Add a public cogl_framebuffer_get_depth_bits() function

Cogl publicly exposes the depth buffer state so we might as well have
a function to query the number of depth bits of a framebuffer.

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

(cherry picked from commit 853143eb10387f50f8d32cf09af31b8829dc1e01)

cogl/cogl-framebuffer-private.h

@@ -111,6 +111,7 @@ typedef struct
   int blue;
   int green;
   int alpha;
+  int depth;
 } CoglFramebufferBits;
 
 struct _CoglFramebuffer

cogl/cogl-framebuffer.c

@@ -1133,6 +1133,17 @@ cogl_framebuffer_get_alpha_bits (CoglFramebuffer *framebuffer)
   return bits.alpha;
 }
 
+int
+cogl_framebuffer_get_depth_bits (CoglFramebuffer *framebuffer)
+{
+  CoglContext *ctx = framebuffer->context;
+  CoglFramebufferBits bits;
+
+  ctx->driver_vtable->framebuffer_query_bits (framebuffer, &bits);
+
+  return bits.depth;
+}
+
 CoglColorMask
 cogl_framebuffer_get_color_mask (CoglFramebuffer *framebuffer)
 {

cogl/cogl-framebuffer.h

@@ -719,6 +719,20 @@ cogl_framebuffer_get_blue_bits (CoglFramebuffer *framebuffer);
 int
 cogl_framebuffer_get_alpha_bits (CoglFramebuffer *framebuffer);
 
+/**
+ * cogl_framebuffer_get_depth_bits:
+ * @framebuffer: a pointer to a #CoglFramebuffer
+ *
+ * Retrieves the number of depth bits of @framebuffer
+ *
+ * Return value: the number of bits
+ *
+ * Since: 2.0
+ * Stability: unstable
+ */
+int
+cogl_framebuffer_get_depth_bits (CoglFramebuffer *framebuffer);
+
 /**
  * cogl_framebuffer_get_dither_enabled:
  * @framebuffer: a pointer to a #CoglFramebuffer

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

@@ -920,6 +920,8 @@ _cogl_framebuffer_init_bits (CoglFramebuffer *framebuffer)
               offsetof (CoglFramebufferBits, blue) },
             { GL_COLOR_ATTACHMENT0, GL_FRAMEBUFFER_ATTACHMENT_ALPHA_SIZE,
               offsetof (CoglFramebufferBits, alpha) },
+            { GL_DEPTH_ATTACHMENT, GL_FRAMEBUFFER_ATTACHMENT_DEPTH_SIZE,
+              offsetof (CoglFramebufferBits, depth) },
           };
       int i;
 
@@ -940,11 +942,12 @@ _cogl_framebuffer_init_bits (CoglFramebuffer *framebuffer)
       GE( ctx, glGetIntegerv (GL_GREEN_BITS, &framebuffer->bits.green) );
       GE( ctx, glGetIntegerv (GL_BLUE_BITS,  &framebuffer->bits.blue)  );
       GE( ctx, glGetIntegerv (GL_ALPHA_BITS, &framebuffer->bits.alpha) );
+      GE( ctx, glGetIntegerv (GL_DEPTH_BITS, &framebuffer->bits.depth) );
     }
 
 
   COGL_NOTE (OFFSCREEN,
-             "RGBA Bits for framebuffer[%p, %s]: %d, %d, %d, %d",
+             "RGBA/D Bits for framebuffer[%p, %s]: %d, %d, %d, %d, %d",
              framebuffer,
              framebuffer->type == COGL_FRAMEBUFFER_TYPE_OFFSCREEN
                ? "offscreen"
@@ -952,7 +955,8 @@ _cogl_framebuffer_init_bits (CoglFramebuffer *framebuffer)
              framebuffer->bits.red,
              framebuffer->bits.blue,
              framebuffer->bits.green,
-             framebuffer->bits.alpha);
+             framebuffer->bits.alpha,
+             framebuffer->bits.depth);
 
   framebuffer->dirty_bitmasks = FALSE;
 }

doc/reference/cogl-2.0-experimental/cogl-2.0-experimental-sections.txt

@@ -511,6 +511,7 @@ cogl_framebuffer_get_red_bits
 cogl_framebuffer_get_green_bits
 cogl_framebuffer_get_blue_bits
 cogl_framebuffer_get_alpha_bits
+cogl_framebuffer_get_depth_bits
 cogl_framebuffer_get_color_mask
 cogl_framebuffer_set_color_mask
 cogl_framebuffer_get_samples_per_pixel