lossy RLE for apple

1 files changed, 77 insertions, 42 deletions

diff --git a/user/apple.c b/user/apple.c
index a0a7e9a..578a075 100644
--- a/user/apple.c
+++ b/user/apple.c
@@ -1,62 +1,81 @@
-
 #include <incbin.h>
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 #include <unistd.h>
 
 INCBIN(APPLE, "data/apple.bin");
 
-#define APPLE_WIDTH 256
-#define APPLE_HEIGHT 144
-#define APPLE_FPS 12
-#define APPLE_FRAMES 2630
+#define APPLE_WIDTH 480
+#define APPLE_HEIGHT 360
+#define APPLE_FPS 30
+#define APPLE_FRAMES 6572
+#define VSYNC_FPS 60
 
 #define MIN(a, b) (((a) < (b)) ? (a) : (b))
 
 // returned from drm
 static uint32_t *fb;
 static int width, height, bpp, scale;
+size_t fb_size;
 
-// meta
-static size_t frame = 0;
-static size_t frame_size;
-static size_t ticks_off;
+// decompress state
+static size_t d_offset = 0, d_length = 0;
+static unsigned char d_value;
 
-#define PIXEL(x, y)                                         \
-	gAPPLEData[offset +                                     \
-			   (((x + APPLE_WIDTH % APPLE_WIDTH) / scale) + \
-				((y + APPLE_HEIGHT % APPLE_HEIGHT) / scale) * APPLE_WIDTH)]
+// frame counter
+static size_t last_frame = SIZE_MAX, frame = 0;
 
-static void draw_frame(void)
-{
-	size_t offset = frame_size * frame;
+// frame buffer
+static unsigned char frame_buf[APPLE_WIDTH * APPLE_HEIGHT];
 
-	for (int y = 0; y < APPLE_HEIGHT * scale; y++) {
-		for (int x = 0; x < APPLE_WIDTH * scale; x++) {
-			uint8_t colors[9];
-			colors[0] = PIXEL(x, y);
-			colors[1] = PIXEL(x - 1, y);
-			colors[2] = PIXEL(x + 1, y);
-			colors[3] = PIXEL(x, y - 1);
-			colors[4] = PIXEL(x - 1, y - 1);
-			colors[5] = PIXEL(x + 1, y - 1);
-			colors[6] = PIXEL(x, y + 1);
-			colors[7] = PIXEL(x - 1, y + 1);
-			colors[8] = PIXEL(x + 1, y + 1);
+// backbuffer
+static uint32_t *back_fb;
 
-			// anti aliasing
-			uint8_t color = (colors[0] + colors[0] + colors[0] + colors[0] +
-							 colors[1] + colors[2] + colors[3] + colors[4] +
-							 colors[5] + colors[6] + colors[7] + colors[8]) /
-							12;
+// start tick
+static size_t tick_start;
 
-			fb[x + y * width] = (color << 16) | (color << 8) | (color << 0);
-		}
+static unsigned char read_byte(void)
+{
+	while (d_length < 1) {
+		unsigned char len;
+
+		d_length = 0;
+		do {
+			len = gAPPLEData[d_offset++];
+			d_length += len;
+		} while (len == 255);
+		d_value = gAPPLEData[d_offset++];
 	}
 
-	frame = ((ticks() - ticks_off) / (1000 / APPLE_FPS));
+	d_length--;
+	return d_value;
+}
 
-	if (frame >= APPLE_FRAMES)
-		exit(0);
+static void read_frame(void)
+{
+	for (size_t i = 0; i < sizeof(frame_buf); i++)
+		frame_buf[i] = read_byte();
+}
+
+static void swap_buffers(void)
+{
+	// terrible :3
+	uint32_t count = width * height / 2;
+	__asm__ volatile("rep movsq" ::"S"(back_fb), "D"(fb), "c"(count)
+					 : "memory");
+}
+
+static void draw_frame(void)
+{
+	for (int y = 0; y < APPLE_HEIGHT * scale; y++) {
+		for (int x = 0; x < APPLE_WIDTH * scale; x++) {
+			unsigned char color =
+				frame_buf[(x / scale) + (y / scale) * APPLE_WIDTH];
+			back_fb[x + y * width] = (color << 16) | (color << 8) |
+									 (color << 0);
+		}
+	}
 }
 
 int main(void)
@@ -68,12 +87,28 @@ int main(void)
 		return 1;
 	}
 
-	ticks_off = ticks();
-	frame_size = APPLE_WIDTH * APPLE_HEIGHT;
+	fb_size = (width * height * bpp) / 8;
+	back_fb = malloc(fb_size);
+	if (back_fb == NULL) {
+		fprintf(stderr, "failure but 2\n");
+		return 1;
+	}
+
+	tick_start = ticks();
 	scale = MIN(width / APPLE_WIDTH, height / APPLE_HEIGHT);
 
-	while (1)
-		draw_frame();
+	while (1) {
+		if (last_frame != frame) {
+			read_frame();
+			draw_frame();
+			swap_buffers();
+		}
+
+		last_frame = frame;
+		frame = ((ticks() - tick_start) / (1000 / APPLE_FPS));
+		if (frame >= APPLE_FRAMES)
+			break;
+	}
 
 	return 0;
 }