demo8_6.cpp

《Windows游戏编程大师技巧（第二版）》源代码

// DEMO8_6.CPP 8-bit polygon transformation demo with matrices

// INCLUDES ///////////////////////////////////////////////

#define WIN32_LEAN_AND_MEAN  // just say no to MFC

#define INITGUID

#include <windows.h>   // include important windows stuff
#include <windowsx.h> 
#include <mmsystem.h>
#include <iostream.h> // include important C/C++ stuff
#include <conio.h>
#include <stdlib.h>
#include <malloc.h>
#include <memory.h>
#include <string.h>
#include <stdarg.h>
#include <stdio.h> 
#include <math.h>
#include <io.h>
#include <fcntl.h>

#include <ddraw.h> // include directdraw

// DEFINES ////////////////////////////////////////////////

// defines for windows 
#define WINDOW_CLASS_NAME "WINCLASS1"

// default screen size
#define SCREEN_WIDTH    640  // size of screen
#define SCREEN_HEIGHT   480
#define SCREEN_BPP      8    // bits per pixel

#define BITMAP_ID            0x4D42 // universal id for a bitmap
#define MAX_COLORS_PALETTE   256

const double PI = 3.1415926535;

// TYPES //////////////////////////////////////////////////////

// basic unsigned types
typedef unsigned short USHORT;
typedef unsigned short WORD;
typedef unsigned char  UCHAR;
typedef unsigned char  BYTE;

// a 2D vertex
typedef struct VERTEX2DI_TYP
        {
        int x,y; // the vertex
        } VERTEX2DI, *VERTEX2DI_PTR;

// a 2D vertex
typedef struct VERTEX2DF_TYP
        {
        float x,y; // the vertex
        } VERTEX2DF, *VERTEX2DF_PTR;


// a 2D polygon
typedef struct POLYGON2D_TYP
        {
        int state;        // state of polygon
        int num_verts;    // number of vertices
        int x0,y0;        // position of center of polygon  
        int xv,yv;        // initial velocity
        DWORD color;      // could be index or PALETTENTRY
        VERTEX2DF *vlist; // pointer to vertex list
 
        } POLYGON2D, *POLYGON2D_PTR;


// matrices
typedef struct MATRIX1X2_TYP
        {
        float M[2]; // data storage
        } MATRIX1X2, *MATRIX1X2_PTR;
// note that 1x2 has the same memory layout as a VERTEX2DF, hence we
// can use the matrix function written for a MATRIX1X2 to multiply a 
// VERTEX2DF by casting

typedef struct MATRIX3X2_TYP
        {
        float M[3][2]; // data storage
        } MATRIX3X2, *MATRIX3X2_PTR;


// PROTOTYPES  //////////////////////////////////////////////

int Draw_Text_GDI(char *text, int x,int y,int color, LPDIRECTDRAWSURFACE7 lpdds);

int DDraw_Fill_Surface(LPDIRECTDRAWSURFACE7 lpdds,int color);

int Draw_Line(int x0, int y0, int x1, int y1, UCHAR color, UCHAR *vb_start, int lpitch);

int Draw_Clip_Line(int x0,int y0, int x1, int y1,UCHAR color, 
                    UCHAR *dest_buffer, int lpitch);

int Clip_Line(int &x1,int &y1,int &x2, int &y2);

int Draw_Polygon2D(POLYGON2D_PTR poly, UCHAR *vbuffer, int lpitch);

int Translate_Polygon2D(POLYGON2D_PTR poly, int dx, int dy);

int Rotate_Polygon2D(POLYGON2D_PTR poly, int theta);

int Scale_Polygon2D(POLYGON2D_PTR poly, float sx, float sy);

int Translate_Polygon2D_Mat(POLYGON2D_PTR poly, int dx, int dy);

int Rotate_Polygon2D_Mat(POLYGON2D_PTR poly, int theta);

int Scale_Polygon2D_Mat(POLYGON2D_PTR poly, float sx, float sy);

int Mat_Mul1X2_3X2(MATRIX1X2_PTR ma, 
                   MATRIX3X2_PTR mb,
                   MATRIX1X2_PTR mprod);

inline int Mat_Init_3X2(MATRIX3X2_PTR ma, 
                        float m00, float m01,
                        float m10, float m11,
                        float m20, float m21);


// MACROS /////////////////////////////////////////////////

// tests if a key is up or down
#define KEYDOWN(vk_code) ((GetAsyncKeyState(vk_code) & 0x8000) ? 1 : 0)
#define KEYUP(vk_code)   ((GetAsyncKeyState(vk_code) & 0x8000) ? 0 : 1)

// initializes a direct draw struct
#define DDRAW_INIT_STRUCT(ddstruct) { memset(&ddstruct,0,sizeof(ddstruct)); ddstruct.dwSize=sizeof(ddstruct); }

// some math macros
#define DEG_TO_RAD(ang) ((ang)*PI/180)
#define RAD_TO_DEG(rads) ((rads)*180/PI)

