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chore: refactor window

This commit is contained in:
Rekai Nyangadzayi Musuka 2022-07-19 20:43:21 -03:00
parent 0f18389eb8
commit 79af17a457
2 changed files with 119 additions and 112 deletions
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8
src/core/bus/io.zig
View File

@ -479,20 +479,20 @@ pub const WinV = extern union {
pub const WinIn = extern union {
w0_bg: Bitfield(u16, 0, 4),
w0_obj: Bit(u16, 4),
w0_colour: Bit(u16, 5),
w0_bld: Bit(u16, 5),
w1_bg: Bitfield(u16, 8, 4),
w1_obj: Bit(u16, 12),
w1_colour: Bit(u16, 13),
w1_bld: Bit(u16, 13),
raw: u16,
};
pub const WinOut = extern union {
out_bg: Bitfield(u16, 0, 4),
out_obj: Bit(u16, 4),
out_colour: Bit(u16, 5),
out_bld: Bit(u16, 5),
obj_bg: Bitfield(u16, 8, 4),
obj_obj: Bit(u16, 12),
obj_colour: Bit(u16, 13),
obj_bld: Bit(u16, 13),
raw: u16,
};

223
src/core/ppu.zig
View File

@ -274,16 +274,17 @@ pub const Ppu = struct {
aff_x += self.aff_bg[n - 2].pa;
aff_y += self.aff_bg[n - 2].pc;
if (!shouldDrawBackground(n, self.bldcnt, &self.scanline, i)) continue;
const x = @bitCast(u32, ix);
const y = @bitCast(u32, iy);
const win_bounds = self.windowBounds(@truncate(u9, x), @truncate(u8, y));
if (!shouldDrawBackground(self, n, win_bounds, i)) continue;
if (self.bg[n].cnt.display_overflow.read()) {
ix = if (ix > px_width) @rem(ix, px_width) else if (ix < 0) px_width + @rem(ix, px_width) else ix;
iy = if (iy > px_height) @rem(iy, px_height) else if (iy < 0) px_height + @rem(iy, px_height) else iy;
} else if (ix > px_width or iy > px_height or ix < 0 or iy < 0) continue;
const x = @bitCast(u32, ix);
const y = @bitCast(u32, iy);
const tile_id: u32 = self.vram.read(u8, screen_base + ((y / 8) * @bitCast(u32, tile_width) + (x / 8)));
const row = y & 7;
const col = x & 7;
@ -293,7 +294,7 @@ pub const Ppu = struct {
if (pal_id != 0) {
const bgr555 = self.palette.read(u16, pal_id * 2);
copyToBackgroundBuffer(n, self.bldcnt, &self.scanline, i, bgr555);
self.copyToBackgroundBuffer(n, win_bounds, i, bgr555);
}
}
@ -322,62 +323,10 @@ pub const Ppu = struct {
var i: u32 = 0;
while (i < width) : (i += 1) {
if (!shouldDrawBackground(n, self.bldcnt, &self.scanline, i)) continue;
const x = hofs + i;
const win0 = self.dispcnt.win_enable.read() & 1 == 1;
const win1 = (self.dispcnt.win_enable.read() >> 1) & 1 == 1;
const winObj = self.dispcnt.obj_win_enable.read();
if (win0 or win1 or winObj) blk: {
// Window is enabled
const win0_in = (self.win.in.w0_bg.read() >> n) & 1 == 1;
const win1_in = (self.win.in.w1_bg.read() >> n) & 1 == 1;
const win_out = (self.win.out.out_bg.read() >> n) & 1 == 1;
if (win0) {
const h = self.win.h[0];
const v = self.win.v[0];
const y1 = v.y1.read();
const y2 = if (y1 > v.y2.read()) 160 else std.math.min(160, v.y2.read());
if (y1 <= y and y < y2) {
// Within Y bounds
const x1 = h.x1.read();
const x2 = if (x1 > h.x2.read()) 240 else std.math.min(240, h.x2.read());
// Within X and & bounds, render Win0 Pixel
if (x1 <= x and x < x2) {
if (win0_in) break :blk else continue;
}
}
}
if (win1) {
const h = self.win.h[1];
const v = self.win.v[1];
const y1 = v.y1.read();
const y2 = if (y1 > v.y2.read()) 160 else std.math.min(160, v.y2.read());
if (y1 <= y and y < y2) {
// Within Y bounds
const x1 = h.x1.read();
const x2 = if (x1 > h.x2.read()) 240 else std.math.min(240, h.x2.read());
