new lua bindings for textures

- output:renderer
- renderer:texture_from_pixels
- renderer:draw_texture

We need to be able to access the renderer outside of the post_render
hook (hence output:renderer) because we can't call
wlr_texture_from_pixels while rendering

texture_from_pixels accepts a string as the data argument not a
userdata, because that matches what we getk from GdkPixbuf.Pixbuf
new_from_file when using gobject-introspection.

kiwmi/kiwmi/luak/kiwmi_output.c

@@ -18,6 +18,7 @@
 #include "luak/kiwmi_lua_callback.h"
 #include "luak/lua_compat.h"
 #include "server.h"
+#include "luak/kiwmi_renderer.h"
 
 static int
 l_kiwmi_output_auto(lua_State *L)
@@ -188,6 +189,36 @@ l_kiwmi_output_usable_area(lua_State *L)
     return 1;
 }
 
+static int
+l_kiwmi_output_renderer(lua_State *L)
+{
+    struct kiwmi_object *obj =
+        *(struct kiwmi_object **)luaL_checkudata(L, 1, "kiwmi_output");
+
+    if (!obj->valid) {
+        return luaL_error(L, "kiwmi_output no longer valid");
+    }
+
+    struct kiwmi_output *output = obj->object;
+
+    struct kiwmi_desktop *desktop = output->desktop;
+    struct kiwmi_server *server   = wl_container_of(desktop, server, desktop);
+    struct wlr_renderer *renderer = server->renderer;
+
+    lua_pushcfunction(L, luaK_kiwmi_renderer_new);
+    lua_pushlightuserdata(L, server->lua);
+    lua_pushlightuserdata(L, renderer);
+    lua_pushlightuserdata(L, output->wlr_output);
+
+    if (lua_pcall(L, 3, 1, 0)) {
+        wlr_log(WLR_ERROR, "%s", lua_tostring(L, -1));
+        lua_pop(L, 1);
+        return 0;
+    }
+    return 1;
+}
+
+
 static const luaL_Reg kiwmi_output_methods[] = {
     {"auto", l_kiwmi_output_auto},
     {"move", l_kiwmi_output_move},
@@ -195,6 +226,7 @@ static const luaL_Reg kiwmi_output_methods[] = {
     {"on", luaK_callback_register_dispatch},
     {"pos", l_kiwmi_output_pos},
     {"redraw", l_kiwmi_output_redraw},
+    {"renderer", l_kiwmi_output_renderer},
     {"size", l_kiwmi_output_size},
     {"set_mode", l_kiwmi_output_set_mode},
     {"usable_area", l_kiwmi_output_usable_area},

kiwmi/kiwmi/luak/kiwmi_renderer.c

@@ -15,6 +15,8 @@
 #include <wlr/types/wlr_output.h>
 #include <wlr/util/log.h>
 
+#include <drm/drm_fourcc.h>
+
 #include "color.h"
 #include "desktop/output.h"
 #include "luak/lua_compat.h"
@@ -57,8 +59,66 @@ l_kiwmi_renderer_draw_rect(lua_State *L)
     return 0;
 }
 
+static int
+l_kiwmi_renderer_draw_texture(lua_State *L)
+{
+    struct kiwmi_renderer *renderer =
+        (struct kiwmi_renderer *) luaL_checkudata(L, 1, "kiwmi_renderer");
+    struct wlr_texture *texture = (struct wlr_texture *) lua_touserdata(L, 2);
+
+    float projection[9];
+
+    for(int i=0; i<9; i++) {
+	lua_pushnumber(L, i+1);
+	lua_gettable(L, 3);
+	projection[i] = lua_tointeger(L, -1);
+    }
+
+    luaL_checktype(L, 4, LUA_TNUMBER); /* x  */
+    luaL_checktype(L, 5, LUA_TNUMBER); /* y  */
+    luaL_checktype(L, 6, LUA_TNUMBER); // alpha
+
+    struct wlr_renderer *wlr_renderer = renderer->wlr_renderer;
+
+    wlr_render_texture(wlr_renderer, texture, projection,
+		       lua_tonumber(L, 4),
+		       lua_tonumber(L, 5),
+		       lua_tonumber(L, 6));
+
+    return 0;
+}
+
+static int
+l_kiwmi_renderer_texture_from_pixels(lua_State *L)
+{
+    struct kiwmi_renderer *renderer =
+        (struct kiwmi_renderer *)luaL_checkudata(L, 1, "kiwmi_renderer");
+
+    struct wlr_renderer *wlr_renderer = renderer->wlr_renderer;
+    struct wlr_texture * texture;
+
+    luaL_checktype(L, 2, LUA_TNUMBER); // stride
+    luaL_checktype(L, 3, LUA_TNUMBER); // width
+    luaL_checktype(L, 4, LUA_TNUMBER); // height
+
+    char *data =  lua_tostring(L, 5);
+
+    texture = wlr_texture_from_pixels(wlr_renderer,
+				      DRM_FORMAT_ARGB8888,
+				      lua_tonumber(L, 2),
+				      lua_tonumber(L, 3),
+				      lua_tonumber(L, 4),
+				      data);
+
+    lua_pushlightuserdata(L, texture);
+
+    return 1;
+}
+
 static const luaL_Reg kiwmi_renderer_methods[] = {
     {"draw_rect", l_kiwmi_renderer_draw_rect},
+    {"draw_texture", l_kiwmi_renderer_draw_texture},
+    {"texture_from_pixels", l_kiwmi_renderer_texture_from_pixels},
     {NULL, NULL},
 };