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video.cc
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/* gameplaySP
*
* Copyright (C) 2006 Exophase <exophase@gmail.com>
* Copyright (C) 2023 David Guillen Fandos <david@davidgf.net>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
extern "C" {
#include "common.h"
}
u16* gba_screen_pixels = NULL;
#define get_screen_pixels() gba_screen_pixels
#define get_screen_pitch() GBA_SCREEN_PITCH
typedef struct {
u16 attr0, attr1, attr2, attr3;
} t_oam;
typedef struct {
u16 pad0[3];
u16 dx;
u16 pad1[3];
u16 dmx;
u16 pad2[3];
u16 dy;
u16 pad3[3];
u16 dmy;
} t_affp;
typedef void (* bitmap_render_function)(
u32 start, u32 end, void *dest_ptr, const u16 *pal);
typedef void (* tile_render_function)(
u32 layer, u32 start, u32 end, void *dest_ptr, const u16 *pal);
typedef void (*render_function_u16)(
u32 start, u32 end, u16 *scanline, u32 enable_flags);
typedef void (*render_function_u32)(
u32 start, u32 end, u32 *scanline, u32 enable_flags);
typedef void (*window_render_function)(u16 *scanline, u32 start, u32 end);
static void render_scanline_conditional(
u32 start, u32 end, u16 *scanline, u32 enable_flags = 0x3F);
typedef struct
{
bitmap_render_function blit_render;
bitmap_render_function scale_render;
bitmap_render_function affine_render;
} bitmap_layer_render_struct;
typedef struct
{
render_function_u16 fullcolor;
render_function_u16 indexed_u16;
render_function_u32 indexed_u32;
render_function_u32 stacked;
} layer_render_struct;
// Object blending modes
#define OBJ_MOD_NORMAL 0
#define OBJ_MOD_SEMITRAN 1
#define OBJ_MOD_WINDOW 2
#define OBJ_MOD_INVALID 3
// BLDCNT color effect modes
#define COL_EFFECT_NONE 0x0
#define COL_EFFECT_BLEND 0x1
#define COL_EFFECT_BRIGHT 0x2
#define COL_EFFECT_DARK 0x3
// Background render modes
#define RENDER_NORMAL 0
#define RENDER_COL16 1
#define RENDER_COL32 2
#define RENDER_ALPHA 3
// Byte lengths of complete tiles and tile rows in 4bpp and 8bpp.
#define tile_width_4bpp 4
#define tile_size_4bpp 32
#define tile_width_8bpp 8
#define tile_size_8bpp 64
// Sprite rendering cycles
#define REND_CYC_MAX 32768 /* Theoretical max is 17920 */
#define REND_CYC_SCANLINE 1210
#define REND_CYC_REDUCED 954
// Generate bit mask (bits 9th and 10th) with information about the pixel
// status (1st and/or 2nd target) for later blending.
static inline u16 color_flags(u32 layer) {
u32 bldcnt = read_ioreg(REG_BLDCNT);
return (
((bldcnt >> layer) & 0x01) | // 1st target
((bldcnt >> (layer + 7)) & 0x02) // 2nd target
) << 9;
}
static const u32 map_widths[] = { 256, 512, 256, 512 };
typedef enum
{
FULLCOLOR, // Regular rendering, output a 16 bit color
INDXCOLOR, // Rendering to indexed color, so we can later apply dark/bright
STCKCOLOR, // Stacks two indexed pixels (+flags) to apply blending
PIXCOPY // Special mode used for sprites, to allow for obj-window drawing
} rendtype;
s32 affine_reference_x[2];
s32 affine_reference_y[2];
static inline s32 signext28(u32 value)
{
s32 ret = (s32)(value << 4);
return ret >> 4;
}
void video_reload_counters()
{
/* This happens every Vblank */
affine_reference_x[0] = signext28(read_ioreg32(REG_BG2X_L));
affine_reference_y[0] = signext28(read_ioreg32(REG_BG2Y_L));
affine_reference_x[1] = signext28(read_ioreg32(REG_BG3X_L));
affine_reference_y[1] = signext28(read_ioreg32(REG_BG3Y_L));
}
// Renders non-affine tiled background layer.
// Will process a full or partial tile (start and end within 0..8) and draw
// it in either 8 or 4 bpp mode. Honors vertical and horizontal flip.
// tile contains the tile info (contains tile index, flip bits, pal info)
// hflip causes the tile pixels lookup to be reversed (from MSB to LSB
// If isbase is not set, color 0 is interpreted as transparent, otherwise
// we are drawing the base layer, so palette[0] is used (backdrop).
template<typename dtype, rendtype rdtype, bool is8bpp, bool isbase, bool hflip>
static inline void rend_part_tile_Nbpp(u32 bg_comb, u32 px_comb,
dtype *dest_ptr, u32 start, u32 end, u16 tile,
const u8 *tile_base, int vertical_pixel_flip, const u16 *paltbl
) {
// Seek to the specified tile, using the tile number and size.
