How to draw Pacman on Bitmap?

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Started by Jeneeus Guruman Aug 9, 2012, 04:09 AM 15 posts View original ↗

Jeneeus Guruman

#1 Aug 9, 2012, 04:09 AM Source
I don't know if this is the right thread to post this.

I just want to ask on what line of code that can draw a circle (solid, outline, or anything as long as it draws a circle) in RGSSx (1, 2 - recommended, or 3) (or only in Ruby if there's no such thing existed in RGSS). I also searched the help files in VX and Ace and I've been googling for hours but nothing found.

I want (to have/to know on how to make) a code to do not just a simple circle but to also can only draw parts of the circle like this:

Spoiler
Thanks in advance.

EDIT: I forgot to tell that I'm not using the image itself to make a circle because I'm making a script that make the circle parts removes from time to time like this one:

Spoiler
EDIT 2: I found a script that draws a circle:

Credits to SephirothSpawn for the script and PK8 for pointing me here.
Spoiler

Code:
#------------------------------------------------------------------------- # * Name : Draw Circle # Info : Draws A Circle # Author : SephirothSpawn # Call Info : Integer X and Y Define Position Center Pt of Circle # Integer Radius Radius of the Circle to Draw # Color color Color of the circle to draw #------------------------------------------------------------------------- def draw_circle(x, y, radius, color = Color.new(255, 255, 255, 255)) # Starts From Left for i in (x - radius)..(x + radius) # Finds Distance From Center sa = (x - i).abs # Finds X Position x_ = i < x ? x - sa : i == x ? x : x + sa # Finds Top Vertical Portion y_ = Integer((radius ** 2 - sa ** 2) ** 0.5) # Draws Vertical Bar self.fill_rect(x_, y - y_, 1, y_ * 2, color) end end
Now I now only need how to cut the circle.
Tsukihime

#2 Aug 9, 2012, 05:45 AM Source

You can look at this

http://rgss3help.tk/?p=109

For a start. Cidiomar has snippets for all sorts of shapes and lines.
Jeneeus Guruman

#3 Aug 9, 2012, 06:02 AM Source

Thanks, Tsukihime for the link and Cidomar for the script. But I really need something that make it like these:
Tsukihime

#4 Aug 9, 2012, 06:37 AM Source

With the arrows?
Jeneeus Guruman

#5 Aug 9, 2012, 06:47 AM Source

Without arrows. Just the circle. Doesn't matter if filled, outlined, or something as long it's circle.

ThallionDarkshine

#6 Aug 9, 2012, 04:26 PM Source

Code:

def draw_circle(x, y, r, color = Color.new(0, 0, 0), fill = true, start_angle = 0, end_angle = 0)
        for i in x - r..x + r
            for e in x - r..x + r
                d = Math.sqrt((i - x).abs ** 2 + (e - x).abs ** 2)
                cs, sn = Math.acos(i / d), Math.asin(e / d)
                angle = (sn < 0) ? cs / Math.PI + 180 : cs / Math.PI
                if (d == r or (d < r and fill)) and ((end_angle < start_angle ? (angle > start_angle and angle < end_angle) : (angle < end_angle or angle > start_angle)) or start_angle == end_angle)
                    self.set_pixel(i, e, color)
                end
            end
        end
    end

This is the code to draw a circle:

Code:

draw_circle(x, y, r[, color, fill, start_angle, end_angle])

Parameters in square brackets are optional.

x: x-pos of center

y: y-pos of center

r: radius

color: color with which to draw the circle

fill: whether to fill in the circle

start_angle: angle to start the circle at

end_angle: angle to end the circle at

note. to draw a full circle, leave start_angle and end_angle alone or set them to the same number

example

Spoiler

To draw this, assuming center 0, 0 and radius 50:

Code:

draw_circle(0, 0, 50, Color.new(50, 50, 50), true, 0, 90)

Tsukihime

#7 Aug 9, 2012, 04:37 PM Source

Ah, geometry. How useful it can be.
Jeneeus Guruman

#8 Aug 9, 2012, 04:50 PM Source
ThallionDarkshine said:

