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program DoubleBuffer;
{$mode objfpc}
uses
ctypes, nds9;
var
backBuffer: pcuint16;
colorMask: cuint16;
iy, ix: integer;
bg: cuint16;
begin
randomize;
//set the mode for 2 text layers and two extended background layers
videoSetMode(MODE_5_2D);
//set the first two banks as background memory and the third as sub background memory
//D is not used..if you need a bigger background then you will need to map
//more vram banks consecutivly (VRAM A-D are all 0x20000 bytes in size)
vramSetPrimaryBanks(VRAM_A_MAIN_BG_0x06000000, VRAM_B_MAIN_BG_0x06020000,
VRAM_C_SUB_BG, VRAM_D_LCD);
consoleDemoInit();
iprintf(#10#10#9 + 'Hello DS devers' + #10);
iprintf(#9 + 'www.drunkencoders.com' + #10);
iprintf(#9 + 'double buffer demo');
bg := bgInit(3, BgType_Bmp16, BgSize_B16_256x256, 0,0);
colorMask := $1F;
backBuffer := pcuint16(bgGetGfxPtr(bg)) + 256*256;
while true do
begin
//draw a box (60,60,196,136)
for iy := 60 to 196 - 60 - 1 do
for ix := 60 to 256 - 60 - 1 do
backBuffer[iy * 256 + ix] := random(colorMask) or BIT(15);
swiWaitForVBlank();
scanKeys();
if (keysDown() and KEY_START) <> 0 then
exit;
//swap the back buffer to the current buffer
backBuffer := pcuint16(bgGetGfxPtr(bg));
//swap the current buffer by changing the base. Each base
//represents 16KB of offset and each screen is 256x256x2 (128KB)
//this requires a map base seperation of 8 (could get away with smaller
//as the screen is really only showing 256x192 (96KB or map base 6)
if (bgGetMapBase(bg) = 8) then
bgSetMapBase(bg, 0)
else
bgSetMapBase(bg, 8);
colorMask := colorMask xor $3FF;
end;
end.
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