snes9x/clip.cpp

235 lines
5.3 KiB
C++

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