1 | /* |
2 | Simple DirectMedia Layer |
3 | Copyright (C) 1997-2025 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 | #ifdef SDL_VIDEO_RENDER_SW |
24 | |
25 | #include "SDL_draw.h" |
26 | #include "SDL_drawline.h" |
27 | #include "SDL_drawpoint.h" |
28 | |
29 | static void SDL_DrawLine1(SDL_Surface *dst, int x1, int y1, int x2, int y2, Uint32 color, |
30 | bool draw_end) |
31 | { |
32 | if (y1 == y2) { |
33 | int length; |
34 | int pitch = (dst->pitch / dst->fmt->bytes_per_pixel); |
35 | Uint8 *pixel; |
36 | if (x1 <= x2) { |
37 | pixel = (Uint8 *)dst->pixels + y1 * pitch + x1; |
38 | length = draw_end ? (x2 - x1 + 1) : (x2 - x1); |
39 | } else { |
40 | pixel = (Uint8 *)dst->pixels + y1 * pitch + x2; |
41 | if (!draw_end) { |
42 | ++pixel; |
43 | } |
44 | length = draw_end ? (x1 - x2 + 1) : (x1 - x2); |
45 | } |
46 | SDL_memset(pixel, color, length); |
47 | } else if (x1 == x2) { |
48 | VLINE(Uint8, DRAW_FASTSETPIXEL1, draw_end); |
49 | } else if (ABS(x1 - x2) == ABS(y1 - y2)) { |
50 | DLINE(Uint8, DRAW_FASTSETPIXEL1, draw_end); |
51 | } else { |
52 | BLINE(x1, y1, x2, y2, DRAW_FASTSETPIXELXY1, draw_end); |
53 | } |
54 | } |
55 | |
56 | static void SDL_DrawLine2(SDL_Surface *dst, int x1, int y1, int x2, int y2, Uint32 color, |
57 | bool draw_end) |
58 | { |
59 | if (y1 == y2) { |
60 | HLINE(Uint16, DRAW_FASTSETPIXEL2, draw_end); |
61 | } else if (x1 == x2) { |
62 | VLINE(Uint16, DRAW_FASTSETPIXEL2, draw_end); |
63 | } else if (ABS(x1 - x2) == ABS(y1 - y2)) { |
64 | DLINE(Uint16, DRAW_FASTSETPIXEL2, draw_end); |
65 | } else { |
66 | Uint8 _r, _g, _b, _a; |
67 | const SDL_PixelFormatDetails *fmt = dst->fmt; |
68 | SDL_GetRGBA(color, fmt, dst->palette, &_r, &_g, &_b, &_a); |
69 | if (fmt->Rmask == 0x7C00) { |
70 | AALINE(x1, y1, x2, y2, |
71 | DRAW_FASTSETPIXELXY2, DRAW_SETPIXELXY_BLEND_RGB555, |
72 | draw_end); |
73 | } else if (fmt->Rmask == 0xF800) { |
74 | AALINE(x1, y1, x2, y2, |
75 | DRAW_FASTSETPIXELXY2, DRAW_SETPIXELXY_BLEND_RGB565, |
76 | draw_end); |
77 | } else { |
78 | AALINE(x1, y1, x2, y2, |
79 | DRAW_FASTSETPIXELXY2, DRAW_SETPIXELXY2_BLEND_RGB, |
80 | draw_end); |
81 | } |
82 | } |
83 | } |
84 | |
85 | static void SDL_DrawLine4(SDL_Surface *dst, int x1, int y1, int x2, int y2, Uint32 color, |
86 | bool draw_end) |
87 | { |
88 | if (y1 == y2) { |
89 | HLINE(Uint32, DRAW_FASTSETPIXEL4, draw_end); |
90 | } else if (x1 == x2) { |
91 | VLINE(Uint32, DRAW_FASTSETPIXEL4, draw_end); |
92 | } else if (ABS(x1 - x2) == ABS(y1 - y2)) { |
93 | DLINE(Uint32, DRAW_FASTSETPIXEL4, draw_end); |
94 | } else { |
95 | Uint8 _r, _g, _b, _a; |
96 | const SDL_PixelFormatDetails *fmt = dst->fmt; |
97 | SDL_GetRGBA(color, fmt, dst->palette, &_r, &_g, &_b, &_a); |
98 | if (fmt->Rmask == 0x00FF0000) { |
99 | if (!fmt->Amask) { |
100 | AALINE(x1, y1, x2, y2, |
101 | DRAW_FASTSETPIXELXY4, DRAW_SETPIXELXY_BLEND_XRGB8888, |
102 | draw_end); |
103 | } else { |
104 | AALINE(x1, y1, x2, y2, |
