Category : C++ Source Code
Archive   : XSHP15.ZIP
Filename : POLYGON.H

/* POLYGON.H: Header file for polygon-filling code, also includes
a number of useful items for 3D animation. */
#define MAX_OBJECTS 100 /* max simultaneous # objects supported */
#define MAX_POLY_LENGTH 4 /* four vertices is the max per poly */
#define SCREEN_WIDTH 320
#define SCREEN_HEIGHT 240
#define PAGE0_START_OFFSET 0
#define PAGE1_START_OFFSET (((long)SCREEN_HEIGHT*SCREEN_WIDTH)/4)
#define NUM_CUBE_VERTS 8 /* # of vertices per cube */
#define NUM_CUBE_FACES 6 /* # of faces per cube */
/* Ratio: distance from viewpoint to projection plane / width of
projection plane. Defines the width of the field of view. Lower
absolute values = wider fields of view; higher values = narrower */
#define PROJECTION_RATIO -2.0 /* negative because visible Z
coordinates are negative */
/* Draws the polygon described by the point list PointList in color
Color with all vertices offset by (X,Y) */
#define DRAW_POLYGON(PointList,NumPoints,Color,X,Y) \
Polygon.Length = NumPoints; Polygon.PointPtr = PointList; \
FillConvexPolygon(&Polygon, Color, X, Y);
#define INT_TO_FIXED(x) (((long)(int)x) << 16)
#define DOUBLE_TO_FIXED(x) ((long) (x * 65536.0 + 0.5))

typedef long Fixedpoint;
typedef unsigned int TAngle; /* angle in tenths of degrees */
typedef Fixedpoint Xform[3][4];
/* Describes a single 2D point */
typedef struct _Point { int X; int Y; } Point;
/* Describes a single 3D point in homogeneous coordinates; the W
coordinate isn't present, though; assumed to be 1 and implied */
typedef struct _Point3 { Fixedpoint X, Y, Z; } Point3;
typedef struct { int X; int Y; int Z; } IntPoint3;
/* Describes a series of points (used to store a list of vertices that
describe a polygon; each vertex is assumed to connect to the two
adjacent vertices; last vertex is assumed to connect to first) */
typedef struct { int Length; Point * PointPtr; } PointListHeader;
/* Describes the beginning and ending X coordinates of a single
horizontal line */
typedef struct { int XStart; int XEnd; } HLine;
/* Describes a Length-long series of horizontal lines, all assumed to
be on contiguous scan lines starting at YStart and proceeding
downward (used to describe a scan-converted polygon to the
low-level hardware-dependent drawing code) */
typedef struct { int Length; int YStart; HLine * HLinePtr;} HLineList;
typedef struct { int Left, Top, Right, Bottom; } Rect;
/* Structure describing one face of an object (one polygon) */
typedef struct { int * VertNums; int NumVerts; int Color; } Face;
typedef struct { TAngle RotateX, RotateY, RotateZ; } RotateControl;
typedef struct { Fixedpoint MoveX, MoveY, MoveZ, MinX, MinY, MinZ,
MaxX, MaxY, MaxZ; } MoveControl;
/* Fields common to every object */
#define BASE_OBJECT \
struct _Object *NextObject; \
struct _Object *PreviousObject; \
Point3 CenterInView; /* coord of center in view space */ \
void (*DrawFunc)(); /* draws object */ \
void (*RecalcFunc)(); /* prepares object for drawing */ \
void (*MoveFunc)(); /* moves object */ \
int RecalcXform; /* 1 to indicate need to recalc */ \
Rect EraseRect[2]; /* rectangle to erase in each page */
/* Basic object */
typedef struct _Object { BASE_OBJECT } Object;
/* Structure describing a polygon-based object */
typedef struct {
BASE_OBJECT
int RDelayCount, RDelayCountBase; /* controls rotation speed */
int MDelayCount, MDelayCountBase; /* controls movement speed */
Xform XformToWorld; /* transform from object->world space */
Xform XformToView; /* transform from object->view space */
RotateControl Rotate; /* controls rotation change over time */
MoveControl Move; /* controls object movement over time */
int NumVerts; /* # vertices in VertexList */
Point3 * VertexList; /* untransformed vertices */
Point3 * XformedVertexList; /* transformed into view space */
Point3 * ProjectedVertexList; /* projected into screen space */
Point * ScreenVertexList; /* converted to screen coordinates */
int NumFaces; /* # of faces in object */
Face * FaceList; /* pointer to face info */
} PObject;

extern void XformVec(Xform, Fixedpoint *, Fixedpoint *);
extern void ConcatXforms(Xform, Xform, Xform);
extern int FillConvexPolygon(PointListHeader *, int, int, int);
extern void Set320x240Mode(void);
extern void ShowPage(unsigned int);
extern void FillRectangleX(int, int, int, int, unsigned int, int);
extern void XformAndProjectPObject(PObject *);
extern void DrawPObject(PObject *);
extern void AppendRotationX(Xform, TAngle);
extern void AppendRotationY(Xform, TAngle);
extern void AppendRotationZ(Xform, TAngle);
extern near Fixedpoint FixedMul(Fixedpoint, Fixedpoint);
extern near Fixedpoint FixedDiv(Fixedpoint, Fixedpoint);
extern void InitializeFixedPoint(void);
extern void RotateAndMovePObject(PObject *);
extern void InitializeCubes(void);
extern void InitializeBalls(void);
extern int DisplayedPage, NonDisplayedPage, RecalcAllXforms;
extern int NumObjects;
extern Object ObjectListStart, ObjectListEnd;
extern Xform WorldViewXform;
extern Object *ObjectList[];
extern Point3 CubeVerts[];
extern void CosSin(TAngle, Fixedpoint *, Fixedpoint *);
extern void AddObject(Object *);
extern void SortObjects(void);
extern void InitializeObjectList(void);