Restructuring of code

code/REDALERT/WIN32LIB/TOBUFF.CPP

@@ -0,0 +1,70 @@
+/**
+ * @file
+ *
+ * @author CCHyper
+ * @author OmniBlade
+ *
+ * @brief Low level software blitters.
+ *
+ * @copyright Chronoshift is free software: you can redistribute it and/or
+ *            modify it under the terms of the GNU General Public License
+ *            as published by the Free Software Foundation, either version
+ *            2 of the License, or (at your option) any later version.
+ *            A full copy of the GNU General Public License can be found in
+ *            LICENSE
+ */
+
+#include <stdint.h>
+#include "gbuffer.h"
+#include "misc.h"
+
+long __cdecl Buffer_To_Buffer(GraphicViewPortClass* vp, int x, int y, int w, int h, void* buffer, int length)
+{
+	int xstart = x;
+	int ystart = y;
+	int xend = x + w - 1;
+	int yend = y + h - 1;
+
+	int xoffset = 0;
+	int yoffset = 0;
+
+	// If we aren't drawing within the viewport, return
+	if (!buffer || length <= 0 || xstart >= vp->Get_Width() || ystart >= vp->Get_Height() || xend < 0 || yend < 0) {
+		return 0;
+	}
+
+	// Clipping
+	if (xstart < 0) {
+		xoffset = -xstart;
+		xstart = 0;
+	}
+
+	if (ystart < 0) {
+		yoffset += h * (-ystart);
+		ystart = 0;
+	}
+
+	xend = min(xend, (int)vp->Get_Width() - 1);
+	yend = min(yend, (int)vp->Get_Height() - 1);
+
+	// Setup parameters for blit
+	int pitch = vp->Get_Pitch() + vp->Get_Width() + vp->Get_XAdd();
+	uint8_t* src = y * pitch + x + (uint8_t*)(vp->Get_Offset());
+	uint8_t* dst = xoffset + w * yoffset + (uint8_t*)(buffer);
+	// int src_pitch = x_pos + pitch - xend + 1;
+	// int dst_pitch = x_pos + width - xend + 1;
+	int lines = yend - ystart + 1;
+	int blit_width = xend - xstart + 1;
+
+	// Is our buffer large enough?
+	if (lines * w <= length) {
+		// blit
+		while (lines--) {
+			memcpy(dst, src, blit_width);
+			src += pitch;
+			dst += w;
+		}
+	}
+
+	return 1;
+}