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Embrace the dark side (asm). 3719 bytes
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@TheSunCat
TheSunCat committed Sep 3, 2023
1 parent 8cb6faf commit 31fbbb6
Showing 1 changed file with 54 additions and 57 deletions.
111 changes: 54 additions & 57 deletions Minecraft4k.c
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Original file line number Diff line number Diff line change
Expand Up @@ -28,39 +28,35 @@ typedef void(*SDL_GL_SwapWindow_t)(SDL_Window*);
typedef Uint64(*SDL_GetTicks64_t)(void);
typedef const Uint8*(*SDL_GetKeyboardState_t)(int*);

static SDL_GetTicks64_t sym_SDL_GetTicks64;
static SDL_GetKeyboardState_t sym_SDL_GetKeyboardState;
SDL_GetTicks64_t sym_SDL_GetTicks64;
SDL_GetKeyboardState_t sym_SDL_GetKeyboardState;

typedef int(*rand_t)(void);
static rand_t sym_rand;
rand_t sym_rand;

// OpenGL IDs
static GLuint shader;
static GLuint worldTex;
static GLuint textureAtlasTex;
GLuint shader;
GLuint worldTex;
GLuint textureAtlasTex;

static uint64_t currentTime()
{
return sym_SDL_GetTicks64();
}

static const int X = 0, Y = 1, Z = 2;
const int X = 0, Y = 1, Z = 2;

// size: 17
// TODO tune this, or use inline x86 ASM
#define TRIG_PRECISION 20
static float my_sin(float x)
float my_sin(float x)
{
// return sinf(x); // looks like this is slightly smaller for now, welp
float sine;

float t = x;
float sine = x;
for (int a=1; a < TRIG_PRECISION; ++a)
{
float mult = -x*x/((2*a+1)*(2*a));
t *= mult;
sine += t;
}
asm (
"fsin;"
"fstps %0;"
: "=m" (sine)
: "t" (x)
);

return sine;
}

Expand All @@ -69,7 +65,7 @@ static float my_cos(float x)
return my_sin(x + M_PI / 2.0f);
}

static float clamp(float x, float min, float max)
float clamp(float x, float min, float max)
{
if(x < min)
return min;
Expand All @@ -78,14 +74,19 @@ static float clamp(float x, float min, float max)
return x;
}

static uint8_t world[WORLD_SIZE * WORLD_HEIGHT * WORLD_SIZE];
uint8_t world[WORLD_SIZE * WORLD_HEIGHT * WORLD_SIZE];

int toIndex(int x, int y, int z)
{
return y + x * WORLD_SIZE + z * WORLD_SIZE * WORLD_HEIGHT;
}

// hacky workaround: remember block placed this frame so we can delete if colliding with
static int blockSetThisFrame = -1;
// size: 134!!
int blockSetThisFrame = -1;

static void setBlock(int x, int y, int z, uint8_t block)
{
blockSetThisFrame = y + x * WORLD_SIZE + z * WORLD_SIZE * WORLD_HEIGHT;
blockSetThisFrame = toIndex(x, y, z);

world[blockSetThisFrame] = block;

Expand All @@ -99,23 +100,20 @@ static void setBlock(int x, int y, int z, uint8_t block)
&block); // data
}

// size: 22
static uint8_t getBlock(int x, int y, int z)
uint8_t getBlock(int x, int y, int z)
{
return world[y + x * WORLD_SIZE + z * WORLD_SIZE * WORLD_HEIGHT];
return world[toIndex(x, y, z)];
}

// size: 23
static int isWithinWorld(int x, int y, int z)
int isWithinWorld(int x, int y, int z)
{
return x >= 0.0f && y >= 0.0f && z >= 0.0f &&
x < WORLD_SIZE && y < WORLD_HEIGHT && z < WORLD_SIZE;
return (x >= 0) & (y >= 0) & (z >= 0) &
(x < WORLD_SIZE) & (y < WORLD_HEIGHT) & (z < WORLD_SIZE);
}

static int hoverBlockX = -100, hoverBlockY = -100, hoverBlockZ = -100;
static int placeBlockX = -100, placeBlockY = -100, placeBlockZ = -100;
int hoverBlockX = -100, hoverBlockY = -100, hoverBlockZ = -100;
int placeBlockX = -100, placeBlockY = -100, placeBlockZ = -100;

// size: none
static void breakBlock()
{
if(hoverBlockX == -100)
Expand All @@ -124,7 +122,6 @@ static void breakBlock()
setBlock(hoverBlockX, hoverBlockY, hoverBlockZ, BLOCK_AIR);
}

