Lot of bugfixes

* Adding clipper to generate the terrain's negative powder-contour offset.
* Fixing RDB issues (fracture, active trigger, performances)
* Fixing blood emission
* Fixing the freezing formula on liquids
* Fixing Steve spawning due to a missed test.
* Reaction table properly build

shaders/intent.comp

@@ -46,6 +46,7 @@ void main() {
     uint c = cells[i];
     uint m = cell_mat(c);
     uint f = mflags(m);
+    if (pc.pass_ == 0 && (terrain_age[i] >> 16) != m) terrain_age[i] = (m << 16) | 0x300u;
     if ((f & (F_AIR | F_STATIC)) != 0u) return;
 
     vec2 e = ext[i];
@@ -84,7 +85,7 @@ void main() {
                             const ivec2 bp = p + ivec2(0, 1);
                             release = r2 < ceilP && in_bounds(bp) && cell_mat(cells[idx(bp)]) == 0u;
                         }
-                        if (release) cells[i] = c & ~(ATTACH_BIT | (3u << 24));
+                        if (release) { cells[i] = c & ~(ATTACH_BIT | (3u << 24)); terrain_age[i] = (m << 16) | 0x300u; }
                     }
                 }
                 return;
@@ -256,6 +257,13 @@ void main() {
 
     if ((f & F_FIRE) != 0u && target == NONE && (rnd(i, 30u) & 15u) == 0u) { cells[i] = 0u; return; }   // 00709fc0: the extinction test (1/16) sits at the tail: a successful move and the early returns bypass it
     if ((f & F_GAS) != 0u && target != NONE) nvy = vy + 1.0;   // 0070aad0: the gas age counts its successful moves
+    // 0070b160: only a resting powder whose state age reaches 20 becomes terrain.
+    // Successful moves reset both swapped cells below in apply.comp.
+    if ((f & F_LIQCELL) != 0u) {
+        const bool resting = target == NONE && nvy == 0.0;
+        const uint age = resting ? min((terrain_age[i] & 255u) + (P == 0 ? 1u : 0u), 255u) : 0u;
+        terrain_age[i] = (m << 16) | (resting ? 0x300u : 0x100u) | age;
+    }
     if (target != NONE) {
         intent[i] = uvec4(target | (flip << 31), prio, floatBitsToUint(nvy), floatBitsToUint(nvx));
         atomicMax(claims[i], prio);