mesa: new BYTE/SHORT_TO_FLOATZ() macros

Rather than redefining the BYTE/SHORT_TO_FLOAT macros, just define new
ones with different names.  These macros preserve zero when converting.

Reviewed-by: Eric Anholt <[email protected]>

1 files changed, 7 insertions, 0 deletions

diff --git a/src/mesa/main/macros.h b/src/mesa/main/macros.h
index 029f609fd93..dbe5b867c29 100644
--- a/src/mesa/main/macros.h
+++ b/src/mesa/main/macros.h
@@ -54,6 +54,10 @@ extern GLfloat _mesa_ubyte_to_float_color_tab[256];
 #define FLOAT_TO_BYTE(X)    ( (((GLint) (255.0F * (X))) - 1) / 2 )
 
 
+/** Convert GLbyte to GLfloat while preserving zero */
+#define BYTE_TO_FLOATZ(B)   ((B) == 0 ? 0.0F : BYTE_TO_FLOAT(B))
+
+
 /** Convert GLbyte in [-128,127] to GLfloat in [-1.0,1.0], texture/fb data */
 #define BYTE_TO_FLOAT_TEX(B)    ((B) == -128 ? -1.0F : (B) * (1.0F/127.0F))
 
@@ -73,6 +77,9 @@ extern GLfloat _mesa_ubyte_to_float_color_tab[256];
 /** Convert GLfloat in [-1.0,1.0] to GLshort in [-32768,32767] */
 #define FLOAT_TO_SHORT(X)   ( (((GLint) (65535.0F * (X))) - 1) / 2 )
 
+/** Convert GLshort to GLfloat while preserving zero */
+#define SHORT_TO_FLOATZ(S)   ((S) == 0 ? 0.0F : SHORT_TO_FLOAT(S))
+
 
 /** Convert GLshort in [-32768,32767] to GLfloat in [-1.0,1.0], texture/fb data */
 #define SHORT_TO_FLOAT_TEX(S)    ((S) == -32768 ? -1.0F : (S) * (1.0F/32767.0F))