i think this is less code maybe but also it doesn't work

readme.md

@@ -16,3 +16,10 @@ make all
 ```
 
 the gameboy rom will be output to `obj/untitled2dshooter.gb`
+
+
+## credits
+
+### art
+
+a cool guy named louie - drew mike

res/sprite_metadata.c

@@ -23,10 +23,10 @@ Sprite sprites_info[] = {
 			},
 		.bitmap_indexes[SI_DOWN] = 12, .bitmap_prop[SI_DOWN] = S_FLIPY,
 			.collision_offset[SI_DOWN] = {
-				.itl = { .x = 8, .y = 8},
-				.itr = { .x = 5, .y = 8},
-				.ibl = { .x = 8, .y = 1},
-				.ibr = { .x = 5, .y = 1},
+				.itl = { .x = 3, .y = 8},
+				.itr = { .x = 1, .y = 8},
+				.ibl = { .x = 3, .y = 1},
+				.ibr = { .x = 1, .y = 1},
 			},
 		.bitmap_indexes[SI_LEFT] = 11, .bitmap_prop[SI_LEFT] = 0,
 			.collision_offset[SI_LEFT] = {
@@ -70,5 +70,141 @@ Sprite sprites_info[] = {
 				.ibl = { .x = 7, .y = 1},
 				.ibr = { .x = 1, .y = 1},
 			}
+	},
+	{
+		.frames_since_last_dash = 0,
+		.frames_since_last_jump = 0,
+		.name = "dodgy_hat_guy",
+		.has_diag_sprites = 0,
+		.bitmap_index = SI_LEFT,
+		.has_joypad = 0,
+		.pos = { .x = 0, .y = 0},
+		.vel = { .x = 0, .y = 0},
+		.acc = { .x = 0, .y = 0},
+
+		.bitmap_indexes[SI_UP] = 14, .bitmap_prop[SI_UP] = 0,
+			.collision_offset[SI_UP] = {
+				.itl = { .x = 8, .y = 8},
+				.itr = { .x = 1, .y = 8},
+				.ibl = { .x = 8, .y = 1},
+				.ibr = { .x = 1, .y = 1},
+			},
+		.bitmap_indexes[SI_DOWN] = 15, .bitmap_prop[SI_DOWN] = 0,
+			.collision_offset[SI_DOWN] = {
+				.itl = { .x = 8, .y = 8},
+				.itr = { .x = 1, .y = 8},
+				.ibl = { .x = 8, .y = 1},
+				.ibr = { .x = 1, .y = 1},
+			},
+		.bitmap_indexes[SI_LEFT] = 14, .bitmap_prop[SI_LEFT] = 0,
+			.collision_offset[SI_LEFT] = {
+				.itl = { .x = 8, .y = 8},
+				.itr = { .x = 1, .y = 8},
+				.ibl = { .x = 8, .y = 1},
+				.ibr = { .x = 1, .y = 1},
+			},
+		.bitmap_indexes[SI_RIGHT] = 14, .bitmap_prop[SI_RIGHT] = S_FLIPX,
+			.collision_offset[SI_RIGHT] = {
+				.itl = { .x = 8, .y = 8},
+				.itr = { .x = 1, .y = 8},
+				.ibl = { .x = 8, .y = 1},
+				.ibr = { .x = 1, .y = 1},
+			},
+		.bitmap_indexes[SI_UP_RIGHT] = 14, .bitmap_prop[SI_UP_RIGHT] = 0,
+			.collision_offset[SI_UP_RIGHT] = {
+				.itl = { .x = 8, .y = 8},
+				.itr = { .x = 1, .y = 8},
+				.ibl = { .x = 8, .y = 1},
+				.ibr = { .x = 1, .y = 1},
+			},
+		.bitmap_indexes[SI_UP_LEFT] = 14, .bitmap_prop[SI_UP_LEFT] = S_FLIPX,
+			.collision_offset[SI_UP_LEFT] = {
+				.itl = { .x = 8, .y = 8},
+				.itr = { .x = 1, .y = 8},
+				.ibl = { .x = 8, .y = 1},
+				.ibr = { .x = 1, .y = 1},
+			},
+		.bitmap_indexes[SI_DOWN_LEFT] = 15, .bitmap_prop[SI_DOWN_LEFT] = 0,
