framebuffer: Bind the framebuffer before querying the bits

The GL framebuffer driver now makes sure to bind the framebuffer
before counting the number of bits. Previously it would just query the
number of bits for whatever framebuffer happened to be used last.

In addition the virtual for querying the framebuffer bits has been
modified to take a pointer to a structure instead of a separate
pointer to each component. This should make it slightly more efficient
and easier to maintain.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit e9c58b2ba23a7cebcd4e633ea7c3191f02056fb5)

cogl/cogl-driver.h

@@ -75,10 +75,7 @@ struct _CoglDriverVtable
 
   void
   (* framebuffer_query_bits) (CoglFramebuffer *framebuffer,
-                              int *red,
+                              CoglFramebufferBits *bits);
-                              int *green,
-                              int *blue,
-                              int *alpha);
 
   void
   (* framebuffer_finish) (CoglFramebuffer *framebuffer);

cogl/cogl-framebuffer-private.h

@@ -105,6 +105,14 @@ typedef enum
   COGL_READ_PIXELS_NO_FLIP = 1L << 30
 } CoglPrivateReadPixelsFlags;
 
+typedef struct
+{
+  int red;
+  int blue;
+  int green;
+  int alpha;
+} CoglFramebufferBits;
+
 struct _CoglFramebuffer
 {
   CoglObject          _parent;
@@ -162,10 +170,7 @@ struct _CoglFramebuffer
 
   /* driver specific */
   CoglBool            dirty_bitmasks;
-  int                 red_bits;
+  CoglFramebufferBits bits;
-  int                 blue_bits;
-  int                 green_bits;
-  int                 alpha_bits;
 
   int                 samples_per_pixel;
 };

cogl/cogl-framebuffer.c

@@ -1093,47 +1093,44 @@ int
 cogl_framebuffer_get_red_bits (CoglFramebuffer *framebuffer)
 {
   CoglContext *ctx = framebuffer->context;
-  int red, green, blue, alpha;
+  CoglFramebufferBits bits;
 
-  ctx->driver_vtable->framebuffer_query_bits (framebuffer,
+  ctx->driver_vtable->framebuffer_query_bits (framebuffer, &bits);
-                                              &red, &green, &blue, &alpha);
 
-  return red;
+  return bits.red;
 }
+
 int
 cogl_framebuffer_get_green_bits (CoglFramebuffer *framebuffer)
 {
   CoglContext *ctx = framebuffer->context;
-  int red, green, blue, alpha;
+  CoglFramebufferBits bits;
 
-  ctx->driver_vtable->framebuffer_query_bits (framebuffer,
+  ctx->driver_vtable->framebuffer_query_bits (framebuffer, &bits);
-                                              &red, &green, &blue, &alpha);
 
-  return green;
+  return bits.green;
 }
 
 int
 cogl_framebuffer_get_blue_bits (CoglFramebuffer *framebuffer)
 {
   CoglContext *ctx = framebuffer->context;
-  int red, green, blue, alpha;
+  CoglFramebufferBits bits;
 
-  ctx->driver_vtable->framebuffer_query_bits (framebuffer,
+  ctx->driver_vtable->framebuffer_query_bits (framebuffer, &bits);
-                                              &red, &green, &blue, &alpha);
 
-  return blue;
+  return bits.blue;
 }
 
 int
 cogl_framebuffer_get_alpha_bits (CoglFramebuffer *framebuffer)
 {
   CoglContext *ctx = framebuffer->context;
-  int red, green, blue, alpha;
+  CoglFramebufferBits bits;
 
-  ctx->driver_vtable->framebuffer_query_bits (framebuffer,
+  ctx->driver_vtable->framebuffer_query_bits (framebuffer, &bits);
-                                              &red, &green, &blue, &alpha);
 