// GLOBALS ////////////////////////////////////////////////

HWND      main_window_handle = NULL; // globally track main window
int       window_closed      = 0;    // tracks if window is closed
HINSTANCE hinstance_app      = NULL; // globally track hinstance

// directdraw stuff

LPDIRECTDRAW7         lpdd         = NULL;   // dd4 object
LPDIRECTDRAWSURFACE7  lpddsprimary = NULL;   // dd primary surface
LPDIRECTDRAWSURFACE7  lpddsback    = NULL;   // dd back surface
LPDIRECTDRAWPALETTE   lpddpal      = NULL;   // a pointer to the created dd palette
LPDIRECTDRAWCLIPPER   lpddclipper  = NULL;   // dd clipper
PALETTEENTRY          palette[256];          // color palette
PALETTEENTRY          save_palette[256];     // used to save palettes
DDSURFACEDESC2        ddsd;                  // a direct draw surface description struct
DDBLTFX               ddbltfx;               // used to fill
DDSCAPS2              ddscaps;               // a direct draw surface capabilities struct
HRESULT               ddrval;                // result back from dd calls
DWORD                 start_clock_count = 0; // used for timing


// global clipping region

int min_clip_x = 0,      // clipping rectangle 
    max_clip_x = SCREEN_WIDTH - 1,
    min_clip_y = 0,
    max_clip_y = SCREEN_HEIGHT - 1;

char buffer[80];                             // general printing buffer

// storage for our lookup tables
float cos_look[360];
float sin_look[360];

POLYGON2D ship; // the ship

// FUNCTIONS ////////////////////////////////////////////////


inline int Mat_Init_3X2(MATRIX3X2_PTR ma, 
                        float m00, float m01,
                        float m10, float m11,
                        float m20, float m21)
{
// this function fills a 3x2 matrix with the sent data in row major form
ma->M[0][0] = m00; ma->M[0][1] = m01; 
ma->M[1][0] = m10; ma->M[1][1] = m11; 
ma->M[2][0] = m20; ma->M[2][1] = m21; 

// return success
return(1);

} // end Mat_Init_3X2

/////////////////////////////////////////////////////////////////

int Mat_Mul1X2_3X2(MATRIX1X2_PTR ma, 
                   MATRIX3X2_PTR mb,
                   MATRIX1X2_PTR mprod)
{
// this function multiplies a 1x2 matrix against a 
// 3x2 matrix - ma*mb and stores the result
// using a dummy element for the 3rd element of the 1x2 
// to make the matrix multiply valid i.e. 1x3 X 3x2

    for (int col=0; col<2; col++)
        {
        // compute dot product from row of ma 
        // and column of mb

        float sum = 0; // used to hold result

        for (int index=0; index<2; index++)
             {
             // add in next product pair
             sum+=(ma->M[index]*mb->M[index][col]);
             } // end for index

        // add in last element * 1 
        sum+= mb->M[index][col];

        // insert resulting col element
        mprod->M[col] = sum;

        } // end for col

return(1);

} // end Mat_Mul_1X2_3X2

///////////////////////////////////////////////////////////////////////

int Draw_Polygon2D(POLYGON2D_PTR poly, UCHAR *vbuffer, int lpitch)
{
// this function draws a POLYGON2D based on 

// test if the polygon is visible
if (poly->state)
   {
   // loop thru and draw a line from vertices 1 to n
   for (int index=0; index < poly->num_verts-1; index++)
        {
        // draw line from ith to ith+1 vertex
        Draw_Clip_Line(poly->vlist[index].x+poly->x0, 
                       poly->vlist[index].y+poly->y0,
                       poly->vlist[index+1].x+poly->x0, 
                       poly->vlist[index+1].y+poly->y0,
                       poly->color,
                       vbuffer, lpitch);

        } // end for

       // now close up polygon
       // draw line from last vertex to 0th
       Draw_Clip_Line(poly->vlist[0].x+poly->x0, 
                      poly->vlist[0].y+poly->y0,
                      poly->vlist[index].x+poly->x0, 
                      poly->vlist[index].y+poly->y0,
                      poly->color,
                      vbuffer, lpitch);

   // return success
   return(1);
   } // end if
else 
   return(0);

} // end Draw_Polygon2D

///////////////////////////////////////////////////////////////

// the following 3 functions are the standard transforms (no matrices)

int Translate_Polygon2D(POLYGON2D_PTR poly, int dx, int dy)
{
// this function translates the center of a polygon

// test for valid pointer
if (!poly)
   return(0);

// translate
poly->x0+=dx;
poly->y0+=dy;

// return success
return(1);

} // end Translate_Polygon2D

///////////////////////////////////////////////////////////////

int Rotate_Polygon2D(POLYGON2D_PTR poly, int theta)
{
// this function rotates the local coordinates of the polygon

// test for valid pointer
if (!poly)
   return(0);

// test for negative rotation angle
if (theta < 0)
   theta+=360;

