c++ - 渲染填充表面时,黑白显示上的阴影效果更好

标签 c++ algorithm graphics rasterizing shading

序言

我终于解决了 AT32UC3xxxxx 和 SSD1306 OLED I2C 显示器之间的硬件不兼容问题(两者都存在导致不兼容的硬件错误),使我能够以 400KBaud(每帧约 26.6ms)使用 HW I2C。因此,我决定重写此 LCD 的旧驱动程序,通过添加填充表面(三角形、四边形)而不只是线条和图案线(我已经实现)来利用新的速度。

问题是显示屏为 128x64 像素,但没有颜色或灰色阴影,只有黑白开/关

因此,为了渲染旋转立方体,我需要以某种方式区分表面。我正在考虑随机填充模式,其中表面填充一定百分比而不是颜色。

这是我当前的代码(整个库但没有错误,它应该正常工作):

LCD_SSD1306_I2C.h

//------------------------------------------------------------------------------------------
//--- SSD1306 I2C OLED LCD driver ver 2.000 ------------------------------------------------
//------------------------------------------------------------------------------------------
#ifndef _LCD_SSD1306_I2C_h
#define _LCD_SSD1306_I2C_h
//------------------------------------------------------------------------------------------
#define SSD1306_SETCONTRAST 0x81
#define SSD1306_DISPLAYALLON_RESUME 0xA4
#define SSD1306_DISPLAYALLON 0xA5
#define SSD1306_NORMALDISPLAY 0xA6
#define SSD1306_INVERTDISPLAY 0xA7
#define SSD1306_DISPLAYOFF 0xAE
#define SSD1306_DISPLAYON 0xAF
#define SSD1306_SETDISPLAYOFFSET 0xD3
#define SSD1306_SETCOMPINS 0xDA
#define SSD1306_SETVCOMDETECT 0xDB
#define SSD1306_SETDISPLAYCLOCKDIV 0xD5
#define SSD1306_SETPRECHARGE 0xD9
#define SSD1306_SETMULTIPLEX 0xA8
#define SSD1306_SETLOWCOLUMN 0x00
#define SSD1306_SETHIGHCOLUMN 0x10
#define SSD1306_SETSTARTLINE 0x40
#define SSD1306_MEMORYMODE 0x20
#define SSD1306_COLUMNADDR 0x21
#define SSD1306_PAGEADDR   0x22
#define SSD1306_COMSCANINC 0xC0
#define SSD1306_COMSCANDEC 0xC8
#define SSD1306_SEGREMAP 0xA0
#define SSD1306_CHARGEPUMP 0x8D
#define SSD1306_SWITCHCAPVCC 0x2
// Scrolling #defines
#define SSD1306_ACTIVATE_SCROLL 0x2F
#define SSD1306_DEACTIVATE_SCROLL 0x2E
#define SSD1306_SET_VERTICAL_SCROLL_AREA 0xA3
#define SSD1306_RIGHT_HORIZONTAL_SCROLL 0x26
#define SSD1306_LEFT_HORIZONTAL_SCROLL 0x27
#define SSD1306_VERTICAL_AND_RIGHT_HORIZONTAL_SCROLL 0x29
#define SSD1306_VERTICAL_AND_LEFT_HORIZONTAL_SCROLL 0x2A
//------------------------------------------------------------------------------------------
//#define I2C_send(adr,buf,siz){}
//------------------------------------------------------------------------------------------
#ifndef _brv8_tab
#define _brv8_tab
static const U8 brv8[256] =     // 8 bit bit reversal
    {
    0,128,64,192,32,160,96,224,16,144,80,208,48,176,112,240,8,136,72,200,40,168,104,232,24,152,
    88,216,56,184,120,248,4,132,68,196,36,164,100,228,20,148,84,212,52,180,116,244,12,140,76,204,
    44,172,108,236,28,156,92,220,60,188,124,252,2,130,66,194,34,162,98,226,18,146,82,210,50,178,
    114,242,10,138,74,202,42,170,106,234,26,154,90,218,58,186,122,250,6,134,70,198,38,166,102,230,
    22,150,86,214,54,182,118,246,14,142,78,206,46,174,110,238,30,158,94,222,62,190,126,254,1,129,
    65,193,33,161,97,225,17,145,81,209,49,177,113,241,9,137,73,201,41,169,105,233,25,153,89,217,57,
    185,121,249,5,133,69,197,37,165,101,229,21,149,85,213,53,181,117,245,13,141,77,205,45,173,109,
    237,29,157,93,221,61,189,125,253,3,131,67,195,35,163,99,227,19,147,83,211,51,179,115,243,11,139,
    75,203,43,171,107,235,27,155,91,219,59,187,123,251,7,135,71,199,39,167,103,231,23,151,87,215,55,
    183,119,247,15,143,79,207,47,175,111,239,31,159,95,223,63,191,127,255
    };
#endif
//------------------------------------------------------------------------------------------
class LCD_SSD1306_I2C           // max 96 lines
    {
public:
    // screen
    int adr;                    // I2C adr
    int xs,ys,sz;               // resoluiton
    U8 _scr[((128*96)>>3)+1];   // screen buffer
    U8 *scr;
    U8 *pyx[96];                // scan lines
    // pattern
    U32 pat,pat_m,pat_b;        // binary pattern,max used bit mask,actual bit mask
    // filling
    U32 seed;
    int bufl[96];
    int bufr[96];

