Add pattern tables viewer in debugger to display the tiles of the game

Debugger/Debugger.cpp

@@ -12,24 +12,33 @@
 #include "ImguiWrapper/imgui_impl_glfw_gl3.h"
 
 #include "../CpuTypes.h"
+#include "../Video.h"
 
 
-Debugger::Debugger( Cpu *cpu, Memory *memory )
+Debugger::Debugger( Cpu *cpu, Memory *memory, Video *video )
     : cpu( cpu )
-    , memory ( memory )
+    , memory( memory )
+    , video( video )
     , mode( DebuggerMode::IDLE )
     , window( nullptr )
 {
 }
 
+Debugger::~Debugger()
+{
+    delete leftPatternTableBuffer;
+    delete rightPatternTableBuffer;
+}
+
+
 void Debugger::StartDebugger()
 {
     glfwInit();
     glfwWindowHint( GLFW_CONTEXT_VERSION_MAJOR, 4 );
     glfwWindowHint( GLFW_CONTEXT_VERSION_MINOR, 5 );
     glfwWindowHint( GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE );
 
-    window = glfwCreateWindow( 1024, 720, "PatNes", nullptr, nullptr );
+    window = glfwCreateWindow( 1920, 1080, "PatNes", nullptr, nullptr );
     if ( window == nullptr )
     {
         glfwTerminate();
@@ -53,6 +62,14 @@ void Debugger::StartDebugger()
     ImGuiGLFW::Init( window, true );
     ImGui::StyleColorsDark();
 
+    leftPatternTableBuffer = new RGB[ 128 * 128 ];
+    ImGuiGLFW::Texture leftPatternTexture = { 0, 128, 128, leftPatternTableBuffer };
+    leftPatternTableTextureID = ImGuiGLFW::CreateTexture( leftPatternTexture );
+
+    rightPatternTableBuffer = new RGB[ 128 * 128 ];
+    ImGuiGLFW::Texture rightPatternTexture = { 0, 128, 128, rightPatternTableBuffer };
+    rightPatternTableTextureID = ImGuiGLFW::CreateTexture( rightPatternTexture );
+
     Update(0.f,0);
 }
 
@@ -105,6 +122,18 @@ void Debugger::ComposeView( u32 cycles )
     ImGuiGLFW::NewFrame();
 
     cpuDebugger.ComposeView( *cpu, *memory, cycles, mode );
+
+    UpdatePatternTable( 0x0000, leftPatternTableBuffer );
+    ImGui::SetNextWindowSize( ImVec2( 560, 560 ), ImGuiCond_FirstUseEver );
+    ImGui::Begin( "VRAM Left" );
+    ImGui::Image( leftPatternTableTextureID, ImVec2( 512, 512 ) );
+    ImGui::End();
+
+    UpdatePatternTable( 0x1000, rightPatternTableBuffer );
+    ImGui::SetNextWindowSize( ImVec2( 560, 560 ), ImGuiCond_FirstUseEver );
+    ImGui::Begin( "VRAM Right" );
+    ImGui::Image( rightPatternTableTextureID, ImVec2( 512, 512 ) );
+    ImGui::End();
 }
 
