Simplify decal system.

Removes the `freedecal` field, and as such, fixes some invariant violations
found in issue #216 that appear to lead to engine crashes.

Performance should remain unchanged, as the decal expiry process performed
full decal copies from end spots to unoccupied spots as part of its
"shuffling" loop anyway.

Fixes issue #216.

diff --git a/client.h b/client.h
index 3cfaf5bfc14fc1861196d66aaf008b2bbc4b4dc0..38acdf98f8434a771c991d2ac566cd4cf821a941 100644 (file)
--- a/client.h
+++ b/client.h
@@ -57,7 +57,6 @@ typedef struct decalsystem_s
        model_t *model;
        double lastupdatetime;
        int maxdecals;
-       int freedecal;
        int numdecals;
        tridecal_t *decals;
        float *vertex3f;

diff --git a/gl_rmain.c b/gl_rmain.c
index a1afc55b3c8ecc24d884b2355be98456ca858f68..f9007cafba90b11c174152e4d4406cb527997a08 100644 (file)
--- a/gl_rmain.c
+++ b/gl_rmain.c
@@ -9141,7 +9141,6 @@ void R_DecalSystem_Reset(decalsystem_t *decalsystem)
 static void R_DecalSystem_SpawnTriangle(decalsystem_t *decalsystem, const float *v0, const float *v1, const float *v2, const float *t0, const float *t1, const float *t2, const float *c0, const float *c1, const float *c2, int triangleindex, int surfaceindex, unsigned int decalsequence)
 {
        tridecal_t *decal;
-       tridecal_t *decals;
        int i;
 
        // expand or initialize the system
@@ -9169,13 +9168,7 @@ static void R_DecalSystem_SpawnTriangle(decalsystem_t *decalsystem, const float
        }
 
        // grab a decal and search for another free slot for the next one
-       decals = decalsystem->decals;
-       decal = decalsystem->decals + (i = decalsystem->freedecal++);
-       for (i = decalsystem->freedecal;i < decalsystem->numdecals && decals[i].color4f[0][3];i++)
-               ;
-       decalsystem->freedecal = i;
-       if (decalsystem->numdecals <= i)
-               decalsystem->numdecals = i + 1;
+       decal = &decalsystem->decals[decalsystem->numdecals++];
 
        // initialize the decal
        decal->lived = 0;
@@ -9541,7 +9534,6 @@ static void R_DrawModelDecals_FadeEntity(entity_render_t *ent)
 {
        int i;
        decalsystem_t *decalsystem = &ent->decalsystem;
-       int numdecals;
        unsigned int killsequence;
        tridecal_t *decal;
        float frametime;
@@ -9567,38 +9559,18 @@ static void R_DrawModelDecals_FadeEntity(entity_render_t *ent)
        else
                frametime = 0;
        decalsystem->lastupdatetime = r_refdef.scene.time;
-       numdecals = decalsystem->numdecals;
 
-       for (i = 0, decal = decalsystem->decals;i < numdecals;i++, decal++)
+       for (i = 0, decal = decalsystem->decals;i < decalsystem->numdecals;i++, decal++)
        {
-               if (decal->color4f[0][3])
+               decal->lived += frametime;
+               if (killsequence > decal->decalsequence || decal->lived >= lifetime)
                {
-                       decal->lived += frametime;
-                       if (killsequence > decal->decalsequence || decal->lived >= lifetime)
-                       {
-                               memset(decal, 0, sizeof(*decal));
-                               if (decalsystem->freedecal > i)
-                                       decalsystem->freedecal = i;
-                       }
+                       *decal = decalsystem->decals[--decalsystem->numdecals];
+                       --i, --decal;  // Consider the just moved decal next.
                }
        }
-       decal = decalsystem->decals;
-       while (numdecals > 0 && !decal[numdecals-1].color4f[0][3])
-               numdecals--;
-
-       // collapse the array by shuffling the tail decals into the gaps
-       for (;;)
-       {
-               while (decalsystem->freedecal < numdecals && decal[decalsystem->freedecal].color4f[0][3])
-                       decalsystem->freedecal++;
-               if (decalsystem->freedecal == numdecals)
-                       break;
-               decal[decalsystem->freedecal] = decal[--numdecals];
-       }
-
-       decalsystem->numdecals = numdecals;
 
-       if (numdecals <= 0)
+       if (decalsystem->numdecals <= 0)
        {
                // if there are no decals left, reset decalsystem
                R_DecalSystem_Reset(decalsystem);