first commit

ghostty/shaders/negative.glsl

@@ -0,0 +1,8 @@
+
+void mainImage( out vec4 fragColor, in vec2 fragCoord )
+{
+    vec2 uv = fragCoord/iResolution.xy;
+    vec4 color = texture(iChannel0, uv);
+    fragColor = vec4(1.0 - color.x, 1.0 - color.y, 1.0 - color.z, color.w);
+}
+