+			.collision_offset[SI_DOWN_LEFT] = {
+				.itl = { .x = 8, .y = 8},
+				.itr = { .x = 1, .y = 8},
+				.ibl = { .x = 8, .y = 1},
+				.ibr = { .x = 1, .y = 1},
+			},
+		.bitmap_indexes[SI_DOWN_RIGHT] = 15, .bitmap_prop[SI_DOWN_RIGHT] = S_FLIPX,
+			.collision_offset[SI_DOWN_RIGHT] = {
+				.itl = { .x = 8, .y = 8},
+				.itr = { .x = 1, .y = 8},
+				.ibl = { .x = 8, .y = 1},
+				.ibr = { .x = 1, .y = 1},
+			}
+	},
+	{
+		.frames_since_last_dash = 0,
+		.frames_since_last_jump = 0,
+		.name = "mike",
+		.has_diag_sprites = 0,
+		.bitmap_index = SI_LEFT,
+		.has_joypad = 0,
+		.pos = { .x = 0, .y = 0},
+		.vel = { .x = 0, .y = 0},
+		.acc = { .x = 0, .y = 0},
+
+		.bitmap_indexes[SI_UP] = 25, .bitmap_prop[SI_UP] = 0,
+			.collision_offset[SI_UP] = {
+				.itl = { .x = 8, .y = 8},
+				.itr = { .x = 1, .y = 8},
+				.ibl = { .x = 8, .y = 1},
+				.ibr = { .x = 1, .y = 1},
+			},
+		.bitmap_indexes[SI_DOWN] = 22, .bitmap_prop[SI_DOWN] = 0,
+			.collision_offset[SI_DOWN] = {
+				.itl = { .x = 8, .y = 8},
+				.itr = { .x = 1, .y = 8},
+				.ibl = { .x = 8, .y = 1},
+				.ibr = { .x = 1, .y = 1},
+			},
+		.bitmap_indexes[SI_LEFT] = 21, .bitmap_prop[SI_LEFT] = 0,
+			.collision_offset[SI_LEFT] = {
+				.itl = { .x = 8, .y = 5},
+				.itr = { .x = 1, .y = 5},
+				.ibl = { .x = 8, .y = 1},
+				.ibr = { .x = 1, .y = 1},
+			},
+		.bitmap_indexes[SI_RIGHT] = 21, .bitmap_prop[SI_RIGHT] = S_FLIPX,
+			.collision_offset[SI_RIGHT] = {
+				.itl = { .x = 8, .y = 5},
+				.itr = { .x = 1, .y = 5},
+				.ibl = { .x = 8, .y = 1},
+				.ibr = { .x = 1, .y = 1},
+			},
+		.bitmap_indexes[SI_UP_RIGHT] = 23, .bitmap_prop[SI_UP_RIGHT] = 0,
+			.collision_offset[SI_UP_RIGHT] = {
+				.itl = { .x = 8, .y = 8},
+				.itr = { .x = 1, .y = 8},
+				.ibl = { .x = 8, .y = 1},
+				.ibr = { .x = 1, .y = 1},
+			},
+		.bitmap_indexes[SI_UP_LEFT] = 23, .bitmap_prop[SI_UP_LEFT] = S_FLIPX,
+			.collision_offset[SI_UP_LEFT] = {
+				.itl = { .x = 8, .y = 8},
+				.itr = { .x = 1, .y = 8},
+				.ibl = { .x = 8, .y = 1},
+				.ibr = { .x = 1, .y = 1},
+			},
+		.bitmap_indexes[SI_DOWN_LEFT] = 24, .bitmap_prop[SI_DOWN_LEFT] = S_FLIPX,
+			.collision_offset[SI_DOWN_LEFT] = {
+				.itl = { .x = 8, .y = 7},
+				.itr = { .x = 1, .y = 7},
+				.ibl = { .x = 8, .y = 1},
+				.ibr = { .x = 1, .y = 1},
+			},
+		.bitmap_indexes[SI_DOWN_RIGHT] = 24, .bitmap_prop[SI_DOWN_RIGHT] = 0,
+			.collision_offset[SI_DOWN_RIGHT] = {
+				.itl = { .x = 8, .y = 7},
+				.itr = { .x = 1, .y = 7},
+				.ibl = { .x = 8, .y = 1},
+				.ibr = { .x = 1, .y = 1},
+			}
 	}
 };

res/sprites.c

@@ -10,7 +10,7 @@
   Compression          : None.
