This repository has been archived by the owner on Feb 11, 2021. It is now read-only.
/
SDL_drawline.c
209 lines (184 loc) · 6.32 KB
/
SDL_drawline.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
/*
Simple DirectMedia Layer
Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
#include "SDL_config.h"
#if !SDL_RENDER_DISABLED
#include "SDL_draw.h"
#include "SDL_drawline.h"
#include "SDL_drawpoint.h"
static void
SDL_DrawLine1(SDL_Surface * dst, int x1, int y1, int x2, int y2, Uint32 color,
SDL_bool draw_end)
{
if (y1 == y2) {
int length;
int pitch = (dst->pitch / dst->format->BytesPerPixel);
Uint8 *pixel;
if (x1 <= x2) {
pixel = (Uint8 *)dst->pixels + y1 * pitch + x1;
length = draw_end ? (x2-x1+1) : (x2-x1);
} else {
pixel = (Uint8 *)dst->pixels + y1 * pitch + x2;
if (!draw_end) {
++pixel;
}
length = draw_end ? (x1-x2+1) : (x1-x2);
}
SDL_memset(pixel, color, length);
} else if (x1 == x2) {
VLINE(Uint8, DRAW_FASTSETPIXEL1, draw_end);
} else if (ABS(x1 - x2) == ABS(y1 - y2)) {
DLINE(Uint8, DRAW_FASTSETPIXEL1, draw_end);
} else {
BLINE(x1, y1, x2, y2, DRAW_FASTSETPIXELXY1, draw_end);
}
}
static void
SDL_DrawLine2(SDL_Surface * dst, int x1, int y1, int x2, int y2, Uint32 color,
SDL_bool draw_end)
{
if (y1 == y2) {
HLINE(Uint16, DRAW_FASTSETPIXEL2, draw_end);
} else if (x1 == x2) {
VLINE(Uint16, DRAW_FASTSETPIXEL2, draw_end);
} else if (ABS(x1 - x2) == ABS(y1 - y2)) {
DLINE(Uint16, DRAW_FASTSETPIXEL2, draw_end);
} else {
Uint8 _r, _g, _b, _a;
const SDL_PixelFormat * fmt = dst->format;
SDL_GetRGBA(color, fmt, &_r, &_g, &_b, &_a);
if (fmt->Rmask == 0x7C00) {
AALINE(x1, y1, x2, y2,
DRAW_FASTSETPIXELXY2, DRAW_SETPIXELXY_BLEND_RGB555,
draw_end);
} else if (fmt->Rmask == 0xF800) {
AALINE(x1, y1, x2, y2,
DRAW_FASTSETPIXELXY2, DRAW_SETPIXELXY_BLEND_RGB565,
draw_end);
} else {
AALINE(x1, y1, x2, y2,
DRAW_FASTSETPIXELXY2, DRAW_SETPIXELXY2_BLEND_RGB,
draw_end);
}
}
}
static void
SDL_DrawLine4(SDL_Surface * dst, int x1, int y1, int x2, int y2, Uint32 color,
SDL_bool draw_end)
{
if (y1 == y2) {
HLINE(Uint32, DRAW_FASTSETPIXEL4, draw_end);
} else if (x1 == x2) {
VLINE(Uint32, DRAW_FASTSETPIXEL4, draw_end);
} else if (ABS(x1 - x2) == ABS(y1 - y2)) {
DLINE(Uint32, DRAW_FASTSETPIXEL4, draw_end);
} else {
Uint8 _r, _g, _b, _a;
const SDL_PixelFormat * fmt = dst->format;
SDL_GetRGBA(color, fmt, &_r, &_g, &_b, &_a);
if (fmt->Rmask == 0x00FF0000) {
if (!fmt->Amask) {
AALINE(x1, y1, x2, y2,
DRAW_FASTSETPIXELXY4, DRAW_SETPIXELXY_BLEND_RGB888,
draw_end);
} else {
AALINE(x1, y1, x2, y2,
DRAW_FASTSETPIXELXY4, DRAW_SETPIXELXY_BLEND_ARGB8888,
draw_end);
}
} else {
AALINE(x1, y1, x2, y2,
DRAW_FASTSETPIXELXY4, DRAW_SETPIXELXY4_BLEND_RGB,
draw_end);
}
}
}
typedef void (*DrawLineFunc) (SDL_Surface * dst,
int x1, int y1, int x2, int y2,
Uint32 color, SDL_bool draw_end);
static DrawLineFunc
SDL_CalculateDrawLineFunc(const SDL_PixelFormat * fmt)
{
switch (fmt->BytesPerPixel) {
case 1:
if (fmt->BitsPerPixel < 8) {
break;
}
return SDL_DrawLine1;
case 2:
return SDL_DrawLine2;
case 4:
return SDL_DrawLine4;
}
return NULL;
}
int
SDL_DrawLine(SDL_Surface * dst, int x1, int y1, int x2, int y2, Uint32 color)
{
DrawLineFunc func;
if (!dst) {
return SDL_SetError("SDL_DrawLine(): Passed NULL destination surface");
}
func = SDL_CalculateDrawLineFunc(dst->format);
if (!func) {
return SDL_SetError("SDL_DrawLine(): Unsupported surface format");
}
/* Perform clipping */
/* FIXME: We don't actually want to clip, as it may change line slope */
if (!SDL_IntersectRectAndLine(&dst->clip_rect, &x1, &y1, &x2, &y2)) {
return 0;
}
func(dst, x1, y1, x2, y2, color, SDL_TRUE);
return 0;
}
int
SDL_DrawLines(SDL_Surface * dst, const SDL_Point * points, int count,
Uint32 color)
{
int i;
int x1, y1;
int x2, y2;
SDL_bool draw_end;
DrawLineFunc func;
if (!dst) {
return SDL_SetError("SDL_DrawLines(): Passed NULL destination surface");
}
func = SDL_CalculateDrawLineFunc(dst->format);
if (!func) {
return SDL_SetError("SDL_DrawLines(): Unsupported surface format");
}
for (i = 1; i < count; ++i) {
x1 = points[i-1].x;
y1 = points[i-1].y;
x2 = points[i].x;
y2 = points[i].y;
/* Perform clipping */
/* FIXME: We don't actually want to clip, as it may change line slope */
if (!SDL_IntersectRectAndLine(&dst->clip_rect, &x1, &y1, &x2, &y2)) {
continue;
}
/* Draw the end if it was clipped */
draw_end = (x2 != points[i].x || y2 != points[i].y);
func(dst, x1, y1, x2, y2, color, draw_end);
}
if (points[0].x != points[count-1].x || points[0].y != points[count-1].y) {
SDL_DrawPoint(dst, points[count-1].x, points[count-1].y, color);
}
return 0;
}
#endif /* !SDL_RENDER_DISABLED */
/* vi: set ts=4 sw=4 expandtab: */