From 6479b41be7d7634a02be965269a094523dfd394d Mon Sep 17 00:00:00 2001
From: Sajt <sajt@icculus.org>
Date: Sun, 21 Jan 2024 23:59:06 +0200
Subject: [PATCH] models: Add normals convert code

Based on https://icculus.org/projects/qshed/
---
 src/client/refresh/files/mesh.c | 32 ++++++++++++++++++++++++++++++--
 src/client/refresh/ref_shared.h |  1 +
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/src/client/refresh/files/mesh.c b/src/client/refresh/files/mesh.c
index 8aa461fc..6430aade 100644
--- a/src/client/refresh/files/mesh.c
+++ b/src/client/refresh/files/mesh.c
@@ -26,10 +26,38 @@
 
 #include "../ref_shared.h"
 
-static float r_avertexnormals[NUMVERTEXNORMALS][3] = {
+static const float r_avertexnormals[NUMVERTEXNORMALS][3] = {
 #include "../constants/anorms.h"
 };
 
+/* compressed vertex normals used by mdl and md2 model formats */
+byte
+R_CompressNormalMDL(const float *normal)
+{
+	byte i, besti;
+	float dot, bestdot;
+
+	bestdot = normal[0] * r_avertexnormals[0][0] +
+		normal[1] * r_avertexnormals[0][1] +
+		normal[2] * r_avertexnormals[0][2];
+	besti = 0;
+
+	for (i = 1; i < NUMVERTEXNORMALS; i++)
+	{
+		dot = normal[0] * r_avertexnormals[i][0] +
+			normal[1] * r_avertexnormals[i][1] +
+			normal[2] * r_avertexnormals[i][2];
+
+		if (dot > bestdot)
+		{
+			bestdot = dot;
+			besti = i;
+		}
+	}
+
+	return besti;
+}
+
 void
 R_LerpVerts(qboolean powerUpEffect, int nverts, dxtrivertx_t *v, dxtrivertx_t *ov,
 		dxtrivertx_t *verts, float *lerp, const float move[3],
@@ -41,7 +69,7 @@ R_LerpVerts(qboolean powerUpEffect, int nverts, dxtrivertx_t *v, dxtrivertx_t *o
 	{
 		for (i = 0; i < nverts; i++, v++, ov++, lerp += 4)
 		{
-			float *normal = r_avertexnormals[verts[i].lightnormalindex];
+			const float *normal = r_avertexnormals[verts[i].lightnormalindex];
 
 			lerp[0] = move[0] + ov->v[0] * backv[0] + v->v[0] * frontv[0] +
 					  normal[0] * POWERSUIT_SCALE;
diff --git a/src/client/refresh/ref_shared.h b/src/client/refresh/ref_shared.h
index 7035b54d..ada9c105 100644
--- a/src/client/refresh/ref_shared.h
+++ b/src/client/refresh/ref_shared.h
@@ -382,6 +382,7 @@ extern qboolean R_CullAliasMeshModel(dmdx_t *paliashdr, cplane_t *frustum,
 extern void R_LerpVerts(qboolean powerUpEffect, int nverts, dxtrivertx_t *v, dxtrivertx_t *ov,
 		dxtrivertx_t *verts, float *lerp, const float move[3],
 		const float frontv[3], const float backv[3]);
+extern byte R_CompressNormalMDL(const float *normal);
 
 /* Lights logic */
 extern bspxlightgrid_t *Mod_LoadBSPXLightGrid(const bspx_header_t *bspx_header, const byte *mod_base);