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.

1 files changed, 62 insertions, 26 deletions

diff --git a/src/gallium/auxiliary/util/u_blit.c b/src/gallium/auxiliary/util/u_blit.c
index d28201ac8dc..2cef3338b5d 100644
--- a/src/gallium/auxiliary/util/u_blit.c
+++ b/src/gallium/auxiliary/util/u_blit.c
@@ -66,6 +66,8 @@ struct blit_state
    void *fs;
 
    struct pipe_buffer *vbuf;  /**< quad vertices */
+   unsigned vbuf_slot;
+
    float vertices[4][2][4];   /**< vertex/texcoords for quad */
 };
 
@@ -138,17 +140,7 @@ util_create_blit(struct pipe_context *pipe, struct cso_context *cso)
 
    /* fragment shader */
    ctx->fs = util_make_fragment_tex_shader(pipe, &ctx->frag_shader);
-
-   ctx->vbuf = pipe_buffer_create(pipe->screen,
-                                  32,
-                                  PIPE_BUFFER_USAGE_VERTEX,
-                                  sizeof(ctx->vertices));
-   if (!ctx->vbuf) {
-      FREE(ctx);
-      ctx->pipe->delete_fs_state(ctx->pipe, ctx->fs);
-      ctx->pipe->delete_vs_state(ctx->pipe, ctx->vs);
-      return NULL;
-   }
+   ctx->vbuf = NULL;
 
    /* init vertex data that doesn't change */
    for (i = 0; i < 4; i++) {
@@ -181,15 +173,35 @@ util_destroy_blit(struct blit_state *ctx)
 }
 
 
+static unsigned get_next_slot( struct blit_state *ctx )
+{
+   const unsigned max_slots = 4096 / sizeof ctx->vertices;
+
+   if (ctx->vbuf_slot >= max_slots) 
+      util_blit_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;
+}
+                               
+
+
 /**
  * Setup vertex data for the textured quad we'll draw.
  * Note: y=0=top
  */
-static void
+static unsigned
 setup_vertex_data(struct blit_state *ctx,
                   float x0, float y0, float x1, float y1, float z)
 {
    void *buf;
+   unsigned offset;
 
    ctx->vertices[0][0][0] = x0;
    ctx->vertices[0][0][1] = y0;
@@ -215,12 +227,16 @@ setup_vertex_data(struct blit_state *ctx,
    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;
 }
 
 
@@ -228,13 +244,14 @@ setup_vertex_data(struct blit_state *ctx,
  * Setup vertex data for the textured quad we'll draw.
  * Note: y=0=top
  */
-static void
+static unsigned
 setup_vertex_data_tex(struct blit_state *ctx,
                       float x0, float y0, float x1, float y1,
                       float s0, float t0, float s1, float t1,
                       float z)
 {
    void *buf;
+   unsigned offset;
 
    ctx->vertices[0][0][0] = x0;
    ctx->vertices[0][0][1] = y0;
@@ -260,12 +277,16 @@ setup_vertex_data_tex(struct blit_state *ctx,
    ctx->vertices[3][1][0] = s0;
    ctx->vertices[3][1][1] = t1;
 
+   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;
 }
 /**
  * Copy pixel block from src surface to dst surface.
@@ -291,6 +312,7 @@ util_blit_pixels(struct blit_state *ctx,
    const int srcH = abs(srcY1 - srcY0);
    const int srcLeft = MIN2(srcX0, srcX1);
    const int srcTop = MIN2(srcY0, srcY1);
+   unsigned offset;
 
    assert(filter == PIPE_TEX_MIPFILTER_NEAREST ||
           filter == PIPE_TEX_MIPFILTER_LINEAR);
@@ -398,11 +420,11 @@ util_blit_pixels(struct blit_state *ctx,
    cso_set_framebuffer(ctx->cso, &fb);
 
    /* draw quad */
-   setup_vertex_data(ctx,
-                     (float) dstX0, (float) dstY0, 
-                     (float) dstX1, (float) dstY1, z);
+   offset = setup_vertex_data(ctx,
+                              (float) dstX0, (float) dstY0, 
+                              (float) dstX1, (float) dstY1, z);
 
-   util_draw_vertex_buffer(ctx->pipe, ctx->vbuf,
+   util_draw_vertex_buffer(ctx->pipe, ctx->vbuf, offset,
                            PIPE_PRIM_TRIANGLE_FAN,
                            4,  /* verts */
                            2); /* attribs/vert */
@@ -421,6 +443,18 @@ util_blit_pixels(struct blit_state *ctx,
    screen->texture_release(screen, &tex);
 }
 
+
+/* Release vertex buffer at end of frame to avoid synchronous
+ * rendering.
+ */
+void util_blit_flush( struct blit_state *ctx )
+{
+   pipe_buffer_reference(ctx->pipe->screen, &ctx->vbuf, NULL);
+   ctx->vbuf_slot = 0;
+} 
+
+
+
 /**
  * Copy pixel block from src texture to dst surface.
  * Overlapping regions are acceptable.
@@ -442,6 +476,7 @@ util_blit_pixels_tex(struct blit_state *ctx,
    struct pipe_screen *screen = pipe->screen;
    struct pipe_framebuffer_state fb;
    float s0, t0, s1, t1;
+   unsigned offset;
 
    assert(filter == PIPE_TEX_MIPFILTER_NEAREST ||
           filter == PIPE_TEX_MIPFILTER_LINEAR);
@@ -496,13 +531,14 @@ util_blit_pixels_tex(struct blit_state *ctx,
    cso_set_framebuffer(ctx->cso, &fb);
 
    /* draw quad */
-   setup_vertex_data_tex(ctx,
-                     (float) dstX0, (float) dstY0,
-                     (float) dstX1, (float) dstY1,
-                     s0, t0, s1, t1,
-                     z);
-
-   util_draw_vertex_buffer(ctx->pipe, ctx->vbuf,
+   offset = setup_vertex_data_tex(ctx,
+                                  (float) dstX0, (float) dstY0,
+                                  (float) dstX1, (float) dstY1,
+                                  s0, t0, s1, t1,
+                                  z);
+
+   util_draw_vertex_buffer(ctx->pipe, 
+                           ctx->vbuf, offset,
                            PIPE_PRIM_TRIANGLE_FAN,
                            4,  /* verts */
                            2); /* attribs/vert */