From 084ac76f55a8b873217d3ed27a1f95991d5d5fc2 Mon Sep 17 00:00:00 2001
From: Bill Currie <bill@taniwha.org>
Date: Mon, 4 Sep 2023 11:08:55 +0900
Subject: [PATCH] [vulkan] Use identity for vertices with no bone weights

Since the identity matrix is mixed in with the other bones, interesting
things will happen if the bone weights don't add up to 1 and are not all
zero.
---
 libs/video/renderer/vulkan/shader/iqm.vert | 1 +
 1 file changed, 1 insertion(+)

diff --git a/libs/video/renderer/vulkan/shader/iqm.vert b/libs/video/renderer/vulkan/shader/iqm.vert
index 7c86acff5..5362083bd 100644
--- a/libs/video/renderer/vulkan/shader/iqm.vert
+++ b/libs/video/renderer/vulkan/shader/iqm.vert
@@ -46,6 +46,7 @@ main (void)
 	m += bones[vbones.y] * vweights.y;
 	m += bones[vbones.z] * vweights.z;
 	m += bones[vbones.w] * vweights.w;
+	m += mat3x4(1,0,0,0,0,1,0,0,0,0,1,0) * (1 - dot(vweights, vec4(1,1,1,1)));
 	vec4        pos = Model * vec4 (vec4(vposition, 1) * m, 1);
 	if (IQMShadow) {
 		gl_Position = shadowView[MatrixBase + gl_ViewIndex] * pos;