commit c78bc5e88bef99afba8959117d49c31b798369fb
Author: Alvie Rahman <alvierahman90@gmail.com>
Date:   Mon Jun 6 22:19:34 2022 +0100

    first commit - a kind of working thingy

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..0c333d2
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+compile.bat
+obj
diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..6fdf0fc
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "gbdk-2020"]
+	path = gbdk-2020
+	url = https://github.com/gbdk-2020/gbdk-2020.git
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..f172daa
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,60 @@
+#
+# A Makefile that compiles all .c and .s files in "src" and "res" 
+# subdirectories and places the output in a "obj" subdirectory
+#
+
+# If you move this project you can change the directory 
+# to match your GBDK root directory (ex: GBDK_HOME = "C:/GBDK/"
+GBDK_HOME = ./gbdk-2020/
+
+LCC = $(GBDK_HOME)bin/lcc 
+
+# You can set flags for LCC here
+# For example, you can uncomment the line below to turn on debug output
+# LCCFLAGS = -debug
+
+# You can set the name of the .gb ROM file here
+PROJECTNAME    = untitled2dshooter
+
+SRCDIR      = src
+OBJDIR      = obj
+RESDIR      = res
+BINS	    = $(OBJDIR)/$(PROJECTNAME).gb
+CSOURCES    = $(foreach dir,$(SRCDIR),$(notdir $(wildcard $(dir)/*.c))) $(foreach dir,$(RESDIR),$(notdir $(wildcard $(dir)/*.c)))
+ASMSOURCES  = $(foreach dir,$(SRCDIR),$(notdir $(wildcard $(dir)/*.s)))
+OBJS       = $(CSOURCES:%.c=$(OBJDIR)/%.o) $(ASMSOURCES:%.s=$(OBJDIR)/%.o)
+
+all:	prepare $(BINS)
+
+compile.bat: Makefile
+	@echo "REM Automatically generated from Makefile" > compile.bat
+	@make -sn | sed y/\\//\\\\/ | grep -v make >> compile.bat
+
+# Compile .c files in "src/" to .o object files
+$(OBJDIR)/%.o:	$(SRCDIR)/%.c
+	$(LCC) $(LCCFLAGS) -c -o $@ $<
+
+# Compile .c files in "res/" to .o object files
+$(OBJDIR)/%.o:	$(RESDIR)/%.c
+	$(LCC) $(LCCFLAGS) -c -o $@ $<
+
+# Compile .s assembly files in "src/" to .o object files
+$(OBJDIR)/%.o:	$(SRCDIR)/%.s
+	$(LCC) $(LCCFLAGS) -c -o $@ $<
+
+# If needed, compile .c files i n"src/" to .s assembly files
+# (not required if .c is compiled directly to .o)
+$(OBJDIR)/%.s:	$(SRCDIR)/%.c
+	$(LCC) $(LCCFLAGS) -S -o $@ $<
+
+# Link the compiled object files into a .gb ROM file
+$(BINS):	$(OBJS)
+	$(LCC) $(LCCFLAGS) -o $(BINS) $(OBJS)
+
+prepare:
+	mkdir -p $(OBJDIR)
+
+clean:
+#	rm -f  *.gb *.ihx *.cdb *.adb *.noi *.map
+	rm -f  $(OBJDIR)/*.*
+
diff --git a/gbdk-2020 b/gbdk-2020
new file mode 160000
index 0000000..ebbc0b0
--- /dev/null
+++ b/gbdk-2020
@@ -0,0 +1 @@
+Subproject commit ebbc0b0ed11267182c922fcbf87da915b9e90526
diff --git a/readme.md b/readme.md
new file mode 100644
index 0000000..d7527b1
--- /dev/null
+++ b/readme.md
@@ -0,0 +1,11 @@
+# untitled2dshooter
+
+an untitled 2d multiplayer shooter for the gameboy
+
+## compile
+
+```
+make all
+```
+
+the gameboy rom will be output to `obj/untitled2dshooter.gb`
diff --git a/res/map.c b/res/map.c
new file mode 100644
index 0000000..f4bbfbd
--- /dev/null
+++ b/res/map.c
@@ -0,0 +1,65 @@
+/*
+
+ MAP.C
+
+ Map Source File.
