26b6d450df
Also added in depth comments about the currently known variations Returning the RNG seed is now implemented (although it seems no games actually use this functionality, it seems to be just script bugs). Also remove Torin kRandom workarounds.
293 lines
9.5 KiB
C++
293 lines
9.5 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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*/
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#include "sci/engine/state.h"
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#include "sci/engine/kernel.h"
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namespace Sci {
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// Following variations existed:
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// up until including 0.530 (Hoyle 1): will always get 2 parameters, even if 2 parameters were not passed
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// it seems if range is 0, it will return the seed.
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// 0.566 (Hero's Quest) to SCI1MID: check for 2 parameters, if not 2 parameters get seed.
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// SCI1LATE+: 2 parameters -> get random number within range
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// 1 parameter -> set seed
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// any other amount of parameters -> get seed
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//
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// Right now, the weird SCI0 behavior (up until 0.530) for getting parameters and getting the seed is not implemented.
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// We also do not let through more than 2 parameters to kRandom via signatures. In case there is a game doing this,
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// a workaround should be added.
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reg_t kRandom(EngineState *s, int argc, reg_t *argv) {
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Common::RandomSource &rng = g_sci->getRNG();
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if (argc == 2) {
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// get random number
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// numbers are definitely unsigned, for example lsl5 door code in k rap radio is random
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// and 5-digit - we get called kRandom(10000, 65000)
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// some codes in sq4 are also random and 5 digit (if i remember correctly)
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const uint16 fromNumber = argv[0].toUint16();
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const uint16 toNumber = argv[1].toUint16();
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// Some scripts may request a range in the reverse order (from largest
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// to smallest). An example can be found in Longbow, room 710, where a
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// random number is requested from 119 to 83. In this case, we're
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// supposed to return toNumber (determined by the KQ5CD disasm).
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// Fixes bug #3413020.
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if (fromNumber > toNumber)
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return make_reg(0, toNumber);
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uint16 range = toNumber - fromNumber + 1;
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// calculating range is exactly how sierra sci did it and is required for hoyle 4
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// where we get called with kRandom(0, -1) and we are supposed to give back values from 0 to 0
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// the returned value will be used as displace-offset for a background cel
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// note: i assume that the hoyle4 code is actually buggy and it was never fixed because of
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// the way sierra sci handled it - "it just worked". It should have called kRandom(0, 0)
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if (range)
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range--; // the range value was never returned, our random generator gets 0->range, so fix it
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const int randomNumber = fromNumber + (int)rng.getRandomNumber(range);
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return make_reg(0, randomNumber);
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}
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// for other amounts of arguments
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if (getSciVersion() >= SCI_VERSION_1_LATE) {
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if (argc == 1) {
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// 1 single argument is for setting the seed
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// right now we do not change the Common RNG seed.
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// It should never be required unless a game reuses the same seed to get the same combination of numbers multiple times.
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// And in such a case, we would have to add code for such a feature (ScummVM RNG uses a UINT32 seed).
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warning("kRandom: caller requested to set the RNG seed");
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return NULL_REG;
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}
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}
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// treat anything else as if caller wants the seed
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warning("kRandom: caller requested to get the RNG seed");
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return make_reg(0, rng.getSeed());
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}
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reg_t kAbs(EngineState *s, int argc, reg_t *argv) {
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return make_reg(0, ABS(argv[0].toSint16()));
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}
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reg_t kSqrt(EngineState *s, int argc, reg_t *argv) {
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return make_reg(0, (int16) sqrt((float) ABS(argv[0].toSint16())));
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}
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uint16 kGetAngle_SCI0(int16 x1, int16 y1, int16 x2, int16 y2) {
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int16 xRel = x2 - x1;
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int16 yRel = y1 - y2; // y-axis is mirrored.
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int16 angle;
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// Move (xrel, yrel) to first quadrant.
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if (y1 < y2)
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yRel = -yRel;
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if (x2 < x1)
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xRel = -xRel;
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// Compute angle in grads.
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if (yRel == 0 && xRel == 0)
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return 0;
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else
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angle = 100 * xRel / (xRel + yRel);
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// Fix up angle for actual quadrant of (xRel, yRel).
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if (y1 < y2)
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angle = 200 - angle;
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if (x2 < x1)
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angle = 400 - angle;
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// Convert from grads to degrees by merging grad 0 with grad 1,
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// grad 10 with grad 11, grad 20 with grad 21, etc. This leads to
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// "degrees" that equal either one or two grads.
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angle -= (angle + 9) / 10;
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return angle;
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}
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// atan2 for first octant, x >= y >= 0. Returns [0,45] (inclusive)
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int kGetAngle_SCI1_atan2_base(int y, int x) {
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if (x == 0)
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return 0;
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// fixed point tan(a)
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int tan_fp = 10000 * y / x;
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if ( tan_fp >= 1000 ) {
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// For tan(a) >= 0.1, interpolate between multiples of 5 degrees
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// 10000 * tan([5, 10, 15, 20, 25, 30, 35, 40, 45])
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const int tan_table[] = { 875, 1763, 2679, 3640, 4663, 5774,
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7002, 8391, 10000 };
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// Look up tan(a) in our table
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int i = 1;
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while (tan_fp > tan_table[i]) ++i;
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// The angle a is between 5*i and 5*(i+1). We linearly interpolate.
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int dist = tan_table[i] - tan_table[i-1];
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int interp = (5 * (tan_fp - tan_table[i-1]) + dist/2) / dist;
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return 5*i + interp;
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} else {
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// for tan(a) < 0.1, tan(a) is approximately linear in a.
