[win32, graphics] adding example to test rendering in a secondary thread

examples/render_thread/build.bat

@@ -0,0 +1,7 @@
+
+set pthread_dir=..\..\..\..\vcpkg\packages\pthreads_x64-windows
+set INCLUDES=/I ..\..\src /I ..\..\src\util /I ..\..\src\platform /I ../../ext /I ../../ext/angle_headers /I %pthread_dir%\include
+
+cl /we4013 /Zi /Zc:preprocessor /std:c11 %INCLUDES% main.c /link /MANIFEST:EMBED /MANIFESTINPUT:../../src/win32_manifest.xml /LIBPATH:../../bin milepost.dll.lib /LIBPATH:%pthread_dir%\lib pthreadVC3.lib /out:../../bin/example_render_thread.exe
+
+copy %pthread_dir%\bin\pthreadVC3.dll ..\..\bin

examples/render_thread/build.sh

@@ -0,0 +1,14 @@
+#!/bin/bash
+
+BINDIR=../../bin
+RESDIR=../../resources
+SRCDIR=../../src
+EXTDIR=../../ext
+
+INCLUDES="-I$SRCDIR -I$SRCDIR/util -I$SRCDIR/platform -I$SRCDIR/app -I$EXTDIR"
+LIBS="-L$BINDIR -lmilepost"
+FLAGS="-mmacos-version-min=10.15.4 -DDEBUG -DLOG_COMPILE_DEBUG"
+
+clang -g $FLAGS $LIBS $INCLUDES -o $BINDIR/example_render_thread main.c
+
+install_name_tool -add_rpath "@executable_path" $BINDIR/example_render_thread

examples/render_thread/main.c

@@ -0,0 +1,101 @@
+
+#include<stdlib.h>
+#include<stdio.h>
+#include<pthread.h>
+
+#define MG_INCLUDE_GL_API 1
+#include"milepost.h"
+
+mg_surface surface = {0};
+mg_canvas canvas = {0};
+
+void* render_thread(void* user)
+{
+	while(!mp_should_quit())
+	{
+		mp_event* event = 0;
+		while((event = mp_next_event(mem_scratch())) != 0)
+		{
+			switch(event->type)
+			{
+				case MP_EVENT_WINDOW_CLOSE:
+				{
+					mp_request_quit();
+				} break;
+
+				default:
+					break;
+			}
+		}
+
+		mg_surface_prepare(surface);
+		mg_canvas_set_current(canvas);
+
+			mg_set_color_rgba(0, 0, 0.5, 0.5);
+			mg_clear();
+
+			mg_set_color_rgba(1, 0, 0, 1);
+			mg_rectangle_fill(100, 100, 300, 150);
+
+		mg_render(surface, canvas);
+
+		mg_surface_present(surface);
+
+		mem_arena_clear(mem_scratch());
+	}
+	return(0);
+}
+
+int main()
+{
+	mp_init();
+	mp_clock_init(); //TODO put that in mp_init()?
+
+	mp_rect windowRect = {.x = 100, .y = 100, .w = 810, .h = 610};
+	mp_window window = mp_window_create(windowRect, "test", 0);
+
+	mp_rect contentRect = mp_window_get_content_rect(window);
+
+	//NOTE: create surface
+	surface = mg_surface_create_for_window(window, MG_CANVAS);
+	if(mg_surface_is_nil(surface))
+	{
+		printf("Error: couldn't create surface 1\n");
+		return(-1);
+	}
+	mg_surface_swap_interval(surface, 0);
+
+	canvas = mg_canvas_create();
+	if(mg_canvas_is_nil(canvas))
+	{
+		printf("Error: couldn't create canvas 1\n");
+		return(-1);
+	}
+
+	mg_surface dummy = mg_surface_create_for_window(window, MG_CANVAS);
+
+	// start app
+	mp_window_center(window);
+	mp_window_bring_to_front(window);
+	mp_window_focus(window);
+
+	pthread_t renderThread;
+	pthread_create(&renderThread, 0, render_thread, 0);
+
+	while(!mp_should_quit())
+	{
+		mp_pump_events(0);
+	}
+
+	void* res;
+	pthread_join(renderThread, &res);
+
+	mg_canvas_destroy(canvas);
+	mg_surface_destroy(surface);
+
+	mp_window_destroy(window);
+
+	mp_terminate();
+
+	return(0);
+}

src/gl_canvas.c

@@ -1957,9 +1957,6 @@ mg_canvas_backend* gl_canvas_backend_create(mg_wgl_surface* surface)
 	mg_gl_canvas_backend* backend = malloc_type(mg_gl_canvas_backend);
 	if(backend)
 	{
-		//////////////////////////////////////////////////////
-		//TODO
-		//////////////////////////////////////////////////////
 		memset(backend, 0, sizeof(mg_gl_canvas_backend));
 		backend->surface = surface;
 
@@ -1970,14 +1967,6 @@ mg_canvas_backend* gl_canvas_backend_create(mg_wgl_surface* surface)
 		backend->interface.imageDestroy = mg_gl_canvas_image_destroy;
 		backend->interface.imageUploadRegion = mg_gl_canvas_image_upload_region;
 
-		/*
-		backend->interface.destroy = mg_gl_canvas_destroy;
-		backend->interface.begin = mg_gl_canvas_begin;
-		backend->interface.end = mg_gl_canvas_end;
-		backend->interface.clear = mg_gl_canvas_clear;
-		backend->interface.drawBatch = mg_gl_canvas_draw_batch;
-		*/
-
 		surface->interface.prepare((mg_surface_data*)surface);
 
 		glGenVertexArrays(1, &backend->vao);