+
+ Info:
+   Section       : 
+   Bank          : 0
+   Map size      : 20 x 18
+   Tile set      : Z:\home\alvie\d\p\wordboy\res\tiles.gbr
+   Plane count   : 1 plane (8 bits)
+   Plane order   : Tiles are continues
+   Tile offset   : 0
+   Split data    : No
+
+ This file was generated by GBMB v1.8
+
+*/
+
+#define mapWidth 20
+#define mapHeight 18
+#define mapBank 0
+
+unsigned char map[] =
+{
+  0x09,0x02,0x02,0x02,0x02,0x02,0x02,0x08,0x00,0x00,
+  0x00,0x07,0x02,0x02,0x02,0x02,0x02,0x02,0x02,0x0A,
+  0x04,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03,
+  0x04,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03,
+  0x04,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03,
+  0x04,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03,
+  0x04,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03,
+  0x04,0x00,0x00,0x0D,0x00,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03,
+  0x04,0x00,0x00,0x11,0x00,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03,
+  0x04,0x00,0x00,0x03,0x0F,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03,
+  0x04,0x00,0x00,0x11,0x00,0x00,0x0E,0x12,0x12,0x12,
+  0x12,0x12,0x0F,0x00,0x00,0x00,0x00,0x00,0x00,0x03,
+  0x04,0x00,0x00,0x11,0x00,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03,
+  0x04,0x00,0x00,0x11,0x00,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x0E,0x12,0x12,0x0F,0x00,0x00,0x00,0x03,
+  0x04,0x00,0x00,0x10,0x00,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03,
+  0x04,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x05,0x01,0x0B,
+  0x04,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03,0x13,0x13,
+  0x04,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x00,0x00,0x00,0x00,0x05,0x0B,0x13,0x13,
+  0x04,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+  0x00,0x00,0x00,0x00,0x00,0x05,0x0B,0x13,0x13,0x13,
+  0x0C,0x01,0x01,0x01,0x01,0x01,0x01,0x06,0x00,0x00,
+  0x00,0x05,0x01,0x01,0x01,0x0B,0x13,0x13,0x13,0x13
+};
+
+/* End of MAP.C */
diff --git a/res/map.h b/res/map.h
new file mode 100644
index 0000000..16f1362
--- /dev/null
+++ b/res/map.h
@@ -0,0 +1,27 @@
+/*
+
+ MAP.H
+
+ Map Include File.
+
+ Info:
+   Section       : 
+   Bank          : 0
+   Map size      : 20 x 18
+   Tile set      : Z:\home\alvie\d\p\wordboy\res\tiles.gbr
+   Plane count   : 1 plane (8 bits)
+   Plane order   : Tiles are continues
+   Tile offset   : 0
+   Split data    : No
+
+ This file was generated by GBMB v1.8
+
+*/
+
+#define mapWidth 20
+#define mapHeight 18
+#define mapBank 0
+
+extern unsigned char map[];
+
+/* End of MAP.H */
diff --git a/res/sprites.c b/res/sprites.c
new file mode 100644
index 0000000..82adceb
--- /dev/null
+++ b/res/sprites.c
@@ -0,0 +1,52 @@
+/*
+
+ SPRITES.C
+
+ Tile Source File.
+
+ Info:
+  Form                 : All tiles as one unit.
+  Format               : Gameboy 4 color.
+  Compression          : None.
+  Counter              : None.
+  Tile size            : 8 x 8
+  Tiles                : 0 to 10
+
+  Palette colors       : None.
+  SGB Palette          : None.
+  CGB Palette          : None.
+
+  Convert to metatiles : No.
