Moving events into it's own compliation unit and adding library insta…

…ll examples

Makefile

@@ -25,6 +25,11 @@ about:
 	@echo "make test    -  run some basic tests."
 	@echo ""
 
+init:
+	sudo apt install clang-14
+	sudo apt install lld-14
+	sudo apt-get install gcc-multilib
+
 clean:
 	rm -rf build
 
@@ -44,7 +49,7 @@ build: clean
 		-Wl,-z,stack-size=$(STACK_SIZE) \
 		$(NO_BUILT_INS) \
 		-o build/wefx.wasm \
-		src/walloc.c src/math.c src/wefx.c $(MAIN)
+		src/walloc.c src/math.c src/events.c src/wefx.c $(MAIN)
 	cp public/index.html build/index.html
 
 serve: clean build
@@ -71,9 +76,13 @@ install_linux:
 	apt-get install groff pandoc texlive-xetex
 
 test: clean_test
+	@echo "if you get: 'fatal error: 'bits/libc-header-start.h' file not found'"
+	@echo "you need 32 bit libs installed. Either remove -m32 from the flags below"
+	@echo "or run 'sudo apt-get install gcc-multilib' or equivalent."
+
 	mkdir -p build
 # add -lm if you want to test against built in math.h
-	clang -std=c99 -m32 -g \
+	$(CC) -std=c99 -m32 -g \
 		$(NO_BUILT_INS) \
 		src/math.c src/wefx.c src/test.c \
 		-o build/test

README.md

@@ -10,6 +10,12 @@ You can also [download the documentation](https://raw.githubusercontent.com/robr
 
 ![Example Screenshot](https://raw.githubusercontent.com/robrohan/wefx/main/docs/wefx_shot.png)
 
+## Quick Start
+
+If you are using Ubuntu, you can run `make init` to install the correct version of clang and tools. If you are on another system, you will have to install `clang` yourself. 
+
+Once installed, `make build` should compile `examples/example0.c` into WASM (if there are no errors). If successful, and if you have python installed, you can run `make serve` to start a simple HTTP server and browse to http://localhost:8000 to view wasm output.
+
 ## Using The Project
 
 The flow of the project has two steps: the build step, and the serve step:

examples/example0.c

@@ -1,5 +1,6 @@
 #include "../src/wasm.h"
 #include "../src/wefx.h"
+#include "../src/events.h"
 
 /*
  * - the bottom-left is (0,0) and the pixel coordinates increase

examples/example1.c

@@ -1,5 +1,6 @@
 #include "../src/wasm.h"
 #include "../src/wefx.h"
+#include "../src/events.h"
 
