wined3d: Implement WINED3DFMT_YUY2 to WINED3DFMT_B5G6R5_UNORM conversion function.

dlls/wined3d/surface_base.c

@@ -782,6 +782,49 @@ static void convert_yuy2_x8r8g8b8(const BYTE *src, BYTE *dst,
     }
 }
 
+static void convert_yuy2_r5g6b5(const BYTE *src, BYTE *dst,
+        DWORD pitch_in, DWORD pitch_out, unsigned int w, unsigned int h)
+{
+    unsigned int x, y;
+    int c2, d, e, r2 = 0, g2 = 0, b2 = 0;
+
+    TRACE("Converting %ux%u pixels, pitches %u %u\n", w, h, pitch_in, pitch_out);
+
+    for (y = 0; y < h; ++y)
+    {
+        const BYTE *src_line = src + y * pitch_in;
+        WORD *dst_line = (WORD *)(dst + y * pitch_out);
+        for (x = 0; x < w; ++x)
+        {
+            /* YUV to RGB conversion formulas from http://en.wikipedia.org/wiki/YUV:
+             *     C = Y - 16; D = U - 128; E = V - 128;
+             *     R = cliptobyte((298 * C + 409 * E + 128) >> 8);
+             *     G = cliptobyte((298 * C - 100 * D - 208 * E + 128) >> 8);
+             *     B = cliptobyte((298 * C + 516 * D + 128) >> 8);
+             * Two adjacent YUY2 pixels are stored as four bytes: Y0 U Y1 V .
+             * U and V are shared between the pixels.
+             */
+            if (!(x & 1))         /* for every even pixel, read new U and V */
+            {
+                d = (int) src_line[1] - 128;
+                e = (int) src_line[3] - 128;
+                r2 = 409 * e + 128;
+                g2 = - 100 * d - 208 * e + 128;
+                b2 = 516 * d + 128;
+            }
+            c2 = 298 * ((int) src_line[0] - 16);
+            dst_line[x] = (cliptobyte((c2 + r2) >> 8) >> 3) << 11    /* red   */
+                | (cliptobyte((c2 + g2) >> 8) >> 2) << 5     /* green */
+                | (cliptobyte((c2 + b2) >> 8) >> 3);         /* blue  */
+                /* Scale RGB values to 0..255 range,
+                 * then clip them if still not in range (may be negative),
+                 * then shift them within DWORD if necessary.
+                 */
+            src_line += 2;
+        }
+    }
+}
+
 struct d3dfmt_convertor_desc
 {
     enum wined3d_format_id from, to;
@@ -794,6 +837,7 @@ static const struct d3dfmt_convertor_desc convertors[] =
     {WINED3DFMT_B5G6R5_UNORM,   WINED3DFMT_B8G8R8X8_UNORM,  convert_r5g6b5_x8r8g8b8},
     {WINED3DFMT_B8G8R8A8_UNORM, WINED3DFMT_B8G8R8X8_UNORM,  convert_a8r8g8b8_x8r8g8b8},
     {WINED3DFMT_YUY2,           WINED3DFMT_B8G8R8X8_UNORM,  convert_yuy2_x8r8g8b8},
+    {WINED3DFMT_YUY2,           WINED3DFMT_B5G6R5_UNORM,    convert_yuy2_r5g6b5},
 };
 
 static inline const struct d3dfmt_convertor_desc *find_convertor(enum wined3d_format_id from, enum wined3d_format_id to)