From f612b97fc9d08538af966bda20f92e63b26ae5ca Mon Sep 17 00:00:00 2001
From: Eukara <eukara@users.sourceforge.net>
Date: Mon, 3 Jan 2022 01:57:23 +0000
Subject: [PATCH] Animate surfaces at twice the speed when rendering HLBSP.

git-svn-id: https://svn.code.sf.net/p/fteqw/code/trunk@6147 fc73d0e0-1445-4013-8a0c-d673dee63da5
---
 engine/gl/gl_model.c | 35 ++++++++++++++++++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)

diff --git a/engine/gl/gl_model.c b/engine/gl/gl_model.c
index c48a26e8..befb302f 100644
--- a/engine/gl/gl_model.c
+++ b/engine/gl/gl_model.c
@@ -2709,6 +2709,37 @@ static void Mod_UpdateBatchShader_Q1 (struct batch_s *batch)
 
 	batch->shader = base->shader;
 }
+
+// copy of Q1s, but with a different framerate
+static void Mod_UpdateBatchShader_HL (struct batch_s *batch)
+{
+	texture_t *base = batch->texture;
+	unsigned int	relative;
+	int				count;
+
+	if (batch->ent->framestate.g[FS_REG].frame[0])
+	{
+		if (base->alternate_anims)
+			base = base->alternate_anims;
+	}
+
+	if (base->anim_total)
+	{
+		relative = (unsigned int)(cl.time*20) % base->anim_total;
+
+		count = 0;
+		while (base->anim_min > relative || base->anim_max <= relative)
+		{
+			base = base->anim_next;
+			if (!base)
+				Sys_Error ("R_TextureAnimation: broken cycle");
+			if (++count > 100)
+				Sys_Error ("R_TextureAnimation: infinite cycle");
+		}
+	}
+
+	batch->shader = base->shader;
+}
 #endif
 
 #ifdef Q2BSPS
@@ -2882,9 +2913,11 @@ static int Mod_Batches_Generate(model_t *mod)
 #endif
 #ifdef Q1BSPS
 				case fg_quake:
-				case fg_halflife:
 					batch->buildmeshes = Mod_UpdateBatchShader_Q1;
 					break;
+				case fg_halflife:
+					batch->buildmeshes = Mod_UpdateBatchShader_HL;
+					break;
 #endif
 				default:
 					break;