Small refactor

examples/affine.cr

@@ -7,6 +7,7 @@ module PF
     @bricks : Sprite
     @transform : Transform2d = Transform2d.new
     @angle = 0.0
+    @size = 1.0
 
     def initialize(*args, **kwargs)
       super
@@ -25,6 +26,7 @@ module PF
         .reset
         .translate(-(@bricks.size // 2))
         .rotate(@angle)
+        .scale(@size)
         .translate(viewport // 2)
 
       b1, b2 = @transform.bounding_box(@bricks.size.x, @bricks.size.y).map(&.to_i)
@@ -35,8 +37,7 @@ module PF
         b1.x.upto(b2.x) do |x|
           point = @transform.apply(x, y).to_i
           if point >= Vector[0, 0] && point < @bricks.size
-            color = @bricks.sample(point.x, point.y)
-            draw_point(x.to_i, y.to_i, color)
+            draw_point(x.to_i, y.to_i, @bricks.peak(point))
           end
         end
       end

examples/snow_scroll.cr

@@ -8,7 +8,7 @@ class Snow < PF::Game
     super
 
     @pixels = @screen.pixels
-    clear(0, 0, 25)
+    clear(0, 0, 0x25)
   end
 
   def update(dt, event)
@@ -23,10 +23,10 @@ class Snow < PF::Game
 
       0.upto(@width - 1) do |x|
         if rand(0..250) == 0
-          shade = rand(0..255)
-          @pixels[x] = LibSDL.map_rgba(@screen.format, shade, shade, shade, 255)
+          shade = rand(25_u8..255_u8)
+          @pixels[x] = PF::Pixel.new(shade, shade, shade).to_u32
         else
-          @pixels[x] = LibSDL.map_rgba(@screen.format, 0, 0, 25, 255)
+          @pixels[x] = 0x000025FF
         end
       end
     end

examples/sprite_example.cr

@@ -3,11 +3,11 @@ require "../src/sprite"
 
 module PF
   class SpriteExample < Game
-    @bricks : Sprite
+    @sprite : Sprite
 
     def initialize(*args, **kwargs)
       super
-      @bricks = Sprite.new("./assets/pf-font.png")
+      @sprite = Sprite.new("./assets/pf-font.png")
     end
 
     def update(dt, event)
@@ -15,7 +15,7 @@ module PF
 
     def draw
       clear(255, 255, 255)
-      @bricks.draw_to(@screen, width // 2 - @bricks.width // 2, height // 2 - @bricks.height // 2)
+      @sprite.draw_to(screen, (viewport // 2) - @sprite.size // 2)
     end
   end
 end

spec/pixel_spec.cr

@@ -0,0 +1,23 @@
+require "./spec_helper"
+require "../src/pixel"
+
+include PF
+
+describe Pixel do
+  describe "#initialize" do
+    it "breaks out a UInt32 into rgba components" do
+      p = Pixel.new(0x11223344)
+      p.r.should eq(0x11_u8)
+      p.g.should eq(0x22_u8)
+      p.b.should eq(0x33_u8)
+      p.a.should eq(0x44_u8)
+    end
+  end
+
+  describe "#to_u32" do
+    it "combines components into a UInt32 value" do
+      p = Pixel.new(0x11_u8, 0x22_u8, 0x33_u8, 0x44_u8)
+      p.to_u32.should eq(0x11223344_u32)
+    end
+  end
+end

src/game.cr

@@ -7,14 +7,16 @@ module PF
     FPS_INTERVAL = 1.0
     SHOW_FPS     = true
 
-    getter width : Int32
-    getter height : Int32
-    @viewport : Vector(Int32, 2)? = nil
     property scale : Int32
     property title : String
     property running = true
     property screen : Sprite
 
+    getter width : Int32
+    getter height : Int32
+
+    @viewport : Vector(Int32, 2)? = nil
+
     delegate :draw_point, :draw_line, :draw_circle, :draw_triangle, :draw_rect, :draw_shape,
       :fill_triangle, :fill_rect, :fill_shape, to: @screen
 
