Changeset 684 for soft

Timestamp:

Aug 3, 2015, 7:07:03 PM (9 years ago)

Author:

guerin

Message:

raycast: mirror textures

Mirror textures internally to use cache more efficiently. Instead of
accessing columns, we are now accessing rows which are contiguous.

2453934 -> 2364988 cycles/frame (-3.7%) w/ 4 cpus, 512x512

File:

• soft/giet_vm/applications/raycast/disp.c (modified) (7 diffs)

soft/giet_vm/applications/raycast/disp.c

@@ -34 +34 @@
 // Local functions
 
-static void dispDrawColumnTex(int x, int y0, int y1, unsigned char *tex, int tx)
+static void dispDrawColumnTex(int x, int y0, int y1, unsigned char *line)
 {
     int y;
@@ -47 +47 @@
         int ty = (y - y0) * TEX_SIZE / (y1 - y0);
 
-        buf[cur_buf][y * FBUF_X_SIZE + x] = tex[ty * TEX_SIZE + tx];
+        buf[cur_buf][y * FBUF_X_SIZE + x] = line[ty];
     }
 }
@@ -66 +66 @@
 }
 
-static void dispDrawSlice(Game *game, int x, int height, int type, float tx)
+static void dispDrawSlice(Game *game, int x, int height, int type, int tx)
 {
     // Ceiling
@@ -82 +82 @@
                           (FBUF_Y_SIZE - height) / 2,
                           (FBUF_Y_SIZE + height) / 2,
-                          tex,
-                          (int)(tx * TEX_SIZE));
+                          &tex[tx * TEX_SIZE]);
     }
     else {
@@ -172 +171 @@
 }
 
+static void dispMirror(unsigned char *buf, unsigned int size)
+{
+    int i, j;
+    unsigned char pixel;
+
+    for (i = 0; i < size; i++) {
+        for (j = i + 1; j < size; j++) {
+            int ai = i * size + j;
+            int bi = j * size + i;
+
+            pixel = buf[ai];
+            buf[ai] = buf[bi];
+            buf[bi] = pixel;
+        }
+    }
+}
+
 static unsigned char *dispLoadTexture(char *path)
 {
@@ -186 +202 @@
     giet_fat_read(fd, tex, TEX_SIZE * TEX_SIZE);
     giet_fat_close(fd);
+
+    dispMirror(tex, TEX_SIZE);
+
     giet_tty_printf("[RAYCAST] loaded tex %s\n", path);
 
@@ -253 +272 @@
 
     // Draw ceiling, wall and floor
-    dispDrawSlice(game, x, FBUF_Y_SIZE / dist, type, tx);
+    dispDrawSlice(game, x, FBUF_Y_SIZE / dist, type, tx * TEX_SIZE);
 
     // Signal this slice is done