// tile_base already points to the right tile-line vertical offset
const u8 *tile_ptr = &tile_base[(tile & 0x3FF) * (is8bpp ? 64 : 32)];
u16 bgcolor = paltbl[0];
// On vertical flip, apply the mirror offset
if (tile & 0x800)
tile_ptr += vertical_pixel_flip;
if (is8bpp) {
// Each byte is a color, mapped to a palete. 8 bytes can be read as 64bit
for (u32 i = start; i < end; i++, dest_ptr++) {
// Honor hflip by selecting bytes in the correct order
u32 sel = hflip ? (7-i) : i;
u8 pval = tile_ptr[sel];
// Alhpa mode stacks previous value (unless rendering the first layer)
if (pval) {
if (rdtype == FULLCOLOR)
*dest_ptr = paltbl[pval];
else if (rdtype == INDXCOLOR)
*dest_ptr = pval | px_comb; // Add combine flags
else if (rdtype == STCKCOLOR)
// Stack pixels on top of the pixel value and combine flags
*dest_ptr = pval | px_comb | ((isbase ? bg_comb : *dest_ptr) << 16);
}
else if (isbase) {
if (rdtype == FULLCOLOR)
*dest_ptr = bgcolor;
else
*dest_ptr = 0 | bg_comb; // Add combine flags
}
}
} else {
// In 4bpp mode, the tile[15..12] bits contain the sub-palette number.
u16 tilepal = (tile >> 12) << 4;
u16 pxflg = px_comb | tilepal;
const u16 *subpal = &paltbl[tilepal];
// Read packed pixel data, skip start pixels
u32 tilepix = eswap32(*(u32*)tile_ptr);
if (hflip) tilepix <<= (start * 4);
else tilepix >>= (start * 4);
// Only 32 bits (8 pixels * 4 bits)
for (u32 i = start; i < end; i++, dest_ptr++) {
u8 pval = hflip ? tilepix >> 28 : tilepix & 0xF;
if (pval) {
if (rdtype == FULLCOLOR)
*dest_ptr = subpal[pval];
else if (rdtype == INDXCOLOR)
*dest_ptr = pxflg | pval;
else if (rdtype == STCKCOLOR) // Stack pixels
*dest_ptr = pxflg | pval | ((isbase ? bg_comb : *dest_ptr) << 16);
}
else if (isbase) {
if (rdtype == FULLCOLOR)
*dest_ptr = bgcolor;
else
*dest_ptr = 0 | bg_comb;
}
// Advance to next packed data
if (hflip) tilepix <<= 4;
else tilepix >>= 4;
}
}
}
// Same as above, but optimized for full tiles. Skip comments here.
template<typename dtype, rendtype rdtype, bool is8bpp, bool isbase, bool hflip>
static inline void render_tile_Nbpp(
u32 bg_comb, u32 px_comb, dtype *dest_ptr, u16 tile,
const u8 *tile_base, int vertical_pixel_flip, const u16 *paltbl
) {
const u8 *tile_ptr = &tile_base[(tile & 0x3FF) * (is8bpp ? 64 : 32)];
u16 bgcolor = paltbl[0];
if (tile & 0x800)
tile_ptr += vertical_pixel_flip;
if (is8bpp) {
for (u32 j = 0; j < 2; j++) {
u32 tilepix = eswap32(((u32*)tile_ptr)[hflip ? 1-j : j]);
if (tilepix) {
for (u32 i = 0; i < 4; i++, dest_ptr++) {
u8 pval = hflip ? (tilepix >> (24 - i*8)) : (tilepix >> (i*8));
if (pval) {
if (rdtype == FULLCOLOR)
*dest_ptr = paltbl[pval];
else if (rdtype == INDXCOLOR)
*dest_ptr = pval | px_comb; // Add combine flags
else if (rdtype == STCKCOLOR)
*dest_ptr = pval | px_comb | ((isbase ? bg_comb : *dest_ptr) << 16);
}
else if (isbase) {
*dest_ptr = (rdtype == FULLCOLOR) ? bgcolor : 0 | bg_comb;
}
}
} else {
for (u32 i = 0; i < 4; i++, dest_ptr++)
if (isbase)
*dest_ptr = (rdtype == FULLCOLOR) ? bgcolor : 0 | bg_comb;
}
}
} else {
u32 tilepix = eswap32(*(u32*)tile_ptr);
if (tilepix) { // We can skip it all if the row is transparent
u16 tilepal = (tile >> 12) << 4;
u16 pxflg = px_comb | tilepal;
const u16 *subpal = &paltbl[tilepal];
for (u32 i = 0; i < 8; i++, dest_ptr++) {
u8 pval = (hflip ? (tilepix >> ((7-i)*4)) : (tilepix >> (i*4))) & 0xF;
if (pval) {
if (rdtype == FULLCOLOR)
*dest_ptr = subpal[pval];
else if (rdtype == INDXCOLOR)
*dest_ptr = pxflg | pval;
else if (rdtype == STCKCOLOR)
*dest_ptr = pxflg | pval | ((isbase ? bg_comb : *dest_ptr) << 16);
}
else if (isbase) {
*dest_ptr = (rdtype == FULLCOLOR) ? bgcolor : 0 | bg_comb;
}
}
} else if (isbase) {
// In this case we simply fill the pixels with background pixels
for (u32 i = 0; i < 8; i++, dest_ptr++)
*dest_ptr = (rdtype == FULLCOLOR) ? bgcolor : 0 | bg_comb;
}
}
}
template<typename stype, rendtype rdtype, bool isbase, bool is8bpp>
static void render_scanline_text_fast(u32 layer,
u32 start, u32 end, void *scanline, const u16 * paltbl)
{
u32 bg_control = read_ioreg(REG_BGxCNT(layer));
u16 vcount = read_ioreg(REG_VCOUNT);
u32 map_size = (bg_control >> 14) & 0x03;
u32 map_width = map_widths[map_size];
u32 hoffset = (start + read_ioreg(REG_BGxHOFS(layer))) % 512;
u32 voffset = (vcount + read_ioreg(REG_BGxVOFS(layer))) % 512;
stype *dest_ptr = ((stype*)scanline) + start;
// Calculate combine masks. These store 2 bits of info: 1st and 2nd target.