    // system api
    void init(int _adr,int _xs,int _ys);                    // initialize LCD: I2C_adr,xs,ys
    void _command(U8 cmd);                                  // *internal* do not cal it (sends command to LCD over I2C)
    void rfsscr();                                          // copy actual screen buffer to LCD (by I2C)
    // gfx rendering col = <0,1>
    void clrscr();                                          // clear screen buffer
    void rotate(int ang);                                   // rotate 180 deg
    void pixel(int x,int y,bool col);                       // set/res pixel
    bool pixel(int x,int y);                                // get pixel
    void line(int x0,int y0,int x1,int y1,bool col);        // line
    void triangle(int x0,int y0,int x1,int y1,int x2,int y2,bool col);// triangle
    void quad(int x0,int y0,int x1,int y1,int x2,int y2,int x3,int y3,bool col);
    void rect(int x0,int y0,int x1,int y1,bool col);        // rectangle using diagonal points
    // patern rendering
    void pat_set(char *s);                                  // set binary pattern from bianry number string MSB renders first
    void pat_beg();                                         // set pattern state to start of pattern
    void pat_line(int x0,int y0,int x1,int y1,bool col);
    void pat_triangle(int x0,int y0,int x1,int y1,int x2,int y2,bool col);
    void pat_quad(int x0,int y0,int x1,int y1,int x2,int y2,int x3,int y3,bool col);
    void pat_rect(int x0,int y0,int x1,int y1,bool col);
    // filled polygons col = <0,255>
    void _fill_line(int x0,int y0,int x1,int y1);           // *internal* do not call it (render line into bufl/bufr)
    void _fill_seed();                                      // *internal* do not call it (reset seed)
    U8   _fill_rand();                                      // *internal* do not call it (get pseudo random number)
    void fill_triangle(int x0,int y0,int x1,int y1,int x2,int y2,U8 col);
    void fill_quad(int x0,int y0,int x1,int y1,int x2,int y2,int x3,int y3,U8 col);
    // text rendering
    void prnchr(int x,int y,char c);                        // render char at x,y (y is rounded to multiple of 8)
    void prntxt(int x,int y,const char *txt);               // render text at x,y (y is rounded to multiple of 8)
    };
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::_command(U8 cmd)
    {
    U8 buf[2]=
        {
        0x00,       // 0x40 data/command
        cmd,
        };
    I2C_send(adr,buf,2);
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::init(int _adr,int _xs,int _ys)
    {
    int y;
    adr=_adr;
    xs=_xs;
    ys=_ys;
    sz=xs*(ys>>3);
    const bool _external_Vcc=false;
    // VRAM buffer
    scr=_scr+1;                                         // skip first Byte (VRAM/command selection)
    for (y=0;y<ys;y++) pyx[y]=scr+((y>>3)*xs);          // scanlines for fast direct pixel access
    clrscr();
    // Init sequence
    U8 comPins = 0x02;
    U8 contrast = 0x8F;
         if((xs == 128) && (ys == 32)) { comPins = 0x02; contrast = 0x8F; }
    else if((xs == 128) && (ys == 64)) { comPins = 0x12; contrast = (_external_Vcc) ? 0x9F : 0xCF; }
    else if((xs ==  96) && (ys == 16)) { comPins = 0x02; contrast = (_external_Vcc) ? 0x10 : 0xAF; }
    else {} // Other screens
    static U8 init0[27]=
        {
        0x00,                                           // commands
        SSD1306_DISPLAYOFF,                             // 0xAE
        SSD1306_SETDISPLAYCLOCKDIV,0x80,                // 0xD5
        SSD1306_SETMULTIPLEX,ys-1,                      // 0xA8
        SSD1306_SETDISPLAYOFFSET,0x00,                  // 0xD3 no offset
        SSD1306_SETSTARTLINE | 0x0,                     // line 0
        SSD1306_CHARGEPUMP,(_external_Vcc)?0x10:0x14,   // 0x8D
        SSD1306_MEMORYMODE,0x00,                        // 0x20 horizontal (scanlines)
        SSD1306_SEGREMAP | 0x1,
        SSD1306_COMSCANDEC,
        SSD1306_SETCOMPINS,comPins,
        SSD1306_SETCONTRAST,contrast,
        SSD1306_SETPRECHARGE,(_external_Vcc)?0x22:0xF1, // 0xd9
        SSD1306_SETVCOMDETECT,0x40,                     // 0xDB
        SSD1306_DISPLAYALLON_RESUME,                    // 0xA4
        SSD1306_NORMALDISPLAY,                          // 0xA6
        SSD1306_DEACTIVATE_SCROLL,
        SSD1306_DISPLAYON,                              // Main screen turn on
        };
    I2C_send(adr,init0,sizeof(init0));
    // init default pattern
    pat_set("111100100");
    // clear filling buffers
    for (y=0;y<96;y++)
        {
        bufl[y]=-1;
        bufr[y]=-1;
        }
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::clrscr()
    {
    for (int a=0;a<sz;a++) scr[a]=0x00;
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::rotate(int ang)
    {
    U8 a0,a1;
    int x0,y0,x1,y1;
    if (ang==180)
     for (y0=0,y1=ys-8;y0<y1;y0+=8,y1-=8)
      for (x0=0,x1=xs-1;x0<xs;x0++,x1--)
          {
          a0=brv8[pyx[y0][x0]];
          a1=brv8[pyx[y1][x1]];
          pyx[y0][x0]=a1;
          pyx[y1][x1]=a0;
          }
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::rfsscr()
    {
    static const U8 init1[] =
        {
        0x00,                           // commands
        SSD1306_MEMORYMODE,0,           // horizontal addresing mode
        SSD1306_COLUMNADDR,0,xs-1,      // Column start/end address (0/127 reset)
        SSD1306_PAGEADDR,0,(ys>>3)-1,   // Page start/end address (0 reset)
        };
    I2C_send(adr,(U8*)init1,sizeof(init1));

    _scr[0]=0x40;                       // 0x40 VRAM
    // SW I2C can pass whole VRAM in single packet
//  I2C_send(adr,_scr,sz+1);

