From 7243b51149a73d2cd5d90d5e73640628ce3e56d0 Mon Sep 17 00:00:00 2001
From: Camden Dixie O'Brien <cobrien@witekio.com>
Date: Wed, 1 Oct 2025 19:48:17 +0100
Subject: [PATCH] Apply skinning matrix in vertex shader

---
 vert.glsl | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/vert.glsl b/vert.glsl
index 56e63a4..2ab6447 100644
--- a/vert.glsl
+++ b/vert.glsl
@@ -13,7 +13,18 @@ layout(binding = 0) uniform mvp_t {
 	mat4 proj;
 } mvp;
 
+layout(binding = 1) uniform skeleton_t {
+	mat4 matrices[32];
+} bones;
+
 void main() {
-	gl_Position = mvp.proj * mvp.view * mvp.model * vec4(position, 1.0);
-	frag_normal = mat3(mvp.model) * normal;
+	const mat4 skinning_matrix
+		= weights.x * bones.matrices[bone_indices.x]
+		+ weights.y * bones.matrices[bone_indices.y]
+		+ weights.z * bones.matrices[bone_indices.z]
+		+ weights.w * bones.matrices[bone_indices.w];
+	gl_Position = mvp.proj * mvp.view * mvp.model * skinning_matrix
+		* vec4(position, 1.0);
+	frag_normal
+		= transpose(inverse(mat3(mvp.model * skinning_matrix))) * normal;
 }