// If set, the current pixel belongs to a layer that is 1st or 2nd target.
u32 bg_comb = color_flags(5), px_comb = color_flags(layer);
// Background map data is in vram, at an offset specified in 2K blocks.
// (each map data block is 32x32 tiles, at 16bpp, so 2KB)
u32 base_block = (bg_control >> 8) & 0x1F;
u16 *map_base = (u16 *)&vram[base_block * 2048];
u16 *map_ptr, *second_ptr;
end -= start;
// Skip the top one/two block(s) if using the bottom half
if ((map_size & 0x02) && (voffset >= 256))
map_base += ((map_width / 8) * 32);
// Skip the top tiles within the block
map_base += (((voffset % 256) / 8) * 32);
// we might need to render from two charblocks, store a second pointer.
second_ptr = map_ptr = map_base;
if(map_size & 0x01) { // If background is 512 pixels wide
if(hoffset >= 256) {
// If we are rendering the right block, skip a whole charblock
hoffset -= 256;
map_ptr += (32 * 32);
} else {
// If we are rendering the left block, we might overrun into the right
second_ptr += (32 * 32);
}
} else {
hoffset %= 256; // Background is 256 pixels wide
}
// Skip the left blocks within the block
map_ptr += hoffset / 8;
// Render a single scanline of text tiles
u32 tilewidth = is8bpp ? tile_width_8bpp : tile_width_4bpp;
u32 vert_pix_offset = (voffset % 8) * tilewidth;
// Calculate the pixel offset between a line and its "flipped" mirror.
// The values can be {56, 40, 24, 8, -8, -24, -40, -56}
s32 vflip_off = is8bpp ?
tile_size_8bpp - 2*vert_pix_offset - tile_width_8bpp :
tile_size_4bpp - 2*vert_pix_offset - tile_width_4bpp;
// The tilemap base is selected via bgcnt (16KiB chunks)
u32 tilecntrl = (bg_control >> 2) & 0x03;
// Account for the base offset plus the tile vertical offset
u8 *tile_base = &vram[tilecntrl * 16*1024 + vert_pix_offset];
// Number of pixels available until the end of the tile block
u32 pixel_run = 256 - hoffset;
u32 tile_hoff = hoffset % 8;
u32 partial_hcnt = 8 - tile_hoff;
if (tile_hoff) {
// First partial tile, only right side is visible.
u32 todraw = MIN(end, partial_hcnt); // [1..7]
u32 stop = tile_hoff + todraw; // Usually 8, unless short run.
u16 tile = eswap16(*map_ptr++);
if (tile & 0x400) // Tile horizontal flip
rend_part_tile_Nbpp<stype, rdtype, is8bpp, isbase, true>(
bg_comb, px_comb, dest_ptr, tile_hoff, stop, tile, tile_base, vflip_off, paltbl);
else
rend_part_tile_Nbpp<stype, rdtype, is8bpp, isbase, false>(
bg_comb, px_comb, dest_ptr, tile_hoff, stop, tile, tile_base, vflip_off, paltbl);
dest_ptr += todraw;
end -= todraw;
pixel_run -= todraw;
}
if (!end)
return;
// Now render full tiles
u32 todraw = MIN(end, pixel_run) / 8;
for (u32 i = 0; i < todraw; i++, dest_ptr += 8) {
u16 tile = eswap16(*map_ptr++);
if (tile & 0x400) // Tile horizontal flip
render_tile_Nbpp<stype, rdtype, is8bpp, isbase, true>(
bg_comb, px_comb, dest_ptr, tile, tile_base, vflip_off, paltbl);
else
render_tile_Nbpp<stype, rdtype, is8bpp, isbase, false>(
bg_comb, px_comb, dest_ptr, tile, tile_base, vflip_off, paltbl);
}
end -= todraw * 8;
pixel_run -= todraw * 8;
if (!end)
return;
// Switch to the next char block if we ran out of tiles
if (!pixel_run)
map_ptr = second_ptr;
todraw = end / 8;
for (u32 i = 0; i < todraw; i++, dest_ptr += 8) {
u16 tile = eswap16(*map_ptr++);
if (tile & 0x400) // Tile horizontal flip
render_tile_Nbpp<stype, rdtype, is8bpp, isbase, true>(
bg_comb, px_comb, dest_ptr, tile, tile_base, vflip_off, paltbl);
else
render_tile_Nbpp<stype, rdtype, is8bpp, isbase, false>(
bg_comb, px_comb, dest_ptr, tile, tile_base, vflip_off, paltbl);
}
end -= todraw * 8;
// Finalize the tile rendering the left side of it (from 0 up to "end").
