rect = rect.intersection(Rect2(0, 0, im.get_width(), im.get_height()))
   var min_x := int(rect.position.x)
   var min_y := int(rect.position.y)
   var max_x := min_x + int(rect.size.x)
   var max_y := min_y + int(rect.size.y)

   var sum := 0.0
   
   for y in range(min_y, max_y):
      for x in range(min_x, max_x):
         sum += im.get_pixel(x, y).r

   return sum


func get_red_sum_weighted(im: Image, brush: Image, pos: Vector2, factor: float) -> float:
   var min_x = int(pos.x)
   var min_y = int(pos.y)
   var max_x = min_x + brush.get_width()
   var max_y = min_y + brush.get_height()
   var min_noclamp_x = min_x
   var min_noclamp_y = min_y

   min_x = clampi(min_x, 0, im.get_width())
   min_y = clampi(min_y, 0, im.get_height())
   max_x = clampi(max_x, 0, im.get_width())
   max_y = clampi(max_y, 0, im.get_height())

   var sum = 0.0

   for y in range(min_y, max_y):
      var by = y - min_noclamp_y

      for x in range(min_x, max_x):
         var bx = x - min_noclamp_x
         
         var shape_value = brush.get_pixel(bx, by).r
         sum += im.get_pixel(x, y).r * shape_value * factor

   return sum


func add_red_brush(im: Image, brush: Image, pos: Vector2, factor: float):
   var min_x = int(pos.x)
   var min_y = int(pos.y)
   var max_x = min_x + brush.get_width()
   var max_y = min_y + brush.get_height()
   var min_noclamp_x = min_x
   var min_noclamp_y = min_y

   min_x = clampi(min_x, 0, im.get_width())
   min_y = clampi(min_y, 0, im.get_height())
   max_x = clampi(max_x, 0, im.get_width())
   max_y = clampi(max_y, 0, im.get_height())

   for y in range(min_y, max_y):
      var by = y - min_noclamp_y

      for x in range(min_x, max_x):
         var bx = x - min_noclamp_x

         var shape_value = brush.get_pixel(bx, by).r
         var r = im.get_pixel(x, y).r + shape_value * factor
         im.set_pixel(x, y, Color(r, r, r))


func lerp_channel_brush(im: Image, brush: Image, pos: Vector2, 
   factor: float, target_value: float, channel: int):
      
   var min_x = int(pos.x)
   var min_y = int(pos.y)
   var max_x = min_x + brush.get_width()
   var max_y = min_y + brush.get_height()
   var min_noclamp_x = min_x
   var min_noclamp_y = min_y

   min_x = clampi(min_x, 0, im.get_width())
   min_y = clampi(min_y, 0, im.get_height())
   max_x = clampi(max_x, 0, im.get_width())
   max_y = clampi(max_y, 0, im.get_height())

   for y in range(min_y, max_y):
      var by = y - min_noclamp_y

      for x in range(min_x, max_x):
         var bx = x - min_noclamp_x

         var shape_value = brush.get_pixel(bx, by).r
         var c = im.get_pixel(x, y)
         c[channel] = lerp(c[channel], target_value, shape_value * factor)
         im.set_pixel(x, y, c)


func lerp_color_brush(im: Image, brush: Image, pos: Vector2, 
   factor: float, target_value: Color):
      
   var min_x = int(pos.x)
   var min_y = int(pos.y)
   var max_x = min_x + brush.get_width()
   var max_y = min_y + brush.get_height()
   var min_noclamp_x = min_x
   var min_noclamp_y = min_y

   min_x = clampi(min_x, 0, im.get_width())
   min_y = clampi(min_y, 0, im.get_height())
   max_x = clampi(max_x, 0, im.get_width())
   max_y = clampi(max_y, 0, im.get_height())

   for y in range(min_y, max_y):
      var by = y - min_noclamp_y

      for x in range(min_x, max_x):
         var bx = x - min_noclamp_x

         var shape_value = brush.get_pixel(bx, by).r
         var c = im.get_pixel(x, y).lerp(target_value, factor * shape_value)
         im.set_pixel(x, y, c)


func generate_gaussian_brush(im: Image) -> float:
   var sum := 0.0
   var center := Vector2(im.get_width() / 2, im.get_height() / 2)
   var radius := minf(im.get_width(), im.get_height()) / 2.0

   for y in im.get_height():
      for x in im.get_width():
         var d := Vector2(x, y).distance_to(center) / radius
         var v := clampf(1.0 - d * d * d, 0.0, 1.0)
         im.set_pixel(x, y, Color(v, v, v))
         sum += v;

   return sum


func blur_red_brush(im: Image, brush: Image, pos: Vector2, factor: float):
   factor = clampf(factor, 0.0, 1.0)
   
   if _blur_buffer == null:
      _blur_buffer = Image.new()
   var buffer := _blur_buffer
   
   var buffer_width := brush.get_width() + 2
   var buffer_height := brush.get_height() + 2
   
   if buffer_width != buffer.get_width() or buffer_height != buffer.get_height():
      buffer.create(buffer_width, buffer_height, false, Image.FORMAT_RF)
   
