[WIP] Update screen update/refresh to avoid forking

2 files changed, 46 insertions, 127 deletions

diff --git a/src/main.c b/src/main.c
index 53aa5c3..f2d373b 100644
--- a/src/main.c
+++ b/src/main.c
@@ -523,7 +523,8 @@ main(int argc, char *argv[]) {
 
     // Main loop.
     Time frame_time = time_now();
-    size_t frames = 0;
+    size_t frames_update = 0;
+    size_t frames_refresh = 0;
     while (true) {
         poll_input();
         size_t elapsed = time_elapsed(frame_time);
@@ -535,26 +536,18 @@ main(int argc, char *argv[]) {
 
             // Blit ppu.pixels to the framebuffer.
             blit_framebuffer();
-            if (++frames > 5) {
-                // memset(framebuffer, 0xFF, screen_width * screen_height * bpp);
-                // system("echo 0 > /dev/graphics/fb0");
-                // redraw_screen();
-                // blit_framebuffer();
-
-                // FIXME: Thre HAS to be a better way to refresh the display lol.
-                system("echo 0 > /dev/graphics/fb0");
-
-                // Time t = time_now();
-                // while (time_elapsed(t) < 16666666 * 2) {
-                //     // nop wait X frames for the refresh?
-                // }
-                // wait(ret);
-                // memset(framebuffer, 0xFF, screen_width * screen_height * bpp);
-                // redraw_screen();
-                // memset(framebuffer, 0x00, screen_width * screen_height * bpp);
-                // redraw_screen();
-
-                frames = 0;
+            // TODO: make update frames and refresh frames as parameters instead
+            // of hardcoded
+            if (++frames_update > 5) {
+                write(fb_file, "0", 0);
+                frames_update = 0;
+            }
+            // NOTE: Maybe this should happen on blit_framebuffer depending on
+            // the number of actual updates (uxn applications that don't modify
+            // the framebuffer shouldn't have to blink).
+            if (++frames_refresh > 360) {
+                write(refresh_file, "1", 1);
+                frames_refresh = 0;
             }
             frame_time = time_now();
         }
@@ -562,95 +555,3 @@ main(int argc, char *argv[]) {
 
     return 0;
 }
-
-// int
-// main(int argc, char *argv[]) {
-//     // FIXME: Experimental
-//     int fb = open("/dev/graphics/fb0", O_RDWR);
-//     if (fb <= 0) {
-//         fprintf(stderr, "error: couldn't open the framebuffer\n");
-//         exit(EXIT_FAILURE);
-//     }
-//     struct fb_var_screeninfo info;
-//     if (ioctl(fb, FBIOGET_VSCREENINFO, &info) != 0) {
-//         fprintf(stderr, "error: couldn't get the framebuffer size\n");
-//         exit(EXIT_FAILURE);
-//     }
-//     size_t screen_width = info.xres;
-//     size_t screen_height = info.yres;
-//     size_t bpp = info.bits_per_pixel / 8;
-//     size_t len = bpp * screen_width * screen_height;
-//     u8 *framebuffer = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED, fb, 0);
-//     if (framebuffer == MAP_FAILED) {
-//         fprintf(stderr, "error: couldn't mmap the framebuffer\n");
-//         exit(EXIT_FAILURE);
-//     }
-
-//     // Print all relevant elements from the fb_var_screeninfo struct
-//     printf("> xres: %d\n"
-//            "> yres: %d\n"
-//            "> xres_virtual: %d\n"
-//            "> yres_virtual: %d\n"
-//            "> xoffset: %d\n"
-//            "> yoffset: %d\n"
-//            "> bits_per_pixel: %d\n"
-//            "> grayscale: %d\n"
-//            "> activate: %d\n"
-//            "> height: %d\n"
-//            "> width: %d\n"
-//            "> hsync_len: %d\n"
-//            "> vsync_len: %d\n"
-//            "> sync: %d\n"
-//            "> vmode: %d\n"
-//            "> rotate: %d\n"
-//            "> len:  %d\n",
-//            info.xres,
-//            info.yres,
-//            info.xres_virtual,
-//            info.yres_virtual,
-//            info.xoffset,
-//            info.yoffset,
-//            info.bits_per_pixel,
-//            info.grayscale,
-//            info.activate,
-//            info.height,
-//            info.width,
-//            info.hsync_len,
-//            info.vsync_len,
-//            info.sync,
-//            info.vmode,
-//            info.rotate,
-//            len);
-
-
-//     // Clean screen
-//     // memset(framebuffer, 0x00, screen_width * screen_height * 2); // black
-//     memset(framebuffer, 0xFF, len); // white
-//     for (size_t i = 0, k = 0; i < (screen_width * screen_height) / 2; i++) {
-//         for (size_t b = 0; b < bpp; b++) {
-//             framebuffer[k++] = 0xF0;
-//         }
-//         // p[i] = 0xF0F0;
-//         // framebuffer[k++] = 0xFF;
-//         // framebuffer[k++] = 0x00;
-//     }
-
-//     // Main loop.
-//     Time frame_time = time_now();
-//     size_t frames = 0;
-//     while (true) {
-//         size_t elapsed = time_elapsed(frame_time);
-//         if (elapsed >= 16666666) {
-
-//             // FIXME: Thre HAS to be a better way lol.
-//             frame_time = time_now();
-//             frames++;
-//             if (frames > 10) {
-//                 system("echo 0 > /dev/graphics/fb0");
-//                 frames = 0;
-//             }
-//         }
-//     }
-
-//     return 0;
-// }
diff --git a/src/ppu.c b/src/ppu.c
index 175b2a7..3afa533 100644
--- a/src/ppu.c
+++ b/src/ppu.c
@@ -25,6 +25,8 @@
 static size_t screen_width = 0;
 static size_t screen_height = 0;
 static size_t bpp = 0;
+static int fb_file = 0;
+static int refresh_file = 0;
 
