From 2fcf4617c9e6a28566fc46d8184da2eabb070169 Mon Sep 17 00:00:00 2001
From: Alexander Bock <mail@alexanderbock.eu>
Date: Fri, 27 Jan 2023 21:29:12 +0100
Subject: [PATCH] Correctly swizzle the textures for ScreenSpaceImage types to
 allow for 8 bit grayscale images (closes #2330)

---
 modules/base/rendering/screenspaceimagelocal.cpp  | 4 ++++
 modules/base/rendering/screenspaceimageonline.cpp | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/modules/base/rendering/screenspaceimagelocal.cpp b/modules/base/rendering/screenspaceimagelocal.cpp
index 0c16b436f9..7b302a9068 100644
--- a/modules/base/rendering/screenspaceimagelocal.cpp
+++ b/modules/base/rendering/screenspaceimagelocal.cpp
@@ -124,6 +124,10 @@ void ScreenSpaceImageLocal::update() {
             // image is only RGB
             glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 
+            if (texture->format() == ghoul::opengl::Texture::Format::Red) {
+                texture->setSwizzleMask({ GL_RED, GL_RED, GL_RED, GL_ONE });
+            }
+
             texture->uploadTexture();
             texture->setFilter(ghoul::opengl::Texture::FilterMode::LinearMipMap);
             texture->purgeFromRAM();
diff --git a/modules/base/rendering/screenspaceimageonline.cpp b/modules/base/rendering/screenspaceimageonline.cpp
index 7620f14629..c5cb15a5e1 100644
--- a/modules/base/rendering/screenspaceimageonline.cpp
+++ b/modules/base/rendering/screenspaceimageonline.cpp
@@ -127,6 +127,10 @@ void ScreenSpaceImageOnline::update() {
                     // image is only RGB
                     glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 
+                    if (texture->format() == ghoul::opengl::Texture::Format::Red) {
+                        texture->setSwizzleMask({ GL_RED, GL_RED, GL_RED, GL_ONE });
+                    }
+
                     texture->uploadTexture();
                     texture->setFilter(ghoul::opengl::Texture::FilterMode::LinearMipMap);
                     texture->purgeFromRAM();