   Counter              : None.
   Tile size            : 8 x 8
-  Tiles                : 0 to 13
+  Tiles                : 0 to 25
 
   Palette colors       : None.
   SGB Palette          : None.
@@ -52,7 +52,31 @@ unsigned char sprites[] =
   0x00,0x02,0x00,0x07,0x02,0x00,0x02,0x00,
   0x02,0x00,0x00,0x02,0x00,0x07,0x00,0x05,
   0x00,0x03,0x02,0x01,0x04,0x00,0x08,0x00,
-  0x00,0x30,0x00,0x50,0x00,0x20,0x00,0x00
+  0x00,0x30,0x00,0x50,0x00,0x20,0x00,0x00,
+  0x38,0x38,0x7C,0x7C,0x7C,0x44,0x38,0x00,
+  0x18,0x00,0x18,0x18,0xBD,0xBD,0xBD,0xBD,
+  0x38,0x38,0x7C,0x7C,0x7C,0x44,0x39,0x01,
+  0x99,0x81,0x98,0x98,0x3C,0x3C,0x3C,0x3C,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x7E,
+  0x25,0xFE,0x18,0xE7,0x7E,0xFF,0x00,0xDB,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x7C,
+  0x38,0xEE,0x52,0xAD,0x7C,0xFF,0x01,0xD7,
+  0x00,0x38,0x10,0x6E,0x2C,0x77,0x22,0xDD,
+  0x7E,0xFF,0x12,0xC9,0x18,0xE7,0x00,0x7E,
+  0x00,0x38,0x10,0x6C,0x3C,0xC6,0x60,0xBF,
+  0x0E,0xFF,0x78,0xF3,0x00,0xDE,0x00,0x70,
+  0x00,0x00,0x30,0x4C,0x70,0x9E,0x06,0xFB,
+  0x7C,0xF3,0x0E,0x5F,0x00,0x7B,0x00,0x1E,
+  0x00,0x7E,0x18,0xE7,0x36,0xED,0x02,0xFD,
+  0x7E,0xFF,0x08,0x53,0x10,0x6E,0x00,0x38
 };
 
 /* End of SPRITES.C */

res/sprites.h

@@ -10,7 +10,7 @@
   Compression          : None.
   Counter              : None.
   Tile size            : 8 x 8
-  Tiles                : 0 to 13
+  Tiles                : 0 to 25
 
   Palette colors       : None.
   SGB Palette          : None.

src/main.c

@@ -12,14 +12,14 @@
 #include "./sprite.h"
 #include "./vec.h"
 
-#define NO_SCREEN_SPRITES 2
+#define NO_SCREEN_SPRITES 3
 
 void init_gfx()
 {
 	// Load Background tiles and then map
 	set_bkg_data(0, 23, tiles);
 	set_bkg_tiles(0, 0, map.width, map.height, map.data);
-	set_sprite_data(0, 14, sprites);
+	set_sprite_data(0, 26, sprites);
 
 	// Turn the background map on to make it visible
 	SHOW_BKG;
@@ -34,10 +34,10 @@ void main(void)
 	struct Sprites screen_sprites[NO_SCREEN_SPRITES];
 
 
-	memcpy(&(screen_sprites[0]), &(sprites_info[0]), sizeof(Sprite));
-	memcpy(&(screen_sprites[1]), &(sprites_info[0]), sizeof(Sprite));
+	memcpy(&(screen_sprites[0]), &(sprites_info[2]), sizeof(Sprite));
+	memcpy(&(screen_sprites[1]), &(sprites_info[1]), sizeof(Sprite));
+	memcpy(&(screen_sprites[2]), &(sprites_info[0]), sizeof(Sprite));
 	screen_sprites[0].has_joypad = 1;
-	screen_sprites[1].bitmap_index = SI_UP;
 
 	for (i = 0; i < NO_SCREEN_SPRITES; i++) {
 		screen_sprites[i].bitmap_index_prev = -1;
@@ -54,7 +54,6 @@ void main(void)
 		jp = joypad();
 		for (i = 0; i < NO_SCREEN_SPRITES; i++) {
 			sprite_iter_frame(&(screen_sprites[i]), &map, screen_sprites[i].has_joypad ? jp : 0, &fc);
-			//gprintf("x: %d y: %d\n", sprites[i].pos.x, sprites[i].pos.y);
 		}
 
 		// Done processing, yield CPU and wait for start of next frame

src/sprite.c

@@ -5,6 +5,18 @@
 #include "./flags.h"
 #include "./map.h"
 
+#define GET_TILE_INDEX_BY_COORD(x, y)	((((y) / PIXELS_PER_TILE) * 20) + ((x) / PIXELS_PER_TILE))
+
+#define GET_SPRITE_CORNERS(sprite, sc) \
+	sc.itl.x = sprite->pos.x - sprite->collision_offset[sprite->bitmap_index].itl.x; \