// Within X and & bounds, render Win1 Pixel
if (x1 <= x and x < x2) {
if (win1_in) break :blk else continue;
}
}
}
// If not Win0 nor Win1 and WinOut isn't enabled,
// then don't render this pixel
if (!win_out) continue;
}
const win_bounds = self.windowBounds(@truncate(u9, x), @truncate(u8, y));
if (!shouldDrawBackground(self, n, win_bounds, i)) continue;
// Grab the Screen Entry from VRAM
const entry_addr = screen_base + tilemapOffset(size, x, y);
@ -403,7 +352,7 @@ pub const Ppu = struct {
if (pal_id != 0) {
const bgr555 = self.palette.read(u16, pal_id * 2);
copyToBackgroundBuffer(n, self.bldcnt, &self.scanline, i, bgr555);
self.copyToBackgroundBuffer(n, win_bounds, i, bgr555);
}
}
}
@ -583,6 +532,93 @@ pub const Ppu = struct {
return self.palette.getBackdrop();
}
fn copyToBackgroundBuffer(self: *Self, comptime n: u2, bounds: ?WindowBounds, i: usize, bgr555: u16) void {
if (self.bldcnt.mode.read() != 0b00) {
// Standard Alpha Blending
const a_layers = self.bldcnt.layer_a.read();
const is_blend_enabled = (a_layers >> n) & 1 == 1;
// If Alpha Blending is enabled and we've found an eligible layer for
// Pixel A, store the pixel in the bottom pixel buffer
const win_part = if (bounds) |win| blk: {
// Window Enabled
break :blk switch (win) {
.win0 => self.win.in.w0_bld.read(),
.win1 => self.win.in.w1_bld.read(),
.out => self.win.out.out_bld.read(),
};
} else true;
if (win_part and is_blend_enabled) {
self.scanline.btm()[i] = bgr555;
return;
}
}
self.scanline.top()[i] = bgr555;
}
const WindowBounds = enum { win0, win1, out };
fn windowBounds(self: *Self, x: u9, y: u8) ?WindowBounds {
const win0 = self.dispcnt.win_enable.read() & 1 == 1;
const win1 = (self.dispcnt.win_enable.read() >> 1) & 1 == 1;
const winObj = self.dispcnt.obj_win_enable.read();
if (!(win0 or win1 or winObj)) return null;
if (win0 and self.win.inRange(0, x, y)) return .win0;
if (win1 and self.win.inRange(1, x, y)) return .win1;
return .out;
}
fn shouldDrawBackground(self: *Self, comptime n: u2, bounds: ?WindowBounds, i: usize) bool {
// If a pixel has been drawn on the top layer, it's because:
// 1. The pixel is to be blended with a pixel on the bottom layer
// 2. The pixel is not to be blended at all
// Also, if we find a pixel on the top layer we don't need to bother with this I think?
if (self.scanline.top()[i] != null) return false;
if (bounds) |win| {
switch (win) {
.win0 => if ((self.win.in.w0_bg.read() >> n) & 1 == 0) return false,
.win1 => if ((self.win.in.w1_bg.read() >> n) & 1 == 0) return false,
.out => if ((self.win.out.out_bg.read() >> n) & 1 == 0) return false,
}
}
if (self.scanline.btm()[i] != null) {
// The pixel found in the bottom layer is:
// 1. From a higher priority background
// 2. From a background that is marked for blending (Pixel A)
// If Alpha Blending isn't enabled, then we've already found a higher prio
// pixel, we can return early
if (self.bldcnt.mode.read() != 0b01) return false;
const b_layers = self.bldcnt.layer_b.read();
const win_part = if (bounds) |win| blk: {
// Window Enabled
break :blk switch (win) {
.win0 => self.win.in.w0_bld.read(),
.win1 => self.win.in.w1_bld.read(),
.out => self.win.out.out_bld.read(),
};
} else true;
// If the Background is not marked for blending, we've already found
// a higher priority pixel, move on.
