From a77471ae984e1a2b98885ad1c6d1200608faf3c1 Mon Sep 17 00:00:00 2001
From: Nat Quayle Nelson <natquaylenelson@gmail.com>
Date: Sun, 4 Feb 2024 14:47:42 -0700
Subject: [PATCH] basic checkerboard shader

---
 shader-test/source/PlayState.kiss         |  8 ++++++--
 src/kiss_flixel/shaders/CheckerBoard.frag | 20 ++++++++++++++++++++
 2 files changed, 26 insertions(+), 2 deletions(-)
 create mode 100644 src/kiss_flixel/shaders/CheckerBoard.frag

diff --git a/shader-test/source/PlayState.kiss b/shader-test/source/PlayState.kiss
index 82666d8..dcd6e0c 100644
--- a/shader-test/source/PlayState.kiss
+++ b/shader-test/source/PlayState.kiss
@@ -14,14 +14,18 @@
         (bg.setGraphicSize FlxG.width FlxG.height)
         (bg.screenCenter)
         (add bg))
-    (set shader (new CShader))
-    (set shader.data.invert.value [true])
+    (set shader (new kiss_flixel.shaders.CheckerBoard))
+    // (set shader.data.invert.value [true])
+    (set shader.data.color1.value [1.0 1.0 1.0 1.0])
+    (set shader.data.color2.value [0.0 0.0 0.0 1.0])
+    (set shader.data.checkSize.value [64.0])
     (let [:BitmapFilter filter (new ShaderFilter shader)
             :Array<BitmapFilter> filters [filter]]
         (FlxG.camera.setFilters filters)))
 
 (method &override :Void update [:Float elapsed]
     (super.update elapsed)
+    (+= FlxG.camera.scroll.x 1)
 
     (when FlxG.keys.justPressed.SPACE
         (set shader.data.invert.value [!(first shader.data.invert.value)])))
\ No newline at end of file
diff --git a/src/kiss_flixel/shaders/CheckerBoard.frag b/src/kiss_flixel/shaders/CheckerBoard.frag
new file mode 100644
index 0000000..487414b
--- /dev/null
+++ b/src/kiss_flixel/shaders/CheckerBoard.frag
@@ -0,0 +1,20 @@
+#pragma header
+
+uniform vec4 color1 = vec4(1.0, 1.0, 1.0, 1.0);
+uniform vec4 color2 = vec4(0.0, 0.0, 0.0, 1.0);
+uniform float checkSize = 64;
+
+void main()
+{
+    vec2 position = openfl_TextureCoordv * iResolution;
+    float row = floor(position.y / checkSize);
+    float col = floor(position.x / checkSize);
+
+    bool oddRow = mod(row, 2) == 1;
+    bool oddCol = mod(col, 2) == 1;
+
+    vec4 oddColor = oddRow ? color1 : color2;
+    vec4 evenColor = oddRow ? color2 : color1;
+
+    gl_FragColor = oddCol ? oddColor: evenColor;
+}
\ No newline at end of file