Documentation, heightmap example and custom begin and end draw.

src/core.c

@@ -494,6 +494,28 @@ int lcoreClearBackground( lua_State *L ) {
 	return 1;
 }
 
+/*
+> RL_BeginDrawing()
+
+Setup canvas ( framebuffer ) to start drawing
+*/
+int lcoreBeginDrawing( lua_State *L ) {
+	BeginDrawing();
+
+	return 1;
+}
+
+/*
+> RL_EndDrawing()
+
+End canvas drawing and swap buffers ( double buffering )
+*/
+int lcoreEndDrawing( lua_State *L ) {
+	EndDrawing();
+
+	return 1;
+}
+
 /*
 > success = RL_BeginBlendMode( int mode )
 

src/lua_core.c

@@ -228,6 +228,10 @@ bool luaCallMain() {
 /* If web, set path to resources folder. */
 #ifdef EMSCRIPTEN
 	sprintf( path, "resources/main.lua" );
+	/* Alternatively look for main. Could be precompiled binary file. */
+	if ( !FileExists( path ) ) {
+		sprintf( path, "resources/main" );
+	}
 #else
 	sprintf( path, "%smain.lua", state->exePath );
 	/* Alternatively look for main. Could be precompiled binary file. */
@@ -347,6 +351,8 @@ void luaRegister() {
 	lua_register( L, "RL_IsCursorOnScreen", lcoreIsCursorOnScreen );
 		/* Drawing. */
 	lua_register( L, "RL_ClearBackground", lcoreClearBackground );
+	lua_register( L, "RL_BeginDrawing", lcoreBeginDrawing );
+	lua_register( L, "RL_EndDrawing", lcoreEndDrawing );
 	lua_register( L, "RL_BeginBlendMode", lcoreBeginBlendMode );
 	lua_register( L, "RL_EndBlendMode", lcoreEndBlendMode );
 	lua_register( L, "RL_BeginScissorMode", lcoreBeginScissorMode );

src/models.c

@@ -939,7 +939,14 @@ int lmodelsGenMeshHeightmap( lua_State *L ) {
 	}
 	Vector3 size = uluaGetVector3( L );
 	lua_pop( L, 1 );
-	Image *heightmap = state->images[ lua_tointeger( L, -1 ) ];
+	size_t imageId = lua_tointeger( L, -1 );
+
+	if ( !validImage( imageId ) ) {
+		lua_pushboolean( L, false );
+		return 1;
+	}
+
+	Image *heightmap = state->images[ imageId ];
 	int i = 0;
 
 	for ( i = 0; i < state->meshCount; i++ ) {
@@ -1112,7 +1119,7 @@ int lmodelsDrawMesh( lua_State *L ) {
 	return 1;
 }
 
-/* TODO Needs shader to work. Test it when we have shaders. */
+/* TODO Not testet. */
 /*
 > success = RL_DrawMeshInstanced( Mesh mesh, Material material, Matrix{} transforms, int instances )