Polymer: slightly more complete handling of (multi-tile) ART skies.

- Use the proper tile sequence when multiple pskies are present in a map.
  However, there's still only *one* psky chosen at map load time.
- Handle three horizfrac cases:
 * 0, psky always at same level wrt screen
 * 65536, psky horiz follows camera horiz (e.g. E4L9)
 * otherwise, fall back to default hard-coded parallax implemented as an
   angle fraction

git-svn-id: https://svn.eduke32.com/eduke32@3977 1a8010ca-5511-0410-912e-c29ae57300e0

polymer/eduke32/build/src/engine.c

@@ -4485,7 +4485,7 @@ static void parascan(int32_t dax1, int32_t dax2, int32_t sectnum, char dastat, i
     if (tsizy==0)
         return;
 
-    dapskyoff = getpsky(&dapyscale, &dapskybits);
+    dapskyoff = getpsky(globalpicnum, &dapyscale, &dapskybits);
 
     globalshiftval = logtilesizy;
 

polymer/eduke32/build/src/engine_priv.h

@@ -214,15 +214,16 @@ static inline void bricolor(palette_t *wpptr, int32_t dacol)
 
 // Get properties of parallaxed sky to draw.
 // Returns: pointer to tile offset array. Sets-by-pointer the other two.
-static inline const int8_t *getpsky(int32_t *dapyscale, int32_t *dapskybits)
+static inline const int8_t *getpsky(int32_t picnum, int32_t *dapyscale, int32_t *dapskybits)
 {
     int32_t j;
 
     // First, try a multi-sky.
     for (j=pskynummultis; j>0; j--)  // NOTE: j==0 on non-early loop end
-        if (globalpicnum == multipskytile[j])
+        if (picnum == multipskytile[j])
             break;  // Have a match.
 
+    if (dapskybits)
         *dapskybits = multipsky[j].lognumtiles;
     if (dapyscale)
         *dapyscale = multipsky[j].horizfrac;

polymer/eduke32/build/src/polymer.c

@@ -689,9 +689,10 @@ _prmirror       mirrors[10];
 
 GLUtesselator*  prtess;
 
-int16_t         cursky;
-char            curskypal;
-int8_t          curskyshade;
+static int16_t  cursky;
+static char     curskypal;
+static int8_t   curskyshade;
+static float    curskyangmul = 1;
 
 _pranimatespritesinfo asi;
 
@@ -979,6 +980,9 @@ void                polymer_loadboard(void)
     if (pr_verbosity >= 1 && numsectors) OSD_Printf("PR : Board loaded.\n");
 }
 
+// The parallaxed ART sky angle divisor corresponding to a horizfrac of 32768.
+#define DEFAULT_ARTSKY_ANGDIV 4.3027f
+
 void                polymer_drawrooms(int32_t daposx, int32_t daposy, int32_t daposz, int16_t daang, int32_t dahoriz, int16_t dacursectnum)
 {
     int16_t         cursectnum;
@@ -1028,10 +1032,10 @@ void                polymer_drawrooms(int32_t daposx, int32_t daposy, int32_t da
     drawingskybox = 0;
 
     // if it's not a skybox, make the sky parallax
-    // the angle factor is computed from eyeballed values
+    // DEFAULT_ARTSKY_ANGDIV is computed from eyeballed values
     // need to recompute it if we ever change the max horiz amplitude
     if (!pth || !(pth->flags & 4))
-        skyhoriz /= 4.3027f;
+        skyhoriz *= curskyangmul;
 
     bglMatrixMode(GL_MODELVIEW);
     bglLoadIdentity();
@@ -3820,9 +3824,30 @@ static void         polymer_getsky(void)
     {
         if (sector[i].ceilingstat & 1)
         {
+            int32_t horizfrac;
+
             cursky = sector[i].ceilingpicnum;
             curskypal = sector[i].ceilingpal;
             curskyshade = sector[i].ceilingshade;
+
+            getpsky(cursky, &horizfrac, NULL);
+
+            switch (horizfrac)
+            {
+            case 0:
+                // psky always at same level wrt screen
+                curskyangmul = 0.f;
+                break;
+            case 65536:
+                // psky horiz follows camera horiz
+                curskyangmul = 1.f;
+                break;
+            default:
+                // sky has hard-coded parallax
+                curskyangmul = 1/DEFAULT_ARTSKY_ANGDIV;
+                break;
+            }
+
             return;
         }
         i++;
@@ -3879,10 +3904,18 @@ static void         polymer_drawartsky(int16_t tilenum, char palnum, int8_t shad
     int32_t         i, j;
     GLfloat         height = 2.45f / 2.0f;
 
+    int32_t dapskybits;
+    const int8_t *dapskyoff = getpsky(tilenum, NULL, &dapskybits);
+    const int32_t numskytilesm1 = (1<<dapskybits)-1;
+
     i = 0;
     while (i <= PSKYOFF_MAX)
     {
         int16_t picnum = tilenum + i;
+        // Prevent oob by bad user input:
+        if (picnum >= MAXTILES)
+            picnum = MAXTILES-1;
+
         DO_TILE_ANIM(picnum, 0);
         if (!waloff[picnum])
             loadtile(picnum);
@@ -3914,11 +3947,12 @@ static void         polymer_drawartsky(int16_t tilenum, char palnum, int8_t shad
     }
 
     i = 0;
-    j = 8; //(1<<g_psky.lognumtiles);
+    j = 8;  // In Polymer, an ART sky has always 8 sides...
     while (i < j)
     {
         GLint oldswrap;
-        const int8_t tileofs = multipsky[g_pskyidx].tileofs[i];
+        // ... but in case a multi-psky specifies less than 8, repeat cyclically:
+        const int8_t tileofs = dapskyoff[i&numskytilesm1];
 
         bglColor4f(glcolors[tileofs][0], glcolors[tileofs][1], glcolors[tileofs][2], 1.0f);
         bglBindTexture(GL_TEXTURE_2D, glpics[tileofs]);

polymer/eduke32/build/src/polymost.c

@@ -2368,7 +2368,7 @@ static void polymost_drawalls(int32_t bunch)
 
         DO_TILE_ANIM(globalpicnum, sectnum);
 
-        dapskyoff = getpsky(NULL, &dapskybits);
+        dapskyoff = getpsky(globalpicnum, NULL, &dapskybits);
 
         global_cf_shade = sec->floorshade, global_cf_pal = sec->floorpal; global_cf_z = sec->floorz;  // REFACT
         global_cf_xpanning = sec->floorxpanning; global_cf_ypanning = sec->floorypanning, global_cf_heinum = sec->floorheinum;
@@ -2635,7 +2635,7 @@ static void polymost_drawalls(int32_t bunch)
 
         DO_TILE_ANIM(globalpicnum, sectnum);
 
-        dapskyoff = getpsky(NULL, &dapskybits);
+        dapskyoff = getpsky(globalpicnum, NULL, &dapskybits);
 
         global_cf_shade = sec->ceilingshade, global_cf_pal = sec->ceilingpal; global_cf_z = sec->ceilingz;  // REFACT
         global_cf_xpanning = sec->ceilingxpanning; global_cf_ypanning = sec->ceilingypanning, global_cf_heinum = sec->ceilingheinum;