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+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the demonstration applications of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain
+** additional rights. These rights are described in the Nokia Qt LGPL
+** Exception version 1.1, included in the file LGPL_EXCEPTION.txt in this
+** package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QtCore>
+#include <QtGui>
+
+#include <math.h>
+
+#ifndef M_PI
+#define M_PI 3.14159265358979323846
+#endif
+
+#define WORLD_SIZE 8
+int world_map[WORLD_SIZE][WORLD_SIZE] = {
+ { 1, 1, 1, 1, 6, 1, 1, 1 },
+ { 1, 0, 0, 1, 0, 0, 0, 7 },
+ { 1, 1, 0, 1, 0, 1, 1, 1 },
+ { 6, 0, 0, 0, 0, 0, 0, 3 },
+ { 1, 8, 8, 0, 8, 0, 8, 1 },
+ { 2, 2, 0, 0, 8, 8, 7, 1 },
+ { 3, 0, 0, 0, 0, 0, 0, 5 },
+ { 2, 2, 2, 2, 7, 4, 4, 4 },
+};
+
+#define TEXTURE_SIZE 64
+#define TEXTURE_BLOCK (TEXTURE_SIZE * TEXTURE_SIZE)
+
+class Raycasting: public QWidget
+{
+public:
+ Raycasting(QWidget *parent = 0)
+ : QWidget(parent)
+ , angle(0.5)
+ , playerPos(1.5, 1.5)
+ , angleDelta(0)
+ , moveDelta(0) {
+
+ // http://www.areyep.com/RIPandMCS-TextureLibrary.html
+ textureImg.load(":/textures.png");
+ textureImg = textureImg.convertToFormat(QImage::Format_ARGB32);
+ Q_ASSERT(textureImg.width() == TEXTURE_SIZE * 2);
+ Q_ASSERT(textureImg.bytesPerLine() == 4 * TEXTURE_SIZE * 2);
+ textureCount = textureImg.height() / TEXTURE_SIZE;
+
+ watch.start();
+ ticker.start(25, this);
+ setAttribute(Qt::WA_OpaquePaintEvent, true);
+ }
+
+ void updatePlayer() {
+ int interval = qBound(20, watch.elapsed(), 250);
+ watch.start();
+ angle += angleDelta * interval / 1000;
+ qreal step = moveDelta * interval / 1000;
+ qreal dx = cos(angle) * step;
+ qreal dy = sin(angle) * step;
+ QPointF pos = playerPos + 3 * QPointF(dx, dy);
+ int xi = static_cast<int>(pos.x());
+ int yi = static_cast<int>(pos.y());
+ if (world_map[yi][xi] == 0)
+ playerPos = playerPos + QPointF(dx, dy);
+ }
+
+ void showFps() {
+ static QTime frameTick;
+ static int totalFrame = 0;
+ if (!(totalFrame & 31)) {
+ int elapsed = frameTick.elapsed();
+ frameTick.start();
+ int fps = 32 * 1000 / (1 + elapsed);
+ setWindowTitle(QString("Raycasting (%1 FPS)").arg(fps));
+ }
+ totalFrame++;
+ }
+
+ void render() {
+
+ // setup the screen surface
+ if (buffer.size() != size())
+ buffer = QImage(size(), QImage::Format_ARGB32);
+ int bufw = buffer.width();
+ int bufh = buffer.height();
+
+ // we intentionally cheat here, to avoid detach
+ const uchar *ptr = buffer.bits();
+ QRgb *start = (QRgb*)(ptr);
+ QRgb stride = buffer.bytesPerLine() / 4;
+ QRgb *finish = start + stride * bufh;
+
+ // prepare the texture pointer
+ const uchar *src = textureImg.bits();
+ const QRgb *texsrc = reinterpret_cast<const QRgb*>(src);
+
+ // cast all rays here
+ qreal sina = sin(angle);
+ qreal cosa = cos(angle);
+ qreal u = cosa - sina;
+ qreal v = sina + cosa;
+ qreal du = 2 * sina / bufw;
+ qreal dv = -2 * cosa / bufw;
+
+ for (int ray = 0; ray < bufw; ++ray, u += du, v += dv) {
+ // everytime this ray advances 'u' units in x direction,
+ // it also advanced 'v' units in y direction
+ qreal uu = (u < 0) ? -u : u;
+ qreal vv = (v < 0) ? -v : v;
+ qreal duu = 1 / uu;
+ qreal dvv = 1 / vv;
+ int stepx = (u < 0) ? -1 : 1;
+ int stepy = (v < 0) ? -1 : 1;
+
+ // the cell in the map that we need to check
+ qreal px = playerPos.x();
+ qreal py = playerPos.y();
+ int mapx = static_cast<int>(px);
+ int mapy = static_cast<int>(py);
+
+ // the position and texture for the hit
+ int texture = 0;
+ qreal hitdist = 0.1;
+ qreal texofs = 0;
+ bool dark = false;
