paint: update draw shaders

paint/shaders/layer_view.kong

@@ -1,9 +1,7 @@
 
 #[set(everything)]
 const constants: {
-	pos: float4; // xywh
-	tex: float4; // xywh
-	col: float4;
+	empty: float4;
 	channel: int;
 };
 
@@ -15,6 +13,8 @@ const tex: tex2d;
 
 struct vert_in {
 	pos: float2;
+	tex: float2;
+	col: float4;
 }
 
 struct vert_out {
@@ -25,16 +25,9 @@ struct vert_out {
 
 fun layer_view_vert(input: vert_in): vert_out {
 	var output: vert_out;
-
-	var cpos: float4 = constants.pos;
-	var ctex: float4 = constants.tex;
-
 	output.pos = float4(input.pos, 0.0, 1.0);
-	output.pos.xy = output.pos.xy * cpos.zw + cpos.xy;
-	output.pos.xy = output.pos.xy * 2.0 - 1.0;
-	output.pos.y = -output.pos.y;
-	output.tex = input.pos * ctex.zw + ctex.xy;
-	output.col = constants.col;
+	output.tex = input.tex;
+	output.col = input.col;
 	return output;
 }