 #define W 1024
 #define H 768

src/events.c

@@ -0,0 +1,160 @@
+#include "events.h"
+#include "wasm.h"
+/*
+
+Here we reserve a spot for an event queue where we will store user events from the browser.
+E.g. Mouse down, mouse move, key down, etc.
+
+*/
+EXPORT wefx_event_queue *wefx_q = NULL;
+/*
+
+# Event Queue
+
+In order to process browser events (keyboard and mouse input), we use
+a simple Queue. The Javascript that hosts this code will capture events
+in the browser and pass them into C using the queue. We can then use the
+queue to look at and process those events.
+
+## Open Events - wefx_open_events
+
+Similar to how _wefx\_open_ created screen memory, the _wefx_open_events_
+function allocates memory for the event queue.
+
+*/
+wefx_event_queue *wefx_open_events()
+{
+    wefx_q = malloc(sizeof(struct wefx_event_queue));
+    // wefx_q = &(const struct wefx_event_queue){ 0 };
+    if (wefx_q != NULL)
+    {
+        wefx_init_queue(wefx_q);
+        return wefx_q;
+    }
+
+    return NULL;
+}
+/*
+
+When we create a new queue, we want to set the head and tail to null to
+mark it as empty. This is not strictly necessary, but it will make knowing
+if the queue is empty a bit easier.
+
+*/
+void wefx_init_queue(wefx_event_queue *q)
+{
+    q->head = NULL;
+    q->tail = NULL;
+}
+/*
+
+## Add Events from Javascript
+
+Javascript will call this function directly to register that an event has
+occurred.
+
+Here we just take the parameters passed in from Javascript, put them into
+the _wefx\_event_ struct, and add it to the end of the queue.
+
+*/
+EXPORT void wefx_add_queue_event(int type, int button, int timestamp, int key, int x, int y)
+{
+    // if we don't care about events drop everything
+    if (wefx_q == NULL)
+        return;
+
+    wefx_event *e = malloc(sizeof(struct wefx_event));
+    if (e == NULL)
+    {
+        // we couldn't create memory for some reason
+        // this seems to happen a bit when running in
+        // wasm (or maybe walloc)
+        return;
+    }
+    e->type = type;
+    e->button = button;
+    e->timestamp = timestamp;
+    e->key = (char)key;
+    e->x = x;
+    e->y = y;
+
+    wefx_enqueue(wefx_q, e);
+}
+/*
+
+## Add an Event to a Queue
+
+_wefx\_enqueue_ takes an event and adds it to the given queue. It does a number of
+checks to make sure the queue is in a valid state, and adds the event if
+everything is ok.
+
+*/
+int wefx_enqueue(wefx_event_queue *q, wefx_event *event)
+{
+    // create a new node to store the event
+    wefx_event_node *node = malloc(sizeof(struct wefx_event_node));
+    if (node == NULL)
+    {
+        return -1;
+    }
+
+    node->event = event;
+    node->next = NULL;
+
+    // if the queue has a tail, add us as the next behind the tail
+    if (q->tail != NULL)
+    {
+        q->tail->next = node;
+    }
+    // now really make us the last node
+    q->tail = node;
+
+    // if we are first in line, go to the head
+    if (q->head == NULL)
+    {
+        q->head = node;
+    }
+
+    return 1;
+}
+/*
+
+## Remove an Event from a Queue
+
+Take the first event in the queue off the queue, and return it.
+
+*/
+wefx_event *wefx_dequeue(wefx_event_queue *q)
+{
+    if (q == NULL)
+        return NULL;
+
+    wefx_event *e = NULL;
+
+    if (q->head == NULL)
+        return NULL;
+
+    wefx_event_node *n = q->head;
+
+    if(n->event == NULL) {
+        goto clean_up;
+    }
+
+    e = n->event;
+
+    if(n->next == NULL) {
+        goto clean_up;
+    }
+    q->head = n->next;
+
+    // if our new head is null, make sure the
+    // tail is set to null
+    if (q->head == NULL)
+        q->tail = NULL;
+
+clean_up:
+    if (n != NULL)
+        free(n);
+
+    return e;
+}

src/events.h

@@ -0,0 +1,55 @@
+#ifndef WEFX_EVENTS_H
+#define WEFX_EVENTS_H
+
+enum wefx_button_type
+{
+    WEFX_NONE = 0,
+    WEFX_LEFT,
+    WEFX_RIGHT,
+};
+
+enum wefx_event_type
+{
+    WEFX_KEYDOWN = 0,
+    WEFX_KEYPRESS = 1,
+    WEFX_KEYUP = 2,
+    WEFX_MOUSEMOVE = 3,
+    WEFX_MOUSEDOWN = 4,
+    WEFX_MOUSEUP = 5,
+    WEFX_CLICK = 6
+};
+
+typedef struct wefx_event
+{
+    enum wefx_event_type type;
+    enum wefx_button_type button;
+    char key; // TODO: this wont work with utf8
+              // keyCode is deprecated in javascript
+    int timestamp;
+    int x;
+    int y;
+} wefx_event;
+
+typedef struct wefx_event_node
+{
+    struct wefx_event *event;
+    struct wefx_event_node *next;
+} wefx_event_node;
+
+typedef struct wefx_event_queue
+{
+    wefx_event_node *head;
+    wefx_event_node *tail;
+} wefx_event_queue;
+
+//////////////////////////////////////////////
+
+wefx_event_queue *wefx_open_events();
+
+void wefx_init_queue(wefx_event_queue *q);
+
+int wefx_enqueue(wefx_event_queue *q, wefx_event *event);
+
+wefx_event *wefx_dequeue(wefx_event_queue *q);
+
+#endif

src/wasm.h

@@ -15,6 +15,10 @@ to be able to call a C function from within Javascript.
 #include "math.h"
 #include "walloc.h"
 
+#ifndef NULL
+#define NULL ((void *)0)
+#endif
+
 #define EXPORT __attribute__((visibility("default")))
 
 #endif