+	sc.itl.y = sprite->pos.y - sprite->collision_offset[sprite->bitmap_index].itl.y - 8; \
+	sc.itr.x = sprite->pos.x - sprite->collision_offset[sprite->bitmap_index].itr.x; \
+	sc.itr.y = sprite->pos.y - sprite->collision_offset[sprite->bitmap_index].itr.y - 8; \
+	sc.ibl.x = sprite->pos.x - sprite->collision_offset[sprite->bitmap_index].ibl.x; \
+	sc.ibl.y = sprite->pos.y - sprite->collision_offset[sprite->bitmap_index].ibl.y - 8; \
+	sc.ibr.x = sprite->pos.x - sprite->collision_offset[sprite->bitmap_index].ibr.x; \
+	sc.ibr.y = sprite->pos.y - sprite->collision_offset[sprite->bitmap_index].ibr.y - 8;
+
 
 typedef struct SpriteCorners {
 	UVec itl;
@@ -33,37 +45,20 @@ typedef struct Sprites {
 
 
 int get_tile_index_by_coord(unsigned int x, unsigned int y);
-void get_sprite_corners(Sprite *sprite, SpriteCorners *r);
 void sprite_iter_frame(Sprite *sprite, Map *map, int joypad, unsigned int *fc);
-unsigned int sprite_internal_collision(Map *map, Sprite *sprite);
-unsigned int sprite_collision(Map *map, Sprite *sprite);
 void sprite_draw_to_screen(Sprite *sprite);
 void sprite_update_bitmap(Sprite *sprite);
 
 
-int get_tile_index_by_coord(unsigned int x, unsigned int y)
-{
-	return ((y / PIXELS_PER_TILE) * 20) + (x / PIXELS_PER_TILE);
-}
-
-
-void get_sprite_corners(Sprite *sprite, SpriteCorners *sc)
-{
-	sc->itl.x = sprite->pos.x - sprite->collision_offset[sprite->bitmap_index].itl.x;
-	sc->itl.y = sprite->pos.y - sprite->collision_offset[sprite->bitmap_index].itl.y - 8;
-	sc->itr.x = sprite->pos.x - sprite->collision_offset[sprite->bitmap_index].itr.x;
-	sc->itr.y = sprite->pos.y - sprite->collision_offset[sprite->bitmap_index].itr.y - 8;
-	sc->ibl.x = sprite->pos.x - sprite->collision_offset[sprite->bitmap_index].ibl.x;
-	sc->ibl.y = sprite->pos.y - sprite->collision_offset[sprite->bitmap_index].ibl.y - 8;
-	sc->ibr.x = sprite->pos.x - sprite->collision_offset[sprite->bitmap_index].ibr.x;
-	sc->ibr.y = sprite->pos.y - sprite->collision_offset[sprite->bitmap_index].ibr.y - 8;
-}
-
-
 // update a sprite for stuff that changes every frame
 void sprite_iter_frame(Sprite *sprite, Map *map, int joypad, unsigned int *fc)
 {
-	int c, collision_check_steps;
+	SpriteCorners sc;
+	int c, collision_check_steps, sprite_internal_collision,
+	    absvelx = abs(sprite->vel.x), absvely = abs(sprite->vel.y);
+	int b_right = joypad & J_RIGHT, b_left = joypad & J_LEFT, b_up = joypad & J_UP,
+	    b_down = joypad & J_DOWN, b_a = joypad & J_A, b_b = joypad & J_B;
+	int tl, tr, bl, br, lt, lb, rt, rb;
 
 	// target displacement is sprite->vel but may collide, giving actual displacment
 	Vec displacement = {.x = 0, .y = 0};
@@ -78,68 +73,92 @@ void sprite_iter_frame(Sprite *sprite, Map *map, int joypad, unsigned int *fc)
 	}
 
 	// player move left/right
-	if ((joypad & J_RIGHT) && (sprite->vel.x < TERM_VELX)) sprite->acc.x = 1;
-	else if ((joypad & J_LEFT) && (sprite->vel.x > -TERM_VELX)) sprite->acc.x = -1;
-	else sprite->acc.x = -sprite->vel.x/abs(sprite->vel.x);
+	if ((joypad & b_right) && (sprite->vel.x < TERM_VELX)) sprite->acc.x = 1;
+	else if ((joypad & b_left) && (sprite->vel.x > -TERM_VELX)) sprite->acc.x = -1;
