Module: Mesa Branch: master Commit: 92234b1b2aaf6ba68e786498806cefd4bd99dabc URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=92234b1b2aaf6ba68e786498806cefd4bd99dabc
Author: Kenneth Graunke <[email protected]> Date: Mon Mar 24 01:16:57 2014 -0700 mesa: Introduce a _mesa_format_has_color_component() helper. When considering color write masks, we often want to know whether an RGBA component actually contains any meaningful data. This function provides an easy way to answer that question, and handles luminance, intensity, and alpha formats correctly. Signed-off-by: Kenneth Graunke <[email protected]> Reviewed-by: Brian Paul <[email protected]> Reviewed-by: Eric Anholt <[email protected]> Reviewed-by: Ian Romanick <[email protected]> Tested-by: Dylan Baker <[email protected]> --- src/mesa/main/formats.c | 29 +++++++++++++++++++++++++++++ src/mesa/main/formats.h | 4 ++++ 2 files changed, 33 insertions(+) diff --git a/src/mesa/main/formats.c b/src/mesa/main/formats.c index e74625f..fb2501c 100644 --- a/src/mesa/main/formats.c +++ b/src/mesa/main/formats.c @@ -2207,6 +2207,35 @@ _mesa_format_num_components(mesa_format format) /** + * Returns true if a color format has data stored in the R/G/B/A channels, + * given an index from 0 to 3. + */ +bool +_mesa_format_has_color_component(mesa_format format, int component) +{ + const struct gl_format_info *info = _mesa_get_format_info(format); + + assert(info->BaseFormat != GL_DEPTH_COMPONENT && + info->BaseFormat != GL_DEPTH_STENCIL && + info->BaseFormat != GL_STENCIL_INDEX); + + switch (component) { + case 0: + return (info->RedBits + info->IntensityBits + info->LuminanceBits) > 0; + case 1: + return (info->GreenBits + info->IntensityBits + info->LuminanceBits) > 0; + case 2: + return (info->BlueBits + info->IntensityBits + info->LuminanceBits) > 0; + case 3: + return (info->AlphaBits + info->IntensityBits) > 0; + default: + assert(!"Invalid color component: must be 0..3"); + return false; + } +} + + +/** * Return number of bytes needed to store an image of the given size * in the given format. */ diff --git a/src/mesa/main/formats.h b/src/mesa/main/formats.h index 3079f03..89bd021 100644 --- a/src/mesa/main/formats.h +++ b/src/mesa/main/formats.h @@ -34,6 +34,7 @@ #include <GL/gl.h> +#include <stdbool.h> #ifdef __cplusplus @@ -474,6 +475,9 @@ _mesa_get_uncompressed_format(mesa_format format); extern GLuint _mesa_format_num_components(mesa_format format); +extern bool +_mesa_format_has_color_component(mesa_format format, int component); + GLboolean _mesa_format_matches_format_and_type(mesa_format mesa_format, GLenum format, GLenum type, _______________________________________________ mesa-commit mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/mesa-commit