   var min_x := int(pos.x) - 1
   var min_y := int(pos.y) - 1
   var max_x := min_x + buffer.get_width()
   var max_y := min_y + buffer.get_height()
   
   var im_clamp_w = im.get_width() - 1
   var im_clamp_h = im.get_height() - 1
   
   # Copy pixels to temporary buffer
   for y in range(min_y, max_y):
      for x in range(min_x, max_x):
         var ix := clampi(x, 0, im_clamp_w)
         var iy := clampi(y, 0, im_clamp_h)
         var c = im.get_pixel(ix, iy)
         buffer.set_pixel(x - min_x, y - min_y, c)
   
   min_x = int(pos.x)
   min_y = int(pos.y)
   max_x = min_x + brush.get_width()
   max_y = min_y + brush.get_height()
   var min_noclamp_x := min_x
   var min_noclamp_y := min_y

   min_x = clampi(min_x, 0, im.get_width())
   min_y = clampi(min_y, 0, im.get_height())
   max_x = clampi(max_x, 0, im.get_width())
   max_y = clampi(max_y, 0, im.get_height())
   
   # Apply blur
   for y in range(min_y, max_y):
      var by := y - min_noclamp_y

      for x in range(min_x, max_x):
         var bx := x - min_noclamp_x

         var shape_value := brush.get_pixel(bx, by).r * factor

         var p10 = buffer.get_pixel(bx + 1, by    ).r
         var p01 = buffer.get_pixel(bx,     by + 1).r
         var p11 = buffer.get_pixel(bx + 1, by + 1).r
         var p21 = buffer.get_pixel(bx + 2, by + 1).r
         var p12 = buffer.get_pixel(bx + 1, by + 2).r
         
         var m = (p10 + p01 + p11 + p21 + p12) * 0.2
         var p = lerpf(p11, m, shape_value * factor)

         im.set_pixel(x, y, Color(p, p, p))


func paint_indexed_splat(index_map: Image, weight_map: Image, brush: Image, pos: Vector2, \
   texture_index: int, factor: float):
   
   var min_x := pos.x
   var min_y := pos.y
   var max_x := min_x + brush.get_width()
   var max_y := min_y + brush.get_height()
   var min_noclamp_x := min_x
   var min_noclamp_y := min_y

   min_x = clampi(min_x, 0, index_map.get_width())
   min_y = clampi(min_y, 0, index_map.get_height())
   max_x = clampi(max_x, 0, index_map.get_width())
   max_y = clampi(max_y, 0, index_map.get_height())
   
   var texture_index_f := float(texture_index) / 255.0
   var all_texture_index_f := Color(texture_index_f, texture_index_f, texture_index_f)
   var ci := texture_index % 3
   var cm := Color(-1, -1, -1)
   cm[ci] = 1

   for y in range(min_y, max_y):
      var by := y - min_noclamp_y

      for x in range(min_x, max_x):
         var bx := x - min_noclamp_x

         var shape_value := brush.get_pixel(bx, by).r * factor
         if shape_value == 0.0:
            continue

         var i := index_map.get_pixel(x, y)
         var w := weight_map.get_pixel(x, y)
         
         # Decompress third weight to make computations easier
         w[2] = 1.0 - w[0] - w[1]
         
         # The index map tells which textures to blend.
         # The weight map tells their blending amounts.
         # This brings the limitation that up to 3 textures can blend at a time in a given pixel.
         # Painting this in real time can be a challenge.
         
         # The approach here is a compromise for simplicity.
         # Each texture is associated a fixed component of the index map (R, G or B),
         # so two neighbor pixels having the same component won't be guaranteed to blend.
         # In other words, texture T will not be able to blend with T + N * k,
         # where k is an integer, and N is the number of components in the index map (up to 4).
         # It might still be able to blend due to a special case when an area is uniform,
         # but not otherwise.
         
         # Dynamic component assignment sounds like the alternative, however I wasn't able
         # to find a painting algorithm that wasn't confusing, at least the current one is
         # predictable.
         
         # Need to use approximation because Color is float but GDScript uses doubles...
         if abs(i[ci] - texture_index_f) > 0.001:
            # Pixel does not have our texture index,
            # transfer its weight to other components first
            if w[ci] > shape_value:
               w -= cm * shape_value
               
            elif w[ci] >= 0.0:
               w[ci] = 0.0
               i[ci] = texture_index_f
               
         else:
            # Pixel has our texture index, increase its weight
            if w[ci] + shape_value < 1.0:
               w += cm * shape_value
               
            else:
               # Pixel weight is full, we can set all components to the same index.
               # Need to nullify other weights because they would otherwise never reach
               # zero due to normalization
               w = Color(0, 0, 0)
               w[ci] = 1.0
               i = all_texture_index_f
         
         # No `saturate` function in Color??
         w[0] = clampf(w[0], 0.0, 1.0)
         w[1] = clampf(w[1], 0.0, 1.0)
         w[2] = clampf(w[2], 0.0, 1.0)
         
         # Renormalize
         w /= w[0] + w[1] + w[2]
         
         index_map.set_pixel(x, y, i)
         weight_map.set_pixel(x, y, w)