if (end) {
u16 tile = eswap16(*map_ptr++);
if (tile & 0x400) // Tile horizontal flip
rend_part_tile_Nbpp<stype, rdtype, is8bpp, isbase, true>(
bg_comb, px_comb, dest_ptr, 0, end, tile, tile_base, vflip_off, paltbl);
else
rend_part_tile_Nbpp<stype, rdtype, is8bpp, isbase, false>(
bg_comb, px_comb, dest_ptr, 0, end, tile, tile_base, vflip_off, paltbl);
}
}
// A slow version of the above function that allows for mosaic effects
template<typename stype, rendtype rdtype, bool isbase, bool is8bpp>
static void render_scanline_text_mosaic(u32 layer,
u32 start, u32 end, void *scanline, const u16 * paltbl)
{
u32 bg_control = read_ioreg(REG_BGxCNT(layer));
const u32 mosh = (read_ioreg(REG_MOSAIC) & 0xF) + 1;
const u32 mosv = ((read_ioreg(REG_MOSAIC) >> 4) & 0xF) + 1;
u16 vcount = read_ioreg(REG_VCOUNT);
u32 map_size = (bg_control >> 14) & 0x03;
u32 map_width = map_widths[map_size];
u32 hoffset = (start + read_ioreg(REG_BGxHOFS(layer))) % 512;
u16 vmosoff = vcount - vcount % mosv;
u32 voffset = (vmosoff + read_ioreg(REG_BGxVOFS(layer))) % 512;
stype *dest_ptr = ((stype*)scanline) + start;
u32 bg_comb = color_flags(5), px_comb = color_flags(layer);
u32 base_block = (bg_control >> 8) & 0x1F;
u16 *map_base = (u16 *)&vram[base_block * 2048];
u16 *map_ptr, *second_ptr;
if ((map_size & 0x02) && (voffset >= 256))
map_base += ((map_width / 8) * 32);
map_base += (((voffset % 256) / 8) * 32);
second_ptr = map_ptr = map_base;
if(map_size & 0x01) { // If background is 512 pixels wide
if(hoffset >= 256) {
// If we are rendering the right block, skip a whole charblock
hoffset -= 256;
map_ptr += (32 * 32);
} else {
// If we are rendering the left block, we might overrun into the right
second_ptr += (32 * 32);
}
} else {
hoffset %= 256; // Background is 256 pixels wide
}
// Skip the left blocks within the block
map_ptr += hoffset / 8;
// Render a single scanline of text tiles
u32 tilewidth = is8bpp ? tile_width_8bpp : tile_width_4bpp;
u32 vert_pix_offset = (voffset % 8) * tilewidth;
// Calculate the pixel offset between a line and its "flipped" mirror.
// The values can be {56, 40, 24, 8, -8, -24, -40, -56}
s32 vflip_off = is8bpp ?
tile_size_8bpp - 2*vert_pix_offset - tile_width_8bpp :
tile_size_4bpp - 2*vert_pix_offset - tile_width_4bpp;
// The tilemap base is selected via bgcnt (16KiB chunks)
u32 tilecntrl = (bg_control >> 2) & 0x03;
// Account for the base offset plus the tile vertical offset
u8 *tile_base = &vram[tilecntrl * 16*1024 + vert_pix_offset];
u16 bgcolor = paltbl[0];
// Iterate pixel by pixel, loading data every N pixels to honor mosaic effect
u8 pval = 0;
for (u32 i = 0; start < end; start++, i++, dest_ptr++) {
u16 tile = eswap16(*map_ptr);
if (!(i % mosh)) {
const u8 *tile_ptr = &tile_base[(tile & 0x3FF) * (is8bpp ? 64 : 32)];
bool hflip = (tile & 0x400);
if (tile & 0x800)
tile_ptr += vflip_off;
// Load byte or nibble with pixel data.
