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engines/titanic/support/transparency_surface.h

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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program 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 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef TITANIC_TRANSPARENCY_SURFACE_H
+#define TITANIC_TRANSPARENCY_SURFACE_H
+
+#include "common/rect.h"
+#include "graphics/surface.h"
+
+namespace Titanic {
+
+enum TransparencyMode {
+	TRANS_MASK0 = 0, TRANS_MASK255 = 1, TRANS_ALPHA0 = 2,
+	TRANS_ALPHA255 = 3, TRANS_DEFAULT = 4
+};
+
+class CTransparencySurface {
+private:
+	const Graphics::Surface *_surface;
+	Common::Point _pos;
+	int _pitch;
+	int _runLength;
+	bool _flag;
+	byte _transparentColor;
+	byte _opaqueColor;
+private:
+	/**
+	* Returns a a pixel from the transparency surface
+	*/
+	inline uint getPixel() const {
+		byte pixel = *(const byte *)_surface->getBasePtr(_pos.x, _pos.y);
+		return pixel;
+	}
+public:
+	/**
+	 * Constructor
+	 */
+	CTransparencySurface(const Graphics::Surface *surface, TransparencyMode transMode);
+
+	/**
+	 * Sets the row to get transparencies from
+	 */
+	inline void setRow(int yp) { _pos.y = yp; }
+
+	/**
+	 * Sets the column to get transparencies from
+	 */
+	inline void setCol(int xp) { _pos.x = xp; }
+
+	/**
+	 * Moves reading position horizontally by a single pixel
+	 */
+	inline int moveX() {
+		if (++_pos.x >= _surface->w) {
+			_pos.x = 0;
+			++_pos.y;
+		}
+
+		return 1;
+	}
+
+	/**
+	 * Returns the alpha value for the pixel (0-31)
+	 */
+	inline uint getAlpha() const {
+		byte pixel = getPixel();
+		return _opaqueColor ? 0xFF - pixel : pixel;
+	}
+
+	/**
+	 * Returns true if the pixel is opaque
+	 */
+	inline bool isPixelOpaque() const {
+		byte pixel = getPixel();
+		return _opaqueColor ? pixel >= 0xf0 : pixel < 0x10;
+	}
+
+	/**
+	 * Returns true if the pixel is completely transparent
+	 */
+	inline bool isPixelTransparent() const {
+		byte pixel = getPixel();
+		return _transparentColor ? pixel >= 0xf0 : pixel < 0x10;
+	}
+};
+
+} // End of namespace Titanic
+
+#endif /* TITANIC_TRANSPARENCY_SURFACE_H */