// loop and rotate each point, very crude, no lookup!!!
for (int curr_vert = 0; curr_vert < poly->num_verts; curr_vert++)
    {

    // perform rotation
    float xr = (float)poly->vlist[curr_vert].x*cos_look[theta] - 
                    (float)poly->vlist[curr_vert].y*sin_look[theta];

    float yr = (float)poly->vlist[curr_vert].x*sin_look[theta] + 
                    (float)poly->vlist[curr_vert].y*cos_look[theta];

    // store result back
    poly->vlist[curr_vert].x = xr;
    poly->vlist[curr_vert].y = yr;

    } // end for curr_vert

// return success
return(1);

} // end Rotate_Polygon2D

////////////////////////////////////////////////////////

int Scale_Polygon2D(POLYGON2D_PTR poly, float sx, float sy)
{
// this function scalesthe local coordinates of the polygon

// test for valid pointer
if (!poly)
   return(0);

// loop and scale each point
for (int curr_vert = 0; curr_vert < poly->num_verts; curr_vert++)
    {
    // scale and store result back
    poly->vlist[curr_vert].x *= sx;
    poly->vlist[curr_vert].y *= sy;

    } // end for curr_vert

// return success
return(1);

} // end Scale_Polygon2D

///////////////////////////////////////////////////////////////////////

// these are the matrix versions, note they are more inefficient for
// single transforms, but their power comes into play when you concatenate
// multiple transformations, not to mention that all transforms are accomplished
// with the same code, just the matrix differs

int Translate_Polygon2D_Mat(POLYGON2D_PTR poly, int dx, int dy)
{
// this function translates the center of a polygon by using a matrix multiply
// on the the center point, this is incredibly inefficient, but for educational purposes
// if we had an object that wasn't in local coordinates then it would make more sense to
// use a matrix, but since the origin of the object is at x0,y0 then 2 lines of code can
// translate, but lets do it the hard way just to see :)

// test for valid pointer
if (!poly)
   return(0);

MATRIX3X2 mt; // used to hold translation transform matrix

// initialize the matrix with translation values dx dy
Mat_Init_3X2(&mt,1,0, 0,1, dx, dy); 

// create a 1x2 matrix to do the transform
MATRIX1X2 p0 = {poly->x0, poly->y0};
MATRIX1X2 p1 = {0,0}; // this will hold result

// now translate via a matrix multiply
Mat_Mul1X2_3X2(&p0, &mt, &p1);

// now copy the result back into polygon
poly->x0 = p1.M[0];
poly->y0 = p1.M[1];

// return success
return(1);

} // end Translate_Polygon2D_Mat

///////////////////////////////////////////////////////////////

int Rotate_Polygon2D_Mat(POLYGON2D_PTR poly, int theta)
{
// this function rotates the local coordinates of the polygon

// test for valid pointer
if (!poly)
   return(0);

// test for negative rotation angle
if (theta < 0)
   theta+=360;

MATRIX3X2 mr; // used to hold rotation transform matrix

// initialize the matrix with translation values dx dy
Mat_Init_3X2(&mr,cos_look[theta],sin_look[theta], 
                 -sin_look[theta],cos_look[theta], 
                  0, 0); 

// loop and rotate each point, very crude, no lookup!!!
for (int curr_vert = 0; curr_vert < poly->num_verts; curr_vert++)
    {
    // create a 1x2 matrix to do the transform
    MATRIX1X2 p0 = {poly->vlist[curr_vert].x, poly->vlist[curr_vert].y};
    MATRIX1X2 p1 = {0,0}; // this will hold result

    // now rotate via a matrix multiply
    Mat_Mul1X2_3X2(&p0, &mr, &p1);

    // now copy the result back into vertex
    poly->vlist[curr_vert].x = p1.M[0];
    poly->vlist[curr_vert].y = p1.M[1];

    } // end for curr_vert

// return success
return(1);

} // end Rotate_Polygon2D_Mat

////////////////////////////////////////////////////////

int Scale_Polygon2D_Mat(POLYGON2D_PTR poly, float sx, float sy)
{
// this function scalesthe local coordinates of the polygon

// test for valid pointer
if (!poly)
   return(0);


MATRIX3X2 ms; // used to hold scaling transform matrix

// initialize the matrix with translation values dx dy
Mat_Init_3X2(&ms,sx,0, 
                 0,sy, 
                 0, 0); 


// loop and scale each point
for (int curr_vert = 0; curr_vert < poly->num_verts; curr_vert++)
    {
    // scale and store result back
    
    // create a 1x2 matrix to do the transform
    MATRIX1X2 p0 = {poly->vlist[curr_vert].x, poly->vlist[curr_vert].y};
    MATRIX1X2 p1 = {0,0}; // this will hold result

    // now scale via a matrix multiply
    Mat_Mul1X2_3X2(&p0, &ms, &p1);

    // now copy the result back into vertex
    poly->vlist[curr_vert].x = p1.M[0];