+
+ // first hit at constant x and constant y lines
+ qreal distx = (u > 0) ? (mapx + 1 - px) * duu : (px - mapx) * duu;
+ qreal disty = (v > 0) ? (mapy + 1 - py) * dvv : (py - mapy) * dvv;
+
+ // loop until we hit something
+ while (texture <= 0) {
+ if (distx > disty) {
+ // shorter distance to a hit in constant y line
+ hitdist = disty;
+ disty += dvv;
+ mapy += stepy;
+ texture = world_map[mapy][mapx];
+ if (texture > 0) {
+ dark = true;
+ if (stepy > 0) {
+ qreal ofs = px + u * (mapy - py) / v;
+ texofs = ofs - floor(ofs);
+ } else {
+ qreal ofs = px + u * (mapy + 1 - py) / v;
+ texofs = ofs - floor(ofs);
+ }
+ }
+ } else {
+ // shorter distance to a hit in constant x line
+ hitdist = distx;
+ distx += duu;
+ mapx += stepx;
+ texture = world_map[mapy][mapx];
+ if (texture > 0) {
+ if (stepx > 0) {
+ qreal ofs = py + v * (mapx - px) / u;
+ texofs = ofs - floor(ofs);
+ } else {
+ qreal ofs = py + v * (mapx + 1 - px) / u;
+ texofs = ceil(ofs) - ofs;
+ }
+ }
+ }
+ }
+
+ // get the texture, note that the texture image
+ // has two textures horizontally, "normal" vs "dark"
+ int col = static_cast<int>(texofs * TEXTURE_SIZE);
+ col = qBound(0, col, TEXTURE_SIZE - 1);
+ texture = (texture - 1) % textureCount;
+ const QRgb *tex = texsrc + TEXTURE_BLOCK * texture * 2 +
+ (TEXTURE_SIZE * 2 * col);
+ if (dark)
+ tex += TEXTURE_SIZE;
+
+ // start from the texture center (horizontally)
+ int h = static_cast<int>(bufw / hitdist / 2);
+ int dy = (TEXTURE_SIZE << 12) / h;
+ int p1 = ((TEXTURE_SIZE / 2) << 12) - dy;
+ int p2 = p1 + dy;
+
+ // start from the screen center (vertically)
+ // y1 will go up (decrease), y2 will go down (increase)
+ int y1 = bufh / 2;
+ int y2 = y1 + 1;
+ QRgb *pixel1 = start + y1 * stride + ray;
+ QRgb *pixel2 = pixel1 + stride;
+
+ // map the texture to the sliver
+ while (y1 >= 0 && y2 < bufh && p1 >= 0) {
+ *pixel1 = tex[p1 >> 12];
+ *pixel2 = tex[p2 >> 12];
+ p1 -= dy;
+ p2 += dy;
+ --y1;
+ ++y2;
+ pixel1 -= stride;
+ pixel2 += stride;
+ }
+
+ // ceiling and floor
+ for (; pixel1 > start; pixel1 -= stride)
+ *pixel1 = qRgb(0, 0, 0);
+ for (; pixel2 < finish; pixel2 += stride)
+ *pixel2 = qRgb(96, 96, 96);
+ }
+
+ update();
+ }
+
+protected:
+
+ void timerEvent(QTimerEvent*) {
+ updatePlayer();
+ render();
+ showFps();
+ }
+
+ void paintEvent(QPaintEvent *event) {
+ QPainter p(this);
+ p.drawImage(event->rect(), buffer, event->rect());
+ }
+
+ void keyPressEvent(QKeyEvent *event) {
+ event->accept();
+ if (event->key() == Qt::Key_Left)
+ angleDelta = 1.3 * M_PI;
+ if (event->key() == Qt::Key_Right)
+ angleDelta = -1.3 * M_PI;
+ if (event->key() == Qt::Key_Up)
+ moveDelta = 2.5;
+ if (event->key() == Qt::Key_Down)
+ moveDelta = -2.5;
+ }
+
+ void keyReleaseEvent(QKeyEvent *event) {
+ event->accept();
+ if (event->key() == Qt::Key_Left)
+ angleDelta = (angleDelta > 0) ? 0 : angleDelta;
+ if (event->key() == Qt::Key_Right)
+ angleDelta = (angleDelta < 0) ? 0 : angleDelta;
+ if (event->key() == Qt::Key_Up)
+ moveDelta = (moveDelta > 0) ? 0 : moveDelta;
+ if (event->key() == Qt::Key_Down)
+ moveDelta = (moveDelta < 0) ? 0 : moveDelta;
+ }
+
+private:
+ QTime watch;
+ QBasicTimer ticker;
+ QImage buffer;
+ qreal angle;
+ QPointF playerPos;
+ qreal angleDelta;
+ qreal moveDelta;
+ QImage textureImg;
+ int textureCount;
+};
+
+int main(int argc, char **argv)
+{
+ QApplication app(argc, argv);
+
+ Raycasting w;
+ w.setWindowTitle("Raycasting");
+#if defined(Q_OS_SYMBIAN)
+ w.showMaximized();
+#else
+ w.resize(640, 480);
+ w.show();
+#endif
+
+ return app.exec();
+}
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