feat: instance + array buffer

engine/include/engine/components/batch.h

@@ -2,12 +2,15 @@
 #define COMPONENT_BATCH_H_
 
 #include <glm/mat4x4.hpp>
+#include <memory>
+
+#include "engine/opengl/buffers.h"
+
 #include "engine/export.h"
 
 namespace Core {
 // requires mesh component
 struct ENGINE_API batch {
-    friend class Renderer;
 public:
     // requires Transform component
     struct item {
@@ -17,13 +20,18 @@ public:
     batch();
 
     inline const unsigned int id() const { return m_id; }
+    inline const bool Initialized() const { return m_instanceBuffer != nullptr; }
 protected:
     static unsigned int LastID;
 private:
     unsigned int m_id;
     unsigned int m_instance_vbo { 0 };
     unsigned int m_instance_count { 0 };
+
+    // TODO: use static draw when possible
+    std::unique_ptr<OpenGL::InstanceBuffer> m_instanceBuffer = nullptr;
 private:
+    friend class Renderer;
     void prepare(glm::mat4 *instances, unsigned int count);
 };
 }

engine/include/engine/opengl/buffers.h

@@ -17,15 +17,16 @@ namespace OpenGL {
     public:
         Buffer(BufferTarget target, BufferUsage usage);
 
+        inline const BufferID GetID() const { return m_buffer; }
     protected:
         void Data(void* data, size_t size);
         void SubData(void *data, size_t size, size_t offset);
         
-        void BindBuffer(unsigned int index);
-        void BindBufferRanged(unsigned int index, size_t offset, size_t size);
+        void BindBuffer(unsigned int index) const;
+        void BindBufferRanged(unsigned int index, size_t offset, size_t size) const;
     protected:
-        void Bind();
-        void Unbind();
+        void Bind() const;
+        void Unbind() const;
     private:
         BufferID m_buffer;
         BufferTarget m_target;
@@ -36,7 +37,7 @@ namespace OpenGL {
     public:
         UniformBuffer(size_t size, unsigned int index);
 
-        void ConfigureShader(Shader& shader, const char* uniformName);
+        void ConfigureShader(Shader& shader, const char* uniformName) const;
 
         template<typename T, typename S = size_t>
         void UpdateUniform(void* data, S offset) {
@@ -47,6 +48,27 @@ namespace OpenGL {
     private:
         static unsigned int s_bufferNextId;
     };
+
+    class ENGINE_API ArrayBuffer : public Buffer {
+    public:
+        ArrayBuffer(BufferUsage usage);
+    };
+
+    class ENGINE_API InstanceBuffer : public ArrayBuffer {
+    public:
+        InstanceBuffer(BufferUsage usage);
+
+        void Data(void *data, size_t size) {
+            Buffer::Data(data, size);
+        }
+
+        void SubData(void *data, size_t size, size_t offset) {
+            Buffer::SubData(data, size, offset);
+        }
+
+        inline void StartConfigure() const { Bind(); }
+        inline void EndConfigure() const { Unbind(); }
+    };
 } // namespace OpenGL
 
 } // namespace Core

engine/include/engine/renderer/wavefront.h

@@ -11,6 +11,7 @@
 #include "engine/renderer/renderer.h"
 #include "engine/renderer/material.h"
 #include "engine/renderer/mesh.h"
+#include "engine/opengl/buffers.h"
 
 #include "engine/export.h"
 
@@ -43,7 +44,7 @@ public:
     void Render(Shader& shader, unsigned int count);
     [[nodiscard]] inline const std::string Name() const { return m_name; }
 protected:
-    void EnableBatch(unsigned int instanceVBO);
+    void EnableBatch(const OpenGL::InstanceBuffer* instanceBuffer);
 private:
     std::string m_name;
     std::vector<glm::vec3> m_vertices;