 void Debugger::Render()
@@ -117,3 +146,43 @@ void Debugger::Render()
     ImGuiGLFW::RenderDrawLists( ImGui::GetDrawData() );
     glfwSwapBuffers( window );
 }
+
+
+void Debugger::UpdatePatternTable( word address, RGB *buffer )
+{
+    constexpr static RGB palette[4] = { { 255,255,255 },{ 0xCC,0xCC,0xCC },{ 0x77,0x77,0x77 }, { 0x0,0x0,0x0 } };
+
+    const byte * const ppuMemory = video->GetPPUMemory();
+    assert( buffer != nullptr );
+    assert( ppuMemory != nullptr );
+
+    u32 vramPosition = 0;
+    for ( u32 tile = 0; tile < 256; ++tile )
+    {
+        const u32 tileAddress = (tile * 0x10) + address;
+
+        u32 localvramPosition = vramPosition;
+        for ( byte row = 0; row < 8; ++row )
+        {
+            const byte firstByte = ppuMemory[ tileAddress + row ];
+            const byte secondByte = ppuMemory[ tileAddress + row + 0x07 ];
+
+            for ( byte column = 0; column < 8; ++column)
+            {
+                byte mask = 0x01 << column;
+                const byte value = ((secondByte & mask) >> column) << 1;
+                const byte value2 = (firstByte & mask) >> column;
+                const byte finalValue = value | value2;
+
+                buffer[ localvramPosition + (7 - column) ] = palette[ finalValue ];
+            }
+            localvramPosition += 128;
+        }
+        vramPosition += 8;
+
+        if ( tile > 0 && (tile + 1) % 16 == 0)
+        {
+            vramPosition += 128 * 7;
+        }
+    }
+}

Debugger/Debugger.h

@@ -13,29 +13,44 @@ enum class DebuggerMode : byte
 };
 
 struct GLFWwindow;
+class Video;
 
 class Debugger
 {
 public:
-    Debugger( Cpu *cpu, Memory *memory );
+    Debugger( Cpu *cpu, Memory *memory, Video *video );
     Debugger(Debugger &) = delete;
+    ~Debugger();
+
 
     void StartDebugger();
     void Update( float deltaMilliseconds, u32 cycles );
     void CloseDebugger();
 
 private:
 
+    using ImTextureID = void *;
+
     /* Systems */
     Cpu             *cpu;
     Memory          *memory;
+    Video           *video;
 
     /* Specific Debuggers */
     CpuDebugger     cpuDebugger;
 
+    /* Textures */
+    ImTextureID     leftPatternTableTextureID;
+    RGB             *leftPatternTableBuffer;
+
+    ImTextureID     rightPatternTableTextureID;
+    RGB             *rightPatternTableBuffer;
+
     GLFWwindow      *window;
     DebuggerMode    mode;
 
     void ComposeView( u32 cycles );
     void Render();
+
+    void UpdatePatternTable( word address, RGB *buffer );
 };

Types.h

@@ -21,6 +21,19 @@ union Register
     word value;
 };
 
+struct RGB
+{
+    byte red;
+    byte green;
+    byte blue;
+
+    bool isEqual(RGB other) const
+    {
+        return red == other.red && green == other.green && blue == other.blue;
+    }
+};
+
+constexpr RGB PINK = { 0xFF, 0x00, 0x80 };
 
 /* Operators */
 

Video.cpp

@@ -25,3 +25,8 @@ void Video::MapCartridgeCHRToPPU()
     const u32 dataSize = header.chrRomSizeKB * 1_KB;
     memcpy( memory, &cartridgeRom[ offset ], dataSize );
 }
+
+const byte * const Video::GetPPUMemory() const
+{
+    return memory;
+}

Video.h

@@ -39,6 +39,8 @@ class Video
 public:
     Video( Cartridge *memory );
 
+    const byte * const GetPPUMemory() const;
+
 private:
 
     /* Associated Systems */

main.cpp

@@ -3,6 +3,7 @@
 #include "Cartridge.h"
 #include "Memory.h"
 #include "Cpu.h"
+#include "Video.h"
 #include "Debugger/Debugger.h"
 
 static constexpr u32 AVERAGE_CYCLES_PER_FRAME = 29780;
@@ -23,8 +24,9 @@ int main(int argc, char** argv)
 
         Memory memory( &cartridge );
         Cpu cpu( &memory );
-
-        Debugger debugger( &cpu, &memory );
+        Video video( &cartridge );
+
+        Debugger debugger( &cpu, &memory, &video );
         debugger.StartDebugger();
 
         /* Run the first frame for now */