util: Support all SRGB formats.

Based on code from Brian Paul and Michal Krol.

1 files changed, 101 insertions, 0 deletions

diff --git a/src/gallium/auxiliary/util/u_format_srgb.py b/src/gallium/auxiliary/util/u_format_srgb.py
new file mode 100644
index 0000000000..a4c76dc00b
--- /dev/null
+++ b/src/gallium/auxiliary/util/u_format_srgb.py
@@ -0,0 +1,101 @@
+#!/usr/bin/env python
+
+'''
+/**************************************************************************
+ *
+ * Copyright 2010 VMware, Inc.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+/**
+ * @file
+ * SRGB translation.
+ *
+ * @author Brian Paul <brianp@vmware.com>
+ * @author Michal Krol <michal@vmware.com>
+ * @author Jose Fonseca <jfonseca@vmware.com>
+ */
+'''
+
+
+import sys
+import math
+
+
+def srgb_to_linear(x):
+    if x <= 0.04045:
+        return x / 12.92
+    else:
+        return math.pow((x + 0.055) / 1.055, 2.4)
+
+
+def linear_to_srgb(x):
+    if x >= 0.0031308:
+        return 1.055 * math.pow(x, 0.41666) - 0.055
+    else:
+        return 12.92 * x
+
+def generate_srgb_tables():
+    print 'const float'
+    print 'util_format_srgb_8unorm_to_linear_float_table[256] = {'
+    for j in range(0, 256, 4):
+        print '   ',
+        for i in range(j, j + 4):
+            print '%.7e,' % (srgb_to_linear(i / 255.0),),
+        print
+    print '};'
+    print
+    print 'const uint8_t'
+    print 'util_format_srgb_to_linear_8unorm_table[256] = {'
+    for j in range(0, 256, 16):
+        print '   ',
+        for i in range(j, j + 16):
+            print '%3u,' % (int(srgb_to_linear(i / 255.0) * 255.0 + 0.5),),
+        print
+    print '};'
+    print
+    print 'const uint8_t'
+    print 'util_format_linear_to_srgb_8unorm_table[256] = {'
+    for j in range(0, 256, 16):
+        print '   ',
+        for i in range(j, j + 16):
+            print '%3u,' % (int(linear_to_srgb(i / 255.0) * 255.0 + 0.5),),
+        print
+    print '};'
+    print
+
+
+def main():
+    print '/* This file is autogenerated by u_format_srgb.py. Do not edit directly. */'
+    print
+    # This will print the copyright message on the top of this file
+    print __doc__.strip()
+    print
+    print '#include "u_format_srgb.h"'
+    print
+    generate_srgb_tables()    
+
+
+if __name__ == '__main__':
+    main()