From d2c2e9316d043ab584794a3524f22776deb4c777 Mon Sep 17 00:00:00 2001
From: Keith Whitwell <keith@tungstengraphics.com>
Date: Fri, 12 Dec 2008 16:46:34 +0000
Subject: gallium: avoid mapping same vertex buffer in subsequent frames

Quite a few util modules were maintaining a single vertex buffer over multiple
frames, and potentially reusing it in subsequent frames.  Unfortunately that
would force us into syncrhonous rendering as the buffer manager would be
forced to wait for the previous rendering to complete prior to allowing the
map.

This resolves that issue, but requires the state tracker to issue a few new
flush() calls at the end of each frame.
---
 src/gallium/auxiliary/util/u_gen_mipmap.c | 51 +++++++++++++++++++++++++++----
 1 file changed, 45 insertions(+), 6 deletions(-)

(limited to 'src/gallium/auxiliary/util/u_gen_mipmap.c')

diff --git a/src/gallium/auxiliary/util/u_gen_mipmap.c b/src/gallium/auxiliary/util/u_gen_mipmap.c
index 9d305ad763..5f395ec6e9 100644
--- a/src/gallium/auxiliary/util/u_gen_mipmap.c
+++ b/src/gallium/auxiliary/util/u_gen_mipmap.c
@@ -69,6 +69,8 @@ struct gen_mipmap_state
    void *fs;
 
    struct pipe_buffer *vbuf;  /**< quad vertices */
+   unsigned vbuf_slot;
+
    float vertices[4][2][4];   /**< vertex/texcoords for quad */
 };
 
@@ -779,10 +781,28 @@ util_create_gen_mipmap(struct pipe_context *pipe,
 }
 
 
-static void
+static unsigned get_next_slot( struct gen_mipmap_state *ctx )
+{
+   const unsigned max_slots = 4096 / sizeof ctx->vertices;
+
+   if (ctx->vbuf_slot >= max_slots) 
+      util_gen_mipmap_flush( ctx );
+
+   if (!ctx->vbuf) {
+      ctx->vbuf = pipe_buffer_create(ctx->pipe->screen,
+                                     32,
+                                     PIPE_BUFFER_USAGE_VERTEX,
+                                     max_slots * sizeof ctx->vertices);
+   }
+   
+   return ctx->vbuf_slot++ * sizeof ctx->vertices;
+}
+
+static unsigned
 set_vertex_data(struct gen_mipmap_state *ctx, float width, float height)
 {
    void *buf;
+   unsigned offset;
 
    ctx->vertices[0][0][0] = 0.0f; /*x*/
    ctx->vertices[0][0][1] = 0.0f; /*y*/
@@ -804,12 +824,16 @@ set_vertex_data(struct gen_mipmap_state *ctx, float width, float height)
    ctx->vertices[3][1][0] = 0.0f;
    ctx->vertices[3][1][1] = 1.0f;
 
+   offset = get_next_slot( ctx );
+
    buf = pipe_buffer_map(ctx->pipe->screen, ctx->vbuf,
                          PIPE_BUFFER_USAGE_CPU_WRITE);
 
-   memcpy(buf, ctx->vertices, sizeof(ctx->vertices));
+   memcpy((char *)buf + offset, ctx->vertices, sizeof(ctx->vertices));
 
    pipe_buffer_unmap(ctx->pipe->screen, ctx->vbuf);
+
+   return offset;
 }
 
 
@@ -834,6 +858,17 @@ util_destroy_gen_mipmap(struct gen_mipmap_state *ctx)
 }
 
 
+
+/* Release vertex buffer at end of frame to avoid synchronous
+ * rendering.
+ */
+void util_gen_mipmap_flush( struct gen_mipmap_state *ctx )
+{
+   pipe_buffer_reference(ctx->pipe->screen, &ctx->vbuf, NULL);
+   ctx->vbuf_slot = 0;
+} 
+
+
 /**
  * Generate mipmap images.  It's assumed all needed texture memory is
  * already allocated.
@@ -855,6 +890,7 @@ util_gen_mipmap(struct gen_mipmap_state *ctx,
    struct pipe_framebuffer_state fb;
    uint dstLevel;
    uint zslice = 0;
+   uint offset;
 
    /* check if we can render in the texture's format */
    if (!screen->is_format_supported(screen, pt->format, PIPE_TEXTURE_2D,
@@ -925,10 +961,13 @@ util_gen_mipmap(struct gen_mipmap_state *ctx,
       cso_set_sampler_textures(ctx->cso, 1, &pt);
 
       /* quad coords in window coords (bypassing clipping, viewport mapping) */
-      set_vertex_data(ctx,
-                      (float) pt->width[dstLevel],
-                      (float) pt->height[dstLevel]);
-      util_draw_vertex_buffer(ctx->pipe, ctx->vbuf,
+      offset = set_vertex_data(ctx,
+                               (float) pt->width[dstLevel],
+                               (float) pt->height[dstLevel]);
+
+      util_draw_vertex_buffer(ctx->pipe, 
+                              ctx->vbuf,
+                              offset,
                               PIPE_PRIM_TRIANGLE_FAN,
                               4,  /* verts */
                               2); /* attribs/vert */
-- 
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