Code:
def draw_circle(x, y, r, color = Color.new(0, 0, 0), fill = true, start_angle = 0, end_angle = 0) for i in x - r..x + r for e in x - r..x + r d = Math.sqrt((i - x).abs ** 2 + (e - x).abs ** 2) cs, sn = Math.acos(i / d), Math.asin(e / d) angle = (sn < 0) ? cs / Math.PI + 180 : cs / Math.PI if (d == r or (d < r and fill)) and ((end_angle < start_angle ? (angle > start_angle and angle < end_angle) : (angle < end_angle or angle > start_angle)) or start_angle == end_angle) self.set_pixel(i, e, color) end end end end
This is the code to draw a circle:

Code:
draw_circle(x, y, r[, color, fill, start_angle, end_angle])
Parameters in square brackets are optional.

x: x-pos of center

y: y-pos of center

r: radius

color: color with which to draw the circle

fill: whether to fill in the circle

start_angle: angle to start the circle at

end_angle: angle to end the circle at

note. to draw a full circle, leave start_angle and end_angle alone or set them to the same number

example

Spoiler
To draw this, assuming center 0, 0 and radius 50:

Code:
draw_circle(0, 0, 50, Color.new(50, 50, 50), true, 0, 90)
A very big thanks but there's an out of range argument error in this line:
Code:
cs, sn = Math.acos(i / d), Math.asin(e / d)
If you don't have time to fix this, I'll try to fix this myself and find what is wrong.

EDIT: And set_pixel method causes lag. It's the entire loop which lags when updates.

ThallionDarkshine

#9 Aug 9, 2012, 06:14 PM Source

Fixed it. Sorry, but I can't make a filled circle, but I can make an outline.

Code:

def draw_circle(x, y, r, color = Color.new(0, 0, 0), start_angle = 0, end_angle = 0)
        for i in -r..r
            xpos = x + i.to_f
            ypos = Math.sqrt(r ** 2 - (xpos - x) ** 2).to_f
            cs, sn1, sn2 = Math.acos(i / r), Math.asin(ypos / r), Math.asin(-ypos / r)
            a1 = (cs > Math.PI / 2) ? 360 - cs * 180 / Math.PI : cs * 180 / Math.PI + 180
            a2 = cs * 180 / Math.PI
            self.set_pixel(xpos, ypos + y, color) if ((end_angle < start_angle ? (a1 > start_angle and a1 < end_angle) : (a1 < end_angle or a1 > start_angle)) or start_angle == end_angle)
            self.set_pixel(xpos, y - ypos, color) if ((end_angle < start_angle ? (a2 > start_angle and a2 < end_angle) : (a2 < end_angle or a2 > start_angle)) or start_angle == end_angle)
        end
    end

Same parameters as before, just no fill.

Jeneeus Guruman

#10 Aug 10, 2012, 12:41 AM Source

it's working now but it won't give me Pacman. I mean, it's always in full circle even I set it in constant 180 or 270 degress.

EDIT: I found out that the middle-left and middle-right most are not included in set_pixel.
Copern

#11 Aug 10, 2012, 02:26 AM Source

I would recommend using Cidomars script that Tsukihime mentioned. It uses the Mid-Point Circle algoritm which is very fast compared to using trigonometry. The Mid-Point Circle algoritm draws in octants, so in 8 portions, exactly what you need.

You could remove two "set_pixel" lines from "draw_circle" to draw an incomplete circle such that angles 180-270 are not drawn. After that you could use Brensenham's Line algoritm to draw two lines from the two disconnected points toward the center (or in the case of 180-270, just a couple straight lines).

If you want to fill only a partial circle, again remove one or more "verts <<" lines from "fill_circle." This time instead of Bresenham's Line algoritm to fill in the rest, you would set singular points on the Y axis (assuming left or right facing pac-man) along the slope towards the center. Bresenham's Line may set multiple points which isn't necessary in scan-lines. Two scan-lines would be required if you want to fill circles with angles 315 to 45 or angles 135 to 225 missing.

Either way, set_pixel is still slow so this is something you would only want to do once and cache/save the result for later use.

