Merge pull request #73 from skylersaleh/SurfaceCacheRing

[GPU] Add texture surface cache eviction

include/renderer_gl/renderer_gl.hpp

@@ -45,7 +45,7 @@ class Renderer {
 
 	SurfaceCache<DepthBuffer, 10> depthBufferCache;
 	SurfaceCache<ColourBuffer, 10> colourBufferCache;
-	SurfaceCache<Texture, 256> textureCache;
+	SurfaceCache<Texture, 256, true> textureCache;
 
 	OpenGL::uvec2 fbSize;  // The size of the framebuffer (ie both the colour and depth buffer)'
 

include/renderer_gl/surface_cache.hpp

@@ -5,8 +5,9 @@
 #include "textures.hpp"
 
 // Surface cache class that can fit "capacity" instances of the "SurfaceType" class of surfaces
-// SurfaceType *must* have all of the following
+// SurfaceType *must* have all of the following.
-// - An "allocate" function that allocates GL resources for the surfaces
+// - An "allocate" function that allocates GL resources for the surfaces. On overflow it will panic
+//   if evictOnOverflow is false, or kick out the oldest item if it is true (like a ring buffer)
 // - A "free" function that frees up all resources the surface is taking up
 // - A "matches" function that, when provided with a SurfaceType object reference
 // Will tell us if the 2 surfaces match (Only as far as location in VRAM, format, dimensions, etc)
@@ -14,7 +15,7 @@
 // Including equality of the allocated OpenGL resources, which we don't want
 // - A "valid" member that tells us whether the function is still valid or not
 // - A "location" member which tells us which location in 3DS memory this surface occupies
-template <typename SurfaceType, size_t capacity>
+template <typename SurfaceType, size_t capacity, bool evictOnOverflow = false>
 class SurfaceCache {
     // Vanilla std::optional can't hold actual references
     using OptionalRef = std::optional<std::reference_wrapper<SurfaceType>>;
@@ -22,11 +23,13 @@ class SurfaceCache {
         std::is_same<SurfaceType, Texture>(), "Invalid surface type");
 
     size_t size;
+    size_t evictionIndex;
     std::array<SurfaceType, capacity> buffer;
 
 public:
     void reset() {
         size = 0;
+        evictionIndex = 0;
         for (auto& e : buffer) { // Free the VRAM of all surfaces
             e.free();
         }
@@ -51,26 +54,42 @@ public:
     }
 
     // Adds a surface object to the cache and returns it
-    SurfaceType& add(const SurfaceType& surface) {
+	SurfaceType& add(const SurfaceType& surface) {
-        if (size >= capacity) {
+		if (size >= capacity) {
-            Helpers::panic("Surface cache full! Add emptying!");
+			if (evictOnOverflow) {  // Do a ring buffer if evictOnOverflow is true
-        }
+				auto& e = buffer[evictionIndex];
-        size++;
+				evictionIndex = (evictionIndex + 1) % capacity;
 
-        // Find an invalid entry in the cache and overwrite it with the new surface
+				e.valid = false;
-        for (auto& e : buffer) {
+				e.free();
-            if (!e.valid) {
+				e = surface;
-                e = surface;
+				e.allocate();
-                e.allocate();
+				return e;
-                return e;
+			} else {
-            }
+				Helpers::panic("Surface cache full! Add emptying!");
-        }
+			}
+		}
 
-        // This should be unreachable but helps to panic anyways
+		size++;
-        Helpers::panic("Couldn't add surface to cache\n");
+
-    }
+		// Find an invalid entry in the cache and overwrite it with the new surface
+		for (auto& e : buffer) {
+			if (!e.valid) {
+				e = surface;
+				e.allocate();
+				return e;
+			}
+		}
+
+		// This should be unreachable but helps to panic anyways
+		Helpers::panic("Couldn't add surface to cache\n");
+	}
 
     SurfaceType& operator[](size_t i) {
         return buffer[i];
     }
+
+    const SurfaceType& operator[](size_t i) const {
+        return buffer[i];
+    }
 };

src/core/renderer_gl/textures.cpp

@@ -33,10 +33,11 @@ void Texture::setNewConfig(u32 cfg) {
 }
 
 void Texture::free() {
-    valid = false;
+	valid = false;
 
-    if (texture.exists())
+	if (texture.exists()) {
-        Helpers::panic("Make this texture free itself");
+		texture.free();
+	}
 }
 
 u64 Texture::sizeInBytes() {