Erich Hoover : wined3d: Fix LockRect memory location calculation for WINED3DFMT_DXT*.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 01199072dd91dfb0d3003a5d7c9c53bf852db164
URL:    http://source.winehq.org/git/wine.git/?a=commit;h=01199072dd91dfb0d3003a5d7c...

Author: Erich Hoover <ehoover(a)mediaserver>
Date:   Mon Mar 12 17:07:12 2007 -0600

wined3d: Fix LockRect memory location calculation for WINED3DFMT_DXT*.

---

 dlls/d3d9/tests/surface.c |    2 +-
 dlls/wined3d/surface.c    |   14 ++++++++++++--
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/dlls/d3d9/tests/surface.c b/dlls/d3d9/tests/surface.c
index 7063a2a..189ebf6 100644
--- a/dlls/d3d9/tests/surface.c
+++ b/dlls/d3d9/tests/surface.c
@@ -218,7 +218,7 @@ static void test_lockrect_offset(IDirect3DDevice9 *device)
         offset = (BYTE *)locked_rect.pBits - base;
         expected_offset = (rect.top / dxt_formats[i].block_height) * locked_rect.Pitch
                         + (rect.left / dxt_formats[i].block_width) * dxt_formats[i].block_size;
-        todo_wine ok(offset == expected_offset, "Got offset %u, expected offset %u for format %s\n", offset, expected_offset, dxt_formats[i].name);
+        ok(offset == expected_offset, "Got offset %u, expected offset %u for format %s\n", offset, expected_offset, dxt_formats[i].name);
 
         hr = IDirect3DSurface9_UnlockRect(surface);
         ok(SUCCEEDED(hr), "UnlockRect failed (%08x)\n", hr);
diff --git a/dlls/wined3d/surface.c b/dlls/wined3d/surface.c
index a295bc7..1f4ddb6 100644
--- a/dlls/wined3d/surface.c
+++ b/dlls/wined3d/surface.c
@@ -623,8 +623,18 @@ static HRESULT WINAPI IWineD3DSurfaceImpl_LockRect(IWineD3DSurface *iface, WINED
             return WINED3DERR_INVALIDCALL;
         }
 
-        if (This->resource.format == WINED3DFMT_DXT1) { /* DXT1 is half byte per pixel */
-            pLockedRect->pBits = This->resource.allocatedMemory + (pLockedRect->Pitch * pRect->top) + ((pRect->left * This->bytesPerPixel / 2));
+        /* DXTn textures are based on compressed blocks of 4x4 pixels, each
+         * 16 bytes large (8 bytes in case of DXT1). Because of that Pitch has
+         * slightly different meaning compared to regular textures. For DXTn
+         * textures Pitch is the size of a row of blocks, 4 high and "width"
+         * long. The x offset is calculated differently as well, since moving 4
+         * pixels to the right actually moves an entire 4x4 block to right, ie
+         * 16 bytes (8 in case of DXT1). */
+        if (This->resource.format == WINED3DFMT_DXT1) {
+            pLockedRect->pBits = This->resource.allocatedMemory + (pLockedRect->Pitch * pRect->top / 4) + (pRect->left * 2);
+        } else if (This->resource.format == WINED3DFMT_DXT2 || This->resource.format == WINED3DFMT_DXT3
+                || This->resource.format == WINED3DFMT_DXT4 || This->resource.format == WINED3DFMT_DXT5) {
+            pLockedRect->pBits = This->resource.allocatedMemory + (pLockedRect->Pitch * pRect->top / 4) + (pRect->left * 4);
         } else {
             pLockedRect->pBits = This->resource.allocatedMemory + (pLockedRect->Pitch * pRect->top) + (pRect->left * This->bytesPerPixel);
         }