+
+ This file was generated by GBTD v2.2
+
+*/
+
+/* Start of tile array. */
+unsigned char sprites[] =
+{
+  0xF7,0x08,0xED,0x12,0xFE,0x11,0xFF,0x38,
+  0xFE,0x39,0xFE,0x39,0xFF,0x7E,0xFF,0x6E,
+  0xFF,0x00,0xC3,0x42,0x81,0x00,0x81,0x00,
+  0x81,0x00,0x81,0x00,0xC3,0x42,0xFF,0x00,
+  0xC3,0xC3,0xDB,0xDB,0x3C,0x3C,0x7E,0x7E,
+  0x7E,0x7E,0x3C,0x3C,0xDB,0xDB,0xC3,0xC3,
+  0x43,0xC3,0xDB,0xDB,0x3C,0x3C,0x7E,0x7E,
+  0x7E,0x7E,0x3C,0x3C,0xDB,0xDB,0xC3,0xC3,
+  0xC2,0xC3,0xDB,0xDB,0x3C,0x3C,0x7E,0x7E,
+  0x7E,0x7E,0x3C,0x3C,0xDB,0xDB,0xC3,0xC3,
+  0xC3,0xC3,0xDB,0xDB,0x3C,0x3C,0x7E,0x7E,
+  0x7E,0x7E,0x3C,0x3C,0xDB,0xDB,0x43,0xC3,
+  0xC3,0xC3,0xDB,0xDB,0x3C,0x3C,0x7E,0x7E,
+  0x7E,0x7E,0x3C,0x3C,0xDB,0xDB,0xC2,0xC3,
+  0x42,0xC3,0xDB,0xDB,0x3C,0x3C,0x7E,0x7E,
+  0x7E,0x7E,0x3C,0x3C,0xDB,0xDB,0xC3,0xC3,
+  0xC2,0xC3,0xDB,0xDB,0x3C,0x3C,0x7E,0x7E,
+  0x7E,0x7E,0x3C,0x3C,0xDB,0xDB,0xC2,0xC3,
+  0xC3,0xC3,0xDB,0xDB,0x3C,0x3C,0x7E,0x7E,
+  0x7E,0x7E,0x3C,0x3C,0xDB,0xDB,0x42,0xC3,
+  0x43,0xC3,0xDB,0xDB,0x3C,0x3C,0x7E,0x7E,
+  0x7E,0x7E,0x3C,0x3C,0xDB,0xDB,0x43,0xC3
+};
+
+/* End of SPRITES.C */
diff --git a/res/sprites.gbr b/res/sprites.gbr
new file mode 100644
index 0000000..368fb5d
Binary files /dev/null and b/res/sprites.gbr differ
diff --git a/res/sprites.h b/res/sprites.h
new file mode 100644
index 0000000..0fba763
--- /dev/null
+++ b/res/sprites.h
@@ -0,0 +1,31 @@
+/*
+
+ SPRITES.H
+
+ Include File.
+
+ Info:
+  Form                 : All tiles as one unit.
+  Format               : Gameboy 4 color.
+  Compression          : None.
+  Counter              : None.
+  Tile size            : 8 x 8
+  Tiles                : 0 to 10
+
+  Palette colors       : None.
+  SGB Palette          : None.
+  CGB Palette          : None.
+
+  Convert to metatiles : No.
+
+ This file was generated by GBTD v2.2
+
+*/
+
+
+/* Bank of tiles. */
+#define spritesBank 0
+/* Start of tile array. */
+extern unsigned char sprites[];
+
+/* End of SPRITES.H */
diff --git a/res/test.gbm b/res/test.gbm
new file mode 100644
index 0000000..244f9ec
Binary files /dev/null and b/res/test.gbm differ
diff --git a/res/tilemap.gbm b/res/tilemap.gbm
new file mode 100644
index 0000000..36a8e1b
Binary files /dev/null and b/res/tilemap.gbm differ
diff --git a/res/tiles.c b/res/tiles.c
new file mode 100644
index 0000000..0404dab
--- /dev/null
+++ b/res/tiles.c
@@ -0,0 +1,76 @@
+/*
+
+ TILES.C
+
+ Tile Source File.
