glsl: fix UNIFORM_BUFFER_START or UNIFORM_BUFFER_SIZE query when no buffer object is bound

According to ARB_uniform_buffer_object spec:

"If the parameter (starting offset or size) was not specified when the
 buffer object was bound (e.g. if bound with BindBufferBase), or if no
 buffer object is bound to <index>, zero is returned."

Signed-off-by: Samuel Iglesias Gonsalvez <[email protected]>
Reviewed-by: Tapani Pälli <[email protected]>
Reviewed-by: Kristian Høgsberg <[email protected]>

1 files changed, 4 insertions, 2 deletions

diff --git a/src/mesa/main/get.c b/src/mesa/main/get.c
index 2390850a0af..77184ee7986 100644
--- a/src/mesa/main/get.c
+++ b/src/mesa/main/get.c
@@ -1932,7 +1932,8 @@ find_value_indexed(const char *func, GLenum pname, GLuint index, union value *v)
 	 goto invalid_value;
       if (!ctx->Extensions.ARB_uniform_buffer_object)
 	 goto invalid_enum;
-      v->value_int = ctx->UniformBufferBindings[index].Offset;
+      v->value_int = ctx->UniformBufferBindings[index].Offset < 0 ? 0 :
+                     ctx->UniformBufferBindings[index].Offset;
       return TYPE_INT;
 
    case GL_UNIFORM_BUFFER_SIZE:
@@ -1940,7 +1941,8 @@ find_value_indexed(const char *func, GLenum pname, GLuint index, union value *v)
 	 goto invalid_value;
       if (!ctx->Extensions.ARB_uniform_buffer_object)
 	 goto invalid_enum;
-      v->value_int = ctx->UniformBufferBindings[index].Size;
+      v->value_int = ctx->UniformBufferBindings[index].Size < 0 ? 0 :
+                     ctx->UniformBufferBindings[index].Size;
       return TYPE_INT;
 
    /* ARB_shader_storage_buffer_object */