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https://github.com/libretro/snes9x.git
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5f56cadafb
This points to the full license in the root directory.
235 lines
5.3 KiB
C++
235 lines
5.3 KiB
C++
/*****************************************************************************\
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Snes9x - Portable Super Nintendo Entertainment System (TM) emulator.
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This file is licensed under the Snes9x License.
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For further information, consult the LICENSE file in the root directory.
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\*****************************************************************************/
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#include "snes9x.h"
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#include "memmap.h"
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static uint8 region_map[6][6] =
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{
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{ 0, 0x01, 0x03, 0x07, 0x0f, 0x1f },
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{ 0, 0, 0x02, 0x06, 0x0e, 0x1e },
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{ 0, 0, 0, 0x04, 0x0c, 0x1c },
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{ 0, 0, 0, 0, 0x08, 0x18 },
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{ 0, 0, 0, 0, 0, 0x10 }
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};
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static inline uint8 CalcWindowMask (int, uint8, uint8);
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static inline void StoreWindowRegions (uint8, struct ClipData *, int, int16 *, uint8 *, bool8, bool8 s = FALSE);
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static inline uint8 CalcWindowMask (int i, uint8 W1, uint8 W2)
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{
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if (!PPU.ClipWindow1Enable[i])
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{
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if (!PPU.ClipWindow2Enable[i])
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return (0);
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else
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{
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if (!PPU.ClipWindow2Inside[i])
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return (~W2);
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return (W2);
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}
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}
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else
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{
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if (!PPU.ClipWindow2Enable[i])
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{
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if (!PPU.ClipWindow1Inside[i])
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return (~W1);
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return (W1);
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}
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else
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{
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if (!PPU.ClipWindow1Inside[i])
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W1 = ~W1;
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if (!PPU.ClipWindow2Inside[i])
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W2 = ~W2;
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switch (PPU.ClipWindowOverlapLogic[i])
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{
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case 0: // OR
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return (W1 | W2);
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case 1: // AND
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return (W1 & W2);
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case 2: // XOR
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return (W1 ^ W2);
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case 3: // XNOR
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return (~(W1 ^ W2));
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}
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}
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}
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// Never get here
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return (0);
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}
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static inline void StoreWindowRegions (uint8 Mask, struct ClipData *Clip, int n_regions, int16 *windows, uint8 *drawing_modes, bool8 sub, bool8 StoreMode0)
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{
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int ct = 0;
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for (int j = 0; j < n_regions; j++)
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{
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int DrawMode = drawing_modes[j];
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if (sub)
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DrawMode |= 1;
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if (Mask & (1 << j))
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DrawMode = 0;
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if (!StoreMode0 && !DrawMode)
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continue;
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if (ct > 0 && Clip->Right[ct - 1] == windows[j] && Clip->DrawMode[ct - 1] == DrawMode)
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Clip->Right[ct - 1] = windows[j + 1]; // This region borders with and has the same drawing mode as the previous region: merge them.
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else
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{
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// Add a new region to the BG
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Clip->Left[ct] = windows[j];
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Clip->Right[ct] = windows[j + 1];
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Clip->DrawMode[ct] = DrawMode;
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ct++;
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}
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}
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Clip->Count = ct;
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}
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void S9xComputeClipWindows (void)
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{
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int16 windows[6] = { 0, 256, 256, 256, 256, 256 };
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uint8 drawing_modes[5] = { 0, 0, 0, 0, 0 };
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int n_regions = 1;
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int i, j;
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// Calculate window regions. We have at most 5 regions, because we have 6 control points
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// (screen edges, window 1 left & right, and window 2 left & right).
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if (PPU.Window1Left <= PPU.Window1Right)
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{
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if (PPU.Window1Left > 0)
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{
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windows[2] = 256;
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windows[1] = PPU.Window1Left;
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n_regions = 2;
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}
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if (PPU.Window1Right < 255)
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{
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windows[n_regions + 1] = 256;
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windows[n_regions] = PPU.Window1Right + 1;
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n_regions++;
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}
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}
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if (PPU.Window2Left <= PPU.Window2Right)
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{
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for (i = 0; i <= n_regions; i++)
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{
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if (PPU.Window2Left == windows[i])
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break;
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if (PPU.Window2Left < windows[i])
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{
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for (j = n_regions; j >= i; j--)
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windows[j + 1] = windows[j];
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windows[i] = PPU.Window2Left;
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n_regions++;
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break;
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}
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}
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for (; i <= n_regions; i++)
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{
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if (PPU.Window2Right + 1 == windows[i])
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break;
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if (PPU.Window2Right + 1 < windows[i])
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{
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for (j = n_regions; j >= i; j--)
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windows[j + 1] = windows[j];
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windows[i] = PPU.Window2Right + 1;
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n_regions++;
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break;
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}
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}
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}
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// Get a bitmap of which regions correspond to each window.
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uint8 W1, W2;
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if (PPU.Window1Left <= PPU.Window1Right)
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{
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for (i = 0; windows[i] != PPU.Window1Left; i++) ;
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for (j = i; windows[j] != PPU.Window1Right + 1; j++) ;
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W1 = region_map[i][j];
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}
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else
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W1 = 0;
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if (PPU.Window2Left <= PPU.Window2Right)
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{
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for (i = 0; windows[i] != PPU.Window2Left; i++) ;
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for (j = i; windows[j] != PPU.Window2Right + 1; j++) ;
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W2 = region_map[i][j];
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}
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else
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W2 = 0;
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// Color Window affects the drawing mode for each region.
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// Modes are: 3=Draw as normal, 2=clip color (math only), 1=no math (draw only), 0=nothing.
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uint8 CW_color = 0, CW_math = 0;
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uint8 CW = CalcWindowMask(5, W1, W2);
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switch (Memory.FillRAM[0x2130] & 0xc0)
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{
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case 0x00: CW_color = 0; break;
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case 0x40: CW_color = ~CW; break;
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case 0x80: CW_color = CW; break;
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case 0xc0: CW_color = 0xff; break;
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}
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switch (Memory.FillRAM[0x2130] & 0x30)
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{
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case 0x00: CW_math = 0; break;
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case 0x10: CW_math = ~CW; break;
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case 0x20: CW_math = CW; break;
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case 0x30: CW_math = 0xff; break;
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}
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for (i = 0; i < n_regions; i++)
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{
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if (!(CW_color & (1 << i)))
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drawing_modes[i] |= 1;
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if (!(CW_math & (1 << i)))
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drawing_modes[i] |= 2;
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}
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// Store backdrop clip window (draw everywhere color window allows)
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StoreWindowRegions(0, &IPPU.Clip[0][5], n_regions, windows, drawing_modes, FALSE, TRUE);
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StoreWindowRegions(0, &IPPU.Clip[1][5], n_regions, windows, drawing_modes, TRUE, TRUE);
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// Store per-BG and OBJ clip windows
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for (j = 0; j < 5; j++)
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{
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uint8 W = Settings.DisableGraphicWindows ? 0 : CalcWindowMask(j, W1, W2);
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for (int sub = 0; sub < 2; sub++)
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{
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if (Memory.FillRAM[sub + 0x212e] & (1 << j))
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StoreWindowRegions(W, &IPPU.Clip[sub][j], n_regions, windows, drawing_modes, sub);
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else
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StoreWindowRegions(0, &IPPU.Clip[sub][j], n_regions, windows, drawing_modes, sub);
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}
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}
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}
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