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-rw-r--r--src/mesa/main/texcompress.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/src/mesa/main/texcompress.c b/src/mesa/main/texcompress.c
index edfb03625c..c028daa46e 100644
--- a/src/mesa/main/texcompress.c
+++ b/src/mesa/main/texcompress.c
@@ -229,6 +229,28 @@ _mesa_gl_compressed_format_base_format(GLenum format)
* what GL_NUM_COMPRESSED_TEXTURE_FORMATS and
* GL_COMPRESSED_TEXTURE_FORMATS return."
*
+ * The KHR_texture_compression_astc_hdr spec says:
+ *
+ * "Interactions with OpenGL 4.2
+ *
+ * OpenGL 4.2 supports the feature that compressed textures can be
+ * compressed online, by passing the compressed texture format enum as
+ * the internal format when uploading a texture using TexImage1D,
+ * TexImage2D or TexImage3D (see Section 3.9.3, Texture Image
+ * Specification, subsection Encoding of Special Internal Formats).
+ *
+ * Due to the complexity of the ASTC compression algorithm, it is not
+ * usually suitable for online use, and therefore ASTC support will be
+ * limited to pre-compressed textures only. Where on-device compression
+ * is required, a domain-specific limited compressor will typically
+ * be used, and this is therefore not suitable for implementation in
+ * the driver.
+ *
+ * In particular, the ASTC format specifiers will not be added to
+ * Table 3.14, and thus will not be accepted by the TexImage*D
+ * functions, and will not be returned by the (already deprecated)
+ * COMPRESSED_TEXTURE_FORMATS query."
+ *
* There is no formal spec for GL_ATI_texture_compression_3dc. Since the
* formats added by this extension are luminance-alpha formats, it is
* reasonable to expect them to follow the same rules as