    // HW I2C must use packets up to 255 bytes so 128+1 (as TWIM0 on UC3 has 8 bit counter)
    int i,n=128; U8 *p=_scr,a;
    for (i=0;i<sz;i+=n){ a=p[0]; p[0]=0x40; I2C_send(adr,p,n+1); p[0]=a; p+=n; }
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::pixel(int x, int y,bool col)
    {
    // clip to screen
    if ((x<0)||(x>=xs)||(y<0)||(y>=ys)) return;
    // add or remove bit
    if (col) pyx[y][x] |= (1<<(y&7));
    else     pyx[y][x] &= (255)^(1<<(y&7));
    }
//------------------------------------------------------------------------------------------
bool LCD_SSD1306_I2C::pixel(int x, int y)
    {
    // clip to screen
    if ((x<0)||(x>=xs)||(y<0)||(y>=ys)) return false;
    // get bit
    return ((pyx[y][x]>>(y&7))&1);
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::line(int x0,int y0,int x1,int y1,bool col)
    {
    int i,n,cx,cy,sx,sy;
    // line DDA parameters
    x1-=x0; sx=0; if (x1>0) sx=+1; if (x1<0) { sx=-1; x1=-x1; } if (x1) x1++;           n=x1;
    y1-=y0; sy=0; if (y1>0) sy=+1; if (y1<0) { sy=-1; y1=-y1; } if (y1) y1++; if (n<y1) n=y1;
    // single pixel (not a line)
    if (!n){ pixel(x0,y0,col); return; }
    // ND DDA algo i is parameter
    for (cx=cy=n,i=0;i<n;i++)
        {
        pixel(x0,y0,col);
        cx-=x1; if (cx<=0){ cx+=n; x0+=sx; }
        cy-=y1; if (cy<=0){ cy+=n; y0+=sy; }
        }
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::pat_line(int x0,int y0,int x1,int y1,bool col)
    {
    bool ccc;
    int i,n,cx,cy,sx,sy;
    // line DDA parameters
    x1-=x0; sx=0; if (x1>0) sx=+1; if (x1<0) { sx=-1; x1=-x1; } if (x1) x1++;           n=x1;
    y1-=y0; sy=0; if (y1>0) sy=+1; if (y1<0) { sy=-1; y1=-y1; } if (y1) y1++; if (n<y1) n=y1;
    // single pixel (not a line)
    if (!n){ pixel(x0,y0,col); return; }
    // ND DDA algo i is parameter
    for (cx=cy=n,i=0;i<n;i++)
        {
        ccc=(pat&pat_b); ccc^=(!col);
        pat_b>>=1; if (!pat_b) pat_b=pat_m;
        pixel(x0,y0,ccc);
        cx-=x1; if (cx<=0){ cx+=n; x0+=sx; }
        cy-=y1; if (cy<=0){ cy+=n; y0+=sy; }
        }
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::_fill_line(int x0,int y0,int x1,int y1)
    {
    int i,n,cx,cy,sx,sy,*buf;
    // line DDA parameters
    x1-=x0; sx=0; if (x1>0) sx=+1; if (x1<0) { sx=-1; x1=-x1; } if (x1) x1++;           n=x1;
    y1-=y0; sy=0; if (y1>0) sy=+1; if (y1<0) { sy=-1; y1=-y1; } if (y1) y1++; if (n<y1) n=y1;
    // single pixel (not a line)
    if (!n)
        {
        if ((y0>=0)&&(y0<ys))
            {
            bufl[y0]=x0;
            bufr[y0]=x0;
            }
        return;
        }
    // target buffer depend on y direction
    if (sy>0) buf=bufl; else buf=bufr;
    // ND DDA algo i is parameter
    for (cx=cy=n,i=0;i<n;i++)
        {
        if ((y0>=0)&&(y0<ys)) buf[y0]=x0;
        cx-=x1; if (cx<=0){ cx+=n; x0+=sx; }
        cy-=y1; if (cy<=0){ cy+=n; y0+=sy; }
        }
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::_fill_seed()
    {
    seed=0x017A357E1;
//  RandSeed=0x017A357E1;
    }
//------------------------------------------------------------------------------------------
U8 LCD_SSD1306_I2C::_fill_rand()
    {
    U32 a,b,c;
    a= seed     &0x0FFFF;
    b=(seed>>16)&0x0FFFF;
    seed<<=11;
    seed^=(a<<16);
    seed&=0x0FFFF0000;
    seed|=b+17;
    return seed&255;
//  return Random(256);
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::triangle(int x0,int y0,int x1,int y1,int x2,int y2,bool col)
    {
    line(x0,y0,x1,y1,col);
    line(x1,y1,x2,y2,col);
    line(x2,y2,x0,y0,col);
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::pat_triangle(int x0,int y0,int x1,int y1,int x2,int y2,bool col)
    {
    pat_line(x0,y0,x1,y1,col);
    pat_line(x1,y1,x2,y2,col);
    pat_line(x2,y2,x0,y0,col);
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::fill_triangle(int x0,int y0,int x1,int y1,int x2,int y2,U8 col)
    {
    int x,y,X0,X1,Y0,Y1;
    // y range to render
    Y0=Y1=y0;
    if (Y0>y1) Y0=y1;
    if (Y1<y1) Y1=y1;
    if (Y0>y2) Y0=y2;
    if (Y1<y2) Y1=y2;
    // clip to screen in y axis
    if ((Y1<0)||(Y0>=ys)) return;
    if (Y0<  0) Y0=   0;
    if (Y1>=ys) Y1=ys-1;
    // clear buffers
    for (y=Y0;y<=Y1;y++)
        {
        bufl[y]=xs;
        bufr[y]=-1;
        }
    // render circumference
    _fill_line(x0,y0,x1,y1);
    _fill_line(x1,y1,x2,y2);
    _fill_line(x2,y2,x0,y0);
    // fill horizontal lines
    _fill_seed();
    for (y=Y0;y<=Y1;y++)
        {
        // x range to render
        X0=bufl[y];
        X1=bufr[y];
        if (X0>X1){ x=X0; X0=X1; X1=x; }
        // clip to screen in y axis
        if ((X1<0)||(X0>=xs)) continue;
        if (X0<  0) X0=   0;
        if (X1>=xs) X1=xs-1;
             if (col==  0) for (x=X0;x<=X1;x++) pixel(x,y,0);
        else if (col==255) for (x=X0;x<=X1;x++) pixel(x,y,1);
        else for (x=X0;x<=X1;x++) pixel(x,y,(_fill_rand()<=col));
        }
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::quad(int x0,int y0,int x1,int y1,int x2,int y2,int x3,int y3,bool col)
    {
    line(x0,y0,x1,y1,col);
    line(x1,y1,x2,y2,col);
    line(x2,y2,x3,y3,col);
    line(x3,y3,x0,y0,col);
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::pat_quad(int x0,int y0,int x1,int y1,int x2,int y2,int x3,int y3,bool col)
    {
    pat_line(x0,y0,x1,y1,col);
    pat_line(x1,y1,x2,y2,col);
    pat_line(x2,y2,x3,y3,col);
    pat_line(x3,y3,x0,y0,col);
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::fill_quad(int x0,int y0,int x1,int y1,int x2,int y2,int x3,int y3,U8 col)
    {
    int x,y,X0,X1,Y0,Y1;
    // y range to render
    Y0=Y1=y0;
    if (Y0>y1) Y0=y1;
    if (Y1<y1) Y1=y1;
    if (Y0>y2) Y0=y2;
    if (Y1<y2) Y1=y2;
    if (Y0>y3) Y0=y3;
    if (Y1<y3) Y1=y3;
    // clip to screen in y axis
    if ((Y1<0)||(Y0>=ys)) return;
    if (Y0<  0) Y0=   0;
    if (Y1>=ys) Y1=ys-1;
    // clear buffers
    for (y=Y0;y<=Y1;y++)
        {
        bufl[y]=xs;
        bufr[y]=-1;
        }
    // render circumference
    _fill_line(x0,y0,x1,y1);
    _fill_line(x1,y1,x2,y2);
    _fill_line(x2,y2,x3,y3);
    _fill_line(x3,y3,x0,y0);
    // fill horizontal lines
    _fill_seed();
    for (y=Y0;y<=Y1;y++)
        {
        // x range to render
        X0=bufl[y];
        X1=bufr[y];
        if (X0>X1){ x=X0; X0=X1; X1=x; }
        // clip to screen in y axis
        if ((X1<0)||(X0>=xs)) continue;
        if (X0<  0) X0=   0;
        if (X1>=xs) X1=xs-1;
             if (col==  0) for (x=X0;x<=X1;x++) pixel(x,y,0);
        else if (col==255) for (x=X0;x<=X1;x++) pixel(x,y,1);
        else for (x=X0;x<=X1;x++) pixel(x,y,(_fill_rand()<=col));
        }
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::rect(int x0,int y0,int x1,int y1,bool col)
    {
    line(x0,y0,x1,y0,col);
    line(x1,y0,x1,y1,col);
    line(x1,y1,x0,y1,col);
    line(x0,y1,x0,y0,col);
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::pat_rect(int x0,int y0,int x1,int y1,bool col)
    {
    pat_line(x0,y0,x1,y0,col);
    pat_line(x1,y0,x1,y1,col);
    pat_line(x1,y1,x0,y1,col);
    pat_line(x0,y1,x0,y0,col);
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::prnchr(int x,int y,char c)
    {
    y&=0xFFFFFFF8;  // multiple of 8
    if ((y<0)||(y>ys-8)) return;
    int i,a;
    a=c; a<<=3;
    for (i=0;i<8;i++,x++,a++)
     if ((x>=0)&&(x<xs))
      pyx[y][x]=font[a];
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::prntxt(int x,int y,const char *txt)
    {
    for (;*txt;txt++,x+=8) prnchr(x,y,*txt);
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::pat_set(char *s)
    {
    int i=1;
    pat=0;
    if (s!=NULL)
     for (i=0;(*s)&&(i<32);s++,i++)
        {
        pat<<=1;
        if (*s=='1') pat|=1;
        }
    if (!i) i=1;
    pat_m=1<<(i-1);
    pat_beg();
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::pat_beg()
    {
    pat_b=pat_m;
    }
//------------------------------------------------------------------------------------------
#undef I2C_send
//------------------------------------------------------------------------------------------
#endif
//------------------------------------------------------------------------------------------

它是为 AVR32 studio 2.7 编写的,因此在没有 U8/U16/U32 的平台上使用 unsigned int 而不是相同(或更大)的位宽。

代码没有优化,是故意按照原样编写的(不是为了速度,我也在我的讲座中使用它,以便学生可以掌握我在做什么)

现在,当我使用 2D 填充四边形渲染旋转立方体(在 PC 上的 win32 VCL 测试应用程序上)时 using this technique :

