From 3bd646d4ed2df0fd1b6d6e365496b081613e37ca Mon Sep 17 00:00:00 2001
From: Justin Marshall <justinmarshall20@gmail.com>
Date: Thu, 28 May 2026 22:29:54 -0700
Subject: [PATCH] Fixed RR sets motion ids correctly.

---
 neo/engine/opengl/opengl.h          |  1 +
 neo/engine/renderer/draw_common.cpp | 15 +++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/neo/engine/opengl/opengl.h b/neo/engine/opengl/opengl.h
index 308d824e..5e66ab73 100644
--- a/neo/engine/opengl/opengl.h
+++ b/neo/engine/opengl/opengl.h
@@ -1576,6 +1576,7 @@ enum GeometryFlag_t
 };
 
 void APIENTRY glGeometryFlagf(GLfloat flag);
+void APIENTRY glMotionObjectIdui(GLuint objectId);
 
 #endif
 
diff --git a/neo/engine/renderer/draw_common.cpp b/neo/engine/renderer/draw_common.cpp
index 260dc722..4ee7e230 100644
--- a/neo/engine/renderer/draw_common.cpp
+++ b/neo/engine/renderer/draw_common.cpp
@@ -118,6 +118,19 @@ static float RB_EstimatePathTraceSpecularStrength( const idMaterial *shader, con
 	return idMath::ClampFloat( 0.5f, 2.4f, strength );
 }
 
+static GLuint RB_PathTraceMotionObjectId( const drawSurf_t *surf ) {
+	if ( !surf || !surf->space || !surf->space->entityDef ) {
+		return 1;
+	}
+
+	const int entityIndex = surf->space->entityDef->index;
+	if ( entityIndex < 0 ) {
+		return 1;
+	}
+
+	return (GLuint)( entityIndex + 2 );
+}
+
 static idDrawVert *RB_BindAmbientBuffer( const srfTriangles_t *tri ) {
 	if ( tri->ambientVbo ) {
 		glBindBufferARB( GL_ARRAY_BUFFER_ARB, tri->ambientVbo );
@@ -654,6 +667,7 @@ void RB_T_FillDepthBuffer(const drawSurf_t* surf) {
 		else {
 			glGeometryFlagf(GEOMETRY_FLAG_SKELETAL);
 		}
+		glMotionObjectIdui( RB_PathTraceMotionObjectId( surf ) );
 
 		// set texture matrix and texGens. The Quake 4 path needs to know this is a depth fill.
 		RB_PrepareStageTexturing(pStage, surf, ac);
@@ -683,6 +697,7 @@ void RB_T_FillDepthBuffer(const drawSurf_t* surf) {
 		GL_SelectTexture(0);
 		globalImages->BindNull();
 
+		glMotionObjectIdui(0);
 		if (alphaTestWasEnabled) {
 			glDisable(GL_ALPHA_TEST);
 			glEnable(GL_BLEND);