st/dri2: Implement DRI2bufferDamageExtension

Add a pipe_screen->set_damage_region() hook to propagate
set-damage-region requests to the driver, it's then up to the driver to
decide what to do with this piece of information.

If the hook is left unassigned, the buffer-damage extension is
considered unsupported.

Signed-off-by: Daniel Stone <daniels@collabora.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: Qiang Yu <yuq825@gmail.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>

src/gallium/include/pipe/p_screen.h

@@ -474,6 +474,23 @@ struct pipe_screen {
    bool (*is_parallel_shader_compilation_finished)(struct pipe_screen *screen,
                                                    void *shader,
                                                    unsigned shader_type);
+
+   /**
+    * Set the damage region (called when KHR_partial_update() is invoked).
+    * This function is passed an array of rectangles encoding the damage area.
+    * rects are using the bottom-left origin convention.
+    * nrects = 0 means 'reset the damage region'. What 'reset' implies is HW
+    * specific. For tile-based renderers, the damage extent is typically set
+    * to cover the whole resource with no damage rect (or a 0-size damage
+    * rect). This way, the existing resource content is reloaded into the
+    * local tile buffer for every tile thus making partial tile update
+    * possible. For HW operating in immediate mode, this reset operation is
+    * likely to be a NOOP.
+    */
+   void (*set_damage_region)(struct pipe_screen *screen,
+                             struct pipe_resource *resource,
+                             unsigned int nrects,
+                             const struct pipe_box *rects);
 };
 
 

src/gallium/state_trackers/dri/dri2.c

@@ -1847,6 +1847,36 @@ static const __DRI2interopExtension dri2InteropExtension = {
    .export_object = dri2_interop_export_object
 };
 
+/**
+ * \brief the DRI2bufferDamageExtension set_damage_region method
+ */
+static void
+dri2_set_damage_region(__DRIdrawable *dPriv, unsigned int nrects, int *rects)
+{
+   struct dri_drawable *drawable = dri_drawable(dPriv);
+   struct pipe_resource *resource = drawable->textures[ST_ATTACHMENT_BACK_LEFT];
+   struct pipe_screen *screen = resource->screen;
+   struct pipe_box *boxes = NULL;
+
+   if (nrects) {
+      boxes = CALLOC(nrects, sizeof(*boxes));
+      assert(boxes);
+
+      for (unsigned int i = 0; i < nrects; i++) {
+         int *rect = &rects[i * 4];
+
+         u_box_2d(rect[0], rect[1], rect[2], rect[3], &boxes[i]);
+      }
+   }
+
+   screen->set_damage_region(screen, resource, nrects, boxes);
+   FREE(boxes);
+}
+
+static __DRI2bufferDamageExtension dri2BufferDamageExtension = {
+   .base = { __DRI2_BUFFER_DAMAGE, 1 },
+};
+
 /**
  * \brief the DRI2ConfigQueryExtension configQueryb method
  */
@@ -1948,6 +1978,7 @@ static const __DRIextension *dri_screen_extensions[] = {
    &dri2GalliumConfigQueryExtension.base,
    &dri2ThrottleExtension.base,
    &dri2FenceExtension.base,
+   &dri2BufferDamageExtension.base,
    &dri2InteropExtension.base,
    &dri2NoErrorExtension.base,
    &driBlobExtension.base,
@@ -1963,6 +1994,7 @@ static const __DRIextension *dri_robust_screen_extensions[] = {
    &dri2ThrottleExtension.base,
    &dri2FenceExtension.base,
    &dri2InteropExtension.base,
+   &dri2BufferDamageExtension.base,
    &dri2Robustness.base,
    &dri2NoErrorExtension.base,
    &driBlobExtension.base,
@@ -2025,6 +2057,9 @@ dri2_init_screen(__DRIscreen * sPriv)
       }
    }
 
+   if (pscreen->set_damage_region)
+      dri2BufferDamageExtension.set_damage_region = dri2_set_damage_region;
+
    if (pscreen->get_param(pscreen, PIPE_CAP_DEVICE_RESET_STATUS_QUERY)) {
       sPriv->extensions = dri_robust_screen_extensions;
       screen->has_reset_status_query = true;