Allow negative values for the shot origin offset vector. This change reduces precisio...

diff --git a/qcsrc/common/util.qc b/qcsrc/common/util.qc
index df54e3536b10acdf149037ddacc8b6c4c133da12..c0ea0afeafa926fd2ec0abf4f5712dc3d74b000e 100644 (file)
--- a/qcsrc/common/util.qc
+++ b/qcsrc/common/util.qc
@@ -1184,35 +1184,56 @@ vector get_shotvelocity(vector myvel, vector mydir, float spd, float newton_styl
        return myvel + spd * mydir;
 }
 
+// compresses the shot origin offset vector to an int with the following format:
+// xxxxxxxx SSyyyyyy SUzzzzzz
+// 32109876 54321098 76543210
+// 1st byte: x component (it uses all 8 bits)
+// 2nd byte: y component in the last 6 bits and the signs of the x and y components
+// 3rd byte: z component in the last 6 bits and the sign of the z component (the 2nd bit is unused)
+// all values are doubled on compression and halved on decompression
+// so the precision for all components is 0.5
+// values are bound to the following ranges:
+// x: -127.5 +127.5
+// y:  -31.5  +31.5
+// z:  -31.5  +31.5
 float compressShotOrigin(vector v)
 {
-       float rx = rint(v.x * 2);
-       float ry = rint(v.y * 4) + 128;
-       float rz = rint(v.z * 4) + 128;
-       if(rx > 255 || rx < 0)
+       int rx_neg = (v.x < 0) ? 1 : 0;
+       int ry_neg = (v.y < 0) ? 1 : 0;
+       int rz_neg = (v.z < 0) ? 1 : 0;
+       int rx = rint(fabs(v.x) * 2);
+       int ry = rint(fabs(v.y) * 2);
+       int rz = rint(fabs(v.z) * 2);
+       if(rx > 255)
        {
                LOG_DEBUG("shot origin ", vtos(v), " x out of bounds\n");
                rx = bound(0, rx, 255);
        }
-       if(ry > 255 || ry < 0)
+       if(ry > 63)
        {
                LOG_DEBUG("shot origin ", vtos(v), " y out of bounds\n");
-               ry = bound(0, ry, 255);
+               ry = bound(0, ry, 63);
        }
-       if(rz > 255 || rz < 0)
+       if(rz > 63)
        {
                LOG_DEBUG("shot origin ", vtos(v), " z out of bounds\n");
-               rz = bound(0, rz, 255);
+               rz = bound(0, rz, 63);
        }
+       ry |= ry_neg * BIT(6) + rx_neg * BIT(7);
+       rz |= rz_neg * BIT(6); // BIT(7) unused
        return rx * 0x10000 + ry * 0x100 + rz;
 }
 vector decompressShotOrigin(int f)
 {
        vector v;
-       v.x = ((f & 0xFF0000) / 0x10000) / 2;
-       v.y = ((f & 0xFF00) / 0x100 - 128) / 4;
-       v.z = ((f & 0xFF) - 128) / 4;
-       return v;
+       v.x = f >> 16;
+       v.y = (f & 0xFF00) >> 8;
+       v.z = f & 0xFF;
+       // remove sign bits and apply sign
+       if (v.y & BIT(7)) { v.y &= ~BIT(7); v.x *= -1; }
+       if (v.y & BIT(6)) { v.y &= ~BIT(6); v.y *= -1; }
+       if (v.z & BIT(6)) { v.z &= ~BIT(6); v.z *= -1; }
+       return v / 2;
 }
 
 #ifdef GAMEQC