3 // SuperTux - A Jump'n Run
4 // Copyright (C) 2000 Bill Kendrick <bill@newbreedsoftware.com>
6 // This program is free software; you can redistribute it and/or
7 // modify it under the terms of the GNU General Public License
8 // as published by the Free Software Foundation; either version 2
9 // of the License, or (at your option) any later version.
11 // This program is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
16 // You should have received a copy of the GNU General Public License
17 // along with this program; if not, write to the Free Software
18 // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
27 #include <SDL_image.h>
30 #include <sys/types.h>
40 /* Needed for line calculations */
41 #define SGN(x) ((x)>0 ? 1 : ((x)==0 ? 0:(-1)))
42 #define ABS(x) ((x)>0 ? (x) : (-x))
44 /* --- CLEAR SCREEN --- */
46 void clearscreen(int r, int g, int b)
51 glClearColor(r/256, g/256, b/256, 1.0);
52 glClear(GL_COLOR_BUFFER_BIT);
58 SDL_FillRect(screen, NULL, SDL_MapRGB(screen->format, r, g, b));
65 /* --- DRAWS A VERTICAL GRADIENT --- */
67 void drawgradient(Color top_clr, Color bot_clr)
73 glColor3ub(top_clr.red, top_clr.green, top_clr.blue);
76 glColor3ub(bot_clr.red, bot_clr.green, bot_clr.blue);
85 for(float y = 0; y < 480; y += 2)
86 fillrect(0, (int)y, 640, 2,
87 (int)(((float)(top_clr.red-bot_clr.red)/(0-480)) * y + top_clr.red),
88 (int)(((float)(top_clr.green-bot_clr.green)/(0-480)) * y + top_clr.green),
89 (int)(((float)(top_clr.blue-bot_clr.blue)/(0-480)) * y + top_clr.blue), 255);
90 /* calculates the color for each line, based in the generic equation for functions: y = mx + b */
98 /* 'Stolen' from the SDL documentation.
99 * Set the pixel at (x, y) to the given value
100 * NOTE: The surface must be locked before calling this!
102 void putpixel(SDL_Surface *surface, int x, int y, Uint32 pixel)
104 int bpp = surface->format->BytesPerPixel;
105 /* Here p is the address to the pixel we want to set */
106 Uint8 *p = (Uint8 *)surface->pixels + y * surface->pitch + x * bpp;
115 *(Uint16 *)p = pixel;
119 if(SDL_BYTEORDER == SDL_BIG_ENDIAN)
121 p[0] = (pixel >> 16) & 0xff;
122 p[1] = (pixel >> 8) & 0xff;
128 p[1] = (pixel >> 8) & 0xff;
129 p[2] = (pixel >> 16) & 0xff;
134 *(Uint32 *)p = pixel;
139 /* Draw a single pixel on the screen. */
140 void drawpixel(int x, int y, Uint32 pixel)
142 /* Lock the screen for direct access to the pixels */
143 if ( SDL_MUSTLOCK(screen) )
145 if ( SDL_LockSurface(screen) < 0 )
147 fprintf(stderr, "Can't lock screen: %s\n", SDL_GetError());
152 if(!(x < 0 || y < 0 || x > screen->w || y > screen->h))
153 putpixel(screen, x, y, pixel);
155 if ( SDL_MUSTLOCK(screen) )
157 SDL_UnlockSurface(screen);
159 /* Update just the part of the display that we've changed */
160 SDL_UpdateRect(screen, x, y, 1, 1);
163 void drawline(int x1, int y1, int x2, int y2, int r, int g, int b, int a)
169 glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
170 glColor4ub(r, g, b,a);
182 /* Basic unantialiased Bresenham line algorithm */
183 int lg_delta, sh_delta, cycle, lg_step, sh_step;
184 Uint32 color = SDL_MapRGBA(screen->format, r, g, b, a);
188 lg_step = SGN(lg_delta);
189 lg_delta = ABS(lg_delta);
190 sh_step = SGN(sh_delta);
191 sh_delta = ABS(sh_delta);
192 if (sh_delta < lg_delta)
194 cycle = lg_delta >> 1;
197 drawpixel(x1, y1, color);
199 if (cycle > lg_delta)
206 drawpixel(x1, y1, color);
208 cycle = sh_delta >> 1;
211 drawpixel(x1, y1, color);
213 if (cycle > sh_delta)
220 drawpixel(x1, y1, color);
227 /* --- FILL A RECT --- */
229 void fillrect(float x, float y, float w, float h, int r, int g, int b, int a)
246 glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
247 glColor4ub(r, g, b,a);
252 glVertex2f(x+w, y+h);
261 SDL_Surface *temp = NULL;
270 temp = SDL_CreateRGBSurface(screen->flags, rect.w, rect.h, screen->format->BitsPerPixel,
271 screen->format->Rmask,
272 screen->format->Gmask,
273 screen->format->Bmask,
274 screen->format->Amask);
282 SDL_FillRect(temp, &src, SDL_MapRGB(screen->format, r, g, b));
284 SDL_SetAlpha(temp, SDL_SRCALPHA, a);
286 SDL_BlitSurface(temp,0,screen,&rect);
288 SDL_FreeSurface(temp);
291 SDL_FillRect(screen, &rect, SDL_MapRGB(screen->format, r, g, b));
300 /* --- UPDATE SCREEN --- */
302 void updatescreen(void)
304 if(use_gl) /*clearscreen(0,0,0);*/
305 SDL_GL_SwapBuffers();
307 SDL_UpdateRect(screen, 0, 0, screen->w, screen->h);
310 void flipscreen(void)
313 SDL_GL_SwapBuffers();
320 clearscreen(0, 0, 0);
321 white_text->draw_align("Loading...", screen->w/2, screen->h/2, A_HMIDDLE, A_TOP);
325 void update_rect(SDL_Surface *scr, Sint32 x, Sint32 y, Sint32 w, Sint32 h)
328 SDL_UpdateRect(scr, x, y, w, h);