implement display capture for compute renderer

it's actually just all stolen from the regular OpenGL renderer

src/GPU2D_Soft.cpp

@@ -367,7 +367,7 @@ void SoftRenderer::VBlankEnd(Unit* unitA, Unit* unitB)
     {
         if ((unitA->CaptureCnt & (1<<31)) && (((unitA->CaptureCnt >> 29) & 0x3) != 1))
         {
-            //reinterpret_cast<GPU3D::GLRenderer*>(GPU3D::CurrentRenderer.get())->PrepareCaptureFrame();
+            reinterpret_cast<GPU3D::GLRenderer*>(GPU3D::CurrentRenderer.get())->PrepareCaptureFrame();
         }
     }
 #endif

src/GPU3D.h

@@ -158,8 +158,10 @@ public:
     virtual u32* GetLine(int line) = 0;
 
     virtual void SetupAccelFrame() {}
+
 protected:
     Renderer3D(bool Accelerated);
+    virtual void PrepareCaptureFrame() {}
 };
 
 extern int Renderer;

src/GPU3D_Compute.cpp

@@ -154,12 +154,15 @@ bool ComputeRenderer::Init()
         }
     }
 
+    glGenBuffers(1, &PixelBuffer);
+    glBindBuffer(GL_PIXEL_PACK_BUFFER, PixelBuffer);
+    glBufferData(GL_PIXEL_PACK_BUFFER, 256*192*4, NULL, GL_DYNAMIC_READ);
+
     return true;
 }
 
 void ComputeRenderer::DeInit()
 {
-
 }
 
 void ComputeRenderer::Reset()
@@ -1395,7 +1398,26 @@ void ComputeRenderer::RestartFrame()
 
 u32* ComputeRenderer::GetLine(int line)
 {
-    return DummyLine;
+    int stride = 256;
+
+    if (line == 0)
+    {
+        glBindBuffer(GL_PIXEL_PACK_BUFFER, PixelBuffer);
+        u8* data = (u8*)glMapBuffer(GL_PIXEL_PACK_BUFFER, GL_READ_ONLY);
+        if (data) memcpy(&FramebufferCPU[0], data, 4*stride*192);
+        glUnmapBuffer(GL_PIXEL_PACK_BUFFER);
+    }
+
+    u64* ptr = (u64*)&FramebufferCPU[stride * line];
+    for (int i = 0; i < stride; i+=2)
+    {
+        u64 rgb = *ptr & 0x00FCFCFC00FCFCFC;
+        u64 a = *ptr & 0xF8000000F8000000;
+
+        *ptr++ = (rgb >> 2) | (a >> 3);
+    }
+
+    return &FramebufferCPU[stride * line];
 }
 
 void ComputeRenderer::SetupAccelFrame()
@@ -1403,4 +1425,11 @@ void ComputeRenderer::SetupAccelFrame()
     glBindTexture(GL_TEXTURE_2D, Framebuffer);
 }
 
+void ComputeRenderer::PrepareCaptureFrame()
+{
+    glBindBuffer(GL_PIXEL_PACK_BUFFER, PixelBuffer);
+    glBindTexture(GL_TEXTURE_2D, Framebuffer);
+    glGetTexImage(GL_TEXTURE_2D, 0, GL_BGRA, GL_UNSIGNED_BYTE, nullptr);
+}
+
 }

src/GPU3D_Compute.h

@@ -49,6 +49,7 @@ public:
     u32* GetLine(int line) override;
 
     void SetupAccelFrame() override;
+    void PrepareCaptureFrame() override;
 private:
     GLuint ShaderInterpXSpans[2];
     GLuint ShaderBinCombined;
@@ -240,6 +241,9 @@ private:
     u32 TextureDecodingBuffer[1024*1024];
 
     GLuint Framebuffer;
+    GLuint PixelBuffer;
+
+    u32 FramebufferCPU[256*192];
 
     TexCacheEntry& GetTexture(u32 textureParam, u32 paletteParam);
 

src/GPU3D_OpenGL.cpp

@@ -1278,6 +1278,7 @@ void GLRenderer::PrepareCaptureFrame()
     glDrawBuffer(GL_COLOR_ATTACHMENT0);
     glBlitFramebuffer(0, 0, ScreenW, ScreenH, 0, 0, 256, 192, GL_COLOR_BUFFER_BIT, GL_NEAREST);
 
+    glBindBuffer(GL_PIXEL_PACK_BUFFER, PixelbufferID);
     glBindFramebuffer(GL_READ_FRAMEBUFFER, DownscaleFramebuffer);
     glReadPixels(0, 0, 256, 192, GL_BGRA, GL_UNSIGNED_BYTE, NULL);
 }
@@ -1288,6 +1289,7 @@ u32* GLRenderer::GetLine(int line)
 
     if (line == 0)
     {
+        glBindBuffer(GL_PIXEL_PACK_BUFFER, PixelbufferID);
         u8* data = (u8*)glMapBuffer(GL_PIXEL_PACK_BUFFER, GL_READ_ONLY);
         if (data) memcpy(&Framebuffer[stride*0], data, 4*stride*192);
         glUnmapBuffer(GL_PIXEL_PACK_BUFFER);

src/GPU3D_OpenGL.h

@@ -40,6 +40,8 @@ public:
     void SetupAccelFrame() override;
     void PrepareCaptureFrame();
 
+    void PrepareCaptureFrame() override;
+
     static std::unique_ptr<GLRenderer> New() noexcept;
 private:
     // Used by New()