 static u8 *framebuffer = 0;
 
@@ -45,10 +47,13 @@ static u8 blending[5][16] = {
 
 u16
 rgb565(u32 rgba) {
-    u16 r = rgba >> 16  & 0xFF;
-    u16 g = rgba >> 8   & 0xFF;
-    u16 b = rgba >> 0   & 0xFF;
-    return (r << 8) | (g << 3) | (b >> 3);
+    u16 r = (rgba >> 16  & 0xFF);
+    u16 g = (rgba >> 8   & 0xFF);
+    u16 b = (rgba >> 0   & 0xFF);
+    r = r >> 3;
+    g = g >> 2;
+    b = b >> 3;
+    return (r << 11) | (g << 5) | b;
 }
 
 void
@@ -142,13 +147,20 @@ set_tty(bool graphics) {
 int
 ppu_init(void) {
     // Open frambuffer and get the size.
-    int fb = open("/dev/graphics/fb0", O_RDWR);
-    if (fb <= 0) {
+    fb_file = open("/dev/graphics/fb0", O_RDWR);
+    if (fb_file <= 0) {
         fprintf(stderr, "error: couldn't open the framebuffer\n");
         exit(EXIT_FAILURE);
     }
+
+    refresh_file = open("/sys/class/graphics/fb0/epd_refresh", O_RDWR);
+    if (refresh_file == 0) {
+        fprintf(stderr, "error: couldn't open the refresh file\n");
+        exit(EXIT_FAILURE);
+    }
+
     struct fb_var_screeninfo info;
-    if (ioctl(fb, FBIOGET_VSCREENINFO, &info) != 0) {
+    if (ioctl(fb_file, FBIOGET_VSCREENINFO, &info) != 0) {
         fprintf(stderr, "error: couldn't get the framebuffer size\n");
         exit(EXIT_FAILURE);
     }
@@ -156,9 +168,9 @@ ppu_init(void) {
     // Mmap the framebuffer to a buffer object.
     screen_width = info.xres;
     screen_height = info.yres;
-    bpp = info.bits_per_pixel / 8;
-    size_t len = bpp * screen_width * screen_height;
-    framebuffer = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED, fb, 0);
+    bpp = info.bits_per_pixel;
+    size_t len = bpp / 8 * screen_width * screen_height;
+    framebuffer = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED, fb_file, 0);
     if (framebuffer == MAP_FAILED) {
         fprintf(stderr, "error: couldn't mmap the framebuffer\n");
         exit(EXIT_FAILURE);
@@ -208,10 +220,16 @@ blit_framebuffer(void) {
         if (dirty_lines[j] != 0) {
             for (size_t i = 0; i < screen_width; i++) {
                 size_t idx = i + j * screen_width;
-                u16 *p = framebuffer;
-                p[idx] = rgb565(palette[pixels_fg[idx] << 2 | pixels_bg[idx]]);
-                // FIXME: can we generalize this to use bpp instead of having
-                // a version for 32/16 bit color?
+                if (bpp == 16) {
+                    u16 *p = framebuffer;
+                    p[idx] = rgb565(palette[pixels_fg[idx] << 2 | pixels_bg[idx]]);
+                } else if (bpp == 32) {
+                    u32 *p = framebuffer;
+                    p[idx] = palette[pixels_fg[idx] << 2 | pixels_bg[idx]];
+                } else {
+                    fprintf(stderr, "error: wrong bits per pixel (expected 16 or 32)\n");
+                    exit(EXIT_FAILURE);
+                }
             }
         }
         dirty_lines[j] = 0;