From: Maximilian Friedersdorff <max@friedersdorff.com>
Date: Wed, 5 Apr 2017 15:56:21 +0000 (+0100)
Subject: First working implementation
X-Git-Url: https://git.friedersdorff.com/?p=max%2Fgol.git;a=commitdiff_plain;h=cbeb216c0642d5774e3684ffee6cfa1c4c8cfd00

First working implementation
---

diff --git a/array.c b/array.c
index c70c570..751bdfb 100644
--- a/array.c
+++ b/array.c
@@ -1,34 +1,42 @@
 #include <stddef.h>
 #include <stdlib.h>
+#include <stdio.h>
 #include <string.h>
 #include "array.h"
 
 /*
  * Implements a linear search.
  */
-int gol_is_live(struct gol_board *const state, int_least32_t x, int_least32_t y)
+int gol_is_live(struct gol_board *const state, int_least32_t x, int_least32_t y,
+	char *is_live)
 {
 	for (unsigned int i = 0; i < state->n; i += 2) {
 		if (state->live_cells[i] == x &&
 			state->live_cells[i+1] == y) {
+			*is_live = 1;
 			return 1;
 		}
 	}
-	return 0;
+	*is_live = 0;
+	return 1;
 }
 
+/*
+ *  Return values of 0 represent irrecoverable errors. 1 is a success.
+ */
 int gol_vivify(struct gol_board *const state, int_least32_t x, int_least32_t y)
 {
 	int_least32_t *tmp_cells = NULL;
 	size_t tmp_size = 0;
+
 	if (state->n == state->size) {
 		tmp_size = 2 * state->size;
-		tmp_cells = malloc(tmp_size * sizeof(typeof(tmp_cells)));
+		tmp_cells = malloc(tmp_size * sizeof(int_least32_t));
 		if (!tmp_cells) {
-			return 1;
+			return 0;
 		}
 		memcpy(tmp_cells, state->live_cells,
-			tmp_size * sizeof(typeof(tmp_cells)));
+			state->size * sizeof(int_least32_t));
 		state->size = tmp_size;
 		free(state->live_cells);
 		state->live_cells = tmp_cells;
@@ -50,5 +58,6 @@ int gol_vivify(struct gol_board *const state, int_least32_t x, int_least32_t y)
 	} else if (y < state->min_y) {
 		state->min_y = y;
 	}
+
 	return 1;
 }
diff --git a/array.h b/array.h
index 4cbadce..dad89ba 100644
--- a/array.h
+++ b/array.h
@@ -23,7 +23,7 @@ struct gol_board {
 /*
  * Check that a cell located at (x,y) in the game board is live.
  */
-int gol_is_live(struct gol_board *state, int_least32_t x, int_least32_t y);
+int gol_is_live(struct gol_board *state, int_least32_t x, int_least32_t y, char *is_live);
 
 /*
  * Append the coordinates of the live cell to the array.
diff --git a/gol.c b/gol.c
index ebdbba0..a0c5705 100644
--- a/gol.c
+++ b/gol.c
@@ -3,23 +3,31 @@
 #include "array.h"
 #include "tick.h"
 
+const int ZOOM_LEVELS[10] = {1, 2, 3, 5, 8, 12, 20, 30};
+const unsigned int MAX_ZOOM_LEVEL = 7;
+
+struct viewport {
+	int origin_x;
+	int origin_y;
+	int zoom_level;
+};
+
 void quit(int e_st)
 {
 	SDL_Quit();
 	exit(e_st);
 }
 
-void simulate(struct gol_board *state, SDL_Surface *screen, SDL_Window *window);
+int redraw_screen(struct gol_board *state, SDL_Surface *screen, struct viewport viewport);
 
-int redraw_screen(struct gol_board *state, SDL_Surface *screen, int ppc,
-	int origin_x, int origin_y);
+int handle_mousedown(struct gol_board *state, struct viewport viewport, SDL_Event e);
 
 int main(int argc, char* args[])
 {
 	struct gol_board state = {
 		.live_cells = NULL,
 		.n = 0,
-		.size = 0,
+		.size = 10,
 		.max_x = 0,
 		.min_x = 0,
 		.max_y = 0,
@@ -29,21 +37,21 @@ int main(int argc, char* args[])
 	SDL_Surface *screen = NULL;
 
 	char finished = 0;
+	char tick = 0;
 	char redraw = 1;
 