if (is8bpp) {
if (hflip)
pval = tile_ptr[7 - hoffset % 8];
else
pval = tile_ptr[hoffset % 8];
} else {
if (hflip)
pval = (tile_ptr[(7 - hoffset % 8) >> 1] >> (((hoffset & 1) ^ 1) * 4)) & 0xF;
else
pval = (tile_ptr[(hoffset % 8) >> 1] >> ((hoffset & 1) * 4)) & 0xF;
}
}
if (is8bpp) {
if (pval) {
if (rdtype == FULLCOLOR)
*dest_ptr = paltbl[pval];
else if (rdtype == INDXCOLOR)
*dest_ptr = pval | px_comb; // Add combine flags
else if (rdtype == STCKCOLOR)
*dest_ptr = pval | px_comb | ((isbase ? bg_comb : *dest_ptr) << 16);
}
else if (isbase) {
*dest_ptr = (rdtype == FULLCOLOR) ? bgcolor : 0 | bg_comb;
}
} else {
u16 tilepal = (tile >> 12) << 4;
u16 pxflg = px_comb | tilepal;
const u16 *subpal = &paltbl[tilepal];
if (pval) {
if (rdtype == FULLCOLOR)
*dest_ptr = subpal[pval];
else if (rdtype == INDXCOLOR)
*dest_ptr = pxflg | pval;
else if (rdtype == STCKCOLOR)
*dest_ptr = pxflg | pval | ((isbase ? bg_comb : *dest_ptr) << 16);
}
else if (isbase) {
*dest_ptr = (rdtype == FULLCOLOR) ? bgcolor : 0 | bg_comb;
}
}
// Need to continue from the next charblock
hoffset++;
if (hoffset % 8 == 0)
map_ptr++;
if (hoffset >= 256) {
hoffset = 0;
map_ptr = second_ptr;
}
}
}
template<typename stype, rendtype rdtype, bool isbase>
static void render_scanline_text(u32 layer,
u32 start, u32 end, void *scanline, const u16 * paltbl)
{
// Tile mode has 4 and 8 bpp modes.
u32 bg_control = read_ioreg(REG_BGxCNT(layer));
bool is8bpp = (read_ioreg(REG_BGxCNT(layer)) & 0x80);
const u32 mosamount = read_ioreg(REG_MOSAIC) & 0xFF;
bool has_mosaic = (bg_control & 0x40) && (mosamount != 0);
if (has_mosaic) {
if (is8bpp)
render_scanline_text_mosaic<stype, rdtype, isbase, true>(
layer, start, end, scanline, paltbl);
else
render_scanline_text_mosaic<stype, rdtype, isbase, false>(
layer, start, end, scanline, paltbl);
} else {
if (is8bpp)
render_scanline_text_fast<stype, rdtype, isbase, true>(
layer, start, end, scanline, paltbl);
else
render_scanline_text_fast<stype, rdtype, isbase, false>(
layer, start, end, scanline, paltbl);
}
}
static inline u8 lookup_pix_8bpp(
u32 px, u32 py, const u8 *tile_base, const u8 *map_base, u32 map_size
) {
// Pitch represents the log2(number of tiles per row) (from 16 to 128)
u32 map_pitch = map_size + 4;
// Given coords (px,py) in the background space, find the tile.
u32 mapoff = (px / 8) + ((py / 8) << map_pitch);
// Each tile is 8x8, so 64 bytes each.
const u8 *tile_ptr = &tile_base[map_base[mapoff] * tile_size_8bpp];
// Read the 8bit color within the tile.
return tile_ptr[(px % 8) + ((py % 8) * 8)];
}
template<typename dsttype, rendtype rdtype, bool isbase>
static inline void rend_pix_8bpp(
dsttype *dest_ptr, u8 pval, u32 bg_comb, u32 px_comb, const u16 *pal
) {
// Alhpa mode stacks previous value (unless rendering the first layer)
if (pval) {
if (rdtype == FULLCOLOR)
*dest_ptr = pal[pval];
else if (rdtype == INDXCOLOR)
*dest_ptr = pval | px_comb; // Add combine flags
else if (rdtype == STCKCOLOR)
// Stack pixels. If base, stack the base pixel.
*dest_ptr = pval | px_comb | ((isbase ? bg_comb : *dest_ptr) << 16);
}
else if (isbase) {
// Transparent pixel, but we are base layer, so render background.
if (rdtype == FULLCOLOR)
*dest_ptr = pal[0];
else
*dest_ptr = 0 | bg_comb; // Just backdrop color and combine flags
}
}
template<typename dsttype, rendtype rdtype>
static inline void render_bdrop_pixel_8bpp(
dsttype *dest_ptr, u32 bg_comb, u16 bgcol) {
// Alhpa mode stacks previous value (unless rendering the first layer)
if (rdtype == FULLCOLOR)
*dest_ptr = bgcol;
else
*dest_ptr = 0 | bg_comb;
}
typedef void (*affine_render_function) (
u32 layer, u32 start, u32 cnt, const u8 *map_base,
u32 map_size, const u8 *tile_base, void *dst_ptr,
const u16* pal);
// Affine background rendering logic.