Jeneeus Guruman

#12 Aug 10, 2012, 12:53 PM Source

I change my use of the method to Cidomars' and I already have the quarter and semi circles (0, 90, 180, 270, and 360 degress) work. If anyone can help me with this before I solve this problem, you can.

Below is my edited code from Cidomars' draw_circle method.

Spoiler

Code:

def draw_circle(cx, cy, rad, color, thick = 1, start_angle = 0, end_angle = 90)
     rad -= 1
     error = -rad
     x, y = rad, 0
     while (x >= y)
          # Draw a pixel in each octet
          self.fill_rect(cx + x, cy + y, thick, thick, color) if (end_angle >= 270)
	      self.fill_rect(cx - x, cy + y, thick, thick, color) if (x != 0 && end_angle > 90)
	      self.fill_rect(cx + x, cy - y, thick, thick, color) if (y != 0 && end_angle > 270)
	      self.fill_rect(cx - x, cy - y, thick, thick, color) if (x != 0 && y != 0 && end_angle >= 90)
          if (x != y)
               self.fill_rect(cx + y, cy + x, thick, thick, color) if (end_angle > 180)
               self.fill_rect(cx - y, cy + x, thick, thick, color) if (y != 0 && end_angle >= 180)
               self.fill_rect(cx + y, cy - x, thick, thick, color) if (x != 0 && end_angle >= 360)
               self.fill_rect(cx - y, cy - x, thick, thick, color) if (y != 0 && x != 0 && end_angle > 0)
          end
          #
          #-----
          # Error correction
          error += y
          y	 += 1
          error += y
          if (error >= 0)
               error -= x
               x	 -= 1
               error -= x
               end
          print(x.to_s + " : " + y.to_s)
     end
end

EDIT: Also works for angles divisible by 45 (45, 135, 225, and 315 degrees). Anyone can solve this having angles not mentioned here?

Jeneeus Guruman

#13 Aug 11, 2012, 02:00 AM Source

Finally done with the angled circle.

In my modded code from Cidomar, I placed additional parameters, thick, start_angle, and end_angle. The angle (0 degrees) starts at the middle top and rotates counter-clockwise until 360. Start_angle doesn't work yet and you can help me too (if you want).

Spoiler

Code:

  def draw_circle(cx, cy, rad, color, thick = 1, start_angle = 0, end_angle = 280)
    rad -= 1
    error   = -rad
    x, y    = rad, 0
    while (x >= y)
	  self.fill_rect(cx + x, cy + y, thick, thick, color) if (end_angle >= 270 - (61 * y / rad))
	  self.fill_rect(cx - x, cy + y, thick, thick, color) if (x != 0 && end_angle > 90 + (61 * y / rad))
	  self.fill_rect(cx + x, cy - y, thick, thick, color) if (y != 0 && end_angle > 270 + (61 * y / rad))
	  self.fill_rect(cx - x, cy - y, thick, thick, color) if (x != 0 && y != 0 && end_angle >= 90 - (61 * y / rad))
	  if (x != y)
	    self.fill_rect(cx + y, cy + x, thick, thick, color) if (end_angle > 180 + (61 * y / rad))
	    self.fill_rect(cx - y, cy + x, thick, thick, color) if (y != 0 && end_angle >= 180 - (61 * y / rad))
	    self.fill_rect(cx + y, cy - x, thick, thick, color) if (x != 0 && end_angle >= 360 - (61 * y / rad))
	    self.fill_rect(cx - y, cy - x, thick, thick, color) if (y != 0 && x != 0 && end_angle > (61 * y / rad))
	  end
	  error += y
	  y	 += 1
	  error += y
	  if (error >= 0)
	    error -= x
	    x	 -= 1
	    error -= x
	  end
    end
  end

ThallionDarkshine

#14 Aug 11, 2012, 05:48 AM Source

I'll work on this tomorrow, and once someone's completed it, i'll make a dll for it to speed it up a lot.
Jeneeus Guruman

#15 Aug 11, 2012, 06:11 AM Source

Thanks. I already solved this problem but maybe yours are better. I'll wait till then.