 	// The coordinates of the cell to draw in the bottom left corner of the
 	// canvas
-	int origin_x = 0;
-	int origin_y = 0;
-
-	int ppc = 10;
+	struct viewport viewport = {0, 0, 4};
 
 	SDL_Event e;
 
-	//state.live_cells = malloc(10 * sizeof(typeof(*state.live_cells)));
-	//if (!state.live_cells) {
-	//	return 1;
-	//}
+	state.live_cells = malloc(10 * sizeof(int_least32_t));
+	if (!state.live_cells) {
+		return 1;
+	}
+
+	gol_vivify(&state, 10, 10);
 	
 	if (SDL_Init(SDL_INIT_EVERYTHING) < 0) {
 		quit(1);
@@ -53,7 +61,7 @@ int main(int argc, char* args[])
 	                          SDL_WINDOWPOS_UNDEFINED,
 	                          SDL_WINDOWPOS_UNDEFINED,
 	                          640,
-	                          320,
+	                          480,
 	                          SDL_WINDOW_SHOWN);
 	if (!window) {
 		quit(1);
@@ -77,68 +85,64 @@ int main(int argc, char* args[])
 					break;
 				case SDLK_PLUS:
 				case SDLK_EQUALS:
-					ppc *= 1.2;
+					if (viewport.zoom_level != MAX_ZOOM_LEVEL)
+						viewport.zoom_level++;
 					redraw = 1;
 					break;
 				case SDLK_MINUS:
 				case SDLK_UNDERSCORE:
-					ppc /= 1.2;
+					if (viewport.zoom_level != 0)
+						viewport.zoom_level--;
 					redraw = 1;
 					break;
+				case SDLK_SPACE:
+					tick = 1;
 				default:
 					break;
 				}
+			} else if (e.type == SDL_MOUSEBUTTONDOWN) {
+				handle_mousedown(&state, viewport, e);
+				redraw = 1;
 			}
 		}
+		if (tick) {
+			tick = 0;
+			gol_tick(&state);
+			redraw = 1;
+		}
 		if (redraw) {
-			redraw_screen(&state, screen, ppc, origin_x, origin_y);
+			redraw = 0;
+			redraw_screen(&state, screen, viewport);
+			SDL_UpdateWindowSurface(window);
 		}
 	}
 
-	// Main loop
-	// simulate(&state, screen, window);
-	
-
 	SDL_DestroyWindow(window);
 	quit(0);
 }
 
 
-void simulate(struct gol_board *state, SDL_Surface *screen, SDL_Window *window)
-{
-	SDL_Rect cell;
-	double ppc_x;
-	double ppc_y;
-	for (unsigned int i = 0; i < 1000; ++i) {
-		printf("Generation %d\n", i);
-		ppc_x = SCREEN_WIDTH/(state->max_x - state->min_x);
-		ppc_y = SCREEN_HEIGHT/(state->max_y - state->min_y);
-		for (unsigned int j = 0; j < state->n; j += 2) {
-			printf("(%d, %d)\n", state->live_cells[j],
-				state->live_cells[j + 1]);
-			
-		}
-		printf("\n");
-		if (!gol_tick(state)) {
-			return;
-		}
-		SDL_UpdateWindowSurface(window);
-	}
-}
-
 int redraw_screen(struct gol_board *state, SDL_Surface *screen,
-	int ppc, int origin_x, int origin_y)
+	struct viewport viewport)
 {
 	SDL_Rect rect;
-	int i, j;
+	int i, j, ppc;
+	char is_live;
+
+	ppc = ZOOM_LEVELS[viewport.zoom_level];
+
+	SDL_FillRect(screen, NULL, SDL_MapRGB(screen->format, 255, 255, 255));
 
