add debug GUI render mode (F8)

src/graphics/core/Batch2D.cpp

@@ -142,7 +142,7 @@ void Batch2D::rect(
     bool flippedY,
     glm::vec4 tint
 ) {
-    if (index + 6*B2D_VERTEX_SIZE >= capacity) {
+    if (index + 6 * B2D_VERTEX_SIZE >= capacity) {
         flush();
     }
     setPrimitive(DrawPrimitive::triangle);
@@ -230,6 +230,11 @@ void Batch2D::rect(
 }
 
 void Batch2D::lineRect(float x, float y, float w, float h) {
+    if (index + 8 * B2D_VERTEX_SIZE >= capacity) {
+        flush();
+    }
+    setPrimitive(DrawPrimitive::line);
+
     vertex(x, y, 0.0f, 0.0f, color.r, color.g, color.b, color.a);
     vertex(x, y+h, 0.0f, 1.0f, color.r, color.g, color.b, color.a);
     

src/graphics/core/Batch2D.hpp

@@ -48,10 +48,14 @@ public:
     void sprite(float x, float y, float w, float h, float skew, int atlasRes, int index, glm::vec4 tint);
     void point(float x, float y, float r, float g, float b, float a);
     
-    void setColor(glm::vec4 color) {
+    void setColor(const glm::vec4& color) {
         this->color = color;
     }
 
+    void setColor(int r, int g, int b, int a=255) {
+        this->color = glm::vec4(r / 255.0f, g / 255.0f, b / 255.0f, a / 255.0f);
+    }
+
     void resetColor() {
         this->color = glm::vec4(1.0f);
     }