SDL  2.0
SDL_blendpoint.c
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1 /*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
4 
5  This software is provided 'as-is', without any express or implied
6  warranty. In no event will the authors be held liable for any damages
7  arising from the use of this software.
8 
9  Permission is granted to anyone to use this software for any purpose,
10  including commercial applications, and to alter it and redistribute it
11  freely, subject to the following restrictions:
12 
13  1. The origin of this software must not be misrepresented; you must not
14  claim that you wrote the original software. If you use this software
15  in a product, an acknowledgment in the product documentation would be
16  appreciated but is not required.
17  2. Altered source versions must be plainly marked as such, and must not be
18  misrepresented as being the original software.
19  3. This notice may not be removed or altered from any source distribution.
20 */
21 #include "../../SDL_internal.h"
22 
23 #if !SDL_RENDER_DISABLED
24 
25 #include "SDL_draw.h"
26 #include "SDL_blendpoint.h"
27 
28 
29 static int
30 SDL_BlendPoint_RGB555(SDL_Surface * dst, int x, int y, SDL_BlendMode blendMode, Uint8 r,
31  Uint8 g, Uint8 b, Uint8 a)
32 {
33  unsigned inva = 0xff - a;
34 
35  switch (blendMode) {
36  case SDL_BLENDMODE_BLEND:
37  DRAW_SETPIXELXY_BLEND_RGB555(x, y);
38  break;
39  case SDL_BLENDMODE_ADD:
40  DRAW_SETPIXELXY_ADD_RGB555(x, y);
41  break;
42  case SDL_BLENDMODE_MOD:
43  DRAW_SETPIXELXY_MOD_RGB555(x, y);
44  break;
45  default:
46  DRAW_SETPIXELXY_RGB555(x, y);
47  break;
48  }
49  return 0;
50 }
51 
52 static int
53 SDL_BlendPoint_RGB565(SDL_Surface * dst, int x, int y, SDL_BlendMode blendMode, Uint8 r,
54  Uint8 g, Uint8 b, Uint8 a)
55 {
56  unsigned inva = 0xff - a;
57 
58  switch (blendMode) {
59  case SDL_BLENDMODE_BLEND:
60  DRAW_SETPIXELXY_BLEND_RGB565(x, y);
61  break;
62  case SDL_BLENDMODE_ADD:
63  DRAW_SETPIXELXY_ADD_RGB565(x, y);
64  break;
65  case SDL_BLENDMODE_MOD:
66  DRAW_SETPIXELXY_MOD_RGB565(x, y);
67  break;
68  default:
69  DRAW_SETPIXELXY_RGB565(x, y);
70  break;
71  }
72  return 0;
73 }
74 
75 static int
76 SDL_BlendPoint_RGB888(SDL_Surface * dst, int x, int y, SDL_BlendMode blendMode, Uint8 r,
77  Uint8 g, Uint8 b, Uint8 a)
78 {
79  unsigned inva = 0xff - a;
80 
81  switch (blendMode) {
82  case SDL_BLENDMODE_BLEND:
83  DRAW_SETPIXELXY_BLEND_RGB888(x, y);
84  break;
85  case SDL_BLENDMODE_ADD:
86  DRAW_SETPIXELXY_ADD_RGB888(x, y);
87  break;
88  case SDL_BLENDMODE_MOD:
89  DRAW_SETPIXELXY_MOD_RGB888(x, y);
90  break;
91  default:
92  DRAW_SETPIXELXY_RGB888(x, y);
93  break;
94  }
95  return 0;
96 }
97 
98 static int
99 SDL_BlendPoint_ARGB8888(SDL_Surface * dst, int x, int y, SDL_BlendMode blendMode,
100  Uint8 r, Uint8 g, Uint8 b, Uint8 a)
101 {
102  unsigned inva = 0xff - a;
103 
104  switch (blendMode) {
105  case SDL_BLENDMODE_BLEND:
106  DRAW_SETPIXELXY_BLEND_ARGB8888(x, y);
107  break;
108  case SDL_BLENDMODE_ADD:
109  DRAW_SETPIXELXY_ADD_ARGB8888(x, y);
110  break;
111  case SDL_BLENDMODE_MOD:
112  DRAW_SETPIXELXY_MOD_ARGB8888(x, y);
113  break;
114  default:
115  DRAW_SETPIXELXY_ARGB8888(x, y);
116  break;
117  }
118  return 0;
119 }
120 
121 static int
122 SDL_BlendPoint_RGB(SDL_Surface * dst, int x, int y, SDL_BlendMode blendMode, Uint8 r,
123  Uint8 g, Uint8 b, Uint8 a)
124 {
125  SDL_PixelFormat *fmt = dst->format;
126  unsigned inva = 0xff - a;
127 
128  switch (fmt->BytesPerPixel) {
129  case 2:
130  switch (blendMode) {
131  case SDL_BLENDMODE_BLEND:
132  DRAW_SETPIXELXY2_BLEND_RGB(x, y);
133  break;
134  case SDL_BLENDMODE_ADD:
135  DRAW_SETPIXELXY2_ADD_RGB(x, y);
136  break;
137  case SDL_BLENDMODE_MOD:
138  DRAW_SETPIXELXY2_MOD_RGB(x, y);
139  break;
140  default:
141  DRAW_SETPIXELXY2_RGB(x, y);
142  break;
143  }
144  return 0;
145  case 4:
146  switch (blendMode) {
147  case SDL_BLENDMODE_BLEND:
148  DRAW_SETPIXELXY4_BLEND_RGB(x, y);
149  break;
150  case SDL_BLENDMODE_ADD:
151  DRAW_SETPIXELXY4_ADD_RGB(x, y);
152  break;
153  case SDL_BLENDMODE_MOD:
154  DRAW_SETPIXELXY4_MOD_RGB(x, y);
155  break;
156  default:
157  DRAW_SETPIXELXY4_RGB(x, y);
158  break;
159  }
160  return 0;
161  default:
162  return SDL_Unsupported();
163  }
164 }
165 
166 static int
167 SDL_BlendPoint_RGBA(SDL_Surface * dst, int x, int y, SDL_BlendMode blendMode, Uint8 r,
168  Uint8 g, Uint8 b, Uint8 a)
169 {
170  SDL_PixelFormat *fmt = dst->format;
171  unsigned inva = 0xff - a;
172 
173  switch (fmt->BytesPerPixel) {
174  case 4:
175  switch (blendMode) {
176  case SDL_BLENDMODE_BLEND:
177  DRAW_SETPIXELXY4_BLEND_RGBA(x, y);
178  break;
179  case SDL_BLENDMODE_ADD:
180  DRAW_SETPIXELXY4_ADD_RGBA(x, y);
181  break;
182  case SDL_BLENDMODE_MOD:
183  DRAW_SETPIXELXY4_MOD_RGBA(x, y);
184  break;
185  default:
186  DRAW_SETPIXELXY4_RGBA(x, y);
187  break;
188  }
189  return 0;
190  default:
191  return SDL_Unsupported();
192  }
193 }
194 
195 int
196 SDL_BlendPoint(SDL_Surface * dst, int x, int y, SDL_BlendMode blendMode, Uint8 r,
197  Uint8 g, Uint8 b, Uint8 a)
198 {
199  if (!dst) {
200  return SDL_SetError("Passed NULL destination surface");
201  }
202 
203  /* This function doesn't work on surfaces < 8 bpp */
204  if (dst->format->BitsPerPixel < 8) {
205  return SDL_SetError("SDL_BlendPoint(): Unsupported surface format");
206  }
207 
208  /* Perform clipping */
209  if (x < dst->clip_rect.x || y < dst->clip_rect.y ||
210  x >= (dst->clip_rect.x + dst->clip_rect.w) ||
211  y >= (dst->clip_rect.y + dst->clip_rect.h)) {
212  return 0;
213  }
214 
215  if (blendMode == SDL_BLENDMODE_BLEND || blendMode == SDL_BLENDMODE_ADD) {
216  r = DRAW_MUL(r, a);
217  g = DRAW_MUL(g, a);
218  b = DRAW_MUL(b, a);
219  }
220 
221  switch (dst->format->BitsPerPixel) {
222  case 15:
223  switch (dst->format->Rmask) {
224  case 0x7C00:
225  return SDL_BlendPoint_RGB555(dst, x, y, blendMode, r, g, b, a);
226  }
227  break;
228  case 16:
229  switch (dst->format->Rmask) {
230  case 0xF800:
231  return SDL_BlendPoint_RGB565(dst, x, y, blendMode, r, g, b, a);
232  }
233  break;
234  case 32:
235  switch (dst->format->Rmask) {
236  case 0x00FF0000:
237  if (!dst->format->Amask) {
238  return SDL_BlendPoint_RGB888(dst, x, y, blendMode, r, g, b, a);
239  } else {
240  return SDL_BlendPoint_ARGB8888(dst, x, y, blendMode, r, g, b, a);
241  }
242  /* break; -Wunreachable-code-break */
243  }
244  break;
245  default:
246  break;
247  }
248 
249  if (!dst->format->Amask) {
250  return SDL_BlendPoint_RGB(dst, x, y, blendMode, r, g, b, a);
251  } else {
252  return SDL_BlendPoint_RGBA(dst, x, y, blendMode, r, g, b, a);
253  }
254 }
255 
256 int
257 SDL_BlendPoints(SDL_Surface * dst, const SDL_Point * points, int count,
258  SDL_BlendMode blendMode, Uint8 r, Uint8 g, Uint8 b, Uint8 a)
259 {
260  int minx, miny;
261  int maxx, maxy;
262  int i;
263  int x, y;
264  int (*func)(SDL_Surface * dst, int x, int y,
265  SDL_BlendMode blendMode, Uint8 r, Uint8 g, Uint8 b, Uint8 a) = NULL;
266  int status = 0;
267 
268  if (!dst) {
269  return SDL_SetError("Passed NULL destination surface");
270  }
271 
272  /* This function doesn't work on surfaces < 8 bpp */
273  if (dst->format->BitsPerPixel < 8) {
274  return SDL_SetError("SDL_BlendPoints(): Unsupported surface format");
275  }
276 
277  if (blendMode == SDL_BLENDMODE_BLEND || blendMode == SDL_BLENDMODE_ADD) {
278  r = DRAW_MUL(r, a);
279  g = DRAW_MUL(g, a);
280  b = DRAW_MUL(b, a);
281  }
282 
283  /* FIXME: Does this function pointer slow things down significantly? */
284  switch (dst->format->BitsPerPixel) {
285  case 15:
286  switch (dst->format->Rmask) {
287  case 0x7C00:
288  func = SDL_BlendPoint_RGB555;
289  break;
290  }
291  break;
292  case 16:
293  switch (dst->format->Rmask) {
294  case 0xF800:
295  func = SDL_BlendPoint_RGB565;
296  break;
297  }
298  break;
299  case 32:
300  switch (dst->format->Rmask) {
301  case 0x00FF0000:
302  if (!dst->format->Amask) {
303  func = SDL_BlendPoint_RGB888;
304  } else {
305  func = SDL_BlendPoint_ARGB8888;
306  }
307  break;
308  }
309  break;
310  default:
311  break;
312  }
313 
314  if (!func) {
315  if (!dst->format->Amask) {
316  func = SDL_BlendPoint_RGB;
317  } else {
318  func = SDL_BlendPoint_RGBA;
319  }
320  }
321 
322  minx = dst->clip_rect.x;
323  maxx = dst->clip_rect.x + dst->clip_rect.w - 1;
324  miny = dst->clip_rect.y;
325  maxy = dst->clip_rect.y + dst->clip_rect.h - 1;
326 
327  for (i = 0; i < count; ++i) {
328  x = points[i].x;
329  y = points[i].y;
330 
331  if (x < minx || x > maxx || y < miny || y > maxy) {
332  continue;
333  }
334  status = func(dst, x, y, blendMode, r, g, b, a);
335  }
336  return status;
337 }
338 
339 #endif /* !SDL_RENDER_DISABLED */
340 
341 /* vi: set ts=4 sw=4 expandtab: */