+
+ Info:
+  Form                 : All tiles as one unit.
+  Format               : Gameboy 4 color.
+  Compression          : None.
+  Counter              : None.
+  Tile size            : 8 x 8
+  Tiles                : 0 to 22
+
+  Palette colors       : None.
+  SGB Palette          : None.
+  CGB Palette          : None.
+
+  Convert to metatiles : No.
+
+ This file was generated by GBTD v2.2
+
+*/
+
+/* Start of tile array. */
+unsigned char tiles[] =
+{
+  0x10,0x00,0x00,0x00,0x08,0x00,0x10,0x00,
+  0x30,0x00,0x20,0x00,0x60,0x00,0x50,0x20,
+  0xFF,0xFF,0xFF,0xFF,0x00,0xFF,0x00,0xFF,
+  0x00,0xFF,0x00,0xFF,0x00,0xFF,0x00,0xFF,
+  0x00,0xFF,0x00,0xFF,0x00,0xFF,0x00,0xFF,
+  0x00,0xFF,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,
+  0xC0,0xFF,0xC0,0xFF,0xC0,0xFF,0xC0,0xFF,
+  0xC0,0xFF,0xC0,0xFF,0xC0,0xFF,0xC0,0xFF,
+  0x03,0xFF,0x03,0xFF,0x03,0xFF,0x03,0xFF,
+  0x03,0xFF,0x03,0xFF,0x03,0xFF,0x03,0xFF,
+  0x7F,0x7F,0xFF,0xFF,0xF0,0xFF,0xE0,0xFF,
+  0xC0,0xFF,0xC0,0xFF,0xC0,0xFF,0xC0,0xFF,
+  0xFE,0xFE,0xFF,0xFF,0x0F,0xFF,0x07,0xFF,
+  0x03,0xFF,0x03,0xFF,0x03,0xFF,0x03,0xFF,
+  0xC0,0xFF,0xC0,0xFF,0xC0,0xFF,0xC0,0xFF,
+  0xE0,0xFF,0xF0,0xFF,0xFF,0xFF,0x7F,0x7F,
+  0x03,0xFF,0x03,0xFF,0x03,0xFF,0x03,0xFF,
+  0x07,0xFF,0x0F,0xFF,0xFF,0xFF,0xFE,0xFE,
+  0x00,0xFF,0x00,0xFF,0x00,0xFF,0x00,0xFF,
+  0x00,0xFF,0x00,0xFF,0x01,0xFF,0x03,0xFF,
+  0x00,0xFF,0x00,0xFF,0x00,0xFF,0x00,0xFF,
+  0x00,0xFF,0x00,0xFF,0x80,0xFF,0xC0,0xFF,
+  0xC0,0xFF,0x80,0xFF,0x00,0xFF,0x00,0xFF,
+  0x00,0xFF,0x00,0xFF,0x00,0xFF,0x00,0xFF,
+  0x03,0xFF,0x01,0xFF,0x00,0xFF,0x00,0xFF,
+  0x00,0xFF,0x00,0xFF,0x00,0xFF,0x00,0xFF,
+  0x7E,0x7E,0xFF,0xFF,0xE7,0xFF,0xC3,0xFF,
+  0xC3,0xFF,0xC3,0xFF,0xC3,0xFF,0xC3,0xFF,
+  0x7F,0x7F,0xFF,0xFF,0xE0,0xFF,0xC0,0xFF,
+  0xC0,0xFF,0xE0,0xFF,0xFF,0xFF,0x7F,0x7F,
+  0xFE,0xFE,0xFF,0xFF,0x07,0xFF,0x03,0xFF,
+  0x03,0xFF,0x07,0xFF,0xFF,0xFF,0xFE,0xFE,
+  0xC3,0xFF,0xC3,0xFF,0xC3,0xFF,0xC3,0xFF,
+  0xC3,0xFF,0xE7,0xFF,0xFF,0xFF,0x7E,0x7E,
+  0xC3,0xFF,0xC3,0xFF,0xC3,0xFF,0xC3,0xFF,
+  0xC3,0xFF,0xC3,0xFF,0xC3,0xFF,0xC3,0xFF,
+  0xFF,0xFF,0xFF,0xFF,0x00,0xFF,0x00,0xFF,
+  0x00,0xFF,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,
+  0x00,0xFF,0x00,0xFF,0x00,0xFF,0x00,0xFF,
+  0x00,0xFF,0x00,0xFF,0x00,0xFF,0x00,0xFF,
+  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
+};
+
+/* End of TILES.C */
diff --git a/res/tiles.gbr b/res/tiles.gbr
new file mode 100644
index 0000000..8ff2090
Binary files /dev/null and b/res/tiles.gbr differ
diff --git a/res/tiles.h b/res/tiles.h
new file mode 100644
index 0000000..ff45776
