Add mouse tracking, add null-texture gen function

Refactor the creation of the null-texture into a function. Used for
blitting rectangles that don't have any texture associated with it.

src/Renderer.c

@@ -1,4 +1,6 @@
 #include "Dengine/Renderer.h"
+#include "Dengine/AssetManager.h"
+#include "Dengine/Assets.h"
 #include "Dengine/Debug.h"
 #include "Dengine/Entity.h"
 #include "Dengine/OpenGL.h"
@@ -138,6 +140,13 @@ INTERNAL void renderObject(Renderer *renderer, v2 pos, v2 size, v2 pivotPoint,
 	GL_CHECK_ERROR();
 }
 
+RenderTex renderer_createNullRenderTex(AssetManager *assetManager)
+{
+	Texture *emptyTex = asset_getTexture(assetManager, texlist_empty);
+	RenderTex result  = {emptyTex, V4(0, 1, 1, 0)};
+	return result;
+}
+
 void renderer_rect(Renderer *const renderer, v4 cameraBounds, v2 pos, v2 size,
                    v2 pivotPoint, f32 rotate, RenderTex renderTex, v4 color)
 {

src/WorldTraveller.c

@@ -1124,6 +1124,10 @@ void worldTraveller_gameUpdateAndRender(GameState *state, f32 dt)
 	}
 
 	/* Draw ui */
+	RenderTex nullRenderTex = renderer_createNullRenderTex(assetManager);
+	renderer_staticRect(renderer, state->input.mouse, hero->hitboxSize,
+	                    V2(0, 0), 0, nullRenderTex, V4(0.5f, 0, 0, 0.5f));
+
 	/* Draw hero avatar */
 	TexAtlas *heroAtlas  = asset_getTextureAtlas(assetManager, texlist_hero);
 	v4 heroAvatarTexRect = heroAtlas->texRect[herorects_head];
@@ -1157,9 +1161,8 @@ void worldTraveller_gameUpdateAndRender(GameState *state, f32 dt)
 			f32 angle        = math_atan2f(difference.y, difference.x);
 			f32 angleDegrees = RADIANS_TO_DEGREES(angle);
 
-			Texture *emptyTex = asset_getTexture(assetManager, texlist_empty);
 			v2 heroCenter = v2_add(hero->pos, v2_scale(hero->hitboxSize, 0.5f));
-			RenderTex renderTex = {emptyTex, V4(0, 1, 1, 0)};
+			RenderTex renderTex = renderer_createNullRenderTex(assetManager);
 			f32 distance        = v2_magnitude(hero->pos, entity->pos);
 			renderer_rect(&state->renderer, cameraBounds, heroCenter,
 			              V2(distance, 2.0f), V2(0, 0), angle, renderTex,

src/include/Dengine/Renderer.h

@@ -5,11 +5,12 @@
 #include "Dengine/Math.h"
 
 /* Forward Declaration */
-typedef struct Shader Shader;
+typedef struct AssetManager AssetManager;
 typedef struct Entity Entity;
-typedef struct MemoryArena MemoryArena;
-typedef struct Texture Texture;
 typedef struct Font Font;
+typedef struct MemoryArena MemoryArena;
+typedef struct Shader Shader;
+typedef struct Texture Texture;
 
 typedef struct Renderer
 {
@@ -27,6 +28,8 @@ typedef struct RenderTex
 	v4 texRect;
 } RenderTex;
 
+RenderTex renderer_createNullRenderTex(AssetManager *assetManager);
+
 // TODO(doyle): Clean up lines
 // Renderer::~Renderer() { glDeleteVertexArrays(1, &this->quadVAO); }
 void renderer_rect(Renderer *const renderer, v4 cameraBounds, v2 pos, v2 size,