+	else sprite->acc.x = -sprite->vel.x/absvelx;
 	sprite->vel.x += sprite->acc.x;
 
 	// player dash
-	if ((joypad & J_B) && (sprite->frames_since_last_dash > DASH_TIMEOUT_FRAMES)) {
+	if (b_b && (sprite->frames_since_last_dash > DASH_TIMEOUT_FRAMES)) {
 		int frames_since_last_dash_copy = sprite->frames_since_last_dash;
 		sprite->frames_since_last_dash = 0;
 
-		if ((joypad & J_LEFT) && !(joypad & (J_UP | J_RIGHT | J_DOWN))) {
-			sprite->vel.x = -DASH_VELL;
-		} else if ((joypad & J_RIGHT) && !(joypad & (J_UP | J_LEFT | J_DOWN))) {
-			sprite->vel.x = DASH_VELL;
-		} else if ((joypad & J_UP) && !(joypad & (J_RIGHT | J_LEFT | J_DOWN))) {
-			sprite->vel.y = -DASH_VELL;
-		} else if ((joypad & J_DOWN) && !(joypad & (J_UP | J_LEFT | J_RIGHT))) {
-			sprite->vel.y = DASH_VELL;
-		} else if ((joypad & J_RIGHT) && (joypad & J_UP)) {
-			sprite->vel.x = DASH_VELD;
-			sprite->vel.y = -DASH_VELD;
-		} else if ((joypad & J_LEFT) && (joypad & J_UP)) {
+		if (b_left) {
+			if (b_up) {
 				sprite->vel.x = -DASH_VELD;
 				sprite->vel.y = -DASH_VELD;
-		} else if ((joypad & J_LEFT) && (joypad & J_DOWN)) {
+			} else if (b_down) {
 				sprite->vel.x = -DASH_VELD;
 				sprite->vel.y = DASH_VELD;
-		} else if ((joypad & J_RIGHT) && (joypad & J_DOWN)) {
+			} else {
+				sprite->vel.x = -DASH_VELL;
+			}
+		} else if (b_right) {
+			if (b_up) {
+				sprite->vel.x = DASH_VELD;
+				sprite->vel.y = -DASH_VELD;
+			} else if (b_down) {
 				sprite->vel.x = DASH_VELD;
 				sprite->vel.y = DASH_VELD;
 			} else {
+				sprite->vel.x = DASH_VELL;
+			}
+		}
+		else if (b_up) sprite->vel.y = -DASH_VELL;
+		else if (b_down) sprite->vel.y = DASH_VELL;
 		// if player doesn't hold the right buttons to dash, don't dash and set the
 		// frames_since_last_dash counter back to what it was before
-			sprite->frames_since_last_dash = frames_since_last_dash_copy;
-		}
+		else sprite->frames_since_last_dash = frames_since_last_dash_copy;
 	}
 
 	// slow down sprite in kind of realistic way
 	// (in real life i think it's drag is proportional to sprite->vel square but not
 	// sure if that is worth the compute yet cause everythign else is shit)
-	if (sprite->vel.y > TERM_VELY) sprite->vel.y  -= (abs(sprite->vel.y)-TERM_VELY)/TERM_VELY_DIVISOR;
-	if (sprite->vel.y < -TERM_VELY) sprite->vel.y += (abs(sprite->vel.y)-TERM_VELY)/TERM_VELY_DIVISOR;
-	if (sprite->vel.x > TERM_VELX) sprite->vel.x  -= (abs(sprite->vel.x)-TERM_VELX)/TERM_VELX_DIVISOR;
-	if (sprite->vel.x < -TERM_VELX) sprite->vel.x += (abs(sprite->vel.x)-TERM_VELX)/TERM_VELX_DIVISOR;
+	if (sprite->vel.y > TERM_VELY) sprite->vel.y  -= (absvely-TERM_VELY)/TERM_VELY_DIVISOR;
+	if (sprite->vel.y < -TERM_VELY) sprite->vel.y += (absvely-TERM_VELY)/TERM_VELY_DIVISOR;
+	if (sprite->vel.x > TERM_VELX) sprite->vel.x  -= (absvelx-TERM_VELX)/TERM_VELX_DIVISOR;
+	if (sprite->vel.x < -TERM_VELX) sprite->vel.x += (absvelx-TERM_VELX)/TERM_VELX_DIVISOR;
 	
-	c = sprite_collision(map, sprite);
+	absvelx = abs(sprite->vel.x);
+	absvely = abs(sprite->vel.y);
+
+	// if sprite not moving, no more logic needs to be done --- right?
