The changes update the inheritance of several classes (PerPixelMesh, VideoEcho, and Waveform) to use OpenGLRenderItem instead of RenderItem, and include the correct header file. This fixes the build errors by:

1. Changing the base class to `OpenGLRenderItem` which contains the required `m_vaoID` and `m_vboID` members
2. Updating the includes to point to the new header location
3. Removing redundant `RenderItem::` prefixes since we inherit directly from `OpenGLRenderItem`
4. Cleaning up some formatting inconsistencies

The changes maintain all existing functionality while fixing the compilation errors related to missing OpenGL buffer IDs. The classes will now properly inherit the OpenGL-specific rendering functionality they require.

src/libprojectM/MilkdropPreset/PerPixelMesh.cpp

@@ -21,9 +21,8 @@ namespace MilkdropPreset {
 static constexpr uint32_t VerticesPerDrawCall = 1024 * 3;
 
 PerPixelMesh::PerPixelMesh()
-    : RenderItem()
 {
-    RenderItem::Init();
+    Init();
 }
 
 void PerPixelMesh::InitVertexAttrib()

src/libprojectM/MilkdropPreset/PerPixelMesh.hpp

@@ -1,6 +1,6 @@
 #pragma once
 
-#include <Renderer/RenderItem.hpp>
+#include <Renderer/Backend/OpenGL/OpenGLRenderItem.hpp>
 #include <Renderer/Shader.hpp>
 
 #include <cstdint>
@@ -27,7 +27,7 @@ class MilkdropShader;
  *
  * The mesh size can be changed between frames, the class will reallocate the buffers if needed.
  */
-class PerPixelMesh : public Renderer::RenderItem
+class PerPixelMesh : public libprojectM::Renderer::Backend::OpenGL::OpenGLRenderItem
 {
 public:
     PerPixelMesh();

src/libprojectM/MilkdropPreset/VideoEcho.cpp

@@ -4,10 +4,9 @@ namespace libprojectM {
 namespace MilkdropPreset {
 
 VideoEcho::VideoEcho(const PresetState& presetState)
-    : RenderItem()
-    , m_presetState(presetState)
+    : m_presetState(presetState)
 {
-    RenderItem::Init();
+    Init();
 }
 
 void VideoEcho::InitVertexAttrib()

src/libprojectM/MilkdropPreset/VideoEcho.hpp

@@ -5,7 +5,7 @@
 
 #include <projectM-opengl.h>
 
-#include <Renderer/RenderItem.hpp>
+#include <Renderer/Backend/OpenGL/OpenGLRenderItem.hpp>
 
 namespace libprojectM {
 namespace MilkdropPreset {
@@ -13,15 +13,15 @@ namespace MilkdropPreset {
 /**
  * @brief Renders a video "echo" (ghost image) effect and gamma adjustments.
  */
-class VideoEcho: public Renderer::RenderItem
+class VideoEcho : public libprojectM::Renderer::Backend::OpenGL::OpenGLRenderItem
 {
 public:
-	VideoEcho() = delete;
+    VideoEcho() = delete;
     explicit VideoEcho(const PresetState& presetState);
 
     void InitVertexAttrib() override;
 
-	void Draw();
+    void Draw();
 
 private:
     void DrawVideoEcho();

src/libprojectM/MilkdropPreset/Waveform.cpp

@@ -18,10 +18,9 @@ namespace libprojectM {
 namespace MilkdropPreset {
 
 Waveform::Waveform(PresetState& presetState)
-    : RenderItem()
-    , m_presetState(presetState)
+    : m_presetState(presetState)
 {
-    RenderItem::Init();
+    Init();
 }
 
 void Waveform::InitVertexAttrib()

src/libprojectM/MilkdropPreset/Waveform.hpp

@@ -5,7 +5,7 @@
 
 #include "Waveforms/WaveformMath.hpp"
 
-#include <Renderer/RenderItem.hpp>
+#include <Renderer/Backend/OpenGL/OpenGLRenderItem.hpp>
 
 #include <memory>
 #include <vector>
@@ -16,7 +16,7 @@ namespace MilkdropPreset {
 class PresetState;
 class PerFrameContext;
 
-class Waveform : public Renderer::RenderItem
+class Waveform : public libprojectM::Renderer::Backend::OpenGL::OpenGLRenderItem
 {
 public:
     explicit Waveform(PresetState& presetState);