--- /dev/null
+++ b/res/tiles.h
@@ -0,0 +1,31 @@
+/*
+
+ TILES.H
+
+ Include File.
+
+ Info:
+  Form                 : All tiles as one unit.
+  Format               : Gameboy 4 color.
+  Compression          : None.
+  Counter              : None.
+  Tile size            : 8 x 8
+  Tiles                : 0 to 22
+
+  Palette colors       : None.
+  SGB Palette          : None.
+  CGB Palette          : None.
+
+  Convert to metatiles : No.
+
+ This file was generated by GBTD v2.2
+
+*/
+
+
+/* Bank of tiles. */
+#define tilesBank 0
+/* Start of tile array. */
+extern unsigned char tiles[];
+
+/* End of TILES.H */
diff --git a/src/constants.h b/src/constants.h
new file mode 100644
index 0000000..08c62b3
--- /dev/null
+++ b/src/constants.h
@@ -0,0 +1,21 @@
+#ifndef CONSTANTS_LOADED
+#define CONSTANTS_LOADED
+
+#define GRAV_ACC 1
+#define TERM_VELY 3
+#define TERM_VELX 2
+#define TERM_VELY_DIVISOR 3
+#define TERM_VELX_DIVISOR 3
+
+#define JUMP_VEL 4
+#define JUMP_TIMEOUT_FRAMES 18
+
+#define DASH_VELL 7
+#define DASH_VELD 5
+#define DASH_TIMEOUT_FRAMES 30
+
+#define SPRITE_WIDTH 8
+#define SPRITE_HEIGHT 8
+#define PIXELS_PER_TILE 8
+#define TILES_PER_ROW 20
+#endif
diff --git a/src/flags.h b/src/flags.h
new file mode 100644
index 0000000..585ee16
--- /dev/null
+++ b/src/flags.h
@@ -0,0 +1,39 @@
+#define SPRITE_PROP_BEHIND          0b10000000
+#define SPRITE_PROP_VERTICAL_FLIP   0b01000000
+#define SPRITE_PROP_HORIZONTAL_FLIP 0b00100000
+
+#define COLLISION_TOP_LEFT          0b10000000
+#define COLLISION_TOP_RIGHT         0b01000000
+#define COLLISION_BOTTOM_LEFT       0b00100000
+#define COLLISION_BOTTOM_RIGHT      0b00010000
+
+
+// Sprite Collision flags used by uint8_t collision(uint8_t, uint8_t, uint8_t, uint8_t)
+
+#define SC_TL 0b10000000
+#define SC_TR 0b01000000
+#define SC_BL 0b00100000
+#define SC_BR 0b00010000
+#define SC_LT 0b00001000
+#define SC_LB 0b00000100
+#define SC_RT 0b00000010
+#define SC_RB 0b00000001
+
+#define SC_ITL 0b1000
+#define SC_ITR 0b0100
+#define SC_IBL 0b0010
+#define SC_IBR 0b0001
+
+/* Sprite Collision point diagram:
+ *      x TL    LT x
+ *      ------------
+ * LT x|x ITL  ITR x|x RT
+ *     |            |
+ *     |            |
+ *     |            |
+ *     |            |
+ *     |            |
+ * LB x|x IBL  IBR x|x RB
+ *      ------------
+ *      x TL    LT x
+ */
diff --git a/src/main.c b/src/main.c
new file mode 100644
index 0000000..e5ca645
--- /dev/null
+++ b/src/main.c
@@ -0,0 +1,224 @@
+#include <gb/gb.h>
+#include <stdlib.h>
+#include "../res/tiles.h"