+	if ((absvelx == 0) && (absvely == 0)) return;
+
+	GET_SPRITE_CORNERS(sprite, sc);
 
 	// don't let player move in a direction which they are already touching something
-	if (((c & SC_TL) | (c & SC_TR)) && (sprite->vel.y < 0)) { sprite->vel.y = 0; }
-	if (((c & SC_BL) | (c & SC_BR)) && (sprite->vel.y > 0)) {
+	if (sprite->vel.y > 0) {
+		br = map->data[GET_TILE_INDEX_BY_COORD(sc.ibl.x, sc.ibl.y+1)];
+		bl = map->data[GET_TILE_INDEX_BY_COORD(sc.ibr.x, sc.ibr.y+1)];
+
+		if (bl | br) {
+			sprite->vel.y = 0;
 			// player jump
-		if ((joypad & J_A) && (sprite->frames_since_last_jump > JUMP_TIMEOUT_FRAMES)) {
+			if (b_a && (sprite->frames_since_last_jump > JUMP_TIMEOUT_FRAMES)) {
 				sprite->vel.y = -JUMP_VEL;
 				sprite->frames_since_last_jump = 0;
 			}
-		else sprite->vel.y = 0;
 		}
-	if (((c & SC_RT) | (c & SC_RB)) && (sprite->vel.x > 0)) { sprite->vel.x = 0; }
-	if (((c & SC_LT) | (c & SC_LB)) && (sprite->vel.x < 0)) { sprite->vel.x = 0; }
+	} else if (sprite->vel.y < 0) {
+		tl = map->data[GET_TILE_INDEX_BY_COORD(sc.itl.x, sc.itl.y-1)];
+		tr = map->data[GET_TILE_INDEX_BY_COORD(sc.itr.x, sc.itr.y-1)];
+		if (tl | tr) sprite->vel.y = 0;
+	}
+
+	if (sprite->vel.x > 0) {
+		rt = map->data[GET_TILE_INDEX_BY_COORD(sc.itr.x+1, sc.itr.y)];
+		rb = map->data[GET_TILE_INDEX_BY_COORD(sc.ibr.x+1, sc.ibr.y)];
+		if (rt | rb) sprite->vel.x = 0;
+	} else if (sprite->vel.x < 0) {
+		lt = map->data[GET_TILE_INDEX_BY_COORD(sc.itl.x-1, sc.itl.y)];
+		lb = map->data[GET_TILE_INDEX_BY_COORD(sc.ibl.x-1, sc.ibl.y)];
+		if (lt | lb) sprite->vel.x = 0;
+	}
+
+	absvelx = abs(sprite->vel.x);
+	absvely = abs(sprite->vel.y);
 
-	int absvelx = abs(sprite->vel.x);
-	int absvely = abs(sprite->vel.y);
 	collision_check_steps =  (absvelx > absvely) ? absvelx : absvely;
 
 	original_position.x = sprite->pos.x;
@@ -149,54 +168,23 @@ void sprite_iter_frame(Sprite *sprite, Map *map, int joypad, unsigned int *fc)
 		sprite->pos.x = original_position.x + ((step * sprite->vel.x)/collision_check_steps);
 		sprite->pos.y = original_position.y + ((step * sprite->vel.y)/collision_check_steps);
 
-		if (!sprite_internal_collision(map, sprite)) break;
+		sprite_internal_collision = 0;
+		if (map->data[GET_TILE_INDEX_BY_COORD(sc.itl.x, sc.itl.y)]) sprite_internal_collision++;
+		if (map->data[GET_TILE_INDEX_BY_COORD(sc.itr.x, sc.itr.y)]) sprite_internal_collision++;
+		if (map->data[GET_TILE_INDEX_BY_COORD(sc.ibl.x, sc.ibl.y)]) sprite_internal_collision++;
+		if (map->data[GET_TILE_INDEX_BY_COORD(sc.ibr.x, sc.ibr.y)]) sprite_internal_collision++;
