From 4f3f5ea02d8ccab6fb2b72ca11050b24787391cf Mon Sep 17 00:00:00 2001
From: Bearborg <orblob@gmail.com>
Date: Wed, 25 Dec 2019 11:34:28 -0500
Subject: [PATCH] Replace deprecated GL_LUMINANCE and GL_LUMINANCE_ALPHA
 texture formats

---
 src/Core/Resource/CTexture.cpp | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/Core/Resource/CTexture.cpp b/src/Core/Resource/CTexture.cpp
index d7104613..4dd956ee 100644
--- a/src/Core/Resource/CTexture.cpp
+++ b/src/Core/Resource/CTexture.cpp
@@ -49,11 +49,11 @@ bool CTexture::BufferGL()
     switch (mTexelFormat)
     {
         case ETexelFormat::Luminance:
-            GLFormat = GL_LUMINANCE;
+            GLFormat = GL_R;
             GLType = GL_UNSIGNED_BYTE;
             break;
         case ETexelFormat::LuminanceAlpha:
-            GLFormat = GL_LUMINANCE_ALPHA;
+            GLFormat = GL_RG;
             GLType = GL_UNSIGNED_BYTE;
             break;
         case ETexelFormat::RGB565:
@@ -104,6 +104,13 @@ bool CTexture::BufferGL()
     glTexParameteri(BindTarget, GL_TEXTURE_BASE_LEVEL, 0);
     glTexParameteri(BindTarget, GL_TEXTURE_MAX_LEVEL, mNumMipMaps - 1);
 
+    // Swizzling for luminance textures:
+    if (mTexelFormat == ETexelFormat::Luminance || mTexelFormat == ETexelFormat::LuminanceAlpha)
+    {
+        GLint SwizzleMask[] = {GL_RED, GL_RED, GL_RED, GLFormat == GL_RG ? GL_GREEN : GL_ONE};
+        glTexParameteriv(BindTarget, GL_TEXTURE_SWIZZLE_RGBA, SwizzleMask);
+    }
+
     // Linear filtering on mipmaps:
     glTexParameteri(BindTarget, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
     glTexParameteri(BindTarget, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);