added psuedo_vram

src/app/gfx/psuedo_vram.cc

@@ -0,0 +1,7 @@
+#include "psuedo_vram.h"
+
+namespace yaze {
+namespace app {
+namespace gfx {}
+}  // namespace app
+}  // namespace yaze

src/app/gfx/psuedo_vram.h

@@ -0,0 +1,53 @@
+#ifndef YAZE_APP_GFX_PSUEDO_VRAM_H
+#define YAZE_APP_GFX_PSUEDO_VRAM_H
+
+#include <SDL2/SDL.h>
+
+#include <cstdint>
+#include <unordered_map>
+
+#include "app/core/gfx/bitmap.h"
+
+namespace yaze {
+namespace app {
+namespace gfx {
+
+// Picture Processor Unit: 15-Bit
+
+// Video RAM: 64 KB of VRAM for screen maps (for 'background' layers) and tile
+// sets (for backgrounds and objects); 512 + 32 bytes of 'OAM' (Object Attribute
+// Memory) for objects; 512 bytes of 'CGRAM' for palette data.
+
+// Palette: 256 entries; 15-Bit color (BGR555) for a total of 32,768 colors.
+// Maximum colors per layer per scanline: 256. Maximum colors on-screen: 32,768
+// (using color arithmetic for transparency effects).
+
+// Resolution: between 256x224 and 512x448. Most games used 256x224 pixels since
+// higher resolutions caused slowdown, flicker, and/or had increased limitations
+// on layers and colors (due to memory bandwidth constraints); the higher
+// resolutions were used for less processor-intensive games, in-game menus,
+// text, and high resolution images.
+
+// Maximum onscreen objects (sprites): 128 (32 per line, up to 34 8x8 tiles per
+// line).
+
+// Maximum number of sprite pixels on one scanline: 256. The renderer was
+// designed such that it would drop the frontmost sprites instead of the
+// rearmost sprites if a scanline exceeded the limit, allowing for creative
+// clipping effects.
+
+// Most common display modes: Pixel-to-pixel text mode 1 (16 colors per tile; 3
+// scrolling layers) and affine mapped text mode 7 (256 colors per tile; one
+// rotating/scaling layer).
+class psuedo_vram {
+ public:
+ private:
+  std::unordered_map<uint32_t, Bitmap> m_vram;
+  static const uint32_t REAL_VRAM_SIZE = 0x8000;
+};
+
+}  // namespace gfx
+}  // namespace app
+}  // namespace yaze
+
+#endif