Atlas - SDL_dosmouse.c
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1/*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2026 Sam Lantinga <[email protected]>
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_DRIVER_DOSVESA
24
25// https://stanislavs.org/helppc/int_33.html
26
27#include "SDL_dosmouse.h"
28#include "SDL_dosvideo.h"
29
30#include "../../events/SDL_mouse_c.h"
31#include "../../events/default_cursor.h"
32#include "../SDL_sysvideo.h"
33
34// Create a cursor from a surface
35static SDL_Cursor *DOSVESA_CreateCursor(SDL_Surface *surface, int hot_x, int hot_y)
36{
37    SDL_CursorData *curdata;
38    SDL_Cursor *cursor;
39
40    SDL_assert(surface->format == SDL_PIXELFORMAT_ARGB8888);
41    SDL_assert(surface->pitch == surface->w * 4);
42
43    cursor = (SDL_Cursor *)SDL_calloc(1, sizeof(*cursor));
44    if (!cursor) {
45        return NULL;
46    }
47    curdata = (SDL_CursorData *)SDL_calloc(1, sizeof(*curdata));
48    if (!curdata) {
49        SDL_free(cursor);
50        return NULL;
51    }
52
53    curdata->surface = SDL_DuplicateSurface(surface);
54    if (!curdata->surface) {
55        SDL_free(curdata);
56        SDL_free(cursor);
57        return NULL;
58    }
59
60    SDL_SetSurfaceBlendMode(curdata->surface, SDL_BLENDMODE_BLEND);
61
62    curdata->hot_x = hot_x;
63    curdata->hot_y = hot_y;
64    curdata->w = surface->w;
65    curdata->h = surface->h;
66
67    cursor->internal = curdata;
68
69    return cursor;
70}
71
72static SDL_Cursor *DOSVESA_CreateDefaultCursor(void)
73{
74    return SDL_CreateCursor(default_cdata, default_cmask, DEFAULT_CWIDTH, DEFAULT_CHEIGHT, DEFAULT_CHOTX, DEFAULT_CHOTY);
75}
76
77// Show the specified cursor, or hide if cursor is NULL
78static bool DOSVESA_ShowCursor(SDL_Cursor *cursor)
79{
80    return true; // we handle this elsewhere.
81}
82
83// Free a window manager cursor
84static void DOSVESA_FreeCursor(SDL_Cursor *cursor)
85{
86    SDL_CursorData *curdata;
87
88    if (cursor) {
89        curdata = cursor->internal;
90
91        if (curdata) {
92            SDL_DestroySurface(curdata->surface);
93            SDL_DestroySurface(curdata->converted_surface);
94            SDL_free(cursor->internal);
95        }
96        SDL_free(cursor);
97    }
98}
99
100static bool DOSVESA_WarpMouseGlobal(float x, float y)
101{
102    SDL_Mouse *mouse = SDL_GetMouse();
103
104    if (!mouse || !mouse->cur_cursor || !mouse->cur_cursor->internal) {
105        return true;
106    }
107
108    // warp mouse in the driver, so we get correct screen coordinates from it.
109    __dpmi_regs regs;
110    regs.x.ax = 0x4;
111    regs.x.cx = (Uint16)x;
112    regs.x.dx = (Uint16)y;
113    __dpmi_int(0x33, &regs);
114
115    // Update internal mouse position.
116    SDL_SendMouseMotion(0, mouse->focus, SDL_GLOBAL_MOUSE_ID, false, x, y);
117
118    return true;
119}
120
121static bool DOSVESA_WarpMouse(SDL_Window *window, float x, float y)
122{
123    return DOSVESA_WarpMouseGlobal(x, y);
124}
125
126// This is called when a mouse motion event occurs
127static bool DOSVESA_MoveCursor(SDL_Cursor *cursor)
128{
129    return true; // we handle this elsewhere.
130}
131
132void DOSVESA_InitMouse(SDL_VideoDevice *_this)
133{
134    SDL_Mouse *mouse = SDL_GetMouse();
135    mouse->internal = NULL;
136
137    __dpmi_regs regs;
138    regs.x.ax = 0;
139    __dpmi_int(0x33, &regs);
140    if (regs.x.ax == 0) {
141        return; // no mouse found, don't hook up cursor support, etc.
142    }
143
144    mouse->internal = SDL_calloc(1, 1); // just something non-NULL (and safely freeable) to say "there's a mouse available."
145
146    // Query mouse sensitivity (mickeys per pixel) via INT 33h function 0x1B
147    SDL_VideoData *data = _this->internal;
148    regs.x.ax = 0x1B; // Get Mouse Sensitivity
149    __dpmi_int(0x33, &regs);
150    data->mickeys_per_hpixel = (regs.x.bx > 0) ? (float)regs.x.bx : 8.0f;
151    data->mickeys_per_vpixel = (regs.x.cx > 0) ? (float)regs.x.cx : 16.0f;
152
153    mouse->CreateCursor = DOSVESA_CreateCursor;
154    mouse->ShowCursor = DOSVESA_ShowCursor;
155    mouse->MoveCursor = DOSVESA_MoveCursor;
156    mouse->FreeCursor = DOSVESA_FreeCursor;
157    mouse->WarpMouse = DOSVESA_WarpMouse;
158    mouse->WarpMouseGlobal = DOSVESA_WarpMouseGlobal;
159
160    SDL_SetDefaultCursor(DOSVESA_CreateDefaultCursor());
161}
162
163void DOSVESA_QuitMouse(SDL_VideoDevice *_this)
164{
165    SDL_Mouse *mouse = SDL_GetMouse();
166    SDL_free(mouse->internal);
167    mouse->internal = NULL;
168}
169
170#endif // SDL_VIDEO_DRIVER_DOSVESA
171
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