From 6cd699e55fb6c59fd96c37dc3d85dbf96aeae684 Mon Sep 17 00:00:00 2001
From: valid-ptr <konstantin.matveyev@eligovision.ru>
Date: Fri, 4 Dec 2020 18:19:29 +0300
Subject: [PATCH] GLExtensions: isTextureCompressionASTCSupported (ASTC
 compression texture), isTextureLODBiasSupported (is needed for
 GL_TEXTURE_LOD_BIAS) flags added

---
 include/osg/GLExtensions |  2 ++
 src/osg/GLExtensions.cpp | 19 ++++++++++++++-----
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/include/osg/GLExtensions b/include/osg/GLExtensions
index aa868e9cf..f7196ae81 100644
--- a/include/osg/GLExtensions
+++ b/include/osg/GLExtensions
@@ -521,6 +521,7 @@ class OSG_EXPORT GLExtensions : public osg::Referenced
         bool isTextureCompressionETC2Supported;
         bool isTextureCompressionRGTCSupported;
         bool isTextureCompressionPVRTCSupported;
+        bool isTextureCompressionASTCSupported;
         bool isTextureMirroredRepeatSupported;
         bool isTextureEdgeClampSupported;
         bool isTextureBorderClampSupported;
@@ -530,6 +531,7 @@ class OSG_EXPORT GLExtensions : public osg::Referenced
         bool isShadowSupported;
         bool isShadowAmbientSupported;
         bool isTextureMaxLevelSupported;
+        bool isTextureLODBiasSupported;
         GLint maxTextureSize;
         bool isClientStorageSupported;
         bool isTextureIntegerEXTSupported;
diff --git a/src/osg/GLExtensions.cpp b/src/osg/GLExtensions.cpp
index c2cf99eb5..932230b92 100644
--- a/src/osg/GLExtensions.cpp
+++ b/src/osg/GLExtensions.cpp
@@ -866,6 +866,11 @@ GLExtensions::GLExtensions(unsigned int in_contextID):
     isTextureCompressionRGTCSupported = validContext && isGLExtensionSupported(contextID,"GL_EXT_texture_compression_rgtc");
     isTextureCompressionPVRTCSupported = isTextureCompressionPVRTC2BPPSupported;//covered by same extension
 
+    isTextureCompressionASTCSupported = validContext && (isGLExtensionSupported(contextID, "GL_KHR_texture_compression_astc_hdr") ||
+                                                         isGLExtensionSupported(contextID, "GL_KHR_texture_compression_astc_ldr") ||
+                                                         isGLExtensionSupported(contextID, "GL_OES_texture_compression_astc") ||
+                                                         isGLExtensionSupported(contextID, "WEBGL_compressed_texture_astc"));
+
     isTextureMirroredRepeatSupported = validContext &&
                                        (builtInSupport ||
                                         isGLExtensionOrVersionSupported(contextID,"GL_IBM_texture_mirrored_repeat", 1.4f) ||
@@ -906,18 +911,22 @@ GLExtensions::GLExtensions(unsigned int in_contextID):
     {
         maxTextureSize = osg_max_size;
     }
+
+#if defined(__EMSCRIPTEN__)
+    isTextureMaxLevelSupported = (glVersion >= 3.0f);    // WebGL 2.0 (OpenGL ES 3.0)
+    isTextureLODBiasSupported  = (glVersion >= 3.0f) || isGLExtensionSupported(contextID, "GL_EXT_texture_lod_bias");
+#else
     isTextureMaxLevelSupported = (glVersion >= 1.2f);
+    isTextureLODBiasSupported  = (glVersion >= 1.2f) || isGLExtensionSupported(contextID, "GL_EXT_texture_lod_bias");
+#endif
 
     isTextureStorageEnabled = validContext && ((glVersion >= 4.2f) || isGLExtensionSupported(contextID, "GL_ARB_texture_storage"));
 
     if (isTextureStorageEnabled)
     {
         std::string value;
-        if (getEnvVar("OSG_GL_TEXTURE_STORAGE", value))
-        {
-            if (value=="OFF" || value=="DISABLE") isTextureStorageEnabled = false;
-            else isTextureStorageEnabled = true;
-        }
+        if (getEnvVar("OSG_GL_TEXTURE_STORAGE", value) && (value == "OFF" || value == "DISABLE"))
+            isTextureStorageEnabled = false;
     }
 
     setGLExtensionFuncPtr(glTexStorage1D,"glTexStorage1D","glTexStorage1DARB", validContext);