From 39c44fe3e23672a080670a91e0b02c0bc7b7074f Mon Sep 17 00:00:00 2001
From: Zack Buhman <zack@buhman.org>
Date: Fri, 23 Jan 2026 20:11:40 -0600
Subject: [PATCH] src: reorder skinned mesh input layout

---
 src/effect/main.fx | 14 +++++-----
 src/main.cpp       | 70 +++++++++++++++++++++++-----------------------
 2 files changed, 42 insertions(+), 42 deletions(-)

diff --git a/src/effect/main.fx b/src/effect/main.fx
index f4ed79a..793de88 100644
--- a/src/effect/main.fx
+++ b/src/effect/main.fx
@@ -17,19 +17,19 @@ SamplerState samLinear {
 struct VS_INPUT
 {
   float4 Pos : POSITION;
-  float4 Weight : TEXCOORD0;
-  float4 Joint : TEXCOORD1;
   float3 Normal : NORMAL;
-  float2 Tex : TEXCOORD2;
+  float2 Tex : TEXCOORD0;
+  float4 Weight : BLENDWEIGHT0;
+  float4 Joint : BLENDINDICES0;
 };
 
 struct PS_INPUT
 {
   float4 Pos : SV_POSITION;
-  float4 Weight : TEXCOORD0;
-  float4 Joint : TEXCOORD1;
-  float3 Normal : TEXCOORD2;
-  float2 Tex : TEXCOORD3;
+  float3 Normal : NORMAL;
+  float2 Tex : TEXCOORD0;
+  float4 Weight : BLENDWEIGHT0;
+  float4 Joint : BLENDINDICES0;
 };
 
 PS_INPUT VS(VS_INPUT input)
diff --git a/src/main.cpp b/src/main.cpp
index 6f7e5a6..7d7d394 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -389,32 +389,6 @@ HRESULT LoadMesh()
     return hr;
   }
 
-  // weights
-  bd.Usage = D3D10_USAGE_IMMUTABLE;
-  bd.ByteWidth = mesh->weights_0_size;
-  bd.BindFlags = D3D10_BIND_VERTEX_BUFFER;
-  bd.CPUAccessFlags = 0;
-  bd.MiscFlags = 0;
-  initData.pSysMem = mesh->weights_0;
-  hr = g_pd3dDevice->CreateBuffer(&bd, &initData, &g_pVertexBuffers[1]);
-  if (FAILED(hr)) {
-    print("CreateBuffer\n");
-    return hr;
-  }
-
-  // joints
-  bd.Usage = D3D10_USAGE_IMMUTABLE;
-  bd.ByteWidth = mesh->joints_0_size;
-  bd.BindFlags = D3D10_BIND_VERTEX_BUFFER;
-  bd.CPUAccessFlags = 0;
-  bd.MiscFlags = 0;
-  initData.pSysMem = mesh->joints_0;
-  hr = g_pd3dDevice->CreateBuffer(&bd, &initData, &g_pVertexBuffers[2]);
-  if (FAILED(hr)) {
-    print("CreateBuffer\n");
-    return hr;
-  }
-
   // normals
   bd.Usage = D3D10_USAGE_IMMUTABLE;
   bd.ByteWidth = mesh->normal_size;
@@ -422,7 +396,7 @@ HRESULT LoadMesh()
   bd.CPUAccessFlags = 0;
   bd.MiscFlags = 0;
   initData.pSysMem = mesh->normal;
-  hr = g_pd3dDevice->CreateBuffer(&bd, &initData, &g_pVertexBuffers[3]);
+  hr = g_pd3dDevice->CreateBuffer(&bd, &initData, &g_pVertexBuffers[1]);
   if (FAILED(hr)) {
     print("CreateBuffer\n");
     return hr;
@@ -435,6 +409,32 @@ HRESULT LoadMesh()
   bd.CPUAccessFlags = 0;
   bd.MiscFlags = 0;
   initData.pSysMem = mesh->texcoord_0;
+  hr = g_pd3dDevice->CreateBuffer(&bd, &initData, &g_pVertexBuffers[2]);
+  if (FAILED(hr)) {
+    print("CreateBuffer\n");
+    return hr;
+  }
+
+  // weights
+  bd.Usage = D3D10_USAGE_IMMUTABLE;
+  bd.ByteWidth = mesh->weights_0_size;
+  bd.BindFlags = D3D10_BIND_VERTEX_BUFFER;
+  bd.CPUAccessFlags = 0;
+  bd.MiscFlags = 0;
+  initData.pSysMem = mesh->weights_0;
+  hr = g_pd3dDevice->CreateBuffer(&bd, &initData, &g_pVertexBuffers[3]);
+  if (FAILED(hr)) {
+    print("CreateBuffer\n");
+    return hr;
+  }
+
+  // joints
+  bd.Usage = D3D10_USAGE_IMMUTABLE;
+  bd.ByteWidth = mesh->joints_0_size;
+  bd.BindFlags = D3D10_BIND_VERTEX_BUFFER;
+  bd.CPUAccessFlags = 0;
+  bd.MiscFlags = 0;
+  initData.pSysMem = mesh->joints_0;
   hr = g_pd3dDevice->CreateBuffer(&bd, &initData, &g_pVertexBuffers[4]);
   if (FAILED(hr)) {
     print("CreateBuffer\n");
@@ -1010,7 +1010,7 @@ HRESULT InitDirect3DDevice()
     D3D10_CREATE_DEVICE_DEBUG,
     (D3D10_CREATE_DEVICE_FLAG)0,
   };
-  UINT numFlags = (sizeof (flags)) / (sizeof (flags[0]));  
+  UINT numFlags = (sizeof (flags)) / (sizeof (flags[0]));
 
