mouse.c

/*
 * Copyright (c) 2010 Toni Spets <toni.spets@iki.fi>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/* This is a special mouse coordinate fix for games that use GetCursorPos and expect to be in fullscreen */

#include <windows.h>
#include <stdio.h>
#include "main.h"
#include "surface.h"

#define MAX_HOOKS 16

BOOL mouse_active = FALSE;
int real_height = 0;

struct hook { char name[32]; void *func; };
struct hack
{
    char name[32];
    struct hook hooks[MAX_HOOKS];
};

BOOL WINAPI fake_GetCursorPos(LPPOINT lpPoint)
{
    POINT pt;

    if(mouse_active && ddraw->locked)
    {
        GetCursorPos(&pt);

        if(ddraw->sensitivity > 0 && ddraw->sensitivity < 10)
        {
            ddraw->cursor.x += (pt.x - ddraw->center.x) * ddraw->sensitivity;
            ddraw->cursor.y += (pt.y - ddraw->center.y) * ddraw->sensitivity;
        }
        else if(ddraw->adjmouse)
        {
            ddraw->cursor.x += (pt.x - ddraw->center.x) * ((float)ddraw->width / ddraw->render.width);
            ddraw->cursor.y += (pt.y - ddraw->center.y) * ((float)ddraw->height / ddraw->render.height);
        }
        else
        {
            ddraw->cursor.x += pt.x - ddraw->center.x;
            ddraw->cursor.y += pt.y - ddraw->center.y;
        }

        if(ddraw->cursor.x < 0) ddraw->cursor.x = 0;
        if(ddraw->cursor.y < 0) ddraw->cursor.y = 0;
        if(ddraw->cursor.x > ddraw->cursorclip.width-1) ddraw->cursor.x = ddraw->cursorclip.width-1;

        if(real_height > 0 && real_height < ddraw->cursorclip.height)
        {
            if(ddraw->cursor.y > real_height-1) ddraw->cursor.y = real_height-1;
        }
        else
        {
            if(ddraw->cursor.y > ddraw->cursorclip.height-1) ddraw->cursor.y = ddraw->cursorclip.height-1;
        }

        if(pt.x != ddraw->center.x || pt.y != ddraw->center.y)
        {
            SetCursorPos(ddraw->center.x, ddraw->center.y);
        }
    }

    if (lpPoint)
    {
        lpPoint->x = (int)ddraw->cursor.x;
        lpPoint->y = (int)ddraw->cursor.y;
    }
    return TRUE;
}

BOOL WINAPI fake_ClipCursor(const RECT *lpRect)
{
    if(lpRect)
    {
        /* hack for 640x480 mode */
        real_height = lpRect->bottom;
    }
    return TRUE;
}

int WINAPI fake_ShowCursor(BOOL bShow)
{
    return TRUE;
}

HCURSOR WINAPI fake_SetCursor(HCURSOR hCursor)
{
    return NULL;
}

struct hack hacks[] =
{
    {
        "user32.dll",
        {
            { "GetCursorPos", fake_GetCursorPos },
            { "ClipCursor", fake_ClipCursor },
            { "ShowCursor", fake_ShowCursor },
            { "SetCursor", fake_SetCursor } ,
            { "", NULL }
        }
    },
    {
        "",
        {
            { "", NULL }
        }
    }
};

void hack_iat(struct hack *hck)
{
    int i;
    char buf[32];
    struct hook *hk;
    DWORD dwWritten;
    IMAGE_DOS_HEADER dos_hdr;
    IMAGE_NT_HEADERS nt_hdr;
    IMAGE_IMPORT_DESCRIPTOR *dir;
    IMAGE_THUNK_DATA thunk;
    PDWORD ptmp;

    HMODULE base = GetModuleHandle(NULL);
    HANDLE hProcess = GetCurrentProcess();

