From 25e6865fa5fd7f26c6201b4a2974361c7dc3a1a6 Mon Sep 17 00:00:00 2001
From: Bill Currie <bill@taniwha.org>
Date: Fri, 25 Mar 2022 14:48:01 +0900
Subject: [PATCH] [glsl] Update particle arrays when maximum changes

The cvar setup for particles is a bit wonky in that the arrays get
initialized using the default max particle count but never updated.
Though things could be improved some more, this solution works (and has
been more or less copied to gl, but I couldn't reproduce the crash
there, or even the valgrind error).
---
 libs/video/renderer/gl/gl_dyn_part.c      | 20 +++++++---
 libs/video/renderer/glsl/glsl_particles.c | 45 ++++++++++++++---------
 2 files changed, 42 insertions(+), 23 deletions(-)

diff --git a/libs/video/renderer/gl/gl_dyn_part.c b/libs/video/renderer/gl/gl_dyn_part.c
index b64cd9481..151a2ed72 100644
--- a/libs/video/renderer/gl/gl_dyn_part.c
+++ b/libs/video/renderer/gl/gl_dyn_part.c
@@ -63,23 +63,23 @@ static int						pVAsize;
 static int					   *pVAindices;
 static varray_t2f_c4ub_v3f_t   *particleVertexArray;
 
-void
-gl_R_InitParticles (void)
+static void
+alloc_arrays (psystem_t *ps)
 {
 	int		i;
 
-	if (r_psystem.maxparticles && r_init) {
+	if (ps->maxparticles && r_init) {
 		if (vaelements) {
 			partUseVA = 0;
-			pVAsize = r_psystem.maxparticles * 4;
+			pVAsize = ps->maxparticles * 4;
 			Sys_MaskPrintf (SYS_dev,
 							"Particles: Vertex Array use disabled.\n");
 		} else {
 			if (vaelements > 3)
 				pVAsize = min ((unsigned int) (vaelements - (vaelements % 4)),
-							   r_psystem.maxparticles * 4);
+							   ps->maxparticles * 4);
 			else if (vaelements >= 0)
-				pVAsize = r_psystem.maxparticles * 4;
+				pVAsize = ps->maxparticles * 4;
 			Sys_MaskPrintf (SYS_dev,
 							"Particles: %i maximum vertex elements.\n",
 							pVAsize);
@@ -109,6 +109,12 @@ gl_R_InitParticles (void)
 	}
 }
 
+void
+gl_R_InitParticles (void)
+{
+	alloc_arrays (&r_psystem);
+}
+
 void
 gl_R_DrawParticles (psystem_t *psystem)
 {
@@ -238,12 +244,14 @@ static void
 r_particles_f (cvar_t *var)
 {
 	R_MaxParticlesCheck (var, r_particles_max);
+	alloc_arrays (&r_psystem);
 }
 
 static void
 r_particles_max_f (cvar_t *var)
 {
 	R_MaxParticlesCheck (r_particles, var);
+	alloc_arrays (&r_psystem);
 }
 
 void
diff --git a/libs/video/renderer/glsl/glsl_particles.c b/libs/video/renderer/glsl/glsl_particles.c
index 74957ce3e..89645e72c 100644
--- a/libs/video/renderer/glsl/glsl_particles.c
+++ b/libs/video/renderer/glsl/glsl_particles.c
@@ -63,6 +63,7 @@
 # define GL_VERTEX_PROGRAM_POINT_SIZE 0x8642
 #endif
 
+static uint32_t     maxparticles;
 static GLushort    *pVAindices;
 static partvert_t  *particleVertexArray;
 
@@ -130,11 +131,34 @@ static struct {
 	{"fog", 1},
 };
 
+static void
+alloc_arrays (psystem_t *ps)
+{
+	if (ps->maxparticles > maxparticles) {
+		maxparticles = ps->maxparticles;
+		if (particleVertexArray)
+			free (particleVertexArray);
+		particleVertexArray = calloc (ps->maxparticles * 4,
+									  sizeof (partvert_t));
+
+		if (pVAindices)
+			free (pVAindices);
+		pVAindices = calloc (ps->maxparticles * 6, sizeof (GLushort));
+		for (uint32_t i = 0; i < ps->maxparticles; i++) {
+			pVAindices[i * 6 + 0] = i * 4 + 0;
+			pVAindices[i * 6 + 1] = i * 4 + 1;
+			pVAindices[i * 6 + 2] = i * 4 + 2;
+			pVAindices[i * 6 + 3] = i * 4 + 0;
+			pVAindices[i * 6 + 4] = i * 4 + 2;
+			pVAindices[i * 6 + 5] = i * 4 + 3;
+		}
+	}
+}
+
 void
 glsl_R_InitParticles (void)
 {
 	shader_t   *vert_shader, *frag_shader;
-	unsigned    i;
 	int         vert;
 	int         frag;
 	float       v[2] = {0, 0};
@@ -196,22 +220,7 @@ glsl_R_InitParticles (void)
 					   GL_UNSIGNED_BYTE, tex->data);
 	free (tex);
 
-	if (particleVertexArray)
-		free (particleVertexArray);
-	particleVertexArray = calloc (r_psystem.maxparticles * 4,
-								  sizeof (partvert_t));
-
-	if (pVAindices)
-		free (pVAindices);
-	pVAindices = calloc (r_psystem.maxparticles * 6, sizeof (GLushort));
-	for (i = 0; i < r_psystem.maxparticles; i++) {
-		pVAindices[i * 6 + 0] = i * 4 + 0;
-		pVAindices[i * 6 + 1] = i * 4 + 1;
-		pVAindices[i * 6 + 2] = i * 4 + 2;
-		pVAindices[i * 6 + 3] = i * 4 + 0;
-		pVAindices[i * 6 + 4] = i * 4 + 2;
-		pVAindices[i * 6 + 5] = i * 4 + 3;
-	}
+	alloc_arrays (&r_psystem);
 }
 
 static void
@@ -426,12 +435,14 @@ static void
 r_particles_f (cvar_t *var)
 {
 	R_MaxParticlesCheck (var, r_particles_max);
+	alloc_arrays (&r_psystem);
 }
 
 static void
 r_particles_max_f (cvar_t *var)
 {
 	R_MaxParticlesCheck (r_particles, var);
+	alloc_arrays (&r_psystem);
 }
 
 void