pbo: fix glIsBuffer() tests

glIsBuffer() should return GL_FALSE if the buffer was generated with
glGenBuffers() but never bound with glBindBuffer().

This was incorrect in Mesa until yesteday.  Mesa now agrees with
AMD, Apple and Intel drivers.  NVIDIA is the odd one out.

Also, improve error messages and remove another unneeded glIsBuffer()
call later.

1 files changed, 3 insertions, 5 deletions

diff --git a/src/glean/tpbo.cpp b/src/glean/tpbo.cpp
index 7d86279..85a7dba 100644
--- a/src/glean/tpbo.cpp
+++ b/src/glean/tpbo.cpp
@@ -200,8 +200,8 @@ bool PBOTest::testSanity(void)
 
    glGenBuffersARB_func(1, pbs);
 
-   if (glIsBufferARB_func(pbs[0]) != GL_TRUE) {
-      REPORT_FAILURE("Failed to call glIsBuffersARB");
+   if (glIsBufferARB_func(pbs[0]) != GL_FALSE) {
+      REPORT_FAILURE("glIsBufferARB failed");
       return false;
    }
 
@@ -224,7 +224,7 @@ bool PBOTest::testSanity(void)
    glDeleteBuffersARB_func(1, pbs);
 
    if (glIsBufferARB_func(pbs[0]) == GL_TRUE) {
-      REPORT_FAILURE("Failed to call glIsBuffersARB");
+      REPORT_FAILURE("glIsBufferARB failed");
       return false;
    }
 
@@ -615,8 +615,6 @@ bool PBOTest::testTexImage(void)
                  breakCOWTexture++) {
                if (useTexUnpackBuffer) {
                   glGenBuffersARB_func(1, unpack_pb);
-                  if (glIsBufferARB_func(unpack_pb[0]) == false)
-                     return false;
                   glBindBufferARB_func(GL_PIXEL_UNPACK_BUFFER_ARB, unpack_pb[0]);
                   glBufferDataARB_func(GL_PIXEL_UNPACK_BUFFER_ARB,
                                TEXSIZE * TEXSIZE * 3 * sizeof(GLfloat), NULL,