    ReadProcessMemory(hProcess, (void *)base, &dos_hdr, sizeof(IMAGE_DOS_HEADER), &dwWritten);
    ReadProcessMemory(hProcess, (void *)base+dos_hdr.e_lfanew, &nt_hdr, sizeof(IMAGE_NT_HEADERS), &dwWritten);
    dir = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, (nt_hdr.OptionalHeader.DataDirectory[1].Size));
    ReadProcessMemory(hProcess, (void *)base+nt_hdr.OptionalHeader.DataDirectory[1].VirtualAddress, dir, nt_hdr.OptionalHeader.DataDirectory[1].Size, &dwWritten);

    while(dir->Name > 0)
    {
        memset(buf, 0, 32);
        ReadProcessMemory(hProcess, (void *)base+dir->Name, buf, 32, &dwWritten);
        if(stricmp(buf, hck->name) == 0)
        {
            ptmp = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(DWORD) * 64);
            ReadProcessMemory(hProcess, (void *)base+dir->Characteristics, ptmp, sizeof(DWORD) * 64, &dwWritten);
            i=0;
            while(*ptmp)
            {
                memset(buf, 0, 32);
                ReadProcessMemory(hProcess, (void *)base+(*ptmp)+2, buf, 32, &dwWritten);

                hk = &hck->hooks[0];
                while(hk->func)
                {
                    if(stricmp(hk->name, buf) == 0)
                    {
                        thunk.u1.Function = (DWORD)hk->func;
                        thunk.u1.Ordinal = (DWORD)hk->func;
                        thunk.u1.AddressOfData = (DWORD)hk->func;
                        VirtualProtectEx(hProcess, (void *)base+dir->FirstThunk+(sizeof(IMAGE_THUNK_DATA) * i), sizeof(IMAGE_THUNK_DATA), PAGE_EXECUTE_READWRITE, &dwWritten);
                        WriteProcessMemory(hProcess, (void *)base+dir->FirstThunk+(sizeof(IMAGE_THUNK_DATA) * i), &thunk, sizeof(IMAGE_THUNK_DATA), &dwWritten);
                        mouse_active = TRUE;
                    }
                    hk++;
                }

                ptmp++;
                i++;
            }
        }
        dir++;
    }

    CloseHandle(hProcess);
}

void mouse_lock()
{
    RECT rc;

    if (ddraw->devmode)
    {
        while(ShowCursor(FALSE) > 0);
        return;
    }

    if (mouse_active && !ddraw->locked)
    {
        GetWindowRect(ddraw->hWnd, &rc);
        
        ddraw->center.x = (rc.right + rc.left) / 2;
        ddraw->center.y = (rc.top + rc.bottom) / 2;

        SetCursorPos(ddraw->center.x, ddraw->center.y);
        SetCapture(ddraw->hWnd);
        ClipCursor(&rc);

        while(ShowCursor(FALSE) > 0);
        ddraw->locked = TRUE;
    }
}

void mouse_unlock()
{
    RECT rc;
    POINT pt;

    if (ddraw->devmode)
    {
        while(ShowCursor(TRUE) < 0);
        return;
    }

    if(!mouse_active)
    {
        return;
    }

    if(ddraw->locked)
    {
        ddraw->locked = FALSE;

        GetWindowRect(ddraw->hWnd, &rc);

        pt.x = (rc.right - rc.left - ddraw->render.width) / 2;
        pt.y = (rc.bottom - rc.top - ddraw->render.height - pt.x);
        rc.left += pt.x;
        rc.top += pt.y;

        SetCursorPos(rc.left + (ddraw->cursor.x * ddraw->render.width / ddraw->width), rc.top + (ddraw->cursor.y * ddraw->render.height / ddraw->height));
        while(ShowCursor(TRUE) < 0);
        SetCursor(LoadCursor(NULL, IDC_ARROW));

        ClipCursor(NULL);
        ReleaseCapture();

    }
}

void mouse_init(HWND hWnd)
{
    if(ddraw->mhack || ddraw->devmode)
    {
        hack_iat(&hacks[0]);
        mouse_active = TRUE;
    }
}