Initial commit

engines/cruise/polys.cpp

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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/>.
+ *
+ */
+
+#include "cruise/cruise_main.h"
+#include "common/util.h"
+
+namespace Cruise {
+
+typedef char ColorP;
+
+#define SCREENHEIGHT 200
+#define MAXPTS 10
+#define putdot(x,y) {if ((y >= 0) && (y < SCREENHEIGHT)) dots[y][counters[y]++] = x;}
+
+void hline(int x1, int x2, int y, char c) {
+	for (; x1 <= x2; x1++) {
+		pixel(x1, y, c);
+	}
+}
+
+void vline(int x, int y1, int y2, char c) {
+	for (; y1 <= y2; y1++) {
+		pixel(x, y1, c);
+	}
+}
+
+void bsubline_1(int x1, int y1, int x2, int y2, char c) {
+	int x, y, ddx, ddy, e;
+	ddx = ABS(x2 - x1);
+	ddy = ABS(y2 - y1) << 1;
+	e = ddx - ddy;
+	ddx <<= 1;
+
+	if (x1 > x2) {
+		SWAP(x1, x2);
+		SWAP(y1, y2);
+	}
+
+	for (x = x1, y = y1; x <= x2; x++) {
+
+		pixel(x, y, c);
+		if (e < 0) {
+			y++;
+			e += ddx - ddy;
+		} else {
+			e -= ddy;
+		}
+	}
+
+}
+
+void bsubline_2(int x1, int y1, int x2, int y2, char c) {
+
+	int x, y, ddx, ddy, e;
+	ddx = ABS(x2 - x1) << 1;
+	ddy = ABS(y2 - y1);
+	e = ddy - ddx;
+	ddy <<= 1;
+
+	if (y1 > y2) {
+		SWAP(x1, x2);
+		SWAP(y1, y2);
+	}
+
+	for (y = y1, x = x1; y <= y2; y++) {
+
+		pixel(x, y, c);
+		if (e < 0) {
+			x++;
+			e += ddy - ddx;
+		} else {
+			e -= ddx;
+		}
+	}
+
+}
+
+void bsubline_3(int x1, int y1, int x2, int y2, char c) {
+
+	int x, y, ddx, ddy, e;
+
+	ddx = ABS(x1 - x2) << 1;
+	ddy = ABS(y2 - y1);
+	e = ddy - ddx;
+	ddy <<= 1;
+
+	if (y1 > y2) {
+		SWAP(x1, x2);
+		SWAP(y1, y2);
+	}
+
+	for (y = y1, x = x1; y <= y2; y++) {
+
+		pixel(x, y, c);
+		if (e < 0) {
+			x--;
+			e += ddy - ddx;
+		} else {
+			e -= ddx;
+		}
+	}
+
+}
+
+void bsubline_4(int x1, int y1, int x2, int y2, char c) {
+
+	int x, y, ddx, ddy, e;
+
+	ddy = ABS(y2 - y1) << 1;
+	ddx = ABS(x1 - x2);
+	e = ddx - ddy;
+	ddx <<= 1;
+
+	if (x1 > x2) {
+		SWAP(x1, x2);
+		SWAP(y1, y2);
+	}
+
+	for (x = x1, y = y1; x <= x2; x++) {
+
+		pixel(x, y, c);
+		if (e < 0) {
+			y--;
+			e += ddx - ddy;
+		} else {
+			e -= ddy;
+		}
+	}
+}
+
+void line(int x1, int y1, int x2, int y2, char c) {
+	float k;
+
+	if ((x1 == x2) && (y1 == y2)) {
+		pixel(x1, y1, c);
+		return;
+	}
+
+	if (x1 == x2) {
+		vline(x1, MIN(y1, y2), MAX(y1, y2), c);
+		return;
+	}
+
+	if (y1 == y2) {
+		hline(MIN(x1, x2), MAX(x1, x2), y1, c);
+		return;
+	}
+
+	k = (float)(y2 - y1) / (float)(x2 - x1);
+
+	if ((k >= 0) && (k <= 1)) {
+		bsubline_1(x1, y1, x2, y2, c);
+	} else if (k > 1) {
+		bsubline_2(x1, y1, x2, y2, c);
+	} else if ((k < 0) && (k >= -1)) {
+		bsubline_4(x1, y1, x2, y2, c);
+	} else {
+		bsubline_3(x1, y1, x2, y2, c);
+	}
+}
+
+// Filled polygons. This probably isn't pixel-perfect compared to the original,
+// but it seems to work a bit better than the previous version.
+
+static void add_intersect(int *intersect, int x, byte &num) {
+	if (num < MAXPTS) {
+
+		int i = 0;
+		for (i = num; i > 0 && intersect[i - 1] > x; i--)
+			intersect[i] = intersect[i - 1];
+
+		intersect[i] = x;
+		num++;
+	}
+}
+
+void fillpoly(int16 *point_data, int lineCount, ColorP color) {
+	static int intersect[SCREENHEIGHT][MAXPTS];
+	static byte num_intersect[SCREENHEIGHT];
+
+	switch (lineCount) {
+	case 0:		// do nothing
+		return;
+	case 1:		// draw pixel
+		pixel(point_data[0], point_data[1], color);
+		return;
+	case 2:		// draw line
+		line(point_data[0], point_data[1], point_data[2], point_data[3], color);
+		return;
+	default:		// go on and draw polygon
+		break;
+	}
+
+	// Reinit array counters
+	for (int i = 0; i < SCREENHEIGHT; i++) {
+		num_intersect[i] = 0;
+	}
+
+	// Find the top/bottom of the polygon.
+	int top = point_data[1];
+	int bottom = point_data[1];
+
+	for (int i = 1; i < lineCount; i++) {
+		if (point_data[2 * i + 1] < top)
+			top = point_data[2 * i + 1];
+		else if (point_data[2 * i + 1] > bottom)
+			bottom = point_data[2 * i + 1];
+	}
+
+	if (top < 0)
+		top = 0;
+	if (bottom >= SCREENHEIGHT)
+		bottom = SCREENHEIGHT - 1;
+
+	// Calculate intersections for each scan line
+	for (int y = top; y <= bottom; y++) {
+		int x2 = point_data[2 * lineCount - 2];
+		int y2 = point_data[2 * lineCount - 1];
+
+		for (int i = 0; i < lineCount; i++) {
+			int x1 = x2;
+			int y1 = y2;
+			x2 = point_data[2 * i];
+			y2 = point_data[2 * i + 1];
+
+			// Test if the line intersects the scan line
+
+			if ((y < y1) != (y < y2)) {
+				if (y1 == y2) {
+					add_intersect(intersect[y], x1, num_intersect[y]);
+					add_intersect(intersect[y], x2, num_intersect[y]);
+				} else if (x1 == x2) {
+					add_intersect(intersect[y], x1, num_intersect[y]);
+				} else {
+					add_intersect(intersect[y], x1 + ((y - y1) * (x2 - x1)) / (y2 - y1), num_intersect[y]);
+				}
+			}
+		}
+	}
+
+	// Drawing.
+	for (int y = top; y <= bottom; y++) {
+		for (int i = 0; i < num_intersect[y]; i += 2) {
+			hline(intersect[y][i], intersect[y][i + 1], y, color);
+		}
+	}
+}
+
+} // End of namespace Cruise