<div dir="ltr"> <div class="gmail_extra"> <div class="gmail_quote">On Tue, Dec 9, 2014 at 4:07 AM, Iago Toral Quiroga <<a href="mailto:itoral@igalia.com" target="_blank">itoral@igalia.com</a>> wrote:<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">For glReadPixels with a Luminance destination format we compute luminance values from RGBA as L=R+G+B. This, however, requires ad-hoc implementation, since pack/unpack functions or _mesa_swizzle_and_convert won't do this (and thus, neither will _mesa_format_convert). This patch adds helpers to do this computation so they can be used to support conversion to luminance formats. The current implementation of glReadPixels does this computation as part of the span functions in pack.c (see _mesa_pack_rgba_span_float), that do this together with other things like type conversion, etc. We do not want to use these functions but use _mesa_format_convert instead (later patches will remove the color span functions), so we need to extract this functionality as helpers. --- src/mesa/main/pack.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++ src/mesa/main/pack.h | 9 ++++++++ 2 files changed, 72 insertions(+) diff --git a/src/mesa/main/pack.c b/src/mesa/main/pack.c index de6ab27..fa4046c 100644 --- a/src/mesa/main/pack.c +++ b/src/mesa/main/pack.c @@ -4334,4 +4334,67 @@ _mesa_rebase_rgba_uint(GLuint n, GLuint rgba[][4], GLenum baseFormat) } } +void +_mesa_pack_luminance_from_rgba_float(GLuint n, GLfloat rgba[][4], + GLvoid *dstAddr, GLenum dst_format, + GLbitfield transferOps) +{ + int i; + GLfloat *dst = (GLfloat *) dstAddr; + + switch (dst_format) { + case GL_LUMINANCE: + if (transferOps & IMAGE_CLAMP_BIT) { + for (i = 0; i < n; i++) { + GLfloat sum = rgba[i][RCOMP] + rgba[i][GCOMP] + rgba[i][BCOMP]; + dst[i] = CLAMP(sum, 0.0F, 1.0F); + } + } else { + for (i = 0; i < n; i++) { + dst[i] = rgba[i][RCOMP] + rgba[i][GCOMP] + rgba[i][BCOMP]; + } + } + return; + case GL_LUMINANCE_ALPHA: + if (transferOps & IMAGE_CLAMP_BIT) { + for (i = 0; i < n; i++) { + GLfloat sum = rgba[i][RCOMP] + rgba[i][GCOMP] + rgba[i][BCOMP]; + dst[2*i] = CLAMP(sum, 0.0F, 1.0F); + dst[2*i+1] = rgba[i][ACOMP]; + } + } else { + for (i = 0; i < n; i++) { + dst[2*i] = rgba[i][RCOMP] + rgba[i][GCOMP] + rgba[i][BCOMP]; + dst[2*i+1] = rgba[i][ACOMP]; + } + } + return; + default: + assert(!"Unsupported format"); + } +} + +void +_mesa_pack_luminance_from_rgba_integer(GLuint n, GLuint rgba[][4], + GLvoid *dstAddr, GLenum dst_format) +{ + int i; + GLuint *dst = (GLuint *) dstAddr; + + switch (dst_format) { + case GL_LUMINANCE: + for (i = 0; i < n; i++) { + dst[i] = rgba[i][RCOMP] + rgba[i][GCOMP] + rgba[i][BCOMP]; </blockquote><div> </div><div>I know this is getting old, but don't we need to do some clamping here? If we do, then we have to handle signed vs. unsigned seperately. Yeah, that's annoying. </div><div>--Jason </div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> + } + return; + case GL_LUMINANCE_ALPHA: + for (i = 0; i < n; i++) { + dst[2*i] = rgba[i][RCOMP] + rgba[i][GCOMP] + rgba[i][BCOMP]; + dst[2*i+1] = rgba[i][ACOMP]; + } + return; + default: + assert(!"Unsupported format"); + } +} diff --git a/src/mesa/main/pack.h b/src/mesa/main/pack.h index 2173b65..2783f23 100644 --- a/src/mesa/main/pack.h +++ b/src/mesa/main/pack.h @@ -155,4 +155,13 @@ _mesa_rebase_rgba_float(GLuint n, GLfloat rgba[][4], GLenum baseFormat); extern void _mesa_rebase_rgba_uint(GLuint n, GLuint rgba[][4], GLenum baseFormat); +extern void +_mesa_pack_luminance_from_rgba_float(GLuint n, GLfloat rgba[][4], + GLvoid *dstAddr, GLenum dst_format, + GLbitfield transferOps); + +extern void +_mesa_pack_luminance_from_rgba_integer(GLuint n, GLuint rgba[][4], + GLvoid *dstAddr, GLenum dst_format); + #endif -- 1.9.1 _______________________________________________ mesa-dev mailing list <a href="mailto:mesa-dev@lists.freedesktop.org">mesa-dev@lists.freedesktop.org</a> <a href="http://lists.freedesktop.org/mailman/listinfo/mesa-dev" target="_blank">http://lists.freedesktop.org/mailman/listinfo/mesa-dev</a> </blockquote></div></div></div>