+#include "../res/map.h"
+#include"../res/sprites.h"
+#include "./flags.h"
+#include "./constants.h"
+#include "./vec.c"
+
+int getTileIndexByCoord(unsigned int x, unsigned int y)
+{
+	return ((y / PIXELS_PER_TILE) * 20) + (x / PIXELS_PER_TILE);
+}
+
+// check for external collisions (if rectangle is at least touchign something)
+unsigned int collision(unsigned char map[], struct UVec *sprite_pos, struct UVec *sprite_size)
+{
+	unsigned int rv = 0;
+	struct UVec itl, itr, ibl, ibr;
+
+	itl.x = sprite_pos->x-8; itl.y = sprite_pos->y-16;
+	itr.x = sprite_pos->x-1; itr.y = sprite_pos->y-16;
+	ibl.x = sprite_pos->x-8; ibl.y = sprite_pos->y-9;
+	ibr.x = sprite_pos->x-1; ibr.y = sprite_pos->y-9;
+
+	// check if corners are in a non 0 tile
+	if (map[getTileIndexByCoord(itl.x, itl.y-1)]) rv = rv | SC_TL;
+	if (map[getTileIndexByCoord(itr.x, itr.y-1)]) rv = rv | SC_TR;
+
+	if (map[getTileIndexByCoord(ibl.x, ibl.y+1)]) rv = rv | SC_BL;
+	if (map[getTileIndexByCoord(ibr.x, ibr.y+1)]) rv = rv | SC_BR;
+
+	if (map[getTileIndexByCoord(itl.x-1, itl.y)]) rv = rv | SC_LT;
+	if (map[getTileIndexByCoord(ibl.x-1, ibl.y)]) rv = rv | SC_LB;
+
+	if (map[getTileIndexByCoord(itr.x+1, itr.y)]) rv = rv | SC_RT;
+	if (map[getTileIndexByCoord(ibr.x+1, ibr.y)]) rv = rv | SC_RB;
+
+	return rv;
+}
+
+
+// calculate internal collisions from external collisions
+unsigned int icollision(unsigned char map[], struct UVec *sprite_pos, struct UVec *sprite_size)
+{
+	unsigned int c, rv = 0;
+	struct UVec itl, itr, ibl, ibr;
+
+	itl.x = sprite_pos->x-8; itl.y = sprite_pos->y-16;
+	itr.x = sprite_pos->x-1; itr.y = sprite_pos->y-16;
+	ibl.x = sprite_pos->x-8; ibl.y = sprite_pos->y-9;
+	ibr.x = sprite_pos->x-1; ibr.y = sprite_pos->y-9;
+
+	if (map[getTileIndexByCoord(itl.x, itl.y)]) rv = rv | SC_ITL;
+	if (map[getTileIndexByCoord(itr.x, itr.y)]) rv = rv | SC_ITR;
+	if (map[getTileIndexByCoord(ibl.x, ibl.y)]) rv = rv | SC_IBL;
+	if (map[getTileIndexByCoord(ibr.x, ibr.y)]) rv = rv | SC_IBR;
+
+	return rv;
+}
+
+
+void init_gfx()
+{
+	// Load Background tiles and then map
+	set_bkg_data(0, 23, tiles);
+	set_bkg_tiles(0, 0, mapWidth, mapHeight, map);
+
+	set_sprite_data(0, 11, sprites);
+	set_sprite_tile(0, 2);
+	set_sprite_prop(0, 0);
+
+	// Turn the background map on to make it visible
+	SHOW_BKG;
+	SHOW_SPRITES;
+}
+
+void main(void)
+{
+	unsigned int c, search_found, frames_since_last_jump, frames_since_last_dash, fc = 0;
+	int xsearch, ysearch;
+	struct UVec sprite_pos, search_pos, sprite_size;
+	struct Vec velocity, acceleration;
+
+	init_gfx();
+
+	sprite_pos.x = 72;
