On Mon, 2017-07-31 at 23:15 +0100, Chris Wilson wrote: > Quoting Chris Wilson (2017-07-31 22:51:25) > > Luminance/Intensity when converted to RGB should be replicated to > > fill > > the RGB channels, but they differ on how the alpha channel is > > filled, as > > luminance is set to 1 (unless alpha is supplied) and intensity is > > replicated into alpha as well. > > > > https://www.khronos.org/opengl/wiki/Image_Format: > > > > Legacy Image Formats > > > > Warning: This section describes legacy OpenGL APIs that have > > been > > removed from core OpenGL 3.1 and above (they are only > > deprecated in > > OpenGL 3.0). It is recommended that you not use this > > functionality in > > your programs. > > > > As with other deprecated functionality, it is advised that you > > not rely > > on these features. > > > > Luminance and intensity formats are color formats. They are one > > or two > > channel formats like RED or RG, but they specify particular > > behavior. > > > > When a GL_RED format is sampled in a shader, the resulting vec4 > > is (Red, > > 0, 0, 1). When a GL_INTENSITY format is sampled, the resulting > > vec4 is > > (I, I, I, I). The single intensity value is read into all four > > components. For GL_LUMINANCE, the result is (L, L, L, 1). There > > is also > > a two-channel GL_LUMINANCE_ALPHA format, which gives (L, L, L, > > A). > > > > v2: luminance -> xxx1, intensity -> xxxx, luminance_alpha -> xxxw
According to the OpenGL 3.0 spec, Table 3.23 Correspondence of filtered texture components to texture source components: Luminance: LLL1 Luminance_Alpha: LLLA Intensisty: IIII so I think the OpenGL wiki is correct and the patch is valid. I presume that with this patch there are no regressions in CTS, right? Assuming that, this patch is: Reviewed-by: Iago Toral Quiroga <ito...@igalia.com> Also, doesn't this require changes in Piglit? I remember that we had a bunch of tests for luminance/intensity formats that I guess would need to be updated accordingly, right? Will you send a patch to update piglit? > If that quote is the expected behaviour for glReadPixels and > glGetTexSubImage, there's a similar stanza to fix in texgetimage.c > (As well as the piglit tests to update.) Yes, that would need the same fix. Will you send a patch for that too? I'll be happy to review it (both for Mesa and Piglit). > With a quick grep through VK-GL-CTS I didn't anything to refer to. > -Chris _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
