AntonioND/nitro-engine
1
Fork 0
mirror of https://github.com/AntonioND/nitro-engine.git synced 2025-06-18 16:45:33 -04:00
Code Issues Actions Packages Projects Releases Wiki Activity

library: Fix dual 3D DMA mode in BlocksDS

Browse Source 
The fork of libnds of BlocksDS doesn't leave 32 unused characters right
at the beginning of the tileset of the debug console. The code used to
rely on this space being free to store there the first line of a 16-bit
bitmap.

The line has been moved to an actual free part of the VRAM bank.
This commit is contained in:
Antonio Niño Díaz 2023-10-16 02:23:45 +01:00
parent 06ac0eba5b
commit 01b8a9cf9a
1 changed files with 30 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

41
source/NEGeneral.c
View File

@ -543,8 +543,8 @@ void NE_InitConsole(void)
// Sub engine - VRAM_I:
// Available memory: 0x06208000 - 0x0620C000 (16 KB)
// Framebuffer (one line): 0x06208000 - 0x06208200 (512 B)
// Tile base 2: 0x06208000 - 0x06209000 (4 KB)
// Framebuffer (one line): 0x0620B000 - 0x0620B200 (512 B)
// Map base 23: 0x0620B800 - 0x0620C000 (2 KB)
//
// There is an overlap between the framebuffer and the tileset.
@ -553,11 +553,24 @@ void NE_InitConsole(void)
// size, so both the bitmap and tileset need to share the same
// space.
//
// Luckily, 256 bytes for a 4 bpp tileset uses the same amount of
// memory as 256 / (8 * 8 * 4 / 8) = 8 tiles. The first characters
// of the console correspond to non-printable ASCII characters, so
// this overlap isn't a real issue as the first 8 characters won't
// ever be shown anyway.
// Luckily, the tileset of the console doesn't use the whole 16 KB.
// The current console of libnds uses up to 128 characters. The
// absolute maximum would be 256 characters, which requires (for a 4
// bpp tileset) 8 KB of VRAM. This means that anything in the second
// half of the bank (VRAM I is 16 KB in size) can be used for maps
// or to store the pseudo framebuffer line.
//
// 8 KB is the same size as 16 lines in a 16-bit background. We can
// setup our 16-bit bitmap as if it started at the same base as the
// tileset, and we can store our line bitmap at some point between
// 16 and 32 lines.
//
// Now, remember that the map uses the last 2 KB of the VRAM bank,
// and that uses as much memory as 8 lines of a 16-bit bitmap. The
// free lines of the bitmap are actually 16 to 24.
//
// Nitro Engine uses line 20, located at offset 0x3000 from the
// start of the bank.
vramSetBankI(VRAM_I_SUB_BG_0x06208000);
consoleInit(0, 1, BgType_Text4bpp, BgSize_T_256x256, 23, 2, false, true);
@ -667,6 +680,8 @@ static void ne_process_dual_3d(NE_Voidfunc mainscreen, NE_Voidfunc subscreen)
NE_Screen ^= 1;
}
#define NE_DUAL_DMA_3D_LINES_OFFSET 20
static void ne_process_dual_3d_fb(NE_Voidfunc mainscreen, NE_Voidfunc subscreen)
{
NE_UpdateInput();
@ -786,11 +801,12 @@ static void ne_process_dual_3d_dma(NE_Voidfunc mainscreen, NE_Voidfunc subscreen
REG_BG2PC_SUB = 0;
REG_BG2PD_SUB = 0; // Scale first row to expand to the full screen
REG_BG2X_SUB = 0;
REG_BG2Y_SUB = 0;
REG_BG2Y_SUB = NE_DUAL_DMA_3D_LINES_OFFSET << 8;
ne_dma_enabled = 1;
ne_dma_src = (uint32_t)VRAM_C + 0x8000;
ne_dma_dst = (uint32_t)BG_BMP_RAM_SUB(2),
ne_dma_dst = ((uint32_t)BG_BMP_RAM_SUB(2))
+ 256 * NE_DUAL_DMA_3D_LINES_OFFSET * 2;
ne_dma_cr = DMA_COPY_WORDS | (256 * 2 / 4) |
DMA_START_HBL | DMA_REPEAT | DMA_SRC_INC | DMA_DST_RESET;
@ -836,11 +852,12 @@ static void ne_process_dual_3d_dma(NE_Voidfunc mainscreen, NE_Voidfunc subscreen
REG_BG2PC_SUB = 0;
REG_BG2PD_SUB = 0; // Scale first row to expand to the full screen
REG_BG2X_SUB = 0;
REG_BG2Y_SUB = 0;
REG_BG2Y_SUB = NE_DUAL_DMA_3D_LINES_OFFSET << 8;
ne_dma_enabled = 1;
ne_dma_src = (uint32_t)VRAM_D + 0x8000;
ne_dma_dst = (uint32_t)BG_BMP_RAM_SUB(2),
ne_dma_dst = ((uint32_t)BG_BMP_RAM_SUB(2))
+ 256 * NE_DUAL_DMA_3D_LINES_OFFSET * 2;
ne_dma_cr = DMA_COPY_WORDS | (256 * 2 / 4) |
DMA_START_HBL | DMA_REPEAT | DMA_SRC_INC | DMA_DST_RESET;
@ -945,7 +962,9 @@ void NE_VBLFunc(void)
//
// For consistency, in the main screen this is achieved by simply
// scrolling the bitmap background by one pixel.
dmaFillWords(0, BG_BMP_RAM_SUB(2), 256 * 2);
dmaFillWords(0, BG_BMP_RAM_SUB(2) + 256 * NE_DUAL_DMA_3D_LINES_OFFSET,
256 * 2);
ne_do_dma();
}