softpipe: implement conditional rendering

src/gallium/drivers/softpipe/sp_clear.c

@@ -36,6 +36,7 @@
 #include "util/u_pack_color.h"
 #include "sp_clear.h"
 #include "sp_context.h"
+#include "sp_query.h"
 #include "sp_tile_cache.h"
 
 
@@ -55,6 +56,9 @@ softpipe_clear(struct pipe_context *pipe, unsigned buffers, const float *rgba,
    if (softpipe->no_rast)
       return;
 
+   if (!softpipe_check_render_cond(softpipe))
+      return;
+
 #if 0
    softpipe_update_derived(softpipe); /* not needed?? */
 #endif

src/gallium/drivers/softpipe/sp_context.c

@@ -176,6 +176,19 @@ softpipe_is_buffer_referenced( struct pipe_context *pipe,
 }
 
 
+static void
+softpipe_render_condition( struct pipe_context *pipe,
+                           struct pipe_query *query,
+                           uint mode )
+{
+   struct softpipe_context *softpipe = softpipe_context( pipe );
+
+   softpipe->render_cond_query = query;
+   softpipe->render_cond_mode = mode;
+}
+
+
+
 struct pipe_context *
 softpipe_create( struct pipe_screen *screen )
 {
@@ -252,6 +265,8 @@ softpipe_create( struct pipe_screen *screen )
 
    softpipe_init_query_funcs( softpipe );
 
+   softpipe->pipe.render_condition = softpipe_render_condition;
+
    /*
     * Alloc caches for accessing drawing surfaces and textures.
     * Must be before quad stage setup!

src/gallium/drivers/softpipe/sp_context.h

@@ -116,6 +116,10 @@ struct softpipe_context {
 
    unsigned line_stipple_counter;
 
+   /** Conditional query object and mode */
+   struct pipe_query *render_cond_query;
+   uint render_cond_mode;
+
    /** Software quad rendering pipeline */
    struct {
       struct quad_stage *shade;

src/gallium/drivers/softpipe/sp_draw_arrays.c

@@ -38,6 +38,7 @@
 #include "util/u_prim.h"
 
 #include "sp_context.h"
+#include "sp_query.h"
 #include "sp_state.h"
 
 #include "draw/draw_context.h"
@@ -122,6 +123,9 @@ softpipe_draw_range_elements(struct pipe_context *pipe,
    struct draw_context *draw = sp->draw;
    unsigned i;
 
+   if (!softpipe_check_render_cond(sp))
+      return TRUE;
+
    sp->reduced_api_prim = u_reduced_prim(mode);
 
    if (sp->dirty)

src/gallium/drivers/softpipe/sp_query.c

@@ -99,6 +99,32 @@ softpipe_get_query_result(struct pipe_context *pipe,
 }
 
 
+/**
+ * Called by rendering function to check rendering is conditional.
+ * \return TRUE if we should render, FALSE if we should skip rendering
+ */
+boolean
+softpipe_check_render_cond(struct softpipe_context *sp)
+{
+   struct pipe_context *pipe = &sp->pipe;
+   boolean b, wait;
+   uint64_t result;
+
+   if (!sp->render_cond_query) {
+      return TRUE;  /* no query predicate, draw normally */
+   }
+
+   wait = (sp->render_cond_mode == PIPE_RENDER_COND_WAIT ||
+           sp->render_cond_mode == PIPE_RENDER_COND_BY_REGION_WAIT);
+
+   b = pipe->get_query_result(pipe, sp->render_cond_query, wait, &result);
+   if (b)
+      return result > 0;
+   else
+      return TRUE;
+}
+
+
 void softpipe_init_query_funcs(struct softpipe_context *softpipe )
 {
    softpipe->pipe.create_query = softpipe_create_query;

src/gallium/drivers/softpipe/sp_query.h

@@ -32,6 +32,10 @@
 #ifndef SP_QUERY_H
 #define SP_QUERY_H
 
+extern boolean
+softpipe_check_render_cond(struct softpipe_context *sp);
+
+
 struct softpipe_context;
 extern void softpipe_init_query_funcs(struct softpipe_context * );