From 94f6c88dab4fe62d3953968a0b987c2813a5758a Mon Sep 17 00:00:00 2001
From: Hiemanshu Sharma <hiemanshu@gmail.com>
Date: Wed, 21 Nov 2012 11:25:22 -0600
Subject: graphics: add support for "single buffering"

---
 minuitwrp/graphics.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

(limited to 'minuitwrp')

diff --git a/minuitwrp/graphics.c b/minuitwrp/graphics.c
index b30a92ef0..357639201 100644
--- a/minuitwrp/graphics.c
+++ b/minuitwrp/graphics.c
@@ -66,6 +66,7 @@ static GGLSurface gr_font_texture;
 static GGLSurface gr_framebuffer[2];
 static GGLSurface gr_mem_surface;
 static unsigned gr_active_fb = 0;
+static unsigned double_buffering = 0;
 
 static int gr_fb_fd = -1;
 static int gr_vt_fd = -1;
@@ -199,6 +200,12 @@ static int get_framebuffer(GGLSurface *fb)
 
     fb++;
 
+    /* check if we can use double buffering */
+    if (vi.yres * fi.line_length * 2 > fi.smem_len)
+        return fd;
+
+    double_buffering = 1;
+
     fb->version = sizeof(*fb);
     fb->width = vi.xres;
     fb->height = vi.yres;
@@ -230,7 +237,7 @@ static void get_memory_surface(GGLSurface* ms) {
 
 static void set_active_framebuffer(unsigned n)
 {
-    if (n > 1) return;
+    if (n > 1  || !double_buffering) return;
     vi.yres_virtual = vi.yres * 2;
     vi.yoffset = n * vi.yres;
 //    vi.bits_per_pixel = PIXEL_SIZE * 8;
@@ -244,7 +251,8 @@ void gr_flip(void)
     GGLContext *gl = gr_context;
 
     /* swap front and back buffers */
-    gr_active_fb = (gr_active_fb + 1) & 1;
+    if (double_buffering)
+        gr_active_fb = (gr_active_fb + 1) & 1;
 
 #ifdef BOARD_HAS_FLIPPED_SCREEN
     /* flip buffer 180 degrees for devices with physicaly inverted screens */
-- 
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