//---------------------------------------------------------------------------
#include <vcl.h>
#include <math.h>
#pragma hdrstop
#include "win_main.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TMain *Main;
const int sz=4;         // LCD pixel size
int xs,ys;              // LCD resolution * sz
int *psz;               // screen pixel to LCD pixel
Graphics::TBitmap *bmp; // screen buffer
//---------------------------------------------------------------------------
typedef BYTE U8; // here use data types you got like unsigned __int8_t ...
typedef WORD U16;
typedef DWORD U32;
void I2C_send(int adr,U8 *buf,int siz){}
//#include "font_8x8.h"  // font file
static U8 font[256<<3]; // empty font instead (no printing used)
#include "LCD_SSD1306_I2C.h"
LCD_SSD1306_I2C lcd;
//---------------------------------------------------------------------------
const float cube_pos[]=
    {
//  x    y    z     //ix
    -1.0,+1.0,-1.0, //0
    +1.0,+1.0,-1.0, //1
    +1.0,-1.0,-1.0, //2
    -1.0,-1.0,-1.0, //3

    -1.0,-1.0,+1.0, //4
    +1.0,-1.0,+1.0, //5
    +1.0,+1.0,+1.0, //6
    -1.0,+1.0,+1.0, //7

    -1.0,-1.0,-1.0, //3
    +1.0,-1.0,-1.0, //2
    +1.0,-1.0,+1.0, //5
    -1.0,-1.0,+1.0, //4

    +1.0,-1.0,-1.0, //2
    +1.0,+1.0,-1.0, //1
    +1.0,+1.0,+1.0, //6
    +1.0,-1.0,+1.0, //5

    +1.0,+1.0,-1.0, //1
    -1.0,+1.0,-1.0, //0
    -1.0,+1.0,+1.0, //7
    +1.0,+1.0,+1.0, //6

    -1.0,+1.0,-1.0, //0
    -1.0,-1.0,-1.0, //3
    -1.0,-1.0,+1.0, //4
    -1.0,+1.0,+1.0, //7
    };

const float cube_nor[]=
    {
//   nx   ny   nz   //ix
     0.0, 0.0,-1.0, //0
     0.0, 0.0,-1.0, //1
     0.0, 0.0,-1.0, //2
     0.0, 0.0,-1.0, //3

     0.0, 0.0,+1.0, //4
     0.0, 0.0,+1.0, //5
     0.0, 0.0,+1.0, //6
     0.0, 0.0,+1.0, //7

     0.0,-1.0, 0.0, //0
     0.0,-1.0, 0.0, //1
     0.0,-1.0, 0.0, //5
     0.0,-1.0, 0.0, //4

    +1.0, 0.0, 0.0, //1
    +1.0, 0.0, 0.0, //2
    +1.0, 0.0, 0.0, //6
    +1.0, 0.0, 0.0, //5

     0.0,+1.0, 0.0, //2
     0.0,+1.0, 0.0, //3
     0.0,+1.0, 0.0, //7
     0.0,+1.0, 0.0, //6

    -1.0, 0.0, 0.0, //3
    -1.0, 0.0, 0.0, //0
    -1.0, 0.0, 0.0, //4
    -1.0, 0.0, 0.0, //7
    };
//---------------------------------------------------------------------------
void  matrix_mul_pos(float *c,const float *a,const float *b)
    {
    float q[3];
    q[0]=(a[ 0]*b[0])+(a[ 4]*b[1])+(a[ 8]*b[2])+(a[12]);
    q[1]=(a[ 1]*b[0])+(a[ 5]*b[1])+(a[ 9]*b[2])+(a[13]);
    q[2]=(a[ 2]*b[0])+(a[ 6]*b[1])+(a[10]*b[2])+(a[14]);
    for(int i=0;i<3;i++) c[i]=q[i];
    }
void  matrix_mul_dir(float *c,const float *a,const float *b)
    {
    float q[3];
    q[0]=(a[ 0]*b[0])+(a[ 4]*b[1])+(a[ 8]*b[2]);
    q[1]=(a[ 1]*b[0])+(a[ 5]*b[1])+(a[ 9]*b[2]);
    q[2]=(a[ 2]*b[0])+(a[ 6]*b[1])+(a[10]*b[2]);
    for(int i=0;i<3;i++) c[i]=q[i];
    }
void  matrix_mul_mat(float *c,float *a,float *b)
    {
    float q[16];
    q[ 0]=(a[ 0]*b[ 0])+(a[ 1]*b[ 4])+(a[ 2]*b[ 8])+(a[ 3]*b[12]);
    q[ 1]=(a[ 0]*b[ 1])+(a[ 1]*b[ 5])+(a[ 2]*b[ 9])+(a[ 3]*b[13]);
    q[ 2]=(a[ 0]*b[ 2])+(a[ 1]*b[ 6])+(a[ 2]*b[10])+(a[ 3]*b[14]);
    q[ 3]=(a[ 0]*b[ 3])+(a[ 1]*b[ 7])+(a[ 2]*b[11])+(a[ 3]*b[15]);
    q[ 4]=(a[ 4]*b[ 0])+(a[ 5]*b[ 4])+(a[ 6]*b[ 8])+(a[ 7]*b[12]);
    q[ 5]=(a[ 4]*b[ 1])+(a[ 5]*b[ 5])+(a[ 6]*b[ 9])+(a[ 7]*b[13]);
    q[ 6]=(a[ 4]*b[ 2])+(a[ 5]*b[ 6])+(a[ 6]*b[10])+(a[ 7]*b[14]);
    q[ 7]=(a[ 4]*b[ 3])+(a[ 5]*b[ 7])+(a[ 6]*b[11])+(a[ 7]*b[15]);
    q[ 8]=(a[ 8]*b[ 0])+(a[ 9]*b[ 4])+(a[10]*b[ 8])+(a[11]*b[12]);
    q[ 9]=(a[ 8]*b[ 1])+(a[ 9]*b[ 5])+(a[10]*b[ 9])+(a[11]*b[13]);
    q[10]=(a[ 8]*b[ 2])+(a[ 9]*b[ 6])+(a[10]*b[10])+(a[11]*b[14]);
    q[11]=(a[ 8]*b[ 3])+(a[ 9]*b[ 7])+(a[10]*b[11])+(a[11]*b[15]);
    q[12]=(a[12]*b[ 0])+(a[13]*b[ 4])+(a[14]*b[ 8])+(a[15]*b[12]);
    q[13]=(a[12]*b[ 1])+(a[13]*b[ 5])+(a[14]*b[ 9])+(a[15]*b[13]);
    q[14]=(a[12]*b[ 2])+(a[13]*b[ 6])+(a[14]*b[10])+(a[15]*b[14]);
    q[15]=(a[12]*b[ 3])+(a[13]*b[ 7])+(a[14]*b[11])+(a[15]*b[15]);
    for(int i=0;i<16;i++) c[i]=q[i];
    }
//---------------------------------------------------------------------------
float deg=M_PI/180.0,angx=0.0,angy=0.0,angz=5.0*deg;
float view_FOVx=128.0*tan(30.0*deg)*0.5;
void obj2scr(int &x,int &y,const float *m,const float *pos)
    {
    float p[3],d;
    x=0; y=0;
    matrix_mul_pos(p,m,pos);
    if (fabs(p[2])>1e-3) d=view_FOVx/p[2]; else d=0.0;
    p[0]*=d; x=2.5*p[0]; x+=64;
    p[1]*=d; y=2.5*p[1]; y+=32;
    }
//---------------------------------------------------------------------------
void TMain::draw()
    {
    int i,j,n,nz;
    int x,y,x0,y0,x1,y1,x2,y2,x3,y3;
    lcd.clrscr();

