Mesa (mesa_7_4_branch): swrast: return (0,0,0,1) when sampling incomplete textures, not (0,0,0,0)

[Brian Paul]

Module: Mesa
Branch: mesa_7_4_branch
Commit: 4608a9172fd4d8f8fc3ed9be17cde6ead3088b4c
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=4608a9172fd4d8f8fc3ed9be17cde6ead3088b4c

Author: Brian Paul <brianp at vmware.com>
Date:   Sat Feb  7 12:02:22 2009 -0700

swrast: return (0,0,0,1) when sampling incomplete textures, not (0,0,0,0)

Fixes piglit shaders/fp-incomplete-tex test.

(cherry picked from master, commit 1df62651b2e9a8d0afd790738e2695a16ade1eeb)

Conflicts:
	src/mesa/swrast/s_fragprog.c

Also updated the fetch_texel_lod(), fetch_texel_deriv() functions to match
those in git/master.

---

 src/mesa/swrast/s_fragprog.c |   54 ++++++++++++++++++++++++++---------------
 1 files changed, 34 insertions(+), 20 deletions(-)

diff --git a/src/mesa/swrast/s_fragprog.c b/src/mesa/swrast/s_fragprog.c
index 525cf9d..c0bda32 100644
--- a/src/mesa/swrast/s_fragprog.c
+++ b/src/mesa/swrast/s_fragprog.c
@@ -40,20 +40,27 @@ static void
 fetch_texel_lod( GLcontext *ctx, const GLfloat texcoord[4], GLfloat lambda,
                  GLuint unit, GLfloat color[4] )
 {
-   GLchan rgba[4];
-   SWcontext *swrast = SWRAST_CONTEXT(ctx);
    const struct gl_texture_object *texObj = ctx->Texture.Unit[unit]._Current;
 
-   if (texObj)
+   if (texObj) {
+      SWcontext *swrast = SWRAST_CONTEXT(ctx);
+      GLchan rgba[4];
+
       lambda = CLAMP(lambda, texObj->MinLod, texObj->MaxLod);
 
-   /* XXX use a float-valued TextureSample routine here!!! */
-   swrast->TextureSample[unit](ctx, texObj, 1, (const GLfloat (*)[4]) texcoord,
-                               &lambda, &rgba);
-   color[0] = CHAN_TO_FLOAT(rgba[0]);
-   color[1] = CHAN_TO_FLOAT(rgba[1]);
-   color[2] = CHAN_TO_FLOAT(rgba[2]);
-   color[3] = CHAN_TO_FLOAT(rgba[3]);
+      /* XXX use a float-valued TextureSample routine here!!! */
+      swrast->TextureSample[unit](ctx, texObj, 1,
+                                  (const GLfloat (*)[4]) texcoord,
+                                  &lambda, &rgba);
+      color[0] = CHAN_TO_FLOAT(rgba[0]);
+      color[1] = CHAN_TO_FLOAT(rgba[1]);
+      color[2] = CHAN_TO_FLOAT(rgba[2]);
+      color[3] = CHAN_TO_FLOAT(rgba[3]);
+   }
+   else {
+      color[0] = color[1] = color[2] = 0.0F;
+      color[3] = 1.0F;
+   }
 }
 
 
@@ -69,13 +76,14 @@ fetch_texel_deriv( GLcontext *ctx, const GLfloat texcoord[4],
 {
    SWcontext *swrast = SWRAST_CONTEXT(ctx);
    const struct gl_texture_object *texObj = ctx->Texture.Unit[unit]._Current;
-   GLfloat lambda;
-   GLchan rgba[4];
 
    if (texObj) {
-      const struct gl_texture_image *texImg = texObj->Image[0][texObj->BaseLevel];
+      const struct gl_texture_image *texImg =
+         texObj->Image[0][texObj->BaseLevel];
       const GLfloat texW = (GLfloat) texImg->WidthScale;
       const GLfloat texH = (GLfloat) texImg->HeightScale;
+      GLfloat lambda;
+      GLchan rgba[4];
 
       lambda = _swrast_compute_lambda(texdx[0], texdy[0], /* ds/dx, ds/dy */
                                       texdx[1], texdy[1], /* dt/dx, dt/dy */
@@ -85,14 +93,20 @@ fetch_texel_deriv( GLcontext *ctx, const GLfloat texcoord[4],
                                       1.0F / texcoord[3]) + lodBias;
 
       lambda = CLAMP(lambda, texObj->MinLod, texObj->MaxLod);
-   }
 
-   swrast->TextureSample[unit](ctx, texObj, 1, (const GLfloat (*)[4]) texcoord,
-                               &lambda, &rgba);
-   color[0] = CHAN_TO_FLOAT(rgba[0]);
-   color[1] = CHAN_TO_FLOAT(rgba[1]);
-   color[2] = CHAN_TO_FLOAT(rgba[2]);
-   color[3] = CHAN_TO_FLOAT(rgba[3]);
+      /* XXX use a float-valued TextureSample routine here!!! */
+      swrast->TextureSample[unit](ctx, texObj, 1,
+                                  (const GLfloat (*)[4]) texcoord,
+                                  &lambda, &rgba);
+      color[0] = CHAN_TO_FLOAT(rgba[0]);
+      color[1] = CHAN_TO_FLOAT(rgba[1]);
+      color[2] = CHAN_TO_FLOAT(rgba[2]);
+      color[3] = CHAN_TO_FLOAT(rgba[3]);
+   }
+   else {
+      color[0] = color[1] = color[2] = 0.0F;
+      color[3] = 1.0F;
+   }
 }