From 68977ec31186119686858244a447f3c069a30a40 Mon Sep 17 00:00:00 2001
From: Alex Szpakowski <slime73@gmail.com>
Date: Sat, 6 Nov 2021 11:17:23 -0300
Subject: [PATCH] Fix alignment of storage buffers with vec3 or mat3
 components.

---
 src/modules/graphics/Buffer.cpp | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/src/modules/graphics/Buffer.cpp b/src/modules/graphics/Buffer.cpp
index f040cbd51..a64e9654a 100644
--- a/src/modules/graphics/Buffer.cpp
+++ b/src/modules/graphics/Buffer.cpp
@@ -147,11 +147,22 @@ Buffer::Buffer(Graphics *gfx, const Settings &settings, const std::vector<DataDe
 
 			// GLSL's std430 packing rules. We also assume all matrices are
 			// column-major.
-			if (info.isMatrix)
-				alignment = info.matrixRows * info.componentSize;
-			else
-				alignment = info.components * info.componentSize;
+			// https://www.khronos.org/registry/OpenGL/specs/gl/glspec46.core.pdf
 
+			// "If the member is a column-major matrix with C columns and R rows,
+			// the matrix is stored identically to an array of C column vectors
+			// with R components each".
+			// "If the member is a three-component vector with components
+			// consuming N basic machine units, the base alignment is 4N."
+			int components = info.isMatrix ? info.matrixRows : info.components;
+			if (components == 3)
+				alignment = 4 * info.componentSize;
+			else
+				alignment = components * info.componentSize;
+
+			// "If the member is a structure, the base alignment of the structure
+			// is N, where N is the largest base alignment value of any of its
+			// members"
 			structurealignment = std::max(structurealignment, alignment);
 
 			memberoffset = alignUp(memberoffset, alignment);