    // modelview
    float p[3],c,s,m[16],m0[16]=
        {
         1.0, 0.0, 0.0,0.0,
         0.0, 1.0, 0.0,0.0,
         0.0, 0.0, 1.0,0.0,
         0.0, 0.0, 7.0,1.0,
        };
    c=cos(angx); s=sin(angx);
    float rx[16]= { 1, 0, 0, 0,
                     0, c, s, 0,
                     0,-s, c, 0,
                     0, 0, 0, 1 };
    c=cos(angy); s=sin(angy);
    float ry[16]= { c, 0, s, 0,
                    0, 1, 0, 0,
                   -s, 0, c, 0,
                    0, 0, 0, 1 };
    c=cos(angz); s=sin(angz);
    float rz[16]= { c, s, 0, 0,
                   -s, c, 0, 0,
                    0, 0, 1, 0,
                    0, 0, 0, 1 };
    matrix_mul_mat(m,rx,ry);
    matrix_mul_mat(m,m,rz);
    matrix_mul_mat(m,m,m0);
    angx=fmod(angx+1.0*deg,2.0*M_PI);
    angy=fmod(angy+5.0*deg,2.0*M_PI);
    angz=fmod(angz+2.0*deg,2.0*M_PI);

    n=6*4*3;
    for (i=0;i<n;)
        {
        matrix_mul_dir(p,m,cube_nor+i);
        nz=float(-255.0*p[2]*fabs(p[2]));
        obj2scr(x0,y0,m,cube_pos+i); i+=3;
        obj2scr(x1,y1,m,cube_pos+i); i+=3;
        obj2scr(x2,y2,m,cube_pos+i); i+=3;
        obj2scr(x3,y3,m,cube_pos+i); i+=3;
        if (nz>0)
            {
            nz=100+((150*nz)>>8);
            lcd.fill_quad(x0,y0,x1,y1,x2,y2,x3,y3,nz);
            }
        }
    lcd.rfsscr();

    // copy LCD to Canvas to see result
    if (1)
        {
        DWORD col[2]={0x00100018,0x00FFFFFF},*p;
        int x,y,xx,yy;
        for (                           y=0,yy=psz[y];y<ys;y++,yy=psz[y])
         for (p=(DWORD*)bmp->ScanLine[y],x=0,xx=psz[x];x<xs;x++,xx=psz[x])
          p[x]=col[lcd.pixel(xx,yy)];
        }
    Canvas->Draw(0,0,bmp);
    }
//---------------------------------------------------------------------------
__fastcall TMain::TMain(TComponent* Owner) : TForm(Owner)
    {
    lcd.init(0x3C,128,64);
    bmp=new Graphics::TBitmap;
    bmp->HandleType=bmDIB;
    bmp->PixelFormat=pf32bit;
    xs=lcd.xs*sz;
    ys=lcd.ys*sz;
    bmp->SetSize(xs,ys);
    ClientWidth=xs;
    ClientHeight=ys;

    int i,n;
    n=xs; if (n<ys) n=ys;
    psz=new int[n+1];
    for (i=0;i<n;i++) psz[i]=i/sz; psz[n]=0;
    }
//---------------------------------------------------------------------------
void __fastcall TMain::FormDestroy(TObject *Sender)
    {
    delete[] psz;
    delete bmp;
    }
//---------------------------------------------------------------------------
void __fastcall TMain::tim_redrawTimer(TObject *Sender)
    {
    draw();
    }
//---------------------------------------------------------------------------

忽略 VCL 的东西。该应用程序有一个定时器,可以定期重绘屏幕。 lcd 需要首先初始化。 lcd 使用 I2C_send 函数通过 I2C 进行通信,因此您必须实现它才能将其与真正的 LCD 一起使用,如果您只是将屏幕复制到图像或 View (模拟)中,则像我一样为空函数就足够了。打印它需要的文本也是如此 this font (它不适合这里)所以我使用了空的(因为该示例无论如何都不会打印任何内容)。

我得到了这个输出(使用随机着色填充和基本正常着色):

preview

正如您所看到的,由于分辨率较低,立方体几乎无法区分,我希望有更好的东西。

最后我的问题是:

如何在视觉上改善这种阴影

我正在考虑某种与 Freescape 引擎输出更相似的孵化或预定义模式,如下所示:

predefined patterns

您对如何进行这种 2D 凸多边形填充有任何想法或指示吗?

限制是低分辨率 128x64 1bpp 图像、低内存使用,因为目标 AVR32 UC3 平台只有 (16+32+32) KBytes RAM,如果有人想使用 AVR8 芯片,则只有 2 KByte(你知道 Arduino)使用那些)。

速度并不是主要问题,因为目标平台大约有 91 MIPS。

我对黑白着色不太熟练(以前我主要使用线框进行黑白输出),所以甚至有经验用户的提示,例如:

  • 有多少种颜色16/32/256
  • 图案有多大4x4/8x8/16x16
  • 如何生成模式(硬编码或某种算法)
  • 如何处理多边形移动以避免噪音/闪烁(现在我在每个多边形上重置种子)

可能对我有很大帮助。

这里是用于测试的示例输入图像:

sample input

最佳答案

我设法让它工作。我最终得到了硬编码的 17 个大小为 8x8 像素的阴影图案(在 Paint 中手动创建)。这些是阴影:

17 shades

从那里我只使用渲染像素mod 8x,y作为阴影LUT中的坐标。这是结果:

shaded cube

正如您所看到的,它比基于 PRNG 的着色要好得多。这里是更新的代码:

//------------------------------------------------------------------------------------------
//--- SSD1306 I2C OLED LCD driver ver 2.001 ------------------------------------------------
//------------------------------------------------------------------------------------------
/*
 [Notes]
 + I2C transfere size is not limitted on LCD side
 - No memory address reset command present so any corruption while VRAM transfere permanently damages output untill power on/off but somehow after some timeout or overflow the adress is reseted
 - UC3 HW I2C limits up to 255 bytes per packet
 - UC3 glitch on SDA before ACK which confuse LCD to read instead of write operation and do not ACK
 */
#ifndef _LCD_SSD1306_I2C_h
#define _LCD_SSD1306_I2C_h
//------------------------------------------------------------------------------------------
#define SSD1306_SETCONTRAST 0x81
#define SSD1306_DISPLAYALLON_RESUME 0xA4
#define SSD1306_DISPLAYALLON 0xA5
#define SSD1306_NORMALDISPLAY 0xA6
#define SSD1306_INVERTDISPLAY 0xA7
#define SSD1306_DISPLAYOFF 0xAE
#define SSD1306_DISPLAYON 0xAF
#define SSD1306_SETDISPLAYOFFSET 0xD3
#define SSD1306_SETCOMPINS 0xDA
#define SSD1306_SETVCOMDETECT 0xDB
#define SSD1306_SETDISPLAYCLOCKDIV 0xD5
#define SSD1306_SETPRECHARGE 0xD9
#define SSD1306_SETMULTIPLEX 0xA8
#define SSD1306_SETLOWCOLUMN 0x00
#define SSD1306_SETHIGHCOLUMN 0x10
#define SSD1306_SETSTARTLINE 0x40
#define SSD1306_MEMORYMODE 0x20
#define SSD1306_COLUMNADDR 0x21
#define SSD1306_PAGEADDR   0x22
#define SSD1306_COMSCANINC 0xC0
#define SSD1306_COMSCANDEC 0xC8
#define SSD1306_SEGREMAP 0xA0
#define SSD1306_CHARGEPUMP 0x8D
#define SSD1306_SWITCHCAPVCC 0x2
// Scrolling #defines
#define SSD1306_ACTIVATE_SCROLL 0x2F
#define SSD1306_DEACTIVATE_SCROLL 0x2E
#define SSD1306_SET_VERTICAL_SCROLL_AREA 0xA3
#define SSD1306_RIGHT_HORIZONTAL_SCROLL 0x26
#define SSD1306_LEFT_HORIZONTAL_SCROLL 0x27
#define SSD1306_VERTICAL_AND_RIGHT_HORIZONTAL_SCROLL 0x29
#define SSD1306_VERTICAL_AND_LEFT_HORIZONTAL_SCROLL 0x2A
//------------------------------------------------------------------------------------------
//#define I2C_send(adr,buf,siz){}
//------------------------------------------------------------------------------------------
#ifndef _brv8_tab
#define _brv8_tab
static const U8 brv8[256] =     // 8 bit bit reversal
    {
    0,128,64,192,32,160,96,224,16,144,80,208,48,176,112,240,8,136,72,200,40,168,104,232,24,152,
    88,216,56,184,120,248,4,132,68,196,36,164,100,228,20,148,84,212,52,180,116,244,12,140,76,204,
    44,172,108,236,28,156,92,220,60,188,124,252,2,130,66,194,34,162,98,226,18,146,82,210,50,178,
    114,242,10,138,74,202,42,170,106,234,26,154,90,218,58,186,122,250,6,134,70,198,38,166,102,230,
    22,150,86,214,54,182,118,246,14,142,78,206,46,174,110,238,30,158,94,222,62,190,126,254,1,129,
    65,193,33,161,97,225,17,145,81,209,49,177,113,241,9,137,73,201,41,169,105,233,25,153,89,217,57,
    185,121,249,5,133,69,197,37,165,101,229,21,149,85,213,53,181,117,245,13,141,77,205,45,173,109,
    237,29,157,93,221,61,189,125,253,3,131,67,195,35,163,99,227,19,147,83,211,51,179,115,243,11,139,
    75,203,43,171,107,235,27,155,91,219,59,187,123,251,7,135,71,199,39,167,103,231,23,151,87,215,55,
    183,119,247,15,143,79,207,47,175,111,239,31,159,95,223,63,191,127,255
    };
#endif
static const U8 shade8x8[17*8]= // 17 shade patterns 8x8 pixels
    {
      0,  0,  0,  0,  0,  0,  0,  0,
     17,  0,  0,  0, 17,  0,  0,  0,
     17,  0, 68,  0, 17,  0, 68,  0,
     68, 17, 68,  0, 68, 17, 68,  0,
     85,  0,170,  0, 85,  0,170,  0,
     68,170,  0,170, 68,170,  0,170,
     68,170, 17,170, 68,170, 17,170,
     85,136, 85,170, 85,136, 85,170,
     85,170, 85,170, 85,170, 85,170,
     85,238, 85,170,119,170, 85,170,
    221,170,119,170,221,170,119,170,
    221,170,255,170,221,170,255,170,
     85,255,170,255, 85,255,170,255,
    221,119,221,255,221,119,221,255,
    119,255,221,255,119,255,221,255,
    119,255,255,255,119,255,255,255,
    255,255,255,255,255,255,255,255
    };
//------------------------------------------------------------------------------------------
class LCD_SSD1306_I2C           // max 96 lines
    {
public:
    // screen
    int adr;                    // I2C adr
    int xs,ys,sz;               // resoluiton
    U8 _scr[((128*96)>>3)+1];   // screen buffer
    U8 *scr;
    U8 *pyx[96];                // scan lines
    // pattern
    U32 pat,pat_m,pat_b;        // binary pattern,max used bit mask,actual bit mask
    // filling
    int bufl[96];
    int bufr[96];

    // system api
    void init(int _adr,int _xs,int _ys);                    // initialize LCD: I2C_adr,xs,ys
    void _command(U8 cmd);                                  // *internal* do not cal it (sends command to LCD over I2C)
    void rfsscr();                                          // copy actual screen buffer to LCD (by I2C)
    // gfx rendering col = <0,1>
    void clrscr();                                          // clear screen buffer
    void rotate(int ang);                                   // rotate 180 deg
    void pixel(int x,int y,bool col);                       // set/res pixel
    bool pixel(int x,int y);                                // get pixel
    void line(int x0,int y0,int x1,int y1,bool col);        // line
    void triangle(int x0,int y0,int x1,int y1,int x2,int y2,bool col);// triangle
    void quad(int x0,int y0,int x1,int y1,int x2,int y2,int x3,int y3,bool col);
    void rect(int x0,int y0,int x1,int y1,bool col);        // rectangle using diagonal points
    // patern rendering
    void pat_set(char *s);                                  // set binary pattern from bianry number string MSB renders first
    void pat_beg();                                         // set pattern state to start of pattern
    void pat_line(int x0,int y0,int x1,int y1,bool col);
    void pat_triangle(int x0,int y0,int x1,int y1,int x2,int y2,bool col);
    void pat_quad(int x0,int y0,int x1,int y1,int x2,int y2,int x3,int y3,bool col);
    void pat_rect(int x0,int y0,int x1,int y1,bool col);
    // filled polygons col = <0,255>
    void _fill_line(int x0,int y0,int x1,int y1);           // *internal* do not call it (render line into bufl/bufr)
    void _fill(int Y0,int Y1,U8 col);                       // *internal* do not call it (render bufl/bufr onto screen)
    void fill_triangle(int x0,int y0,int x1,int y1,int x2,int y2,U8 col);
    void fill_quad(int x0,int y0,int x1,int y1,int x2,int y2,int x3,int y3,U8 col);
    // text rendering
    void prnchr(int x,int y,char c);                        // render char at x,y (y is rounded to multiple of 8)
    void prntxt(int x,int y,const char *txt);               // render text at x,y (y is rounded to multiple of 8)
    };
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::_command(U8 cmd)
    {
    U8 buf[2]=
        {
        0x00,       // 0x40 data/command
        cmd,
        };
    I2C_send(adr,buf,2);
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::init(int _adr,int _xs,int _ys)
    {
    int y;
    adr=_adr;
    xs=_xs;
    ys=_ys;
    sz=xs*(ys>>3);
    const bool _external_Vcc=false;
    // VRAM buffer
    scr=_scr+1;                                         // skip first Byte (VRAM/command selection)
    for (y=0;y<ys;y++) pyx[y]=scr+((y>>3)*xs);          // scanlines for fast direct pixel access
    clrscr();
    // Init sequence
    U8 comPins = 0x02;
    U8 contrast = 0x8F;
         if((xs == 128) && (ys == 32)) { comPins = 0x02; contrast = 0x8F; }
    else if((xs == 128) && (ys == 64)) { comPins = 0x12; contrast = (_external_Vcc) ? 0x9F : 0xCF; }
    else if((xs ==  96) && (ys == 16)) { comPins = 0x02; contrast = (_external_Vcc) ? 0x10 : 0xAF; }
    else {} // Other screens
    static U8 init0[27]=
        {
        0x00,                                           // commands
        SSD1306_DISPLAYOFF,                             // 0xAE
        SSD1306_SETDISPLAYCLOCKDIV,0x80,                // 0xD5
        SSD1306_SETMULTIPLEX,ys-1,                      // 0xA8
        SSD1306_SETDISPLAYOFFSET,0x00,                  // 0xD3 no offset
        SSD1306_SETSTARTLINE | 0x0,                     // line 0
        SSD1306_CHARGEPUMP,(_external_Vcc)?0x10:0x14,   // 0x8D
        SSD1306_MEMORYMODE,0x00,                        // 0x20 horizontal (scanlines)
        SSD1306_SEGREMAP | 0x1,
        SSD1306_COMSCANDEC,
        SSD1306_SETCOMPINS,comPins,
        SSD1306_SETCONTRAST,contrast,
        SSD1306_SETPRECHARGE,(_external_Vcc)?0x22:0xF1, // 0xd9
        SSD1306_SETVCOMDETECT,0x40,                     // 0xDB
        SSD1306_DISPLAYALLON_RESUME,                    // 0xA4
        SSD1306_NORMALDISPLAY,                          // 0xA6
        SSD1306_DEACTIVATE_SCROLL,
        SSD1306_DISPLAYON,                              // Main screen turn on
        };
    I2C_send(adr,init0,sizeof(init0));
    // init default pattern
    pat_set("111100100");
    // clear filling buffers
    for (y=0;y<96;y++)
        {
        bufl[y]=-1;
        bufr[y]=-1;
        }
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::clrscr()
    {
    for (int a=0;a<sz;a++) scr[a]=0x00;
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::rotate(int ang)
    {
    U8 a0,a1;
    int x0,y0,x1,y1;
    if (ang==180)
     for (y0=0,y1=ys-8;y0<y1;y0+=8,y1-=8)
      for (x0=0,x1=xs-1;x0<xs;x0++,x1--)
          {
          a0=brv8[pyx[y0][x0]];
          a1=brv8[pyx[y1][x1]];
          pyx[y0][x0]=a1;
          pyx[y1][x1]=a0;
          }
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::rfsscr()
    {
    static const U8 init1[] =
        {
        0x00,                           // commands
        SSD1306_MEMORYMODE,0,           // horizontal addresing mode
        SSD1306_COLUMNADDR,0,xs-1,      // Column start/end address (0/127 reset)
        SSD1306_PAGEADDR,0,(ys>>3)-1,   // Page start/end address (0 reset)
        };
    I2C_send(adr,(U8*)init1,sizeof(init1));