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// tan'(0) = 1, so in degrees the slope of atan is 180/pi = 57.29...
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return (57 * y + x/2) / x;
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}
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}
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int kGetAngle_SCI1_atan2(int y, int x) {
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if (y < 0) {
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int a = kGetAngle_SCI1_atan2(-y, -x);
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if (a == 180)
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return 0;
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else
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return 180 + a;
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}
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if (x < 0)
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return 90 + kGetAngle_SCI1_atan2(-x, y);
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if (y > x)
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return 90 - kGetAngle_SCI1_atan2_base(x, y);
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else
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return kGetAngle_SCI1_atan2_base(y, x);
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}
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uint16 kGetAngle_SCI1(int16 x1, int16 y1, int16 x2, int16 y2) {
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// We flip things around to get into the standard atan2 coordinate system
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return kGetAngle_SCI1_atan2(x2 - x1, y1 - y2);
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}
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/**
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* Returns the angle (in degrees) between the two points determined by (x1, y1)
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* and (x2, y2). The angle ranges from 0 to 359 degrees.
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* What this function does is pretty simple but apparently the original is not
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* accurate.
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*/
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uint16 kGetAngleWorker(int16 x1, int16 y1, int16 x2, int16 y2) {
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if (getSciVersion() >= SCI_VERSION_1_EGA_ONLY)
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return kGetAngle_SCI1(x1, y1, x2, y2);
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else
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return kGetAngle_SCI0(x1, y1, x2, y2);
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}
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reg_t kGetAngle(EngineState *s, int argc, reg_t *argv) {
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// Based on behavior observed with a test program created with
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// SCI Studio.
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int x1 = argv[0].toSint16();
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int y1 = argv[1].toSint16();
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int x2 = argv[2].toSint16();
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int y2 = argv[3].toSint16();
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return make_reg(0, kGetAngleWorker(x1, y1, x2, y2));
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}
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reg_t kGetDistance(EngineState *s, int argc, reg_t *argv) {
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int xdiff = (argc > 3) ? argv[3].toSint16() : 0;
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int ydiff = (argc > 2) ? argv[2].toSint16() : 0;
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int angle = (argc > 5) ? argv[5].toSint16() : 0;
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int xrel = (int)(((float) argv[1].toSint16() - xdiff) / cos(angle * M_PI / 180.0)); // This works because cos(0)==1
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int yrel = argv[0].toSint16() - ydiff;
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return make_reg(0, (int16)sqrt((float) xrel*xrel + yrel*yrel));
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}
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reg_t kTimesSin(EngineState *s, int argc, reg_t *argv) {
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int angle = argv[0].toSint16();
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int factor = argv[1].toSint16();
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return make_reg(0, (int16)(factor * sin(angle * M_PI / 180.0)));
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}
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reg_t kTimesCos(EngineState *s, int argc, reg_t *argv) {
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int angle = argv[0].toSint16();
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int factor = argv[1].toSint16();
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return make_reg(0, (int16)(factor * cos(angle * M_PI / 180.0)));
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}
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reg_t kCosDiv(EngineState *s, int argc, reg_t *argv) {
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int angle = argv[0].toSint16();
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int value = argv[1].toSint16();
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double cosval = cos(angle * M_PI / 180.0);
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if ((cosval < 0.0001) && (cosval > -0.0001)) {
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error("kCosDiv: Attempted division by zero");
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return SIGNAL_REG;
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} else
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return make_reg(0, (int16)(value / cosval));
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}
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reg_t kSinDiv(EngineState *s, int argc, reg_t *argv) {
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int angle = argv[0].toSint16();
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int value = argv[1].toSint16();
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double sinval = sin(angle * M_PI / 180.0);
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if ((sinval < 0.0001) && (sinval > -0.0001)) {
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error("kSinDiv: Attempted division by zero");
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return SIGNAL_REG;
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} else
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return make_reg(0, (int16)(value / sinval));
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}
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reg_t kTimesTan(EngineState *s, int argc, reg_t *argv) {
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int param = argv[0].toSint16();
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int scale = (argc > 1) ? argv[1].toSint16() : 1;
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param -= 90;
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if ((param % 90) == 0) {
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error("kTimesTan: Attempted tan(pi/2)");
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return SIGNAL_REG;
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} else
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return make_reg(0, (int16) - (tan(param * M_PI / 180.0) * scale));
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}
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reg_t kTimesCot(EngineState *s, int argc, reg_t *argv) {
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int param = argv[0].toSint16();
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int scale = (argc > 1) ? argv[1].toSint16() : 1;
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if ((param % 90) == 0) {
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error("kTimesCot: Attempted tan(pi/2)");
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return SIGNAL_REG;
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} else
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return make_reg(0, (int16)(tan(param * M_PI / 180.0) * scale));
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}
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#ifdef ENABLE_SCI32
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reg_t kMulDiv(EngineState *s, int argc, reg_t *argv) {
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int16 multiplicant = argv[0].toSint16();
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int16 multiplier = argv[1].toSint16();
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int16 denominator = argv[2].toSint16();
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// Sanity check...
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if (!denominator) {
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error("kMulDiv: attempt to divide by zero (%d * %d / %d", multiplicant, multiplier, denominator);
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return NULL_REG;
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}
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return make_reg(0, multiplicant * multiplier / denominator);
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}
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#endif
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} // End of namespace Sci
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