mesa: provide default implementation of QuerySamplesForFormat

Previously at least i915 failed to provide an implementation, but
exposed ARB_internalformat_query anyway, leading to crashes when
QueryInternalformativ was called.

Default implementation just returns 1 for everything, so is suitable for
any driver which does not support multisampling.

V2: - Move from intel to core mesa.

Signed-off-by: Chris Forbes <chrisf@ijw.co.nz>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/mesa/drivers/common/driverfuncs.c

@@ -28,6 +28,7 @@
 #include "main/accum.h"
 #include "main/arrayobj.h"
 #include "main/context.h"
+#include "main/formatquery.h"
 #include "main/framebuffer.h"
 #include "main/mipmap.h"
 #include "main/queryobj.h"
@@ -90,7 +91,7 @@ _mesa_init_driver_functions(struct dd_function_table *driver)
 
    /* Texture functions */
    driver->ChooseTextureFormat = _mesa_choose_tex_format;
-   driver->QuerySamplesForFormat = NULL;
+   driver->QuerySamplesForFormat = _mesa_query_samples_for_format;
    driver->TexImage = _mesa_store_teximage;
    driver->TexSubImage = _mesa_store_texsubimage;
    driver->GetTexImage = _mesa_meta_GetTexImage;

src/mesa/main/formatquery.c

@@ -30,6 +30,21 @@
 #include "fbobject.h"
 #include "formatquery.h"
 
+/* default implementation of QuerySamplesForFormat driverfunc, for
+ * non-multisample-capable drivers. */
+size_t
+_mesa_query_samples_for_format(struct gl_context *ctx, GLenum target,
+                               GLenum internalFormat, int samples[16])
+{
+   (void) target;
+   (void) internalFormat;
+   (void) ctx;
+
+   samples[0] = 1;
+   return 1;
+}
+
+
 void GLAPIENTRY
 _mesa_GetInternalformativ(GLenum target, GLenum internalformat, GLenum pname,
                           GLsizei bufSize, GLint *params)

src/mesa/main/formatquery.h

@@ -28,6 +28,10 @@
 #include "compiler.h"
 #include "glheader.h"
 
+size_t
+_mesa_query_samples_for_format(struct gl_context *ctx, GLenum target,
+                               GLenum internalFormat, int samples[16]);
+
 extern void GLAPIENTRY
 _mesa_GetInternalformativ(GLenum target, GLenum internalformat,
                           GLenum pname, GLsizei bufSize, GLint *params);