    _scr[0]=0x40;                       // 0x40 VRAM
    // SW I2C can pass whole VRAM in single packet
//  I2C_send(adr,_scr,sz+1);

    // HW I2C must use packets up to 255 bytes so 128+1 (as TWIM0 on UC3 has 8 bit counter)
    int i,n=128; U8 *p=_scr,a;
    for (i=0;i<sz;i+=n){ a=p[0]; p[0]=0x40; I2C_send(adr,p,n+1); p[0]=a; p+=n; }
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::pixel(int x, int y,bool col)
    {
    // clip to screen
    if ((x<0)||(x>=xs)||(y<0)||(y>=ys)) return;
    // add or remove bit
    if (col) pyx[y][x] |= (1<<(y&7));
    else     pyx[y][x] &= (255)^(1<<(y&7));
    }
//------------------------------------------------------------------------------------------
bool LCD_SSD1306_I2C::pixel(int x, int y)
    {
    // clip to screen
    if ((x<0)||(x>=xs)||(y<0)||(y>=ys)) return false;
    // get bit
    return ((pyx[y][x]>>(y&7))&1);
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::line(int x0,int y0,int x1,int y1,bool col)
    {
    int i,n,cx,cy,sx,sy;
    // line DDA parameters
    x1-=x0; sx=0; if (x1>0) sx=+1; if (x1<0) { sx=-1; x1=-x1; } if (x1) x1++;           n=x1;
    y1-=y0; sy=0; if (y1>0) sy=+1; if (y1<0) { sy=-1; y1=-y1; } if (y1) y1++; if (n<y1) n=y1;
    // single pixel (not a line)
    if (!n){ pixel(x0,y0,col); return; }
    // ND DDA algo i is parameter
    for (cx=cy=n,i=0;i<n;i++)
        {
        pixel(x0,y0,col);
        cx-=x1; if (cx<=0){ cx+=n; x0+=sx; }
        cy-=y1; if (cy<=0){ cy+=n; y0+=sy; }
        }
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::pat_line(int x0,int y0,int x1,int y1,bool col)
    {
    bool ccc;
    int i,n,cx,cy,sx,sy;
    // line DDA parameters
    x1-=x0; sx=0; if (x1>0) sx=+1; if (x1<0) { sx=-1; x1=-x1; } if (x1) x1++;           n=x1;
    y1-=y0; sy=0; if (y1>0) sy=+1; if (y1<0) { sy=-1; y1=-y1; } if (y1) y1++; if (n<y1) n=y1;
    // single pixel (not a line)
    if (!n){ pixel(x0,y0,col); return; }
    // ND DDA algo i is parameter
    for (cx=cy=n,i=0;i<n;i++)
        {
        ccc=(pat&pat_b); ccc^=(!col);
        pat_b>>=1; if (!pat_b) pat_b=pat_m;
        pixel(x0,y0,ccc);
        cx-=x1; if (cx<=0){ cx+=n; x0+=sx; }
        cy-=y1; if (cy<=0){ cy+=n; y0+=sy; }
        }
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::_fill_line(int x0,int y0,int x1,int y1)
    {
    int i,n,cx,cy,sx,sy,*buf;
    // line DDA parameters
    x1-=x0; sx=0; if (x1>0) sx=+1; if (x1<0) { sx=-1; x1=-x1; } if (x1) x1++;           n=x1;
    y1-=y0; sy=0; if (y1>0) sy=+1; if (y1<0) { sy=-1; y1=-y1; } if (y1) y1++; if (n<y1) n=y1;
    // single pixel (not a line)
    if (!n)
        {
        if ((y0>=0)&&(y0<ys))
            {
            bufl[y0]=x0;
            bufr[y0]=x0;
            }
        return;
        }
    // target buffer depend on y direction
    if (sy>0) buf=bufl; else buf=bufr;
    // ND DDA algo i is parameter
    for (cx=cy=n,i=0;i<n;i++)
        {
        if ((y0>=0)&&(y0<ys)) buf[y0]=x0;
        cx-=x1; if (cx<=0){ cx+=n; x0+=sx; }
        cy-=y1; if (cy<=0){ cy+=n; y0+=sy; }
        }
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::_fill(int Y0,int Y1,U8 col)
    {
    U8 shd;
    int x,y,X0,X1,i;
    // select shade pattern
    i=col;
    if (i< 0) i=0;
    if (i>17) i=17;
    i<<=3;
    // fill horizontal lines
    for (y=Y0;y<=Y1;y++)
        {
        shd=shade8x8[i+(y&7)];
        // x range to render
        X0=bufl[y];
        X1=bufr[y];
        if (X0>X1){ x=X0; X0=X1; X1=x; }
        // clip to screen in y axis
        if ((X1<0)||(X0>=xs)) continue;
        if (X0<  0) X0=   0;
        if (X1>=xs) X1=xs-1;
             if (col==  0) for (x=X0;x<=X1;x++) pixel(x,y,0);
        else if (col==255) for (x=X0;x<=X1;x++) pixel(x,y,1);
        else for (x=X0;x<=X1;x++) pixel(x,y,shd&(1<<(x&7)));
        }
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::triangle(int x0,int y0,int x1,int y1,int x2,int y2,bool col)
    {
    line(x0,y0,x1,y1,col);
    line(x1,y1,x2,y2,col);
    line(x2,y2,x0,y0,col);
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::pat_triangle(int x0,int y0,int x1,int y1,int x2,int y2,bool col)
    {
    pat_line(x0,y0,x1,y1,col);
    pat_line(x1,y1,x2,y2,col);
    pat_line(x2,y2,x0,y0,col);
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::fill_triangle(int x0,int y0,int x1,int y1,int x2,int y2,U8 col)
    {
    int y,Y0,Y1;
    // y range to render
    Y0=Y1=y0;
    if (Y0>y1) Y0=y1;
    if (Y1<y1) Y1=y1;
    if (Y0>y2) Y0=y2;
    if (Y1<y2) Y1=y2;
    // clip to screen in y axis
    if ((Y1<0)||(Y0>=ys)) return;
    if (Y0<  0) Y0=   0;
    if (Y1>=ys) Y1=ys-1;
    // clear buffers
    for (y=Y0;y<=Y1;y++)
        {
        bufl[y]=xs;
        bufr[y]=-1;
        }
    // render circumference
    _fill_line(x0,y0,x1,y1);
    _fill_line(x1,y1,x2,y2);
    _fill_line(x2,y2,x0,y0);
    // fill horizontal lines
    _fill(Y0,Y1,col);
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::quad(int x0,int y0,int x1,int y1,int x2,int y2,int x3,int y3,bool col)
    {
    line(x0,y0,x1,y1,col);
    line(x1,y1,x2,y2,col);
    line(x2,y2,x3,y3,col);
    line(x3,y3,x0,y0,col);
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::pat_quad(int x0,int y0,int x1,int y1,int x2,int y2,int x3,int y3,bool col)
    {
    pat_line(x0,y0,x1,y1,col);
    pat_line(x1,y1,x2,y2,col);
    pat_line(x2,y2,x3,y3,col);
    pat_line(x3,y3,x0,y0,col);
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::fill_quad(int x0,int y0,int x1,int y1,int x2,int y2,int x3,int y3,U8 col)
    {
    int y,Y0,Y1;
    // y range to render
    Y0=Y1=y0;
    if (Y0>y1) Y0=y1;
    if (Y1<y1) Y1=y1;
    if (Y0>y2) Y0=y2;
    if (Y1<y2) Y1=y2;
    if (Y0>y3) Y0=y3;
    if (Y1<y3) Y1=y3;
    // clip to screen in y axis
    if ((Y1<0)||(Y0>=ys)) return;
    if (Y0<  0) Y0=   0;
    if (Y1>=ys) Y1=ys-1;
    // clear buffers
    for (y=Y0;y<=Y1;y++)
        {
        bufl[y]=xs;
        bufr[y]=-1;
        }
    // render circumference
    _fill_line(x0,y0,x1,y1);
    _fill_line(x1,y1,x2,y2);
    _fill_line(x2,y2,x3,y3);
    _fill_line(x3,y3,x0,y0);
    // fill horizontal lines
    _fill(Y0,Y1,col);
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::rect(int x0,int y0,int x1,int y1,bool col)
    {
    line(x0,y0,x1,y0,col);
    line(x1,y0,x1,y1,col);
    line(x1,y1,x0,y1,col);
    line(x0,y1,x0,y0,col);
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::pat_rect(int x0,int y0,int x1,int y1,bool col)
    {
    pat_line(x0,y0,x1,y0,col);
    pat_line(x1,y0,x1,y1,col);
    pat_line(x1,y1,x0,y1,col);
    pat_line(x0,y1,x0,y0,col);
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::prnchr(int x,int y,char c)
    {
    y&=0xFFFFFFF8;  // multiple of 8
    if ((y<0)||(y>ys-8)) return;
    int i,a;
    a=c; a<<=3;
    for (i=0;i<8;i++,x++,a++)
     if ((x>=0)&&(x<xs))
      pyx[y][x]=font[a];
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::prntxt(int x,int y,const char *txt)
    {
    for (;*txt;txt++,x+=8) prnchr(x,y,*txt);
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::pat_set(char *s)
    {
    int i=1;
    pat=0;
    if (s!=NULL)
     for (i=0;(*s)&&(i<32);s++,i++)
        {
        pat<<=1;
        if (*s=='1') pat|=1;
        }
    if (!i) i=1;
    pat_m=1<<(i-1);
    pat_beg();
    }
//------------------------------------------------------------------------------------------
void LCD_SSD1306_I2C::pat_beg()
    {
    pat_b=pat_m;
    }
//------------------------------------------------------------------------------------------
#undef I2C_send
//------------------------------------------------------------------------------------------
#endif
//------------------------------------------------------------------------------------------

