From 69cbc26173cbc47a7fd0c92ce58745406aa28384 Mon Sep 17 00:00:00 2001
From: Rua <ruawhitepaw@gmail.com>
Date: Sun, 7 Jan 2024 16:14:17 +0100
Subject: [PATCH] Rewrite Mesh Shader Output size calculation

---
 chapters/VK_NV_mesh_shader/mesh.adoc | 57 ++++++++++++++++------------
 1 file changed, 32 insertions(+), 25 deletions(-)

diff --git a/chapters/VK_NV_mesh_shader/mesh.adoc b/chapters/VK_NV_mesh_shader/mesh.adoc
index a0c7c2a2f..e774ff942 100644
--- a/chapters/VK_NV_mesh_shader/mesh.adoc
+++ b/chapters/VK_NV_mesh_shader/mesh.adoc
@@ -169,31 +169,38 @@ These resulting primitives are then further processed as described in
 <<primsrast>>.
 
 ifdef::VK_EXT_mesh_shader[]
-With the exception of primitive indices, all output built-ins and custom
-attributes count towards the total storage size occupied by output variables
-in mesh shaders.
-This size can be calculated as follows, taking into account the fact that
-the number of effective scalar attributes is 4 times the number of effective
-locations used according to the <<interfaces-iointerfaces-locations,location
-assignment rules>>.
-Let latexmath:[v] be the number of views, latexmath:[n_v] be the number of
-effective scalar per-vertex attributes not dependent on code:ViewIndex,
-latexmath:[n_{vpv}] be the number of effective scalar per-vertex attributes
-dependent on code:ViewIndex, latexmath:[m_v] be the maximum number of
-vertices specified by the code:OutputVertices {ExecutionMode},
-latexmath:[g_v] be pname:meshOutputPerVertexGranularity, latexmath:[n_p] be
-the number of effective scalar per-primitive attributes not dependent on
-code:ViewIndex, latexmath:[n_{ppv}] be the number of effective scalar
-per-primitive attributes dependent on code:ViewIndex, latexmath:[m_p] be the
-maximum number of primitives specified by the code:OutputPrimitivesEXT
-{ExecutionMode} and latexmath:[g_p] be
-pname:meshOutputPerPrimitiveGranularity:
-
-[latexmath]
-++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-(n_v + (n_{vpv} \times v)) \times 4 \times \mathrm{align}(m_v, g_v) +
-(n_p + (n_{ppv} \times v)) \times 4 \times \mathrm{align}(m_p, g_p)
-++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+With the exception of primitive indices, all built-in and user-defined
+output variables count towards the total storage size occupied by output
+variables in mesh shaders.
+This size can be calculated as follows, where the effective number of
+components is 4 times the number of locations used according to the
+<<interfaces-iointerfaces-locations,location assignment rules>>.
+
+ * Let code:viewCount be the number of views.
+ * Let code:perVertexComponents and code:perPrimitiveComponents respectively be
+   the effective number of per-vertex and per-primitive components that are
+   not dependent on code:ViewIndex.
+ * Let code:perVertexPerViewComponents and code:perPrimitivePerViewComponents
+   respectively be the effective number of per-vertex and per-primitive
+   components that are dependent on code:ViewIndex.
+ * code:OutputVertices and code:OutputPrimitives are the values specified by
+   the respective {ExecutionMode}.
+ * pname:meshOutputPerVertexGranularity and
+   pname:meshOutputPerPrimitiveGranularity are the respective device
+   properties.
+
+Then the total output memory size is calculated as follows:
+
+[source,c]
+----
+perVertexTotalComponents = perVertexComponents + (perVertexPerViewComponents * viewCount);
+perVertexMemorySize = perVertexTotalComponents * 4 * align(OutputVertices, meshOutputPerVertexGranularity);
+
+perPrimitiveTotalComponents = perPrimitiveComponents + (perPrimitivePerViewComponents * viewCount)
+perPrimitiveMemorySize = perPrimitiveTotalComponents * 4 * align(OutputPrimitives, meshOutputPerPrimitiveGranularity);
+
+memorySize = perVertexMemorySize + perPrimitiveMemorySize;
+----
 
 endif::VK_EXT_mesh_shader[]