+	sprite_pos.y = 35;
+	sprite_size.x = 8;
+	sprite_size.y = 8;
+	frames_since_last_jump = JUMP_TIMEOUT_FRAMES;
+	frames_since_last_dash = DASH_TIMEOUT_FRAMES;
+	velocity.x = 0;
+	velocity.y = 0;
+	acceleration.x = 0;
+	acceleration.y = 0;
+
+	move_sprite(0, sprite_pos.x, sprite_pos.y);
+
+	// Loop forever
+	while(1) {
+		// the gameboy simulates physics too quickly to have good control over the speeds of things
+		// so draw them less often and move them more
+		if (frames_since_last_jump <= JUMP_TIMEOUT_FRAMES) frames_since_last_jump++;
+		if (frames_since_last_dash <= DASH_TIMEOUT_FRAMES) frames_since_last_dash++;
+
+		if (++fc % 2 == 0) {
+			velocity.y += GRAV_ACC;
+			fc = 0;
+		}
+
+		// player move left/right
+		if ((joypad() & J_RIGHT) && (velocity.x < TERM_VELX)) acceleration.x = 1;
+		else if ((joypad() & J_LEFT) && (velocity.x > -TERM_VELX)) acceleration.x = -1;
+		else acceleration.x = -velocity.x/abs(velocity.x);
+		velocity.x += acceleration.x;
+
+		// player dash
+		if ((joypad() & J_B) && (frames_since_last_dash > DASH_TIMEOUT_FRAMES)) {
+			int frames_since_last_dash_copy = frames_since_last_dash;
+			frames_since_last_dash = 0;
+
+			if ((joypad() & J_LEFT) && !(joypad() & (J_UP | J_RIGHT | J_DOWN))) {
+				velocity.x = -DASH_VELL;
+			} else if ((joypad() & J_RIGHT) && !(joypad() & (J_UP | J_LEFT | J_DOWN))) {
+				velocity.x = DASH_VELL;
+			} else if ((joypad() & J_UP) && !(joypad() & (J_RIGHT | J_LEFT | J_DOWN))) {
+				velocity.y = -DASH_VELL;
+			} else if ((joypad() & J_DOWN) && !(joypad() & (J_UP | J_LEFT | J_RIGHT))) {
+				velocity.y = DASH_VELL;
+			} else if ((joypad() & J_RIGHT) && (joypad() & J_UP)) {
+				velocity.x = DASH_VELD;
+				velocity.y = -DASH_VELD;
+			} else if ((joypad() & J_LEFT) && (joypad() & J_UP)) {
+				velocity.x = -DASH_VELD;
+				velocity.y = -DASH_VELD;
+			} else if ((joypad() & J_LEFT) && (joypad() & J_DOWN)) {
+				velocity.x = -DASH_VELD;
+				velocity.y = DASH_VELD;
+			} else if ((joypad() & J_RIGHT) && (joypad() & J_DOWN)) {
+				velocity.x = DASH_VELD;
+				velocity.y = DASH_VELD;
+			} else {
+				// 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
+				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 velocity square but not
+		// sure if that is worth the compute yet)
+		if (velocity.y > TERM_VELY) velocity.y  -= (abs(velocity.y)-TERM_VELY)/TERM_VELY_DIVISOR;
+		if (velocity.y < -TERM_VELY) velocity.y += (abs(velocity.y)-TERM_VELY)/TERM_VELY_DIVISOR;
+		if (velocity.x > TERM_VELX) velocity.x  -= (abs(velocity.x)-TERM_VELX)/TERM_VELX_DIVISOR;
