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EnigmA Amiga Run 1999 March
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EnigmA AMIGA RUN 35 (1999)(G.R. Edizioni)(IT)[!][issue 1999-03].iso
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grafica
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amhelios
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hc_scan.cpp
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C/C++ Source or Header
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1999-01-01
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////////////////////////////////////////////////////////////
//
// HC_SCAN.CPP - Hemicube Scan Conversion Class
//
// Version: 1.03A
//
// History: 94/08/23 - Version 1.00A release.
// 94/12/16 - Version 1.01A release.
// 95/02/05 - Version 1.02A release.
// 95/07/21 - Version 1.02B release.
// 96/02/14 - Version 1.02C release.
// 96/04/01 - Version 1.03A release.
//
// Compilers: Microsoft Visual C/C++ Professional V1.5
// Borland C++ Version 4.5
//
// Author: Ian Ashdown, P.Eng.
// byHeart Software Limited
// 620 Ballantree Road
// West Vancouver, B.C.
// Canada V7S 1W3
// Tel. (604) 922-6148
// Fax. (604) 987-7621
//
// Copyright 1994-1996 byHeart Software Limited
//
// The following source code has been derived from:
//
// Ashdown, I. 1994. Radiosity: A Programmer's
// Perspective. New York, NY: John Wiley & Sons.
//
// It may be freely copied, redistributed, and/or modified
// for personal use ONLY, as long as the copyright notice
// is included with all source code files.
//
////////////////////////////////////////////////////////////
#include "hc_poly.h"
#include "hc_scan.h"
HemiScan::HemiScan() // Class constructor
{
int row; // Loop index
status = TRUE; // Initialize object status
// Allocate edge list
if ((edge_list = new FormEdgeInfo[FF_ArrayRes]) != NULL)
{
// Allocate cell information buffer
if ((cell_buffer = new (FormCellInfo (*[FF_ArrayRes])))
!= NULL)
{
for (row = 0; row < FF_ArrayRes; row++)
{
if ((cell_buffer[row] =
new FormCellInfo[FF_ArrayRes]) == NULL)
{
// Release partially allocated buffer
row--;
for ( ; row >= 0; row--)
delete [] cell_buffer[row];
delete [] cell_buffer;
// Release edge list memory
delete [] edge_list;
status = FALSE;
break;
}
}
}
}
else
{
delete [] edge_list; // Release edge list memory
status = FALSE;
}
}
HemiScan::~HemiScan() // Class destructor
{
int row; // Loop index
delete [] edge_list; // Release edge list memory
// Delete cell information buffer
for (row = 0; row < FF_ArrayRes; row++)
delete [] cell_buffer[row];
delete [] cell_buffer;
}
// Initialize cell information buffer
void HemiScan::InitBuffer()
{
int row, col; // Loop indices
for (row = 0; row < FF_ArrayRes; row++)
for (col = 0; col < FF_ArrayRes; col++)
{
cell_buffer[row][col].depth = FF_Infinity;
cell_buffer[row][col].id = FF_None;
}
}
void HemiScan::DrawEdgeList() // Draw edge list
{
int x, y; // Loop indices
int sx, ex; // Scan line x-axis co-ordinates
double dz; // Pseudodepth delta
double iz; // Element pseudodepth
double x_dist; // X-axis distance
FormEdgeInfo *pedge; // Edge info pointer
FormScanInfo *pss; // Scan line start info pointer
FormScanInfo *pse; // Scan line end info pointer
FormScanInfo *psw; // Swap scan line info pointer
pedge = &(edge_list[ymin]);
for (y = ymin; y < ymax; y++)
{
// Get scan line info pointers
pss = &(pedge->isect[0]);
pse = &(pedge->isect[1]);
if (pss->x > pse->x)
{
// Swap scan line info pointers
psw = pss; pss = pse; pse = psw;
}
// Get scan line x-axis co-ordinates
sx = (int) pss->x;
ex = (int) pse->x;
if (sx < ex) // Ignore zero-length segments
{
// Determine scan line start info
iz = pss->z;
// Determine inverse slopes
x_dist = pse->x - pss->x;
dz = (pse->z - iz) / x_dist;
// Enter scan line
for (x = sx; x < ex; x++)
{
// Check element visibility
if (iz < (double) cell_buffer[y][x].depth)
{
// Update Z-buffer
cell_buffer[y][x].depth = (float) iz;
// Set polygon identifier
cell_buffer[y][x].id = poly_id;
}
// Update element pseudodepth
iz += dz;
}
}
pedge++; // Point to next edge list element
}
}
// Sum delta form factors
void HemiScan::SumDeltas( float *ff_array, int face_id )
{
WORD poly_id; // Polygon identifier
int row, col; // Face cell indices
if (face_id == HC_TopFace)
{
// Scan entire face buffer
for (row = 0; row < FF_ArrayRes; row++)
for (col = 0; col < FF_ArrayRes; col++)
{
if ((poly_id = cell_buffer[row][col].id) !=
FF_None)
ff_array[poly_id - 1] +=
dff.GetTopFactor(row, col);
}
}
else
{
// Scan upper half of face buffer only
for (row = HC_ArrayDim; row < FF_ArrayRes; row++)
for (col = 0; col < FF_ArrayRes; col++)
{
if ((poly_id = cell_buffer[row][col].id) != FF_None)
ff_array[poly_id - 1] +=
dff.GetSideFactor(row, col);
}
}
}