-  return alpha;
+  return bits.alpha;
 }
 
 CoglColorMask

cogl/driver/gl/cogl-framebuffer-gl-private.h

@@ -50,10 +50,7 @@ _cogl_framebuffer_gl_clear (CoglFramebuffer *framebuffer,
 
 void
 _cogl_framebuffer_gl_query_bits (CoglFramebuffer *framebuffer,
-                                 int *red,
+                                 CoglFramebufferBits *bits);
-                                 int *green,
-                                 int *blue,
-                                 int *alpha);
 
 void
 _cogl_framebuffer_gl_finish (CoglFramebuffer *framebuffer);

cogl/driver/gl/cogl-framebuffer-gl.c

@@ -892,54 +892,54 @@ _cogl_framebuffer_init_bits (CoglFramebuffer *framebuffer)
 {
   CoglContext *ctx = framebuffer->context;
 
-  cogl_framebuffer_allocate (framebuffer, NULL);
-
   if (G_LIKELY (!framebuffer->dirty_bitmasks))
     return;
 
+  cogl_framebuffer_allocate (framebuffer, NULL);
+
+  _cogl_framebuffer_flush_state (framebuffer,
+                                 framebuffer,
+                                 COGL_FRAMEBUFFER_STATE_BIND);
+
 #ifdef HAVE_COGL_GL
   if ((ctx->private_feature_flags &
        COGL_PRIVATE_FEATURE_QUERY_FRAMEBUFFER_BITS) &&
       framebuffer->type == COGL_FRAMEBUFFER_TYPE_OFFSCREEN)
+    {
+      static const struct
       {
         GLenum attachment, pname;
+        size_t offset;
+      } params[] =
+          {
+            { GL_COLOR_ATTACHMENT0, GL_FRAMEBUFFER_ATTACHMENT_RED_SIZE,
+              offsetof (CoglFramebufferBits, red) },
+            { GL_COLOR_ATTACHMENT0, GL_FRAMEBUFFER_ATTACHMENT_GREEN_SIZE,
+              offsetof (CoglFramebufferBits, green) },
+            { GL_COLOR_ATTACHMENT0, GL_FRAMEBUFFER_ATTACHMENT_BLUE_SIZE,
+              offsetof (CoglFramebufferBits, blue) },
+            { GL_COLOR_ATTACHMENT0, GL_FRAMEBUFFER_ATTACHMENT_ALPHA_SIZE,
+              offsetof (CoglFramebufferBits, alpha) },
+          };
+      int i;
 
-      attachment = GL_COLOR_ATTACHMENT0;
+      for (i = 0; i < G_N_ELEMENTS (params); i++)
-
+        {
-      pname = GL_FRAMEBUFFER_ATTACHMENT_RED_SIZE;
+          int *value =
+            (int *) ((uint8_t *) &framebuffer->bits + params[i].offset);
           GE( ctx, glGetFramebufferAttachmentParameteriv (GL_FRAMEBUFFER,
-                                                      attachment,
+                                                          params[i].attachment,
-                                                      pname,
+                                                          params[i].pname,
-                                                      &framebuffer->red_bits) );
+                                                          value) );
-
+        }
-      pname = GL_FRAMEBUFFER_ATTACHMENT_GREEN_SIZE;
-      GE( ctx, glGetFramebufferAttachmentParameteriv (GL_FRAMEBUFFER,
-                                                      attachment,
-                                                      pname,
-                                                      &framebuffer->green_bits)
-          );
-
-      pname = GL_FRAMEBUFFER_ATTACHMENT_BLUE_SIZE;
-      GE( ctx, glGetFramebufferAttachmentParameteriv (GL_FRAMEBUFFER,
-                                                      attachment,
-                                                      pname,
-                                                      &framebuffer->blue_bits)
-          );
-
-      pname = GL_FRAMEBUFFER_ATTACHMENT_ALPHA_SIZE;
-      GE( ctx, glGetFramebufferAttachmentParameteriv (GL_FRAMEBUFFER,
-                                                      attachment,
-                                                      pname,
-                                                      &framebuffer->alpha_bits)
-          );
     }
   else
 #endif /* HAVE_COGL_GL */
     {
-      GE( ctx, glGetIntegerv (GL_RED_BITS,   &framebuffer->red_bits)   );
+      GE( ctx, glGetIntegerv (GL_RED_BITS,   &framebuffer->bits.red)   );
-      GE( ctx, glGetIntegerv (GL_GREEN_BITS, &framebuffer->green_bits) );
+      GE( ctx, glGetIntegerv (GL_GREEN_BITS, &framebuffer->bits.green) );
-      GE( ctx, glGetIntegerv (GL_BLUE_BITS,  &framebuffer->blue_bits)  );
+      GE( ctx, glGetIntegerv (GL_BLUE_BITS,  &framebuffer->bits.blue)  );
-      GE( ctx, glGetIntegerv (GL_ALPHA_BITS, &framebuffer->alpha_bits) );
+      GE( ctx, glGetIntegerv (GL_ALPHA_BITS, &framebuffer->bits.alpha) );
     }
 
