Preview the color animation in the animation editor

[trollodel]

Fixes godotengine/godot-proposals#289 for color tracks (not sure if it is enough to close the proposal)

It is done by splitting the link between the 2 keys in chunks.

[timothyqiu]

When I set update mode to discrete, the color still interpolates in the second section.

[trollodel]

@timothyqiu should be fixed now.

[KoBeWi]

Suggested change

	points.write[points.size() - i] = Vector2(x_pos, y_from + fh);
	colors.write[points.size() - i] = color_samples[i];
	points.write[points.size() - i - 1] = Vector2(x_pos, y_from + fh);
	colors.write[points.size() - i - 1] = color_samples[i];

[KoBeWi]

Actually something is wrong when setting easing to high value:

Not sure why.

[trollodel]

Here's a bigger version for reference.

[trollodel]

After debugging a bit, it seems a bug in the renderer as it appears only when there are 8 or more points.
I fix it by splitting the polygon in chunks of 6 points.

[KoBeWi]

Uh, the code looks too complicated now .-.
But that maybe it should be fine if you add a comment saying that this is a workaround for a bug. Or alternatively you could return to the first approach...

[trollodel]

The same issue happens in 3.x, so I think it is better to return to the draw_primitive approach.

chunked draw_polygon approach

  const int polygon_points = 3;

  Vector<Vector2> points;
  Vector<Color> colors;
  points.resize(polygon_points * 2);
  colors.resize(polygon_points * 2);

  int j = 0;
  for (int i = 0; i < color_samples.size() || j == polygon_points; i++) {
  	if (j == polygon_points) {
  		j = 0;
  		i -= 2;
  		draw_polygon(points.duplicate(), colors.duplicate());
  	} else {
  		int x_pos = Math::lerp(x_from, x_to, float(i) / (color_samples.size() - 1));
  		points.write[j] = Vector2(x_pos, y_from);
  		colors.write[j] = color_samples[i];
  		points.write[points.size() - j - 1] = Vector2(x_pos, y_from + fh);
  		colors.write[points.size() - j - 1] = color_samples[i];
  		j++;
  	}
  }

  if (j > 1) {
  	Vector<Vector2> points_aux = points.subarray(points.size() - j, points.size() - 1);
  	Vector<Color> colors_aux = colors.subarray(points.size() - j, points.size() - 1);
  	points.resize(j);
  	colors.resize(j);
  	points.append_array(points_aux);
  	colors.append_array(colors_aux);
  	draw_polygon(points, colors);
  }

[akien-mga]

Thanks!

[akien-mga]

Cherry-picked for 3.4.