-	SDL_FillRect(screen, NULL, SDL_MapRGB(screen->format, 0xFF, 0xFF, 0xFF));
-	for (i = origin_x; i < (screen->w/ppc) + origin_x; ++i) {
-		for (j = origin_y; j < (screen->h/ppc) + origin_y; ++j) {
-			if (gol_is_live(state, i, j)) {
+	for (i = viewport.origin_x;
+	     i < (screen->w/ppc) + viewport.origin_x;
+	     ++i) {
+		for (j = viewport.origin_y;
+		     j < (screen->h/ppc) + viewport.origin_y;
+		     ++j) {
+			if (gol_is_live(state, i, j, &is_live) && is_live) {
 				rect = (SDL_Rect) {
-					((i - origin_x) * ppc),
-					((j - origin_y) * ppc),
+					((i - viewport.origin_x) * ppc),
+					((j - viewport.origin_y) * ppc),
 					ppc,
 					ppc
 				};
@@ -147,4 +151,19 @@ int redraw_screen(struct gol_board *state, SDL_Surface *screen,
 			}
 		}
 	}
+	return 0;
+}
+
+int handle_mousedown(struct gol_board *state, struct viewport viewport, SDL_Event e)
+{
+	int x, y;
+	char is_live;
+	x = e.button.x/ZOOM_LEVELS[viewport.zoom_level] - viewport.origin_x;
+	y = e.button.y/ZOOM_LEVELS[viewport.zoom_level] - viewport.origin_y;
+
+	gol_is_live(state, x, y, &is_live);
+	if (!is_live)
+		gol_vivify(state, x, y);
+
+	return 1;
 }
diff --git a/tick.c b/tick.c
index 07cc195..db98e7d 100644
--- a/tick.c
+++ b/tick.c
@@ -5,8 +5,12 @@
 int gol_tick(struct gol_board *state)
 {
 	struct gol_board tmp_state;
+	char is_live;
+	unsigned char n_live_adj;
+	int i, j;
+
 	tmp_state = (struct gol_board ) {
-		.live_cells = malloc(10 * sizeof(typeof(*tmp_state.live_cells))),
+		.live_cells = malloc(10 * sizeof(int_least32_t)),
 		.n = 0,
 		.size = 10,
 		.max_x = 0,
@@ -14,33 +18,46 @@ int gol_tick(struct gol_board *state)
 		.max_y = 0,
 		.min_y = 0
 	};
+
 	if (!tmp_state.live_cells) {
 		return 0;
 	}
-	unsigned char n_live_adj;
-	for (int i = state->min_x; i < state->max_x; ++i) {
-		for (int j = state->min_y; j < state->max_y; ++j) {
-			n_live_adj = gol_is_live(state, i - 1, j - 1) +
-				gol_is_live(state, i, j - 1) +
-				gol_is_live(state, i + 1, j - 1) +
-				gol_is_live(state, i - 1, j) +
-				gol_is_live(state, i + 1, j) +
-				gol_is_live(state, i - 1 , j + 1) +
-				gol_is_live(state, i, j + 1) +
-				gol_is_live(state, i + 1, j + 1);
-				
+
+	for (i = state->min_x - 1; i <= state->max_x + 1; ++i) {
+		for (j = state->min_y - 1; j <= state->max_y + 1; ++j) {
+			n_live_adj = 0;
+			gol_is_live(state, i - 1, j - 1, &is_live);
+			n_live_adj += is_live;
+			gol_is_live(state, i, j - 1, &is_live);
+			n_live_adj += is_live;
+			gol_is_live(state, i + 1, j - 1, &is_live);
+			n_live_adj += is_live;
+			gol_is_live(state, i - 1, j, &is_live);
+			n_live_adj += is_live;
+			gol_is_live(state, i + 1, j, &is_live);
+			n_live_adj += is_live;
+			gol_is_live(state, i - 1 , j + 1, &is_live);
+			n_live_adj += is_live;
+			gol_is_live(state, i, j + 1, &is_live);
+			n_live_adj += is_live;
+			gol_is_live(state, i + 1, j + 1, &is_live);
+			n_live_adj += is_live;
+
 			switch (n_live_adj) {
 			case (3):
-				gol_vivify(&tmp_state, i, j);
+				if(!gol_vivify(&tmp_state, i, j)) {
+					return 0;
+				}
+
 				break;
 			case(2):
-				if (gol_is_live(state, i, j)) {
+				if (gol_is_live(state, i, j, &is_live) && is_live) {
 					gol_vivify(&tmp_state, i, j);
 				}
+				break;
 			default:
 				break;
 			}
-			
 		}
 	}
 	free(state->live_cells);