Thanks for taking a look at this, Jose. Comments/questions below...
On 09/14/2011 09:19 AM, Jose Fonseca wrote:
Hi Brian,
----- Original Message -----
From: Brian Paul<bri...@vmware.com>
---
src/gallium/auxiliary/util/u_format.c | 77
+++++++++++++++++++++++++++++++++
src/gallium/auxiliary/util/u_format.h | 16 +++++++
2 files changed, 93 insertions(+), 0 deletions(-)
diff --git a/src/gallium/auxiliary/util/u_format.c
b/src/gallium/auxiliary/util/u_format.c
index 34922ab..2bd3737 100644
--- a/src/gallium/auxiliary/util/u_format.c
+++ b/src/gallium/auxiliary/util/u_format.c
@@ -67,6 +67,83 @@ util_format_is_float(enum pipe_format format)
}
+/** Test if the format contains RGB, but not alpha */
+boolean
It might be better to change the name to util_format_is_rgb_no_alpha, as
is_rgb sounds more like a RGB colorspace inquiry.
will do.
+util_format_is_rgb(enum pipe_format format)
+{
+ const struct util_format_description *desc =
+ util_format_description(format);
For callers that call these helpers a lot, all these internal calls to util_format_description()
will be inefficient. In such cases it might be preferrable for these functions to be declared
inline, and take a "const struct util_format_description *desc" argument instead of
"enum pipe_format format", allowing the caller will call util_format_description only
once.
The only caller of these functions now is the sp blend code and it
saves the results to avoid frequent calls.
Most of the existing util_format_is_XXX() calls take a pipe_format
now. I think we should be consistent and have all of them take a
util_format_description or pipe_format. Either way is fine with me.
We can revisit that later.
+
+ if ((desc->colorspace == UTIL_FORMAT_COLORSPACE_RGB ||
+ desc->colorspace == UTIL_FORMAT_COLORSPACE_SRGB)&&
+ desc->nr_channels == 4&&
+ desc->swizzle[0]<= UTIL_FORMAT_SWIZZLE_W&&
+ desc->swizzle[1]<= UTIL_FORMAT_SWIZZLE_W&&
+ desc->swizzle[2]<= UTIL_FORMAT_SWIZZLE_W&&
+ desc->swizzle[3] == UTIL_FORMAT_SWIZZLE_1) {
+ return TRUE;
+ }
+ return FALSE;
+}
The above logic will produce the following unexpected results:
- FALSE for PIPE_FORMAT_R8G8B8_UNORM, because nr_channels == 3.
I'll fix that case.
- FALSE for PIPE_FORMAT_R8G8_UNORM, because nr_channels == 2.
- FALSE for PIPE_FORMAT_R8_UNORM, because nr_channels == 1.
I don't want to return TRUE for R or RG formats.
- FALSE for PIPE_FORMAT_DXT1_RGB, becuase nr_channels == 1 (nr_channels is
always 1 for non PLAIN formats and not really very meaningful in such format
types).
Hmm, ok, I thought nr_channels indicate the logical number of color
channels in the format, even for compressed formats. Could I count
the number of unique swizzles that are <= SWIZZLE_W to determine the
number of logical channels?
- TRUE for signed and mixed signed formats such as
PIPE_FORMAT_R8SG8SB8UX8U_NORM (not sure if this is intended or matters)
I think that's OK. The intention of the function is to return true if
the format logically stores 3 color components, but not alpha.
It might be useful to extend/adapt a test like such as
src/gallium/tests/unit/u_format_compatible_test.c to ensure that this gives the
expected results for all formats.
+boolean
+util_format_is_luminance(enum pipe_format format)
+{
+ const struct util_format_description *desc =
+ util_format_description(format);
+
+ if ((desc->colorspace == UTIL_FORMAT_COLORSPACE_RGB ||
+ desc->colorspace == UTIL_FORMAT_COLORSPACE_SRGB)&&
+ desc->nr_channels == 1&&
+ desc->swizzle[0] == UTIL_FORMAT_SWIZZLE_X&&
+ desc->swizzle[1] == UTIL_FORMAT_SWIZZLE_X&&
+ desc->swizzle[2] == UTIL_FORMAT_SWIZZLE_X&&
+ desc->swizzle[3] == UTIL_FORMAT_SWIZZLE_1) {
+ return TRUE;
+ }
+ return FALSE;
+}
This will produce TRUE for PIPE_FORMAT_LATC1_UNORM...
+
+boolean
+util_format_is_luminance_alpha(enum pipe_format format)
+{
+ const struct util_format_description *desc =
+ util_format_description(format);
+
+ if ((desc->colorspace == UTIL_FORMAT_COLORSPACE_RGB ||
+ desc->colorspace == UTIL_FORMAT_COLORSPACE_SRGB)&&
+ desc->nr_channels == 2&&
+ desc->swizzle[0] == UTIL_FORMAT_SWIZZLE_X&&
+ desc->swizzle[1] == UTIL_FORMAT_SWIZZLE_X&&
+ desc->swizzle[2] == UTIL_FORMAT_SWIZZLE_X&&
+ desc->swizzle[3] == UTIL_FORMAT_SWIZZLE_Y) {
+ return TRUE;
+ }
+ return FALSE;
+}
.. but this will produce FALSE for PIPE_FORMAT_LATC2_UNORM (nr_channels != 2).
Hmmm, ok. Maybe ignore nr_channels and just check the swizzles as-is?
+
+boolean
+util_format_is_intensity(enum pipe_format format)
+{
+ const struct util_format_description *desc =
+ util_format_description(format);
+
+ if ((desc->colorspace == UTIL_FORMAT_COLORSPACE_RGB ||
+ desc->colorspace == UTIL_FORMAT_COLORSPACE_SRGB)&&
+ desc->nr_channels == 1&&
+ desc->swizzle[0] == UTIL_FORMAT_SWIZZLE_X&&
+ desc->swizzle[1] == UTIL_FORMAT_SWIZZLE_X&&
+ desc->swizzle[2] == UTIL_FORMAT_SWIZZLE_X&&
+ desc->swizzle[3] == UTIL_FORMAT_SWIZZLE_X) {
+ return TRUE;
+ }
+ return FALSE;
+}
This looks alright.
Jose
-Brian
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