From 8eddd696162d2f3ca35848ec851cdf850e790af6 Mon Sep 17 00:00:00 2001
From: Alessandro Proto <me@alexdevs.me>
Date: Wed, 1 Feb 2023 10:22:43 +0100
Subject: [PATCH] Add gpu.drawBuffer

---
 Capy64/Runtime/Libraries/GPU.cs | 47 ++++++++++++++++++++++++++-------
 1 file changed, 38 insertions(+), 9 deletions(-)

diff --git a/Capy64/Runtime/Libraries/GPU.cs b/Capy64/Runtime/Libraries/GPU.cs
index 278d4b4..4a9c589 100644
--- a/Capy64/Runtime/Libraries/GPU.cs
+++ b/Capy64/Runtime/Libraries/GPU.cs
@@ -107,6 +107,11 @@ public class GPU : IPlugin
             name = "newBuffer",
             function = L_NewBuffer,
         },
+        new()
+        {
+            name = "drawBuffer",
+            function = L_DrawBuffer,
+        },
         new(), // NULL
     };
 
@@ -420,23 +425,47 @@ public class GPU : IPlugin
     }
 
     // WIP
-    private static int L_CopyBuffer(IntPtr state)
+    private static int L_DrawBuffer(IntPtr state)
     {
         var L = Lua.FromIntPtr(state);
 
-        var x = L.CheckInteger(1);
-        var y = L.CheckInteger(2);
-
-        var from = L.CheckObject<uint[]>(3, GPUBuffer.ObjectType, false);
+        var from = L.CheckObject<uint[]>(1, GPUBuffer.ObjectType, false);
         if (from is null)
         {
-            L.ArgumentError(3, GPUBuffer.ObjectType + " expected, got " + L.TypeName(L.Type(3)));
+            L.ArgumentError(1, GPUBuffer.ObjectType + " expected, got " + L.TypeName(L.Type(1)));
         }
 
-        var origin = new uint[_game.Width * _game.Height];
-        _game.Drawing.Canvas.GetData(origin);
+        var x = (int)L.CheckInteger(2) - 1;
+        var y = (int)L.CheckInteger(3) - 1;
+        var w = (int)L.CheckInteger(4);
+        var h = (int)L.CheckInteger(5);
+        try
+        {
+            _game.Drawing.Canvas.SetData(0, new Rectangle
+            {
+                X = x,
+                Y = y,
+                Width = w,
+                Height = h,
+            }, from, 0, from.Length);
+        }
+        catch (Exception e)
+        {
+            if (w * h != from.Length)
+            {
+                L.Error("buffer size does not match width and height");
+                return 0;
+            }
 
+            if(x < 0 || y < 0 || x + w >= _game.Drawing.Canvas.Width || y + h >= _game.Drawing.Canvas.Height)
+            {
+                L.Error("position out of bounds");
+                return 0;
+            }
 
-        return 0;
+            L.Error(e.ToString());
+        }
+
+        return -1;
     }
 }