From 11801618dffd9be27a45bd81a247e9a890a61403 Mon Sep 17 00:00:00 2001
From: FunkyFr3sh <cc.red.alert.1@googlemail.com>
Date: Tue, 27 Sep 2022 15:28:57 +0200
Subject: [PATCH] add (commented out) clipper support to dds_blt

---
 inc/ddsurface.h |  2 ++
 src/ddsurface.c | 43 +++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/inc/ddsurface.h b/inc/ddsurface.h
index b5ab814..8a3583c 100644
--- a/inc/ddsurface.h
+++ b/inc/ddsurface.h
@@ -7,6 +7,8 @@
 #include "IDirectDrawSurface.h"
 #include "IDirectDraw.h"
 
+#define DDBLT_NO_CLIP (1 << 31)
+
 /* enables redraw via blt/unlock if there wasn't any flip for X ms */
 #define FLIP_REDRAW_TIMEOUT 1000 / 10
 
diff --git a/src/ddsurface.c b/src/ddsurface.c
index fb4c6fb..f960be5 100644
--- a/src/ddsurface.c
+++ b/src/ddsurface.c
@@ -20,8 +20,8 @@ HRESULT dds_AddAttachedSurface(IDirectDrawSurfaceImpl* This, IDirectDrawSurfaceI
 
         if (!This->backbuffer)
         {
-            lpDDSurface->caps |= DDSCAPS_BACKBUFFER;
-            This->backbuffer = lpDDSurface;
+lpDDSurface->caps |= DDSCAPS_BACKBUFFER;
+This->backbuffer = lpDDSurface;
         }
     }
 
@@ -140,6 +140,45 @@ HRESULT dds_Blt(
         BOOL mirror_left_right = got_fx && (lpDDBltFx->dwDDFX & DDBLTFX_MIRRORLEFTRIGHT);
         BOOL mirror_up_down = got_fx && (lpDDBltFx->dwDDFX & DDBLTFX_MIRRORUPDOWN);
 
+        /* keep this commented out until tested and confirmed working
+        if (This->clipper && !(dwFlags & DDBLT_NO_CLIP))
+        {
+            DWORD size = 0;
+
+            if (SUCCEEDED(IDirectDrawClipper_GetClipList(This->clipper, &dst_rect, NULL, &size)) && size > 0)
+            {
+                RGNDATA* list = (RGNDATA*)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, size);
+
+                if (list)
+                {
+                    if (SUCCEEDED(IDirectDrawClipper_GetClipList(This->clipper, &dst_rect, list, &size)))
+                    {
+                        float scale_w = (float)src_w / dst_w;
+                        float scale_h = (float)src_h / dst_h;
+
+                        RECT* dst_c_rect = (RECT*)list->Buffer;
+
+                        for (int i = 0; i < list->rdh.nCount; ++i)
+                        {
+                            RECT src_c_rect = src_rect;
+
+                            src_c_rect.left += (LONG)((dst_c_rect[i].left - dst_rect.left) * scale_w);
+                            src_c_rect.top += (LONG)((dst_c_rect[i].top - dst_rect.top) * scale_h);
+                            src_c_rect.right -= (LONG)((dst_rect.right - dst_c_rect[i].right) * scale_w);
+                            src_c_rect.bottom -= (LONG)((dst_rect.bottom - dst_c_rect[i].bottom) * scale_h);
+
+                            dds_Blt(This, &dst_c_rect[i], src_surface, &src_c_rect, dwFlags | DDBLT_NO_CLIP, lpDDBltFx);
+                        }
+                    }
+
+                    HeapFree(GetProcessHeap(), 0, list);
+
+                    return DD_OK;
+                }
+            }
+        }
+        */
+
         if (This->bpp != src_surface->bpp)
         {
             TRACE_EXT("     NOT_IMPLEMENTED This->bpp=%u, src_surface->bpp=%u\n", This->bpp, src_surface->bpp);