rt: started working on the tile-based rendering

diff --git a/src/scr/raytrace.c b/src/scr/raytrace.c
index bc9d654..ef6760a 100644 (file)
--- a/src/scr/raytrace.c
+++ b/src/scr/raytrace.c
@@ -21,7 +21,20 @@ static struct screen scr = {
        draw
 };
 
-static cgm_vec3 raydir[120][160];
+enum {LASTX = 1, LASTY = 2};
+
+struct tile {
+       int sz;
+       unsigned int flags;
+       struct { int x, y; } cpos[4];   /* corner coordinates */
+       uint16_t *cptr[4];      /* corner pixels */
+};
+
+#define TILESZ         8
+#define NUM_TILES      ((320 / TILESZ) * (240 / TILESZ))
+
+static cgm_vec3 raydir[240][320];
+static struct tile tiles[NUM_TILES];
 static struct rtscene scn;
 
 struct screen *raytrace_screen(void)
@@ -31,17 +44,39 @@ struct screen *raytrace_screen(void)
 
 static int init(void)
 {
-       int i, j;
+       int i, j, k;
        float z = 1.0f / tan(cgm_deg_to_rad(25.0f));
+       struct tile *tptr = tiles;
 
-       for(i=0; i<120; i++) {
+       for(i=0; i<240; i++) {
                cgm_vec3 *vptr = raydir[i];
-               float y = 1.0f - (float)i / 60.0f;
-               for(j=0; j<160; j++) {
-                       vptr->x = ((float)j / 80.0f - 1.0f) * 1.333333f;
+               float y = 1.0f - (float)i / 120.0f;
+               for(j=0; j<320; j++) {
+                       vptr->x = ((float)j / 160.0f - 1.0f) * 1.333333f;
                        vptr->y = y;
                        vptr->z = z;
                        vptr++;
+
+                       if(((j & (TILESZ-1)) | (i & (TILESZ-1))) == 0) {
+                               tptr->sz = TILESZ;
+                               tptr->flags = 0;
+                               if(j + TILESZ >= 320) tptr->flags |= LASTX;
+                               if(i + TILESZ >= 240) tptr->flags |= LASTY;
+
+                               tptr->cpos[0].x = j;
+                               tptr->cpos[0].y = i;
+                               tptr->cpos[1].x = j + (tptr->flags & LASTX ? TILESZ - 1 : TILESZ);
+                               tptr->cpos[1].y = i;
+                               tptr->cpos[2].x = j;
+                               tptr->cpos[2].y = i + (tptr->flags & LASTY ? TILESZ - 1 : TILESZ);
+                               tptr->cpos[3].x = tptr->cpos[1].x;
+                               tptr->cpos[3].y = tptr->cpos[2].y;
+
+                               for(k=0; k<4; k++) {
+                                       tptr->cptr[k] = fb_pixels + tptr->cpos[k].y * 320 + tptr->cpos[k].x;
+                               }
+                               tptr++;
+                       }
                }
        }
 
@@ -71,33 +106,48 @@ static void start(long start_time)
 {
 }
 
+static uint16_t INLINE rend_pixel(int x, int y)
+{
+       int r, g, b;
+       cgm_ray ray;
+       cgm_vec3 col;
+
+       ray.dir = raydir[y][x];
+       cgm_vcons(&ray.origin, 0, 0, -5);
+
+       if(ray_trace(&ray, &scn, 0, &col)) {
+               r = cround64(col.x * 255.0f);
+               g = cround64(col.y * 255.0f);
+               b = cround64(col.z * 255.0f);
+               if(r > 255) r = 255;
+               if(g > 255) g = 255;
+               if(b > 255) b = 255;
+               return PACK_RGB16(r, g, b);
+       }
+       return 0;
+}
+
+#define FBPTR(x, y)    (fb_pixels + ((y) << 8) + ((y) << 6) + (x))
+
 static void draw(void)
 {
-       int i, j, r, g, b;
-       uint16_t pix, *fbptr = fb_pixels;
-
-       for(i=0; i<120; i++) {
-               for(j=0; j<160; j++) {
-                       cgm_ray ray;
-                       cgm_vec3 col;
-                       ray.dir = raydir[i][j];
-                       cgm_vcons(&ray.origin, 0, 0, -5);
-
-                       if(ray_trace(&ray, &scn, 0, &col)) {
-                               r = cround64(col.x * 255.0f);
-                               g = cround64(col.y * 255.0f);
-                               b = cround64(col.z * 255.0f);
-                               if(r > 255) r = 255;
-                               if(g > 255) g = 255;
-                               if(b > 255) b = 255;
-                               pix = PACK_RGB16(r, g, b);
-                       } else {
-                               pix = 0;
+       int i, j, xbound, ybound;
+       uint16_t *fbptr;
+       struct tile *tptr;
+
+       tptr = tiles;
+       for(i=0; i<NUM_TILES; i++) {
+               *tptr->cptr[0] = rend_pixel(tptr->cpos[0].x, tptr->cpos[0].y);
+               if(tptr->flags & LASTX) {
+                       *tptr->cptr[1] = rend_pixel(tptr->cpos[1].x, tptr->cpos[1].y);
+                       if(tptr->flags & LASTY) {
+                               *tptr->cptr[3] = rend_pixel(tptr->cpos[3].x, tptr->cpos[3].y);
                        }
-                       fbptr[0] = fbptr[1] = fbptr[320] = fbptr[321] = pix;
-                       fbptr += 2;
                }
-               fbptr += 320;
+               if(tptr->flags & LASTY) {
+                       *tptr->cptr[2] = rend_pixel(tptr->cpos[2].x, tptr->cpos[2].y);
+               }
+               tptr++;
        }
 
        swap_buffers(0);