我将所有填充移到成员函数_fill中,只是看看LUT shade8x8是如何使用的...

[编辑1] Floyd–Steinberg 抖动

感谢 Scheff,我想尝试这种抖动。遗憾的是,他的代码不可用于多边形光栅化(由于其细节和缺乏输入图像),所以我自己实现了。我花了一段时间才使其正常工作,而按预期工作的唯一方法是:

  • 颜色阈值是最大强度的 50%
  • 错误传播是在有符号整数上完成的

第二个要求带来了巨大的性能损失,因为简单的位移不能再使用,但我认为硬编码的 LUT 将克服这个问题。

这是我当前的展位抖动实现:

void LCD_SSD1306_I2C::_fill(int Y0,int Y1,U8 col)
    {
    int x,y,X0,X1,i;
    const U8 colmax=17;
    // bayer like dithering using precomputed shader patterns
    if (dither_mode==0)
        {
        U8 shd;
        // select shade pattern
        i=col;
        if (i< 0) i=0;
        if (i>17) i=17;
        i<<=3;
        // fill horizontal lines
        for (y=Y0;y<=Y1;y++)
            {
            shd=shade8x8[i+(y&7)];
            // x range to render
            X0=bufl[y];
            X1=bufr[y];
            if (X0>X1){ x=X0; X0=X1; X1=x; }
            // clip to screen in y axis
            if ((X1<0)||(X0>=xs)) continue;
            if (X0<  0) X0=   0;
            if (X1>=xs) X1=xs-1;
                 if (col==     0) for (x=X0;x<=X1;x++) pixel(x,y,0);
            else if (col==colmax) for (x=X0;x<=X1;x++) pixel(x,y,1);
            else for (x=X0;x<=X1;x++) pixel(x,y,shd&(1<<(x&7)));
            }
        }
    // Floyd–Steinberg dithering
    if (dither_mode==1)
        {
        int c0,c1,c2,rows[256+4],*r0=rows+1,*r1=rows+128+3,*rr,thr=colmax/2;
        // clear error;
        c0=0; for (x=0;x<256+4;x++) rows[x]=0;
        // fill horizontal lines
        for (y=Y0;y<=Y1;y++)
            {
            // x range to render
            X0=bufl[y];
            X1=bufr[y];
            if (X0>X1){ x=X0; X0=X1; X1=x; }
            // clip to screen in y axis
            if ((X1<0)||(X0>=xs)) continue;
            if (X0<  0) X0=   0;
            if (X1>=xs) X1=xs-1;
                 if (col==     0) for (x=X0;x<=X1;x++) pixel(x,y,0);
            else if (col==colmax) for (x=X0;x<=X1;x++) pixel(x,y,1);
            else for (x=X0;x<=X1;x++)
                {
                c0=col; c0+=r0[x]; ; r0[x]=0;
                if (c0>thr){ pixel(x,y,1); c0-=colmax; }
                 else        pixel(x,y,0);
                c2=c0;
                c1=(3*c0)/16; r1[x-1] =c1; c2-=c1;
                c1=(5*c0)/16; r1[x  ] =c1; c2-=c1;
                c1=(  c0)/16; r1[x+1] =c1; c2-=c1;
                              r0[x+1]+=c2;
                }
            rr=r0; r0=r1; r1=rr;
            }
        }
    }

dither_mode 只是决定使用哪种抖动。这里是并排预览。左边是拜耳抖动(带有我画的图案),右边是弗洛伊德-斯坦伯格抖动:

side by side

弗洛伊德-斯坦伯格抖动有时会在某些旋转中产生丑陋的(平行线)图案,而恒定的图案在所有情况下看起来都很平滑。所以我会坚持原来的渲染。

关于c++ - 渲染填充表面时,黑白显示上的阴影效果更好,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/66503903/

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