swrast/rgtc: fix rendering issues introduced when fix constants

The max value was wrong and this showed up in the piglit tests.

diff --git a/src/mesa/main/texcompress_rgtc.c b/src/mesa/main/texcompress_rgtc.c
index 2f3a0f2..f6a1825 100644 (file)
--- a/src/mesa/main/texcompress_rgtc.c
+++ b/src/mesa/main/texcompress_rgtc.c
@@ -443,7 +443,7 @@ _mesa_fetch_texel_2d_f_signed_rg_rgtc2(const struct gl_texture_image *texImage,
 #define TAG(x) signed_##x
 #define TYPE GLbyte
 #define T_MIN (GLbyte)-127
-#define T_MAX (GLbyte)127
+#define T_MAX (GLbyte)128
 
 #include "texcompress_rgtc_tmp.h"