// wrap extends the background infinitely, otherwise transparent/backdrop fill
// rotate indicates if there's any rotation (optimized version for no-rotation)
// mosaic applies to horizontal mosaic (vertical is adjusted via affine ref)
template <typename dtype, rendtype rdtype,
bool isbase, bool wrap, bool rotate, bool mosaic>
static inline void render_affine_background(
u32 layer, u32 start, u32 cnt, const u8 *map_base,
u32 map_size, const u8 *tile_base, void *dst_ptr_raw,
const u16* pal) {
dtype *dst_ptr = (dtype*)dst_ptr_raw;
// Backdrop and current layer combine bits.
u32 bg_comb = color_flags(5);
u32 px_comb = color_flags(layer);
s32 dx = (s16)read_ioreg(REG_BGxPA(layer));
s32 dy = (s16)read_ioreg(REG_BGxPC(layer));
s32 source_x = affine_reference_x[layer - 2] + (start * dx);
s32 source_y = affine_reference_y[layer - 2] + (start * dy);
// Maps are squared, four sizes available (128x128 to 1024x1024)
u32 width_height = 128 << map_size;
// Horizontal mosaic effect.
const u32 mosh = (mosaic ? (read_ioreg(REG_MOSAIC)) & 0xF : 0) + 1;
if (wrap) {
// In wrap mode the entire space is covered, since it "wraps" at the edges
u8 pval = 0;
if (rotate) {
for (u32 i = 0; cnt; i++, cnt--) {
u32 pix_x = (u32)(source_x >> 8) & (width_height-1);
u32 pix_y = (u32)(source_y >> 8) & (width_height-1);
// Lookup pixel and draw it (only every Nth if mosaic is on)
if (!mosaic || !(i % mosh))
pval = lookup_pix_8bpp(pix_x, pix_y, tile_base, map_base, map_size);
rend_pix_8bpp<dtype, rdtype, isbase>(dst_ptr++, pval, bg_comb, px_comb, pal);
source_x += dx; source_y += dy; // Move to the next pixel
}
} else {
// Y coordinate stays contant across the walk.
const u32 pix_y = (u32)(source_y >> 8) & (width_height-1);
for (u32 i = 0; cnt; i++, cnt--) {
u32 pix_x = (u32)(source_x >> 8) & (width_height-1);
if (!mosaic || !(i % mosh))
pval = lookup_pix_8bpp(pix_x, pix_y, tile_base, map_base, map_size);
rend_pix_8bpp<dtype, rdtype, isbase>(dst_ptr++, pval, bg_comb, px_comb, pal);
source_x += dx; // Only moving in the X direction.
}
}
} else {
u16 bgcol = pal[0];
if (rotate) {
// Draw backdrop pixels if necessary until we reach the background edge.
while (cnt) {
// Draw backdrop pixels if they lie outside of the background.
u32 pix_x = (u32)(source_x >> 8), pix_y = (u32)(source_y >> 8);
// Stop once we find a pixel that is actually *inside* the map.
if (pix_x < width_height && pix_y < width_height)
break;
// Draw a backdrop pixel if we are the base layer.
if (isbase)
render_bdrop_pixel_8bpp<dtype, rdtype>(dst_ptr, bg_comb, bgcol);
dst_ptr++;
source_x += dx; source_y += dy;
cnt--;
}
// Draw background pixels by looking them up in the map
u8 pval = 0;
for (u32 i = 0; cnt; i++, cnt--) {
u32 pix_x = (u32)(source_x >> 8), pix_y = (u32)(source_y >> 8);
// Check if we run out of background pixels, stop drawing.
if (pix_x >= width_height || pix_y >= width_height)
break;
// Lookup pixel and draw it.
if (!mosaic || !(i % mosh))
pval = lookup_pix_8bpp(pix_x, pix_y, tile_base, map_base, map_size);
rend_pix_8bpp<dtype, rdtype, isbase>(dst_ptr++, pval, bg_comb, px_comb, pal);
// Move to the next pixel, update coords accordingly
source_x += dx; source_y += dy;
}
} else {
// Specialized version for scaled-only backgrounds
u8 pval = 0;
const u32 pix_y = (u32)(source_y >> 8);
if (pix_y < width_height) { // Check if within Y-coord range
// Draw/find till left edge
while (cnt) {
u32 pix_x = (u32)(source_x >> 8);
if (pix_x < width_height)
break;
if (isbase)
render_bdrop_pixel_8bpp<dtype, rdtype>(dst_ptr, bg_comb, bgcol);
dst_ptr++;
source_x += dx;
cnt--;
}
// Draw actual background
for (u32 i = 0; cnt; i++, cnt--) {
u32 pix_x = (u32)(source_x >> 8);
if (pix_x >= width_height)
break;
if (!mosaic || !(i % mosh))
pval = lookup_pix_8bpp(pix_x, pix_y, tile_base, map_base, map_size);
rend_pix_8bpp<dtype, rdtype, isbase>(dst_ptr++, pval, bg_comb, px_comb, pal);
source_x += dx;
}
}
}
// Complete the line on the right, if we ran out over the bg edge.