   HRESULT hr;
   D3D10_DRIVER_TYPE driverType = D3D10_DRIVER_TYPE_NULL;
@@ -1108,11 +1108,11 @@ HRESULT InitDirect3DDevice()
   //////////////////////////////////////////////////////////////////////
 
   D3D10_INPUT_ELEMENT_DESC layout[] = {
-    {"POSITION", 0, DXGI_FORMAT_R32G32B32_FLOAT,    0, 0, D3D10_INPUT_PER_VERTEX_DATA, 0},
-    {"TEXCOORD", 0, DXGI_FORMAT_R32G32B32A32_FLOAT, 1, 0, D3D10_INPUT_PER_VERTEX_DATA, 0},
-    {"TEXCOORD", 1, DXGI_FORMAT_R32G32B32A32_FLOAT, 2, 0, D3D10_INPUT_PER_VERTEX_DATA, 0},
-    {"NORMAL"  , 0, DXGI_FORMAT_R32G32B32_FLOAT,    3, 0, D3D10_INPUT_PER_VERTEX_DATA, 0},
-    {"TEXCOORD", 2, DXGI_FORMAT_R32G32_FLOAT,       4, 0, D3D10_INPUT_PER_VERTEX_DATA, 0},
+    {"POSITION"    , 0, DXGI_FORMAT_R32G32B32_FLOAT,    0, 0, D3D10_INPUT_PER_VERTEX_DATA, 0},
+    {"NORMAL"      , 0, DXGI_FORMAT_R32G32B32_FLOAT,    1, 0, D3D10_INPUT_PER_VERTEX_DATA, 0},
+    {"TEXCOORD"    , 0, DXGI_FORMAT_R32G32_FLOAT,       2, 0, D3D10_INPUT_PER_VERTEX_DATA, 0},
+    {"BLENDWEIGHT" , 0, DXGI_FORMAT_R32G32B32A32_FLOAT, 3, 0, D3D10_INPUT_PER_VERTEX_DATA, 0},
+    {"BLENDINDICES", 0, DXGI_FORMAT_R32G32B32A32_FLOAT, 4, 0, D3D10_INPUT_PER_VERTEX_DATA, 0},
   };
   UINT numElements = (sizeof (layout)) / (sizeof (layout[0]));
 
@@ -1388,10 +1388,10 @@ void RenderModel(float t)
 
   UINT stride[] = {
     (sizeof (mesh->position[0])),
-    (sizeof (mesh->weights_0[0])),
-    (sizeof (mesh->joints_0[0])),
     (sizeof (mesh->normal[0])),
     (sizeof (mesh->texcoord_0[0])),
+    (sizeof (mesh->weights_0[0])),
+    (sizeof (mesh->joints_0[0])),
   };
   UINT offset[] = { 0, 0, 0, 0, 0 };
   g_pd3dDevice->IASetInputLayout(g_pVertexLayout);