105 | DRAW_FASTSETPIXELXY4, DRAW_SETPIXELXY_BLEND_ARGB8888, |
106 | draw_end); |
107 | } |
108 | } else { |
109 | AALINE(x1, y1, x2, y2, |
110 | DRAW_FASTSETPIXELXY4, DRAW_SETPIXELXY4_BLEND_RGB, |
111 | draw_end); |
112 | } |
113 | } |
114 | } |
115 | |
116 | typedef void (*DrawLineFunc)(SDL_Surface *dst, |
117 | int x1, int y1, int x2, int y2, |
118 | Uint32 color, bool draw_end); |
119 | |
120 | static DrawLineFunc SDL_CalculateDrawLineFunc(const SDL_PixelFormatDetails *fmt) |
121 | { |
122 | switch (fmt->bytes_per_pixel) { |
123 | case 1: |
124 | if (fmt->bits_per_pixel < 8) { |
125 | break; |
126 | } |
127 | return SDL_DrawLine1; |
128 | case 2: |
129 | return SDL_DrawLine2; |
130 | case 4: |
131 | return SDL_DrawLine4; |
132 | } |
133 | return NULL; |
134 | } |
135 | |
136 | bool SDL_DrawLine(SDL_Surface *dst, int x1, int y1, int x2, int y2, Uint32 color) |
137 | { |
138 | DrawLineFunc func; |
139 | |
140 | if (!SDL_SurfaceValid(dst)) { |
141 | return SDL_InvalidParamError("SDL_DrawLine(): dst" ); |
142 | } |
143 | |
144 | func = SDL_CalculateDrawLineFunc(dst->fmt); |
145 | if (!func) { |
146 | return SDL_SetError("SDL_DrawLine(): Unsupported surface format" ); |
147 | } |
148 | |
149 | // Perform clipping |
150 | // FIXME: We don't actually want to clip, as it may change line slope |
151 | if (!SDL_GetRectAndLineIntersection(&dst->clip_rect, &x1, &y1, &x2, &y2)) { |
152 | return true; |
153 | } |
154 | |
155 | func(dst, x1, y1, x2, y2, color, true); |
156 | return true; |
157 | } |
158 | |
159 | bool SDL_DrawLines(SDL_Surface *dst, const SDL_Point *points, int count, Uint32 color) |
160 | { |
161 | int i; |
162 | int x1, y1; |
163 | int x2, y2; |
164 | bool draw_end; |
165 | DrawLineFunc func; |
166 | |
167 | if (!SDL_SurfaceValid(dst)) { |
168 | return SDL_InvalidParamError("SDL_DrawLines(): dst" ); |
169 | } |
170 | |
171 | func = SDL_CalculateDrawLineFunc(dst->fmt); |
172 | if (!func) { |
173 | return SDL_SetError("SDL_DrawLines(): Unsupported surface format" ); |
174 | } |
175 | |
176 | for (i = 1; i < count; ++i) { |
177 | x1 = points[i - 1].x; |
178 | y1 = points[i - 1].y; |
179 | x2 = points[i].x; |
180 | y2 = points[i].y; |
181 | |
182 | // Perform clipping |
183 | // FIXME: We don't actually want to clip, as it may change line slope |
184 | if (!SDL_GetRectAndLineIntersection(&dst->clip_rect, &x1, &y1, &x2, &y2)) { |
185 | continue; |
186 | } |
187 | |
188 | // Draw the end if the whole line is a single point or it was clipped |
189 | draw_end = ((x1 == x2) && (y1 == y2)) || (x2 != points[i].x || y2 != points[i].y); |
190 | |
191 | func(dst, x1, y1, x2, y2, color, draw_end); |
192 | } |
193 | if (points[0].x != points[count - 1].x || points[0].y != points[count - 1].y) { |
194 | SDL_DrawPoint(dst, points[count - 1].x, points[count - 1].y, color); |
195 | } |
196 | return true; |
197 | } |
198 | |
199 | #endif // SDL_VIDEO_RENDER_SW |
200 | |