Support alpha in scene layer

engine/engine.c

@@ -235,6 +235,7 @@ bool add_scene_layer(Scene_t* scene, int width, int height, Rectangle render_are
 
     scene->layers.render_layers[scene->layers.n_layers].layer_tex = LoadRenderTexture(width, height);
     scene->layers.render_layers[scene->layers.n_layers].render_area = render_area;
+    scene->layers.render_layers[scene->layers.n_layers].alpha = 1.0f;
     scene->layers.n_layers++;
     return true;
 }
@@ -301,7 +302,7 @@ static void _internal_render_scene(Scene_t* scene)
             layer->layer_tex.texture,
             draw_rec,
             draw_pos,
-            WHITE
+            ColorAlpha(WHITE, layer->alpha)
         );
     }
 }

engine/engine.h

@@ -55,6 +55,7 @@ sc_array_def(system_func_t, systems);
 typedef struct RenderLayer {
     RenderTexture2D layer_tex;
     Rectangle render_area;
+    float alpha;
 }RenderLayer_t;
 
 typedef struct SceneRenderLayers {