From c4b87f129eb036c9615df3adcc1cebd9df10fc84 Mon Sep 17 00:00:00 2001 From: Chad Versace Date: Thu, 29 Dec 2016 13:05:27 -0800 Subject: [PATCH] meta: Disable dithering during glGenerateMipmap Fixes tests 'dEQP-GLES3.functional.texture.mipmap.*.generate.rgba5551*' on Intel Broadwell 0x1616. The GL 4.5 spec describes the algorithm of glGenerateMipmap as: The contents of the derived images are computed by repeated, filtered reduction of the level base image. [...] No particular filter algorithm is required, though a box filter is recommended as the default filter. Consider a texture for which all pixels are identical at level 0. From the spec's description above, one may reasonably assume that the "filtered reduction" of level 0 produces a new miplevel for which again all pixels are identical. For any 2x2 subspan of identical pixels, it is difficult to see how the "filtered reduction" of that subspan can produce a pixel that differs from the source pixels. Dithering during _mesa_meta_GenerateMipmap() violated that reasonable assumption. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99210 Reviewed-by: Kenneth Graunke Cc: mesa-stable@lists.freedesktop.org --- src/mesa/drivers/common/meta_generate_mipmap.c | 1 + 1 file changed, 1 insertion(+) diff --git a/src/mesa/drivers/common/meta_generate_mipmap.c b/src/mesa/drivers/common/meta_generate_mipmap.c index bbe9d6d8863..55093e95537 100644 --- a/src/mesa/drivers/common/meta_generate_mipmap.c +++ b/src/mesa/drivers/common/meta_generate_mipmap.c @@ -182,6 +182,7 @@ _mesa_meta_GenerateMipmap(struct gl_context *ctx, GLenum target, _mesa_meta_begin(ctx, MESA_META_ALL & ~MESA_META_DRAW_BUFFERS); _mesa_ColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE); + _mesa_Disable(GL_DITHER); /* Choose between glsl version and fixed function version of * GenerateMipmap function. -- 2.30.2