Avoid stacking in INVS and FILT, and fix pressurised INVS graphics

Collisions now always work for particles inside INVS and FILT, so
particles don't stack (just a single particle on top of each INVS/FILT).

Pressurised INVS was being drawn using PMODE_FLAT (with no alpha
blending), which sometimes hid particles inside INVS.

Also limit BHOL tmp value to make sure it saves correctly.

2 files changed, 6 insertions, 3 deletions

diff --git a/src/elements/newgraphics.c b/src/elements/newgraphics.c
index 92a1c94..5679b63 100644
--- a/src/elements/newgraphics.c
+++ b/src/elements/newgraphics.c
@@ -249,8 +249,7 @@ int graphics_INVS(GRAPHICS_FUNC_ARGS)
 		*colr = 15;
 		*colg = 0;
 		*colb = 150;
-		*pixel_mode &= PMODE;
-		*pixel_mode |= PMODE_BLEND;
+		*pixel_mode = PMODE_BLEND;
 	} 
 	return 0;
 }
diff --git a/src/powder.c b/src/powder.c
index 9fcb1f0..2e55f49 100644
--- a/src/powder.c
+++ b/src/powder.c
@@ -1567,6 +1567,7 @@ void update_particles_i(pixel *vid, int start, int inc)
 								create_part(i, x, y, PT_NBHL);
 								parts[i].temp = MAX_TEMP;
 								parts[i].tmp = pmap_count[y][x]-NPART;//strength of grav field
+								if (parts[i].tmp>51200) parts[i].tmp = 51200;
 								pmap_count[y][x] = NPART;
 							}
 							else
@@ -2859,7 +2860,10 @@ void update_particles(pixel *vid)//doesn't update the particles themselves, but
 					photons[y][x] = t|(i<<8);
 				else
 				{
-					pmap[y][x] = t|(i<<8);
+					// Particles are sometimes allowed to go inside INVS and FILT
+					// To make particles collide correctly when inside these elements, these elements must not overwrite an existing pmap entry from particles inside them
+					if (!pmap[y][x] || (t!=PT_INVIS && t!= PT_FILT))
+						pmap[y][x] = t|(i<<8);
 					pmap_count[y][x]++;
 				}
 			}