const is_blend_enabled = win_part and ((b_layers >> n) & 1 == 1);
if (!is_blend_enabled) return false;
}
return true;
}
// TODO: Comment this + get a better understanding
fn tilemapOffset(size: u2, x: u32, y: u32) u32 {
// Current Row: (y % PIXEL_COUNT) / 8
@ -844,6 +880,25 @@ const Window = struct {
};
}
fn inRange(self: *const Self, comptime id: u1, x: u9, y: u8) bool {
const h = self.h[id];
const v = self.v[id];
const y1 = v.y1.read();
const y2 = if (y1 > v.y2.read()) 160 else std.math.min(160, v.y2.read());
if (y1 <= y and y < y2) {
// Within Y bounds
const x1 = h.x1.read();
const x2 = if (x1 > h.x2.read()) 240 else std.math.min(240, h.x2.read());
// Within X Bounds
return x1 <= x and x < x2;
}
return false;
}
pub fn setH(self: *Self, value: u32) void {
self.h[0].raw = @truncate(u16, value);
self.h[1].raw = @truncate(u16, value >> 16);
@ -1140,37 +1195,6 @@ fn alphaBlend(top: u16, btm: u16, bldalpha: io.BldAlpha) u16 {
return (bld_b << 10) | (bld_g << 5) | bld_r;
}
fn shouldDrawBackground(comptime n: u2, bldcnt: io.BldCnt, scanline: *Scanline, i: usize) bool {
// If a pixel has been drawn on the top layer, it's because
// Either the pixel is to be blended with a pixel on the bottom layer
// or the pixel is not to be blended at all
// Consequentially, if we find a pixel on the top layer, there's no need
// to render anything I think?
if (scanline.top()[i] != null) return false;
if (scanline.btm()[i] != null) {
// The Pixel found in the Bottom layer is
// 1. From a higher priority
// 2. From a Backround that is marked for Blending (Pixel A)
//
// We now have to confirm whether this current Background can be used
// as Pixel B or not.
// If Alpha Blending isn't enabled, we've aready found a higher
// priority pixel to render. Move on
if (bldcnt.mode.read() != 0b01) return false;
const b_layers = bldcnt.layer_b.read();
const is_blend_enabled = (b_layers >> n) & 1 == 1;
// If the Background is not marked for blending, we've already found
// a higher priority pixel, move on.
if (!is_blend_enabled) return false;
}
return true;
}
fn shouldDrawSprite(bldcnt: io.BldCnt, scanline: *Scanline, x: u9) bool {
if (scanline.top()[x] != null) return false;
@ -1185,23 +1209,6 @@ fn shouldDrawSprite(bldcnt: io.BldCnt, scanline: *Scanline, x: u9) bool {
return true;
}
fn copyToBackgroundBuffer(comptime n: u2, bldcnt: io.BldCnt, scanline: *Scanline, i: usize, bgr555: u16) void {
if (bldcnt.mode.read() != 0b00) {
// Standard Alpha Blending
const a_layers = bldcnt.layer_a.read();
const is_blend_enabled = (a_layers >> n) & 1 == 1;
// If Alpha Blending is enabled and we've found an eligible layer for
// Pixel A, store the pixel in the bottom pixel buffer
if (is_blend_enabled) {
scanline.btm()[i] = bgr555;
return;
}
}
scanline.top()[i] = bgr555;
}
fn copyToSpriteBuffer(bldcnt: io.BldCnt, scanline: *Scanline, x: u9, bgr555: u16) void {
if (bldcnt.mode.read() != 0b00) {
// Alpha Blending