@@ -30,13 +32,7 @@ module PF
       @window = SDL::Window.new(@title, @width * @scale, @height * @scale, flags: window_flags)
       @renderer = SDL::Renderer.new(@window, flags: flags)
       @renderer.scale = {@scale, @scale}
-
-      surface = SDL::Surface.new(LibSDL.create_rgb_surface(
-        flags: 0, width: @width, height: @height, depth: 32,
-        r_mask: 0xFF000000, g_mask: 0x00FF0000, b_mask: 0x0000FF00, a_mask: 0x000000FF
-      ))
-
-      @screen = Sprite.new(surface)
+      @screen = Sprite.new(@width, @height)
     end
 
     abstract def update(dt : Float64, event : SDL::Event)

src/pixel.cr

@@ -39,10 +39,10 @@ module PF
     property r : UInt8, g : UInt8, b : UInt8, a : UInt8
 
     def initialize(rgba : UInt32)
-      @r = ((rgba & 0xFF000000_u32) >> (8 * 3)).to_u8
-      @g = ((rgba & 0x00FF0000_u32) >> (8 * 2)).to_u8
-      @b = ((rgba & 0x0000FF00_u32) >> 8).to_u8
-      @a = ((rgba & 0x000000FF_u32)).to_u8
+      @r = ((rgba >> 24) & 0xFF).to_u8
+      @g = ((rgba >> 16) & 0xFF).to_u8
+      @b = ((rgba >> 8) & 0xFF).to_u8
+      @a = (rgba & 0xFF).to_u8
     end
 
     def initialize(@r : UInt8 = 255, @g : UInt8 = 255, @b : UInt8 = 255, @a : UInt8 = 255)
@@ -67,5 +67,13 @@ module PF
     def -(n : Float64)
       PF::Pixel.new((@r - n).to_u8, (@g - n).to_u8, (@b - n).to_u8, @a)
     end
+
+    def to_u32
+      value = @r.to_u32 << 24
+      value |= @g.to_u32 << 16
+      value |= @b.to_u32 << 8
+      value |= @a.to_u32
+      value
+    end
   end
 end

src/sprite.cr

@@ -15,6 +15,13 @@ module PF
       @surface = SDL::IMG.load(path)
     end
 
+    def initialize(width : Int, height : Int)
+      @surface = SDL::Surface.new(LibSDL.create_rgb_surface(
+        flags: 0, width: width, height: height, depth: 32,
+        r_mask: 0xFF000000, g_mask: 0x00FF0000, b_mask: 0x0000FF00, a_mask: 0x000000FF
+      ))
+    end
+
     def width
       @surface.width
     end
@@ -27,30 +34,49 @@ module PF
       Vector[width, height]
     end
 
+    # Convert the color mode of this sprite to another for optimization
     def convert(other : SDL::Surface)
       @surface = @surface.convert(other)
     end
 
+    # ditto
     def convert(other : Sprite)
       @surface = @surface.convert(other.surface)
     end
 
-    def draw_to(surface : SDL::Surface, x : Int32, y : Int32)
+    # Draw this sprite to another
+    def draw_to(surface : SDL::Surface, x : Int, y : Int)
       @surface.blit(surface, nil, SDL::Rect.new(x, y, width, height))
     end
 
-    def draw_to(sprite : Sprite, x : Int32, y : Int32)
+    # ditto
+    def draw_to(sprite : Sprite, x : Int, y : Int)
       draw_to(sprite.surface, x, y)
     end
 
+    # ditto
+    def draw_to(dest : SDL::Surface | Sprite, at : Vector(Int, 2))
+      draw_to(dest, at.x, at.y)
+    end
+
     # Raw access to the pixels as a Slice
     def pixels
       Slice.new(@surface.pixels.as(Pointer(UInt32)), width * height)
     end
 
+    # Peak at a raw pixel value at (*x*, *y*)
+    def peak(x : Int, y : Int)
+      pixel_pointer(x, y).value
+    end
+
+    # ditto
+    def peak(point : Vector(Int, 2))
+      pixel_pointer(point.x, point.y).value
+    end
+
     # Sample a color at an *x* and *y* position
     def sample(x : Int, y : Int)
-      raw_pixel = pixel_pointer(x, y).value
+      raw_pixel = peak(x, y)
 
       r = uninitialized UInt8
       g = uninitialized UInt8
@@ -78,8 +104,13 @@ module PF
       Pixel.new(r, g, b, a)
     end
 
+    # ditto
+    def sample(point : Vector(Int, 2), alpha = true)
+      sample(point.x, point.y, true)
+    end
+
     # Get the pointer to a pixel
-    private def pixel_pointer(x : Int32, y : Int32)
+    def pixel_pointer(x : Int32, y : Int32)
       target = @surface.pixels + (y * @surface.pitch) + (x * 4)
       target.as(Pointer(UInt32))
     end

src/transform2d.cr

@@ -46,6 +46,10 @@ module PF
       self
     end
 
+    def scale(n : Float | Int)
+      scale(n, n)
+    end
+
     def rotate(angle : Float | Int)
       cos = Math.cos(angle)
       sin = Math.sin(angle)