Initial commit

main.c

@@ -0,0 +1,208 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <SDL.h>
+
+#define WIDTH_CONTROL 100
+
+#ifndef min
+	#define min(a, b) ((a < b) ? a : b)
+#endif
+
+void setPixel(SDL_Surface *affichage, int x, int y, Uint16 coul)
+{
+	*((Uint16**)(affichage->pixels) + x + y * affichage->w) = coul;
+}
+
+void echangerEntiers(int* x, int* y)
+{
+	int t = *x;
+	*x = *y;
+	*y = t;
+}
+ 
+void DrawLine(SDL_Surface *affichage, int x1, int y1, int x2, int y2, Uint32 coul) //Draw line using Bresenham algorithm
+{
+	int d, dx, dy, aincr, bincr, xincr, yincr, x, y;
+	
+	if(x1 == x2 || y1 == y2) //If horizontal or vertical, use the SDL library optimized function
+	{
+		SDL_Rect r;
+		
+		r.x = min(x1, x2);
+		r.y = min(y1, y2);
+		r.w = (x1 == x2) ? 1 : abs(x1 - x2);
+		r.h = (y1 == y2) ? 1 : abs(y1 - y2);
+		
+		SDL_FillRect(affichage, &r, coul);
+	}
+	else if (abs(x2 - x1) < abs(y2 - y1)) //Go through vertical axis
+	{
+		if (y1 > y2)
+		{
+			echangerEntiers(&x1, &x2);
+			echangerEntiers(&y1, &y2);
+		}
+		
+		xincr = x2 > x1 ? 1 : -1;
+		dy = y2 - y1;
+		dx = abs(x2 - x1);
+		d = 2 * dx - dy;
+		aincr = 2 * (dx - dy);
+		bincr = 2 * dx;
+		x = x1;
+		y = y1;
+
+		setPixel(affichage, x, y, coul);
+
+		for (y = y1+1; y <= y2; ++y) 
+		{
+			if (d >= 0) 
+			{
+				x += xincr;
+				d += aincr;
+			}
+			else
+				d += bincr;
+
+			setPixel(affichage, x, y, coul);
+		}
+	} 
+	else //Go through horizontal axis
+	{
+
+		if (x1 > x2) 
+		{
+			echangerEntiers(&x1, &x2);
+			echangerEntiers(&y1, &y2);
+		}
+
+		yincr = y2 > y1 ? 1 : -1;
+		dx = x2 - x1;
+		dy = abs(y2 - y1);
+		d = 2 * dy - dx;
+		aincr = 2 * (dy - dx);
+		bincr = 2 * dy;
+		x = x1;
+		y = y1;
+
+		setPixel(affichage, x, y, coul);
+
+		for (x = x1+1; x <= x2; ++x) 
+		{
+			if (d >= 0) 
+			{
+				y+= yincr;
+				d += aincr;
+			} 
+			else
+				d += bincr;
+				setPixel(affichage, x, y, coul);
+		}
+	}
+}
+
+
+int main(int argc, char *argv[])
+{
+	int continuer = 1;
+	int x_old = -1, y_old = -1;
+	int left = 0;
+	SDL_Event event;
+	SDL_Surface *ecran = NULL, *controles = NULL;
+	
+	if(-1 == SDL_Init(SDL_INIT_VIDEO))
+	{
+		fprintf(stderr, "Erreur de chargement de la SDL : %s\n", SDL_GetError());
+		exit(EXIT_FAILURE);
+	}
+	
+	const SDL_VideoInfo* video_info = SDL_GetVideoInfo();
+	int width = video_info->current_w;
+	int height = video_info->current_h;
+	int bpp = 16; //video_info ->vfmt->BitsPerPixel;
+
+	SDL_Rect position_controles = {width - WIDTH_CONTROL, 0};
+
+	ecran = SDL_SetVideoMode(width, height, bpp, SDL_HWSURFACE | SDL_FULLSCREEN); //Raspi has only a 16 bpp framebuffer
+	controles = SDL_CreateRGBSurface(SDL_HWSURFACE, WIDTH_CONTROL, height, bpp, 0, 0, 0, 0);
+
+	if(NULL == ecran || NULL == controles || NULL == ecran)
+	{
+		fprintf(stderr, "Erreur d'ouverture de la SDL : %s\n", SDL_GetError());
+		exit(EXIT_FAILURE);
+	}
+
+	SDL_FillRect(ecran, NULL, SDL_MapRGB(ecran->format, 255, 255, 255));
+	SDL_FillRect(controles, NULL, SDL_MapRGB(controles->format, 100, 100, 100));
+	SDL_BlitSurface(controles, NULL, ecran, &position_controles);
+
+	SDL_Flip(ecran);
+
+	while(continuer)
+	{
+		SDL_WaitEvent(&event);
+
+		switch(event.type)
+		{
+			case SDL_MOUSEBUTTONDOWN:
+				if(event.button.x < width - WIDTH_CONTROL)
+				{
+					if(SDL_BUTTON_LEFT == event.button.button)
+					{
+						left = 1;
+						x_old = event.button.x;
+						y_old = event.button.y;
+					}
+					else if(SDL_BUTTON_RIGHT == event.button.button)
+					{
+						left = 0;
+						x_old = event.button.x;
+						y_old = event.button.y;
+					}
+				}
+				break;
+
+			case SDL_MOUSEMOTION:
+				if(event.motion.x < width - WIDTH_CONTROL)
+				{
+					if(x_old > 0 && y_old > 0)
+					{
+						if(left)
+							DrawLine(ecran, x_old, y_old, event.motion.x, event.motion.y, SDL_MapRGB(ecran->format, 0, 0, 0));
+						else
+							DrawLine(ecran, x_old, y_old, event.motion.x, event.motion.y, SDL_MapRGB(ecran->format, 255, 255, 255));
+
+						SDL_Flip(ecran);
+						x_old = event.motion.x;
+						y_old = event.motion.y;
+					}
+				}
+				else if(x_old > 0 && y_old > 0)
+				{
+					x_old = width - WIDTH_CONTROL;
+					y_old = event.motion.y;;
+				}
+				break;
+
+			case SDL_MOUSEBUTTONUP:
+				if(SDL_BUTTON_LEFT == event.button.button || SDL_BUTTON_RIGHT == event.button.button)
+				{
+					x_old = -1;
+					y_old = -1;
+				}
+				break;
+
+			case SDL_KEYDOWN:
+				continuer = 0;
+				break;
+
+			case SDL_QUIT:
+				continuer = 0;
+				break;
+		}
+	}
+	
+	SDL_FreeSurface(controles);
+	SDL_Quit();
+	return EXIT_SUCCESS;
+}

makefile

@@ -0,0 +1,4 @@
+all : main
+
+main : main.c
+	gcc -o main main.c `sdl-config --cflags --libs`