// Only necessary for the base layer, otherwise we can safely finish.
if (isbase)
while (cnt--)
render_bdrop_pixel_8bpp<dtype, rdtype>(dst_ptr++, bg_comb, bgcol);
}
}
// Renders affine backgrounds. These differ substantially from non-affine
// ones. Tile maps are byte arrays (instead of 16 bit), limiting the map to
// 256 different tiles (with no flip bits and just one single 256 color pal).
// Optimize for common cases: wrap/non-wrap, scaling/rotation.
template<typename dsttype, rendtype rdtype, bool isbase>
static void render_scanline_affine(u32 layer,
u32 start, u32 end, void *scanline, const u16 *pal)
{
u32 bg_control = read_ioreg(REG_BGxCNT(layer));
u32 map_size = (bg_control >> 14) & 0x03;
// Char block base pointer
u32 base_block = (bg_control >> 8) & 0x1F;
u8 *map_base = &vram[base_block * 2048];
// The tilemap base is selected via bgcnt (16KiB chunks)
u32 tilecntrl = (bg_control >> 2) & 0x03;
u8 *tile_base = &vram[tilecntrl * 16*1024];
dsttype *dest_ptr = ((dsttype*)scanline) + start;
const u32 mosamount = read_ioreg(REG_MOSAIC) & 0xFF;
bool has_mosaic = (bg_control & 0x40) && (mosamount != 0);
bool has_rotation = read_ioreg(REG_BGxPC(layer)) != 0;
bool has_wrap = (bg_control >> 13) & 1;
// Number of pixels to render
u32 cnt = end - start;
// Four specialized versions for faster rendering on specific cases like
// scaling only or non-wrapped backgrounds.
u32 fidx = (has_wrap ? 0x4 : 0) |
(has_rotation ? 0x2 : 0) |
(has_mosaic ? 0x1 : 0);
static const affine_render_function rdfns[8] = {
render_affine_background<dsttype, rdtype, isbase, false, false, false>,
render_affine_background<dsttype, rdtype, isbase, false, false, true>,
render_affine_background<dsttype, rdtype, isbase, false, true, false>,
render_affine_background<dsttype, rdtype, isbase, false, true, true>,
render_affine_background<dsttype, rdtype, isbase, true, false, false>,
render_affine_background<dsttype, rdtype, isbase, true, false, true>,
render_affine_background<dsttype, rdtype, isbase, true, true, false>,
render_affine_background<dsttype, rdtype, isbase, true, true, true>,
};
rdfns[fidx](layer, start, cnt, map_base, map_size, tile_base, dest_ptr, pal);
}
template<rendtype rdmode, typename buftype, unsigned mode, typename pixfmt>
static inline void bitmap_pixel_write(
buftype *dst_ptr, pixfmt val, const u16 * palptr, u16 px_attr
) {
if (mode != 4)
*dst_ptr = convert_palette(val); // Direct color, u16 bitmap
else if (val) {
if (rdmode == FULLCOLOR)
*dst_ptr = palptr[val];
else if (rdmode == INDXCOLOR)
*dst_ptr = val | px_attr; // Add combine flags
else if (rdmode == STCKCOLOR)
*dst_ptr = val | px_attr | ((*dst_ptr) << 16); // Stack pixels
}
}
typedef enum
{
BLIT, // The bitmap has no scaling nor rotation on the X axis
SCALED, // The bitmap features some scaling (on the X axis) but no rotation
ROTATED // Bitmap has rotation (and perhaps scaling too)
} bm_rendmode;
// Renders a bitmap honoring the pixel mode and any affine transformations.
// There's optimized versions for bitmaps without scaling / rotation.
template<rendtype rdtype, typename dsttype, // Rendering target type and format
unsigned mode,
typename pixfmt, // Bitmap source pixel format (8/16)
unsigned width, unsigned height, // Bitmap size (not screen!)
bm_rendmode rdmode, // Rendering mode optimization.
bool mosaic> // Whether mosaic effect is used.
static inline void render_scanline_bitmap(
u32 start, u32 end, void *scanline, const u16 * palptr
) {
s32 dx = (s16)read_ioreg(REG_BG2PA);
s32 dy = (s16)read_ioreg(REG_BG2PC);
s32 source_x = affine_reference_x[0] + (start * dx); // Always BG2
s32 source_y = affine_reference_y[0] + (start * dy);
// Premature abort render optimization if bitmap out of Y coordinate.
if ((rdmode != ROTATED) && ((u32)(source_y >> 8)) >= height)
return;
// Modes 4 and 5 feature double buffering.
bool second_frame = (mode >= 4) && (read_ioreg(REG_DISPCNT) & 0x10);
pixfmt *src_ptr = (pixfmt*)&vram[second_frame ? 0xA000 : 0x0000];
dsttype *dst_ptr = ((dsttype*)scanline) + start;
u16 px_attr = color_flags(2); // Always BG2
const u32 mosh = (mosaic ? (read_ioreg(REG_MOSAIC)) & 0xF : 0) + 1;
if (rdmode == BLIT) {
// We just blit pixels (copy) from buffer to buffer.
const u32 pixel_y = (u32)(source_y >> 8);
if (source_x < 0) {
// The bitmap starts somewhere after "start", skip those pixels.
