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authorBrian Paul <[email protected]>2011-01-25 11:57:10 -0700
committerBrian Paul <[email protected]>2011-01-25 11:57:10 -0700
commit23490d7a8bb77cc0a39ffe7c1ce83ce8e9e9c5bb (patch)
tree8f76c96839ea0cc6e805a8995762f17f7aedce56
parentbb56631f0cb6b3fc552a72e0165816909bf6fdc9 (diff)
st/mesa: add comments in emit_wpos()
-rw-r--r--src/mesa/state_tracker/st_mesa_to_tgsi.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/src/mesa/state_tracker/st_mesa_to_tgsi.c b/src/mesa/state_tracker/st_mesa_to_tgsi.c
index f2a97ae293d..a14551b4345 100644
--- a/src/mesa/state_tracker/st_mesa_to_tgsi.c
+++ b/src/mesa/state_tracker/st_mesa_to_tgsi.c
@@ -850,9 +850,12 @@ emit_wpos(struct st_context *st,
boolean invert = FALSE;
if (fp->OriginUpperLeft) {
+ /* Fragment shader wants origin in upper-left */
if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_FS_COORD_ORIGIN_UPPER_LEFT)) {
+ /* the driver supports upper-left origin */
}
else if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_FS_COORD_ORIGIN_LOWER_LEFT)) {
+ /* the driver supports lower-left origin, need to invert Y */
ureg_property_fs_coord_origin(ureg, TGSI_FS_COORD_ORIGIN_LOWER_LEFT);
invert = TRUE;
}
@@ -860,26 +863,35 @@ emit_wpos(struct st_context *st,
assert(0);
}
else {
+ /* Fragment shader wants origin in lower-left */
if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_FS_COORD_ORIGIN_LOWER_LEFT))
+ /* the driver supports lower-left origin */
ureg_property_fs_coord_origin(ureg, TGSI_FS_COORD_ORIGIN_LOWER_LEFT);
else if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_FS_COORD_ORIGIN_UPPER_LEFT))
+ /* the driver supports upper-left origin, need to invert Y */
invert = TRUE;
else
assert(0);
}
if (fp->PixelCenterInteger) {
+ /* Fragment shader wants pixel center integer */
if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_FS_COORD_PIXEL_CENTER_INTEGER))
+ /* the driver supports pixel center integer */
ureg_property_fs_coord_pixel_center(ureg, TGSI_FS_COORD_PIXEL_CENTER_INTEGER);
else if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_FS_COORD_PIXEL_CENTER_HALF_INTEGER))
+ /* the driver supports pixel center half integer, need to bias X,Y */
emit_adjusted_wpos(t, program, 0.5f, invert ? 0.5f : -0.5f);
else
assert(0);
}
else {
+ /* Fragment shader wants pixel center half integer */
if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_FS_COORD_PIXEL_CENTER_HALF_INTEGER)) {
+ /* the driver supports pixel center half integer */
}
else if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_FS_COORD_PIXEL_CENTER_INTEGER)) {
+ /* the driver supports pixel center integer, need to bias X,Y */
ureg_property_fs_coord_pixel_center(ureg, TGSI_FS_COORD_PIXEL_CENTER_INTEGER);
emit_adjusted_wpos(t, program, 0.5f, invert ? -0.5f : 0.5f);
}