[cairo] [PATCH] cairo-gl: Make VBO size run-time settable

[Bryce W. Harrington]

Signed-off-by: Bryce Harrington <b.harrington at samsung.com>
---
 src/cairo-gl-composite.c |    2 +-
 src/cairo-gl-device.c    |    2 +-
 src/cairo-gl-info.c      |   22 ++++++++++++++++++++++
 src/cairo-gl-private.h   |    8 ++++++--
 4 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/src/cairo-gl-composite.c b/src/cairo-gl-composite.c
index 30b7931..65b0f26 100644
--- a/src/cairo-gl-composite.c
+++ b/src/cairo-gl-composite.c
@@ -875,7 +875,7 @@ _cairo_gl_composite_prepare_buffer (cairo_gl_context_t *ctx,
 	ctx->primitive_type = primitive_type;
     }
 
-    if (ctx->vb_offset + n_vertices * ctx->vertex_size > CAIRO_GL_VBO_SIZE)
+    if (ctx->vb_offset + n_vertices * ctx->vertex_size > _cairo_gl_get_vbo_size())
 	_cairo_gl_composite_flush (ctx);
 }
 
diff --git a/src/cairo-gl-device.c b/src/cairo-gl-device.c
index 054f145..dc2b6d6 100644
--- a/src/cairo-gl-device.c
+++ b/src/cairo-gl-device.c
@@ -297,7 +297,7 @@ _cairo_gl_context_init (cairo_gl_context_t *ctx)
     if (unlikely (status))
         return status;
 
-    ctx->vb = malloc (CAIRO_GL_VBO_SIZE);
+    ctx->vb = malloc (_cairo_gl_get_vbo_size());
     if (unlikely (ctx->vb == NULL)) {
 	    _cairo_cache_fini (&ctx->gradients);
 	    return _cairo_error (CAIRO_STATUS_NO_MEMORY);
diff --git a/src/cairo-gl-info.c b/src/cairo-gl-info.c
index 12a618d..c47033e 100644
--- a/src/cairo-gl-info.c
+++ b/src/cairo-gl-info.c
@@ -29,6 +29,8 @@
  *      Alexandros Frantzis <alexandros.frantzis at linaro.org>
  */
 
+#include <errno.h>
+
 #include "cairoint.h"
 #include "cairo-gl-private.h"
 
@@ -71,6 +73,26 @@ _cairo_gl_get_flavor (void)
     return flavor;
 }
 
+long
+_cairo_gl_get_vbo_size (void)
+{
+    static long vbo_size = -1;
+
+    if (vbo_size < 0) {
+        const char *env = getenv ("CAIRO_GL_VBO_SIZE");
+        if (env == NULL) {
+            vbo_size = CAIRO_GL_VBO_SIZE_DEFAULT;
+	} else {
+	    errno = 0;
+	    vbo_size = strtol (env, NULL, 10);
+	    assert (errno == 0);
+	    assert (vbo_size > 0);
+	}
+    }
+
+    return vbo_size;
+}
+
 cairo_bool_t
 _cairo_gl_has_extension (const char *ext)
 {
diff --git a/src/cairo-gl-private.h b/src/cairo-gl-private.h
index 8379abc..79b67a5 100644
--- a/src/cairo-gl-private.h
+++ b/src/cairo-gl-private.h
@@ -93,8 +93,9 @@
 
 /* VBO size that we allocate, smaller size means we gotta flush more often,
  * but larger means hogging more memory and can cause trouble for drivers
- * (especially on embedded devices). */
-#define CAIRO_GL_VBO_SIZE (16*1024)
+ * (especially on embedded devices). Use the CAIRO_GL_VBO_SIZE environment
+ * variable to set this to a different size. */
+#define CAIRO_GL_VBO_SIZE_DEFAULT (16*1024)
 
 typedef struct _cairo_gl_surface cairo_gl_surface_t;
 
@@ -702,6 +703,9 @@ _cairo_gl_get_version (void);
 cairo_private cairo_gl_flavor_t
 _cairo_gl_get_flavor (void);
 
+cairo_private long
+_cairo_gl_get_vbo_size (void);
+
 cairo_private cairo_bool_t
 _cairo_gl_has_extension (const char *ext);
 
-- 
1.7.9.5