SDL Linux下的使用计算机图形学

使用它来画一条直线

Ultility.h

#ifndef ULTILITY_H_INCLUDED
#define ULTILITY_H_INCLUDED
#ifdef __APPLE__
#include <SDL/SDL.h>
#else
#include <SDL.h>
#endif
//init the screen
int init(SDL_Surface *&screen,SDL_Surface *&pic,int w,int h);
//draw a pixel
void DrawPixel(SDL_Surface *screen, int x,int y,Uint8 R, Uint8 G, Uint8 B);
//show a pic and free the resource
void Load(SDL_Surface *screen,SDL_Surface *pic);
#endif // DRAWPIXEL_H_INCLUDED

SDL Linux下的使用计算机图形学

Example.h

#ifndef EXAMPLE_H_INCLUDED
#define EXAMPLE_H_INCLUDED
#ifdef __APPLE__
#include <SDL/SDL.h>
#else
#include <SDL.h>
#endif
//Line
void DDA_Line(int x0,int y0,int x1,int y1,SDL_Surface *pic);
void MidPoint_Line(int x0,int y0,int x1,int y1,SDL_Surface *pic);
//end Line
#endif // EXAMPLE_H_INCLUDED

Ultility.cpp

#include "Ultility.h"
//init the screen
int init(SDL_Surface *&screen,SDL_Surface *&pic,int w,int h)
{
// initialize SDL video
if ( SDL_Init( SDL_INIT_VIDEO ) < 0 )
{
printf( "Unable to init SDL: %s\n", SDL_GetError() );
return 1;
}
// make sure SDL cleans up before exit
atexit(SDL_Quit);
// create a new window
screen = SDL_SetVideoMode(w, h, 32,SDL_HWSURFACE|SDL_DOUBLEBUF);
pic = SDL_CreateRGBSurface(SDL_SWSURFACE,w,h,32, 0, 0,0,0);
}
//draw a pixel
void DrawPixel(SDL_Surface *screen, int x,int y,Uint8 R, Uint8 G, Uint8 B)
{
Uint32 color = SDL_MapRGB(screen->format, R, G, B);
if ( SDL_MUSTLOCK(screen) ) {
if ( SDL_LockSurface(screen) < 0 ) {
return;
}
}
switch (screen->format->BytesPerPixel) {
case 1: { /* 假定是8-bpp */
Uint8 *bufp;
bufp = (Uint8 *)screen->pixels + y*screen->pitch + x;
*bufp = color;
}
break;
case 2: { /* 可能是15-bpp 或者 16-bpp */
Uint16 *bufp;
bufp = (Uint16 *)screen->pixels + y*screen->pitch/2 + x;
*bufp = color;
}
break;
case 3: { /* 慢速的24-bpp模式，通常不用 */
Uint8 *bufp;
bufp = (Uint8 *)screen->pixels + y*screen->pitch + x;
*(bufp+screen->format->Rshift/8) = R;
*(bufp+screen->format->Gshift/8) = G;
*(bufp+screen->format->Bshift/8) = B;
}
break;
case 4: { /* 可能是32-bpp */
Uint32 *bufp;
bufp = (Uint32 *)screen->pixels + y*screen->pitch/4 + x;
*bufp = color;
}
break;
}
if ( SDL_MUSTLOCK(screen) ) {
SDL_UnlockSurface(screen);
}
SDL_UpdateRect(screen, x, y, 1, 1);
}
void Load(SDL_Surface *screen,SDL_Surface *pic)
{
// centre the bitmap on screen
SDL_Rect dstrect;
dstrect.x = (screen->w - pic->w) / 2;
dstrect.y = (screen->h - pic->h) / 2;
// DRAWING STARTS HERE
// clear screen
SDL_FillRect(screen, 0, SDL_MapRGB(screen->format, 0, 0, 0));
// draw bitmap
SDL_BlitSurface(pic, 0, screen, &dstrect);
// DRAWING ENDS HERE
// finally, update the screen :)
SDL_Flip(screen);
// free loaded bitmap
SDL_FreeSurface(pic);
// all is well ;)
}

SDL Linux下的使用 计算机图形学

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SDL Linux下的使用计算机图形学