u32 delta = (-source_x + 255) >> 8;
dst_ptr += delta;
start += delta;
source_x = 0;
}
u32 pixel_x = (u32)(source_x >> 8);
u32 pixcnt = MIN(end - start, width - pixel_x);
pixfmt *valptr = &src_ptr[pixel_x + (pixel_y * width)];
pixfmt val = 0;
for (u32 i = 0; pixcnt; i++, pixcnt--, valptr++) {
// Pretty much pixel copier
if (!mosaic || !(i % mosh))
val = sizeof(pixfmt) == 2 ? eswap16(*valptr) : *valptr;
bitmap_pixel_write<rdtype, dsttype, mode, pixfmt>(dst_ptr++, val, palptr, px_attr);
}
}
else if (rdmode == SCALED) {
// Similarly to above, but now we need to sample pixels instead.
const u32 pixel_y = (u32)(source_y >> 8);
// Find the "inside" of the bitmap
while (start < end) {
u32 pixel_x = (u32)(source_x >> 8);
if (pixel_x < width)
break;
source_x += dx;
start++;
dst_ptr++;
}
u32 cnt = end - start;
pixfmt val = 0;
for (u32 i = 0; cnt; i++, cnt--) {
u32 pixel_x = (u32)(source_x >> 8);
if (pixel_x >= width)
break; // We reached the end of the bitmap
if (!mosaic || !(i % mosh)) {
pixfmt *valptr = &src_ptr[pixel_x + (pixel_y * width)];
val = sizeof(pixfmt) == 2 ? eswap16(*valptr) : *valptr;
}
bitmap_pixel_write<rdtype, dsttype, mode, pixfmt>(dst_ptr++, val, palptr, px_attr);
source_x += dx;
}
} else {
// Look for the first pixel to be drawn.
while (start < end) {
u32 pixel_x = (u32)(source_x >> 8), pixel_y = (u32)(source_y >> 8);
if (pixel_x < width && pixel_y < height)
break;
start++;
dst_ptr++;
source_x += dx; source_y += dy;
}
pixfmt val = 0;
for (u32 i = 0; start < end; start++) {
u32 pixel_x = (u32)(source_x >> 8), pixel_y = (u32)(source_y >> 8);
// Check if we run out of background pixels, stop drawing.
if (pixel_x >= width || pixel_y >= height)
break;
// Lookup pixel and draw it.
if (!mosaic || !(i % mosh)) {
pixfmt *valptr = &src_ptr[pixel_x + (pixel_y * width)];
val = sizeof(pixfmt) == 2 ? eswap16(*valptr) : *valptr;
}
bitmap_pixel_write<rdtype, dsttype, mode, pixfmt>(dst_ptr++, val, palptr, px_attr);
// Move to the next pixel, update coords accordingly
source_x += dx;
source_y += dy;
}
}
}
// Object/Sprite rendering logic
static const u8 obj_dim_table[3][4][2] = {
{ {8, 8}, {16, 16}, {32, 32}, {64, 64} },
{ {16, 8}, {32, 8}, {32, 16}, {64, 32} },
{ {8, 16}, {8, 32}, {16, 32}, {32, 64} }
};
static u8 obj_priority_list[5][160][128];
static u8 obj_priority_count[5][160];
static u8 obj_alpha_count[160];
typedef struct {
s32 obj_x, obj_y;
s32 obj_w, obj_h;
u32 attr1, attr2;
bool is_double;
} t_sprite;
// Renders a tile row (8 pixels) for a regular (non-affine) object/sprite.
// tile_offset points to the VRAM offset where the data lives.
template<typename dsttype, rendtype rdtype, bool is8bpp, bool hflip>
static inline void render_obj_part_tile_Nbpp(
u32 px_comb, dsttype *dest_ptr, u32 start, u32 end,
u32 tile_offset, u16 palette, const u16 *pal
) {
// Note that the last VRAM bank wrap around, hence the offset aliasing
const u8* tile_ptr = &vram[0x10000 + (tile_offset & 0x7FFF)];
u32 px_attr = px_comb | palette | 0x100; // Combine flags + high palette bit
if (is8bpp) {
// Each byte is a color, mapped to a palete.
for (u32 i = start; i < end; i++, dest_ptr++) {
// Honor hflip by selecting bytes in the correct order
u32 sel = hflip ? (7-i) : i;
u8 pval = tile_ptr[sel];
// Alhpa mode stacks previous value
if (pval) {
if (rdtype == FULLCOLOR)
*dest_ptr = pal[pval];
else if (rdtype == INDXCOLOR)
*dest_ptr = pval | px_attr; // Add combine flags
else if (rdtype == STCKCOLOR) {
// Stack pixels on top of the pixel value and combine flags
// We do not stack OBJ on OBJ, rather overwrite the previous object
if (*dest_ptr & 0x100)
*dest_ptr = pval | px_attr | ((*dest_ptr) & 0xFFFF0000);
else
*dest_ptr = pval | px_attr | ((*dest_ptr) << 16);