+		if (sprite_internal_collision == 0) break;
 	}
 
-	sprite_update_bitmap(sprite);
 	sprite_draw_to_screen(sprite);
+	move_sprite(sprite->gb_sprite_index, sprite->pos.x, sprite->pos.y);
 }
 
 
-// calculate internal collisions
-unsigned int sprite_internal_collision(Map *map, Sprite *sprite)
-{
-	unsigned int rv = 0;
-	SpriteCorners sc;
-	get_sprite_corners(sprite, &sc);
-
-	if (map->data[get_tile_index_by_coord(sc.itl.x, sc.itl.y)]) rv = rv | SC_ITL;
-	if (map->data[get_tile_index_by_coord(sc.itr.x, sc.itr.y)]) rv = rv | SC_ITR;
-	if (map->data[get_tile_index_by_coord(sc.ibl.x, sc.ibl.y)]) rv = rv | SC_IBL;
-	if (map->data[get_tile_index_by_coord(sc.ibr.x, sc.ibr.y)]) rv = rv | SC_IBR;
-
-	return rv;
-}
-
-
-// check for external collisions (if rectangle is at least touchign something)
-unsigned int sprite_collision(Map *map, Sprite *sprite)
-{
-	unsigned int rv = 0;
-	SpriteCorners sc;
-	get_sprite_corners(sprite, &sc);
-
-	// check if corners are in a non 0 tile
-	if (map->data[get_tile_index_by_coord(sc.itl.x,   sc.itl.y-1)]) rv = rv | SC_TL;
-	if (map->data[get_tile_index_by_coord(sc.itr.x,   sc.itr.y-1)]) rv = rv | SC_TR;
-	if (map->data[get_tile_index_by_coord(sc.ibl.x,   sc.ibl.y+1)]) rv = rv | SC_BL;
-	if (map->data[get_tile_index_by_coord(sc.ibr.x,   sc.ibr.y+1)]) rv = rv | SC_BR;
-	if (map->data[get_tile_index_by_coord(sc.itl.x-1, sc.itl.y  )]) rv = rv | SC_LT;
-	if (map->data[get_tile_index_by_coord(sc.ibl.x-1, sc.ibl.y  )]) rv = rv | SC_LB;
-	if (map->data[get_tile_index_by_coord(sc.itr.x+1, sc.itr.y  )]) rv = rv | SC_RT;
-	if (map->data[get_tile_index_by_coord(sc.ibr.x+1, sc.ibr.y  )]) rv = rv | SC_RB;
-
-	return rv;
-}
-
+// set new sprite bitmap
 void sprite_update_bitmap(Sprite *sprite)
 {
 	sprite->bitmap_index_prev = sprite->bitmap_index;
-
 	if ((sprite->vel.y > 0) && (sprite->vel.x > 0)) sprite->bitmap_index = SI_DOWN_RIGHT;
 	else if ((sprite->vel.y < 0) && (sprite->vel.x > 0)) sprite->bitmap_index = SI_UP_RIGHT;
 	else if ((sprite->vel.y > 0) && (sprite->vel.x < 0)) sprite->bitmap_index = SI_DOWN_LEFT;
@@ -210,6 +198,8 @@ void sprite_update_bitmap(Sprite *sprite)
 
 void sprite_draw_to_screen(Sprite *sprite)
 {
+	// only set sprite if sprite to be used has changed
+	sprite_update_bitmap(sprite);
 	if (sprite->bitmap_index_prev != sprite->bitmap_index) {
 		set_sprite_tile(sprite->gb_sprite_index, sprite->bitmap_indexes[sprite->bitmap_index]);
 		set_sprite_prop(sprite->gb_sprite_index, sprite->bitmap_prop[sprite->bitmap_index]);