[Mesa-dev] [PATCH 02/14] gallium: Obtain ARB_framebuffer_no_attachment constants

[Edward O'Callaghan]

Set default values for the constants required in
ARB_framebuffer_no_attachments and obtained the number
of layers from ``PIPE_CAP_MAX_TEXTURE_ARRAY_LAYERS``.

We also obtain the MaxFramebufferSamples value using
a query back to the driver for PIPE_FORMAT_NONE.

V.1:
 Merge if branch predicates into one branch.
 Move const init into st_init_limits()

Signed-off-by: Edward O'Callaghan <eocallaghan at alterapraxis.com>
---
 src/mesa/state_tracker/st_extensions.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/src/mesa/state_tracker/st_extensions.c b/src/mesa/state_tracker/st_extensions.c
index 44d93e3..0d55fe6 100644
--- a/src/mesa/state_tracker/st_extensions.c
+++ b/src/mesa/state_tracker/st_extensions.c
@@ -445,6 +445,18 @@ void st_init_limits(struct pipe_screen *screen,
       extensions->ARB_shader_image_load_store = GL_TRUE;
       extensions->ARB_shader_image_size = GL_TRUE;
    }
+
+   /* ARB_framebuffer_no_attachments */
+   c->MaxFramebufferWidth   = c->MaxViewportWidth;
+   c->MaxFramebufferHeight  = c->MaxViewportHeight;
+   /* NOTE: we cheat here a little by assuming that
+    * PIPE_CAP_MAX_TEXTURE_ARRAY_LAYERS has the same
+    * number of layers as we need, although we technically
+    * could have more the generality is not really useful
+    * in practicality.
+    */
+   c->MaxFramebufferLayers =
+      screen->get_param(screen, PIPE_CAP_MAX_TEXTURE_ARRAY_LAYERS);
 }
 
 
@@ -939,6 +951,9 @@ void st_init_extensions(struct pipe_screen *screen,
       enum pipe_format int_formats[] = {
          PIPE_FORMAT_R8G8B8A8_SINT
       };
+      enum pipe_format void_formats[] = {
+         PIPE_FORMAT_NONE
+      };
 
       consts->MaxSamples =
          get_max_samples_for_formats(screen, ARRAY_SIZE(color_formats),
@@ -959,6 +974,12 @@ void st_init_extensions(struct pipe_screen *screen,
          get_max_samples_for_formats(screen, ARRAY_SIZE(int_formats),
                                      int_formats, consts->MaxSamples,
                                      PIPE_BIND_SAMPLER_VIEW);
+
+      /* ARB_framebuffer_no_attachments, assume max no. of samples 32 */
+      consts->MaxFramebufferSamples =
+         get_max_samples_for_formats(screen, ARRAY_SIZE(void_formats),
+                                     void_formats, 32,
+                                     PIPE_BIND_RENDER_TARGET);
    }
    if (consts->MaxSamples == 1) {
       /* one sample doesn't really make sense */
@@ -1045,6 +1066,13 @@ void st_init_extensions(struct pipe_screen *screen,
          extensions->AMD_vertex_shader_viewport_index = GL_TRUE;
    }
 
+   /* ARB_framebuffer_no_attachments */
+   if ( (screen->get_param(screen, PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT)) &&
+       ((consts->MaxSamples >= 4 && consts->MaxFramebufferLayers >= 2048) ||
+        (consts->MaxFramebufferSamples >= consts->MaxSamples &&
+          consts->MaxFramebufferLayers  >= consts->MaxArrayTextureLayers)) )
+      extensions->ARB_framebuffer_no_attachments = GL_TRUE;
+
    /* GL_ARB_ES3_compatibility.
     *
     * Assume that ES3 is supported if GLSL 3.30 is supported.
-- 
2.5.5