Re: [Mesa-dev] [PATCH] mesa: loosen small matrix determinant check
On Tue, 24 Jul 2012 11:31:59 -0600 Brian Paul bri...@vmware.com wrote: When computing a matrix inverse, if the determinant is too small we could hit a divide by zero. There's a check to prevent this (we basically give up on computing the inverse and return the identity matrix.) This patches loosens this test to fix a lighting bug reported by Lars Henning Wendt. NOTE: This is a candidate for the 8.0 branch. --- src/mesa/math/m_matrix.c |2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/src/mesa/math/m_matrix.c b/src/mesa/math/m_matrix.c index 02aedba..ef377ee 100644 --- a/src/mesa/math/m_matrix.c +++ b/src/mesa/math/m_matrix.c @@ -513,7 +513,7 @@ static GLboolean invert_matrix_3d_general( GLmatrix *mat ) det = pos + neg; - if (det*det 1e-25) + if (det 1e-25) return GL_FALSE; det = 1.0F / det; Hi, just a fly-by question; doesn't that break if determinant is negative? I.e. reflection transformations. Thanks, pq ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] [PATCH] mesa: loosen small matrix determinant check
On Mon, Jul 30, 2012 at 4:31 AM, Pekka Paalanen ppaala...@gmail.com wrote: On Tue, 24 Jul 2012 11:31:59 -0600 Brian Paul bri...@vmware.com wrote: When computing a matrix inverse, if the determinant is too small we could hit a divide by zero. There's a check to prevent this (we basically give up on computing the inverse and return the identity matrix.) This patches loosens this test to fix a lighting bug reported by Lars Henning Wendt. NOTE: This is a candidate for the 8.0 branch. --- src/mesa/math/m_matrix.c |2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/src/mesa/math/m_matrix.c b/src/mesa/math/m_matrix.c index 02aedba..ef377ee 100644 --- a/src/mesa/math/m_matrix.c +++ b/src/mesa/math/m_matrix.c @@ -513,7 +513,7 @@ static GLboolean invert_matrix_3d_general( GLmatrix *mat ) det = pos + neg; - if (det*det 1e-25) + if (det 1e-25) return GL_FALSE; det = 1.0F / det; Hi, just a fly-by question; doesn't that break if determinant is negative? I.e. reflection transformations. Yeah, I think you need a fabsf() there. ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] [PATCH] mesa: loosen small matrix determinant check
On Mon, Jul 30, 2012 at 7:39 AM, Patrick Baggett baggett.patr...@gmail.com wrote: On Mon, Jul 30, 2012 at 4:31 AM, Pekka Paalanen ppaala...@gmail.com wrote: On Tue, 24 Jul 2012 11:31:59 -0600 Brian Paul bri...@vmware.com wrote: When computing a matrix inverse, if the determinant is too small we could hit a divide by zero. There's a check to prevent this (we basically give up on computing the inverse and return the identity matrix.) This patches loosens this test to fix a lighting bug reported by Lars Henning Wendt. NOTE: This is a candidate for the 8.0 branch. --- src/mesa/math/m_matrix.c |2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/src/mesa/math/m_matrix.c b/src/mesa/math/m_matrix.c index 02aedba..ef377ee 100644 --- a/src/mesa/math/m_matrix.c +++ b/src/mesa/math/m_matrix.c @@ -513,7 +513,7 @@ static GLboolean invert_matrix_3d_general( GLmatrix *mat ) det = pos + neg; - if (det*det 1e-25) + if (det 1e-25) return GL_FALSE; det = 1.0F / det; Hi, just a fly-by question; doesn't that break if determinant is negative? I.e. reflection transformations. Yeah, I think you need a fabsf() there. v2 of the patch used abs() and was pushed a while ago. -Brian ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
[Mesa-dev] [PATCH] mesa: loosen small matrix determinant check
When computing a matrix inverse, if the determinant is too small we could hit a divide by zero. There's a check to prevent this (we basically give up on computing the inverse and return the identity matrix.) This patch loosens this test to fix a lighting bug reported by Lars Henning Wendt. v2: use abs(det) to handle negative values NOTE: This is a candidate for the 8.0 branch. --- src/mesa/math/m_matrix.c |2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/src/mesa/math/m_matrix.c b/src/mesa/math/m_matrix.c index 02aedba..ffbdcdb 100644 --- a/src/mesa/math/m_matrix.c +++ b/src/mesa/math/m_matrix.c @@ -513,7 +513,7 @@ static GLboolean invert_matrix_3d_general( GLmatrix *mat ) det = pos + neg; - if (det*det 1e-25) + if (FABSF(det) 1e-25) return GL_FALSE; det = 1.0F / det; -- 1.7.3.4 ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
[Mesa-dev] [PATCH] mesa: loosen small matrix determinant check
When computing a matrix inverse, if the determinant is too small we could hit a divide by zero. There's a check to prevent this (we basically give up on computing the inverse and return the identity matrix.) This patches loosens this test to fix a lighting bug reported by Lars Henning Wendt. NOTE: This is a candidate for the 8.0 branch. --- src/mesa/math/m_matrix.c |2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/src/mesa/math/m_matrix.c b/src/mesa/math/m_matrix.c index 02aedba..ef377ee 100644 --- a/src/mesa/math/m_matrix.c +++ b/src/mesa/math/m_matrix.c @@ -513,7 +513,7 @@ static GLboolean invert_matrix_3d_general( GLmatrix *mat ) det = pos + neg; - if (det*det 1e-25) + if (det 1e-25) return GL_FALSE; det = 1.0F / det; -- 1.7.3.4 ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
