From ea1947ffcc606d757357398b24e74a3f4ecefa07 Mon Sep 17 00:00:00 2001
From: neonloop
Date: Wed, 20 Oct 2021 14:54:27 +0000
Subject: Initial commit from steward-fu release

---
 modules/librender/scaler_scale2x.c | 159 +++++++++++++++++++++++++++++++++++++
 1 file changed, 159 insertions(+)
 create mode 100644 modules/librender/scaler_scale2x.c

(limited to 'modules/librender/scaler_scale2x.c')

diff --git a/modules/librender/scaler_scale2x.c b/modules/librender/scaler_scale2x.c
new file mode 100644
index 0000000..992dc3f
--- /dev/null
+++ b/modules/librender/scaler_scale2x.c
@@ -0,0 +1,159 @@
+/*
+ *  Copyright © 2001, 2002, 2003, 2004 Andrea Mazzoleni
+ *
+ *  Copyright © 2006-2016 SplinterGU (Fenix/Bennugd)
+ *  Copyright © 2002-2006 Fenix Team (Fenix)
+ *  Copyright © 1999-2002 José Luis Cebrián Pagüe (Fenix)
+ *
+ *  This file is part of Bennu - Game Development
+ *
+ *  This software is provided 'as-is', without any express or implied
+ *  warranty. In no event will the authors be held liable for any damages
+ *  arising from the use of this software.
+ *
+ *  Permission is granted to anyone to use this software for any purpose,
+ *  including commercial applications, and to alter it and redistribute it
+ *  freely, subject to the following restrictions:
+ *
+ *     1. The origin of this software must not be misrepresented; you must not
+ *     claim that you wrote the original software. If you use this software
+ *     in a product, an acknowledgment in the product documentation would be
+ *     appreciated but is not required.
+ *
+ *     2. Altered source versions must be plainly marked as such, and must not be
+ *     misrepresented as being the original software.
+ *
+ *     3. This notice may not be removed or altered from any source
+ *     distribution.
+ *
+ */
+
+/*
+ * You can find an high level description of the effect at :
+ *
+ * http://scale2x.sourceforge.net/scale2x.html
+ *
+ * Alternatively at the previous license terms, you are allowed to use this
+ * code in your program with these conditions:
+ * - the program is not used in commercial activities.
+ * - the whole source code of the program is released with the binary.
+ * - derivative works of the program are allowed.
+ */
+
+/* --------------------------------------------------------------------------- */
+
+#include "librender.h"
+
+/* --------------------------------------------------------------------------- */
+
+static void internal_scale2x_16_def( uint16_t *dst0, uint16_t* dst1, const uint16_t* src0, const uint16_t* src1, const uint16_t* src2, unsigned count )
+{
+    /* first pixel */
+    dst0[0] = src1[0];
+    dst1[0] = src1[0];
+
+    if ( src1[1] == src0[0] && src2[0] != src0[0] )
+        dst0[1] = src0[0];
+    else
+        dst0[1] = src1[0];
+
+    if ( src1[1] == src2[0] && src0[0] != src2[0] )
+        dst1[1] = src2[0];
+    else
+        dst1[1] = src1[0];
+
+    ++src0;
+    ++src1;
+    ++src2;
+
+    dst0 += 2;
+    dst1 += 2;
+
+    /* central pixels */
+    count -= 2;
+    while ( count )
+    {
+        if ( src1[-1] == src0[0] && src2[0] != src0[0] && src1[1] != src0[0] )
+            dst0[0] = src0[0];
+        else
+            dst0[0] = src1[0];
+
+        if ( src1[1] == src0[0] && src2[0] != src0[0] && src1[-1] != src0[0] )
+            dst0[1] = src0[0];
+        else
+            dst0[1] = src1[0];
+
+        if ( src1[-1] == src2[0] && src0[0] != src2[0] && src1[1] != src2[0] )
+            dst1[0] = src2[0];
+        else
+            dst1[0] = src1[0];
+
+        if ( src1[1] == src2[0] && src0[0] != src2[0] && src1[-1] != src2[0] )
+            dst1[1] = src2[0];
+        else
+            dst1[1] = src1[0];
+
+        ++src0;
+        ++src1;
+        ++src2;
+
+        dst0 += 2;
+        dst1 += 2;
+
+        --count;
+    }
+
+    /* last pixel */
+    if ( src1[-1] == src0[0] && src2[0] != src0[0] )
+        dst0[0] = src0[0];
+    else
+        dst0[0] = src1[0];
+
+    if ( src1[-1] == src2[0] && src0[0] != src2[0] )
+        dst1[0] = src2[0];
+    else
+        dst1[0] = src1[0];
+
+    dst0[1] = src1[0];
+    dst1[1] = src1[0];
+}
+
+/* --------------------------------------------------------------------------- */
+
+void scale2x( uint8_t *srcPtr, uint32_t srcPitch, uint8_t *dstPtr, uint32_t dstPitch, int width, int height )
+{
+    uint16_t *dst0 = ( uint16_t * )dstPtr;
+    uint16_t *dst1 = dst0 + ( dstPitch / 2 );
+
+    uint16_t *src0 = ( uint16_t * )srcPtr;
+    uint16_t *src1 = src0 + ( srcPitch / 2 );
+    uint16_t *src2 = src1 + ( srcPitch / 2 );
+
+    int count;
+
+    internal_scale2x_16_def( dst0, dst1, src0, src0, src1, width );
+
+    count = height;
+
+    count -= 2;
+    while ( count )
+    {
+        dst0 += dstPitch;
+        dst1 += dstPitch;
+
+        internal_scale2x_16_def( dst0, dst1, src0, src1, src2, width );
+
+        src0 = src1;
+        src1 = src2;
+        src2 += srcPitch / 2;
+
+        --count;
+    }
+    dst0 += dstPitch;
+    dst1 += dstPitch;
+
+    internal_scale2x_16_def( dst0, dst1, src0, src1, src1, width );
+}
+
+/* --------------------------------------------------------------------------- */
+
-- 
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