 
@@ -949,29 +949,23 @@ _cogl_framebuffer_init_bits (CoglFramebuffer *framebuffer)
              framebuffer->type == COGL_FRAMEBUFFER_TYPE_OFFSCREEN
                ? "offscreen"
                : "onscreen",
-             framebuffer->red_bits,
+             framebuffer->bits.red,
-             framebuffer->blue_bits,
+             framebuffer->bits.blue,
-             framebuffer->green_bits,
+             framebuffer->bits.green,
-             framebuffer->alpha_bits);
+             framebuffer->bits.alpha);
 
   framebuffer->dirty_bitmasks = FALSE;
 }
 
 void
 _cogl_framebuffer_gl_query_bits (CoglFramebuffer *framebuffer,
-                                 int *red,
+                                 CoglFramebufferBits *bits)
-                                 int *green,
-                                 int *blue,
-                                 int *alpha)
 {
   _cogl_framebuffer_init_bits (framebuffer);
 
   /* TODO: cache these in some driver specific location not
    * directly as part of CoglFramebuffer. */
-  *red = framebuffer->red_bits;
+  *bits = framebuffer->bits;
-  *green = framebuffer->green_bits;
-  *blue = framebuffer->blue_bits;
-  *alpha = framebuffer->alpha_bits;
 }
 
 void

cogl/driver/nop/cogl-framebuffer-nop-private.h

@@ -53,10 +53,7 @@ _cogl_framebuffer_nop_clear (CoglFramebuffer *framebuffer,
 
 void
 _cogl_framebuffer_nop_query_bits (CoglFramebuffer *framebuffer,
-                                 int *red,
+                                  CoglFramebufferBits *bits);
-                                 int *green,
-                                 int *blue,
-                                 int *alpha);
 
 void
 _cogl_framebuffer_nop_finish (CoglFramebuffer *framebuffer);

cogl/driver/nop/cogl-framebuffer-nop.c

@@ -29,7 +29,7 @@
 #include "cogl-framebuffer-nop-private.h"
 
 #include <glib.h>
-
+#include <string.h>
 
 void
 _cogl_framebuffer_nop_flush_state (CoglFramebuffer *draw_buffer,
@@ -62,15 +62,9 @@ _cogl_framebuffer_nop_clear (CoglFramebuffer *framebuffer,
 
 void
 _cogl_framebuffer_nop_query_bits (CoglFramebuffer *framebuffer,
-                                  int *red,
+                                  CoglFramebufferBits *bits)
-                                  int *green,
-                                  int *blue,
-                                  int *alpha)
 {
-  *red = 0;
+  memset (bits, 0, sizeof (CoglFramebufferBits));
-  *green = 0;
-  *blue = 0;
-  *alpha = 0;
 }
 
 void

tests/conform/test-conform-main.c

@@ -98,9 +98,7 @@ main (int argc, char **argv)
   ADD_TEST (test_bitmask, 0, 0);
 
   ADD_TEST (test_offscreen, 0, 0);
-  ADD_TEST (test_framebuffer_get_bits,
+  ADD_TEST (test_framebuffer_get_bits, TEST_REQUIREMENT_OFFSCREEN, 0);
-            TEST_REQUIREMENT_OFFSCREEN,
-            TEST_KNOWN_FAILURE);
 
   ADD_TEST (test_point_size, 0, 0);
   ADD_TEST (test_point_sprite,