From: Brian Paul <brianp@vmware.com>
Date: Fri, 5 Feb 2010 19:57:11 +0000 (-0700)
Subject: fix bug in perspective corrected interpolants for lines
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=a1a441179bacdd33e83a48651c7a7a2cc4a8a665;p=mesa.git

fix bug in perspective corrected interpolants for lines
---

diff --git a/src/gallium/drivers/softpipe/sp_setup.c b/src/gallium/drivers/softpipe/sp_setup.c
index 9036f32c090..b8590a8cc2c 100644
--- a/src/gallium/drivers/softpipe/sp_setup.c
+++ b/src/gallium/drivers/softpipe/sp_setup.c
@@ -908,7 +908,6 @@ line_persp_coeff(const struct setup_context *setup,
                  uint i,
                  const float v[2])
 {
-   /* XXX double-check/verify this arithmetic */
    const float a0 = v[0] * setup->vmin[0][3];
    const float a1 = v[1] * setup->vmax[0][3];
    const float da = a1 - a0;
@@ -916,7 +915,7 @@ line_persp_coeff(const struct setup_context *setup,
    const float dady = da * setup->emaj.dy * setup->oneoverarea;
    coef->dadx[i] = dadx;
    coef->dady[i] = dady;
-   coef->a0[i] = (v[0] - /* XXX: <-- shouldn't that be a0? */
+   coef->a0[i] = (a0 -
                   (dadx * (setup->vmin[0][0] - setup->pixel_offset) +
                    dady * (setup->vmin[0][1] - setup->pixel_offset)));
 }