+		if (velocity.x < -TERM_VELX) velocity.x += (abs(velocity.x)-TERM_VELX)/TERM_VELX_DIVISOR;
+
+		// don't let player move in a direction which they are already touching something
+		if (((c & SC_TL) | (c & SC_TR)) && (velocity.y < 0)) { velocity.y = 0; }
+		if (((c & SC_BL) | (c & SC_BR)) && (velocity.y > 0)) {
+			// player jump
+			if ((joypad() & J_A) && (frames_since_last_jump > JUMP_TIMEOUT_FRAMES)) {
+				velocity.y = -JUMP_VEL;
+				frames_since_last_jump = 0;
+			}
+			else velocity.y = 0;
+		}
+		if (((c & SC_RT) | (c & SC_RB)) && (velocity.x > 0)) { velocity.x = 0; }
+		if (((c & SC_LT) | (c & SC_LB)) && (velocity.x < 0)) { velocity.x = 0; }
+
+		sprite_pos.x += velocity.x;
+		sprite_pos.y += velocity.y;
+
+		c = collision(map, &sprite_pos, &sprite_size);
+
+		// move player out of tiles by brute force searching :eyes:
+		// TODO this is really stupid and bad and i think it will have to be changed when there
+		// are more players moving around
+		search_found = 0;
+		for (ysearch = 0; ysearch <= SPRITE_HEIGHT; ysearch++) {
+			for (xsearch = 0; xsearch <= SPRITE_WIDTH; xsearch++) {
+				search_pos.x = sprite_pos.x + xsearch;
+				search_pos.y = sprite_pos.y + ysearch;
+				if(icollision(map, &search_pos, &sprite_size) == 0) {
+					sprite_pos.x = search_pos.x;
+					sprite_pos.y = search_pos.y;
+					search_found = 1;
+					break;
+				}
+				search_pos.x = sprite_pos.x - xsearch;
+				search_pos.y = sprite_pos.y + ysearch;
+				if(icollision(map, &search_pos, &sprite_size) == 0) {
+					sprite_pos.x = search_pos.x;
+					sprite_pos.y = search_pos.y;
+					search_found = 1;
+					break;
+				}
+				search_pos.x = sprite_pos.x - xsearch;
+				search_pos.y = sprite_pos.y - ysearch;
+				if(icollision(map, &search_pos, &sprite_size) == 0) {
+					sprite_pos.x = search_pos.x;
+					sprite_pos.y = search_pos.y;
+					search_found = 1;
+					break;
+				}
+				search_pos.x = sprite_pos.x + xsearch;
+				search_pos.y = sprite_pos.y - ysearch;
+				if(icollision(map, &search_pos, &sprite_size) == 0) {
+					sprite_pos.x = search_pos.x;
+					sprite_pos.y = search_pos.y;
+					search_found = 1;
+					break;
+				}
+			}
+			if (search_found) break;
+		}
+
+		// finally move the sprite
+		move_sprite(0, sprite_pos.x, sprite_pos.y);
+
+		// Done processing, yield CPU and wait for start of next frame
+		wait_vbl_done();
+	}
+}
diff --git a/src/vec.c b/src/vec.c
new file mode 100644
index 0000000..ac662ce
--- /dev/null
+++ b/src/vec.c
@@ -0,0 +1,9 @@
+struct UVec {
+	unsigned int x;
+	unsigned int y;
+};
+
+struct Vec {
+	int x;
+	int y;
+};