From d225221e7084a1e8e22c41cbd3c58775d6f298a1 Mon Sep 17 00:00:00 2001 From: Brian Paul Date: Fri, 30 Apr 2010 13:54:31 -0600 Subject: [PATCH] llvmpipe: fix out-of-bounds texture sampling If we're using a wrap mode in which border color sampling is possible it means that texcoords may be outside of the texture image bounds. Fetching the texel may result in a segfault. Use the 'use_border' variable to catch such texcoords and replace the texel offset with zero (which will be in bounds). Fixes segfault in Lightsmark demo, fd.o bug 27877. --- src/gallium/auxiliary/gallivm/lp_bld_sample_soa.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/src/gallium/auxiliary/gallivm/lp_bld_sample_soa.c b/src/gallium/auxiliary/gallivm/lp_bld_sample_soa.c index 7c9c8e2d9f7..54c0ad7ce43 100644 --- a/src/gallium/auxiliary/gallivm/lp_bld_sample_soa.c +++ b/src/gallium/auxiliary/gallivm/lp_bld_sample_soa.c @@ -325,6 +325,18 @@ lp_build_sample_texel_soa(struct lp_build_sample_context *bld, bld->format_desc, x, y, z, y_stride, z_stride); + if (use_border) { + /* If we can sample the border color, it means that texcoords may + * lie outside the bounds of the texture image. We need to do + * something to prevent reading out of bounds and causing a segfault. + * + * Simply AND the texture coords with !use_border. This will cause + * coords which are out of bounds to become zero. Zero's guaranteed + * to be inside the texture image. + */ + offset = lp_build_andc(&bld->uint_coord_bld, offset, use_border); + } + lp_build_fetch_rgba_soa(bld->builder, bld->format_desc, bld->texel_type, -- 2.30.2