GLSL output variables (such as vertex varyings) can be read (they're not
write-only).
chan->u[3] = mach->Addrs[index->i[3]].xyzw[swizzle].u[3];
break;
+ case TGSI_FILE_OUTPUT:
+ /* vertex varying/output vars can be read too */
+ chan->u[0] = mach->Outputs[index->i[0]].xyzw[swizzle].u[0];
+ chan->u[1] = mach->Outputs[index->i[1]].xyzw[swizzle].u[1];
+ chan->u[2] = mach->Outputs[index->i[2]].xyzw[swizzle].u[2];
+ chan->u[3] = mach->Outputs[index->i[3]].xyzw[swizzle].u[3];
+ break;
+
default:
assert( 0 );
}