a-game

commit 305614525c729f70fa18fe26ebc6e223cd06860a
parent 4abcf6af784f6f74e3a974bb7efd9dcca0cef09f
Author: amin <dev@aminmesbah.com>
Date:   Wed, 17 Jul 2019 02:25:23 +0000

Use stack allocator in wasm platform file loading

And finally get rid of that crazy huge stack buffer!

FossilOrigin-Name: e0d80e116e43d2bff03c95976a567ffc85faced474f3d2da5b8ed23c38a7bf21
Diffstat:
M
src/platform_wasm.c
 | 
36
++++++++++++++++++------------------
M
src/platform_wasm.h
 | 
1
+
M
src/platform_wasm_js_symbols.txt
 | 
1
+
M
src/platform_wasm_loader.js
 | 
21
++++++++++++++++++---

4 files changed, 38 insertions(+), 21 deletions(-)
diff --git a/src/platform_wasm.c b/src/platform_wasm.c
@@ -2,7 +2,13 @@
 #include "platform.h"
 #include "platform_wasm.h"
 
-extern unsigned char __heap_base;
+// wasm-ld memory layout:
+//      a       b
+// data | stack | heap
+// a = __data_end
+// b = __heap_base
+extern u8 __heap_base;
+extern u8 __data_end;
 
 // There's no standardized, nondeprecated way to get a numeric ID of a keyboard
 // key, so I guess we have to do that ourselves.
@@ -29,10 +35,6 @@ global_variable struct GameMemory game_memory = {0};
 global_variable struct GameInput game_input = {0};
 global_variable i32 g_width = PLATFORM_SCR_WIDTH;
 global_variable i32 g_height = PLATFORM_SCR_HEIGHT;
-// TODO: For the love of God, replace this with an allocator!
-// NOTE: If this buffer is too small, the browser will freeze up
-global_variable u8 g_mem_buffer[200000] = {0};
-global_variable i32 g_mem_buffer_i = 0;
 global_variable u32 previous_time = 0;
 
 i32 str_length(const char *str)
@@ -117,22 +119,20 @@ PLATFORM_MEMORY_FREE(wasm_memory_free)
     // do nothing
 }
 
-// TODO: robustly return file length
 PLATFORM_READ_ENTIRE_FILE(wasm_read_entire_file)
 {
-    g_mem_buffer_i++;
-    u8 *buf = &g_mem_buffer[g_mem_buffer_i];
-    i32 file_data_length = js_read_entire_file((i32)file_path, str_length(file_path), buf);
-    if(file_data_length)
-    {
-        *out_num_bytes = file_data_length;
-        g_mem_buffer_i += file_data_length;
-        g_mem_buffer[g_mem_buffer_i] = '\0';
-        wasm_print("Succeeded in reading file.");
-    }
-    else
+    i32 num_bytes_in_file = js_get_file_size((i32)file_path, str_length(file_path));
+
+    if (out_num_bytes)
     {
-        wasm_print("Failed to read file.");
+        *out_num_bytes = num_bytes_in_file;
     }
+
+    u8 *buf = mem_st_alloc_buffer(a, u8, num_bytes_in_file + 1);
+    assert(buf);
+
+    js_read_entire_file((i32)file_path, str_length(file_path), buf);
+    buf[num_bytes_in_file] = '\0';
+    wasm_print("Succeeded in reading file.");
     return buf;
 }
diff --git a/src/platform_wasm.h b/src/platform_wasm.h
@@ -5,5 +5,6 @@ PLATFORM_READ_ENTIRE_FILE(wasm_read_entire_file);
 PLATFORM_MEMORY_FREE(wasm_memory_free);
 
 // Functions implemented in the JS loader
+i32 js_get_file_size(i32 file_path, i32 name_len);
 i32 js_read_entire_file(i32 file_path, i32 name_len, u8 *file_data);
 i32 js_print(i32 string, i32 len);
diff --git a/src/platform_wasm_js_symbols.txt b/src/platform_wasm_js_symbols.txt
@@ -42,5 +42,6 @@ webglUniformMatrix4fv
 webglUseProgram
 webglVertexAttribPointer
 webglViewport
+js_get_file_size
 js_read_entire_file
 js_print
diff --git a/src/platform_wasm_loader.js b/src/platform_wasm_loader.js
@@ -204,7 +204,24 @@ imports["webglVertexAttribPointer"] = function(index, size, type, normalized, st
 imports["webglViewport"] = function(x, y, width, height) {
     gl.viewport(x, y, width, height);
 }
-imports["js_read_entire_file"] = function(name, name_len, out_buf, out_len) {
+imports["js_get_file_size"] = function(name, name_len) {
+    let file_name = utf8decoder.decode(memory.subarray(name, name + name_len))
+    let file_size = 0;
+    if (file_name == "shader/main_f.glsl") {
+        var file = files[1];
+    } else if (file_name == "shader/main_v.glsl") {
+        var file = files[2];
+    } else if (file_name == "assets/tile0.tga") {
+        var file = files[3];
+    } else if (file_name == "assets/tileset0.tga") {
+        var file = files[4];
+    } else {
+        return 0;
+    }
+    file_size = file.byteLength;
+    return file_size;
+}
+imports["js_read_entire_file"] = function(name, name_len, out_buf) {
     let file_name = utf8decoder.decode(memory.subarray(name, name + name_len))
     let file_size = 0;
     if (file_name == "shader/main_f.glsl") {
@@ -219,10 +236,8 @@ imports["js_read_entire_file"] = function(name, name_len, out_buf, out_len) {
         return 0;
     }
     let arr = memory.subarray(out_buf, out_buf + file.byteLength);
-    file_size = arr.length * arr.BYTES_PER_ELEMENT;
     let s = String.fromCharCode.apply(null, arr);
     arr.set(new Uint8Array(file));
-    return file_size;
 }
 imports["js_print"] = function(s, len) {
     let arr = memory.subarray(s, s + len);