// size: none
static void placeBlock(uint8_t block)
{
if(placeBlockX == -100)
Expand All @@ -134,17 +131,17 @@ static void placeBlock(uint8_t block)
setBlock(placeBlockX, placeBlockY, placeBlockZ, block);
}

static SDL_Window* window;
static int SCR_WIDTH = SCR_WIDTH_DEFAULT * (float) (1 << SCR_DETAIL);
static int SCR_HEIGHT = SCR_HEIGHT_DEFAULT * (float) (1 << SCR_DETAIL);
SDL_Window* window;
int SCR_WIDTH = SCR_WIDTH_DEFAULT * (float) (1 << SCR_DETAIL);
int SCR_HEIGHT = SCR_HEIGHT_DEFAULT * (float) (1 << SCR_DETAIL);

static float cameraPitch = 0;
static float cameraYaw = 0;
float cameraPitch = 0;
float cameraYaw = 0;

static float playerVelocityX = 0, playerVelocityY = 0, playerVelocityZ = 0;
float playerVelocityX = 0, playerVelocityY = 0, playerVelocityZ = 0;

// spawn player at world center
static float playerPosX = WORLD_SIZE / 2.0f + 0.5f, playerPosY = 1, playerPosZ = WORLD_SIZE / 2.0f + 0.5f;
float playerPosX = WORLD_SIZE / 2.0f + 0.5f, playerPosY = 1, playerPosZ = WORLD_SIZE / 2.0f + 0.5f;

// TODO fix bad

Expand All @@ -153,13 +150,13 @@ static float playerPosX = WORLD_SIZE / 2.0f + 0.5f, playerPosY = 1, playerPosZ =
// ---------------

// size: 4
static float my_fract(float x)
float my_fract(float x)
{
return x - (float)((int) x);
}

// size: 10
static int my_sign(float x)
int my_sign(float x)
{
if(x < 0)
return -1;
Expand All @@ -174,13 +171,13 @@ static void raycastWorld(float sinYaw, float cosYaw, float sinPitch, float cosPi
const float rayDirY = -sinPitch;
const float rayDirZ = cosPitch * cosYaw;

float i = (int)playerPosX;
float j = (int)playerPosY;
float k = (int)playerPosZ;
int i = (int)playerPosX;
int j = (int)playerPosY;
int k = (int)playerPosZ;

const float iStep = my_sign(rayDirX);
const float jStep = my_sign(rayDirY);
const float kStep = my_sign(rayDirZ);
const int iStep = my_sign(rayDirX);
const int jStep = my_sign(rayDirY);
const int kStep = my_sign(rayDirZ);

const float vInvertedX = fabs(1/rayDirX);
const float vInvertedY = fabs(1/rayDirY);
Expand All @@ -195,7 +192,7 @@ static void raycastWorld(float sinYaw, float cosYaw, float sinPitch, float cosPi

int axis = X;

float rayTravelDist = 0;
float rayTravelDist = 0.f;
while(rayTravelDist < PLAYER_REACH)
{
// exit check
Expand Down Expand Up @@ -275,16 +272,16 @@ static void raycastWorld(float sinYaw, float cosYaw, float sinPitch, float cosPi
// BAD ENDS HERE
// -------------

static const uint8_t* kb = NULL;
const uint8_t* kb = NULL;

// size: 505!!
static void updateController()
{
kb = sym_SDL_GetKeyboardState(NULL);
}

static uint64_t lastFrameTime = 0;
static uint64_t lastUpdateTime;
uint64_t lastFrameTime = 0;
uint64_t lastUpdateTime;

// size: 1611
static void on_render()
Expand Down Expand Up @@ -339,7 +336,7 @@ static void on_render()
continue;

// hacky: delete block if it was placed this frame to prevent getting stuck
const int colliderBlockIndex = colliderBlockPosY + colliderBlockPosX * WORLD_SIZE + colliderBlockPosZ * WORLD_SIZE * WORLD_HEIGHT;
const int colliderBlockIndex = toIndex(colliderBlockPosX, colliderBlockPosY, colliderBlockPosZ);
if(colliderBlockIndex == blockSetThisFrame)
setBlock(colliderBlockPosX, colliderBlockPosY, colliderBlockPosZ, BLOCK_AIR);

Expand Down Expand Up @@ -446,7 +443,7 @@ static void generateWorld()
world); // pixels
}

static int textureAtlas[TEXTURE_RES * TEXTURE_RES * 3 * 7];
int textureAtlas[TEXTURE_RES * TEXTURE_RES * 3 * 7];

// size: 624!!
static void generateTextures()
Expand Down

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