| 1 |
bearsoft |
1.1 |
#include "TMapare.h"
|
| 2 |
|
|
|
| 3 |
|
|
TMapare::TMapare(int *iscreen, int iscreenwidth, int iscreenheight)
|
| 4 |
|
|
{
|
| 5 |
|
|
screen=(int*)iscreen;
|
| 6 |
|
|
screenwidth=iscreenwidth; |
| 7 |
|
|
screenheight=iscreenheight; |
| 8 |
|
|
|
| 9 |
|
|
}
|
| 10 |
|
|
|
| 11 |
|
|
TMapare::~TMapare(){}
|
| 12 |
|
|
|
| 13 |
|
|
// Texturemapper with full perspective correction, subpixels and subtexels, |
| 14 |
|
|
// uses floats all the way through |
| 15 |
|
|
|
| 16 |
|
|
void TMapare::drawtpolyperspsubtri(TPolytri *poly) |
| 17 |
|
|
{ |
| 18 |
|
|
float x1, y1, x2, y2, x3, y3; |
| 19 |
|
|
float iz1, uiz1, viz1, iz2, uiz2, viz2, iz3, uiz3, viz3; |
| 20 |
|
|
float dxdy1, dxdy2, dxdy3; |
| 21 |
|
|
float tempf; |
| 22 |
|
|
float denom; |
| 23 |
|
|
float dy; |
| 24 |
|
|
int y1i, y2i, y3i; |
| 25 |
|
|
int side; |
| 26 |
|
|
|
| 27 |
|
|
// Shift XY coordinate system (+0.5, +0.5) to match the subpixeling |
| 28 |
|
|
// technique |
| 29 |
|
|
|
| 30 |
|
|
x1 = (float) poly->x1 + 0.5f; |
| 31 |
|
|
y1 = (float) poly->y1 + 0.5f; |
| 32 |
|
|
x2 = (float) poly->x2 + 0.5f; |
| 33 |
|
|
y2 = (float) poly->y2 + 0.5f; |
| 34 |
|
|
x3 = (float) poly->x3 + 0.5f; |
| 35 |
|
|
y3 = (float) poly->y3 + 0.5f; |
| 36 |
|
|
|
| 37 |
|
|
// Calculate alternative 1/Z, U/Z and V/Z values which will be |
| 38 |
|
|
// interpolated |
| 39 |
|
|
|
| 40 |
|
|
iz1 = 1 / poly->z1; |
| 41 |
|
|
iz2 = 1 / poly->z2; |
| 42 |
|
|
iz3 = 1 / poly->z3; |
| 43 |
|
|
uiz1 = poly->u1 * iz1; |
| 44 |
|
|
viz1 = poly->v1 * iz1; |
| 45 |
|
|
uiz2 = poly->u2 * iz2; |
| 46 |
|
|
viz2 = poly->v2 * iz2; |
| 47 |
|
|
uiz3 = poly->u3 * iz3; |
| 48 |
|
|
viz3 = poly->v3 * iz3; |
| 49 |
|
|
|
| 50 |
|
|
texture = poly->texture; |
| 51 |
|
|
|
| 52 |
|
|
// Sort the vertices in ascending Y order |
| 53 |
|
|
|
| 54 |
|
|
#define swapfloat(x, y) tempf = x; x = y; y = tempf; |
| 55 |
|
|
|
| 56 |
|
|
if (y1 > y2) |
| 57 |
|
|
{ |
| 58 |
|
|
swapfloat(x1, x2); |
| 59 |
|
|
swapfloat(y1, y2); |
| 60 |
|
|
swapfloat(iz1, iz2); |
| 61 |
|
|
swapfloat(uiz1, uiz2); |
| 62 |
|
|
swapfloat(viz1, viz2); |
| 63 |
|
|
} |
| 64 |
|
|
|
| 65 |
|
|
if (y1 > y3) |
| 66 |
|
|
{ |
| 67 |
|
|
swapfloat(x1, x3); |
| 68 |
|
|
swapfloat(y1, y3); |
| 69 |
|
|
swapfloat(iz1, iz3); |
| 70 |
|
|
swapfloat(uiz1, uiz3); |
| 71 |
|
|
swapfloat(viz1, viz3); |
| 72 |
|
|
} |
| 73 |
|
|
|
| 74 |
|
|
if (y2 > y3) |
| 75 |
|
|
{ |
| 76 |
|
|
swapfloat(x2, x3); |
| 77 |
|
|
swapfloat(y2, y3); |
| 78 |
|
|
swapfloat(iz2, iz3); |
| 79 |
|
|
swapfloat(uiz2, uiz3); |
| 80 |
|
|
swapfloat(viz2, viz3); |
| 81 |
|
|
} |
| 82 |
|
|
|
| 83 |
|
|
#undef swapfloat |
| 84 |
|
|
|
| 85 |
|
|
y1i = (int) y1; |
| 86 |
|
|
y2i = (int) y2; |
| 87 |
|
|
y3i = (int) y3; |
| 88 |
|
|
|
| 89 |
|
|
// Skip poly if it's too thin to cover any pixels at all |
| 90 |
|
|
|
| 91 |
|
|
if (y1i == y2i == y3i || (int) x1 == (int) x2 == (int) x3) |
| 92 |
|
|
{
|
| 93 |
|
|
return; |
| 94 |
|
|
}
|
| 95 |
|
|
|
| 96 |
|
|
// Calculate horizontal and vertical increments for UV axes (these |
| 97 |
|
|
// calcs are certainly not optimal, although they're stable |
| 98 |
|
|
// (handles any dy being 0) |
| 99 |
|
|
|
| 100 |
|
|
denom = ((x3 - x1) * (y2 - y1) - (x2 - x1) * (y3 - y1)); |
| 101 |
|
|
|
| 102 |
|
|
if (!denom) // Skip poly if it's an infinitely thin line |
| 103 |
|
|
{
|
| 104 |
|
|
return; |
| 105 |
|
|
}
|
| 106 |
|
|
|
| 107 |
|
|
denom = 1 / denom; // Reciprocal for speeding up |
| 108 |
|
|
dizdx = ((iz3 - iz1) * (y2 - y1) - (iz2 - iz1) * (y3 - y1)) * denom; |
| 109 |
|
|
duizdx = ((uiz3 - uiz1) * (y2 - y1) - (uiz2 - uiz1) * (y3 - y1)) * denom; |
| 110 |
|
|
dvizdx = ((viz3 - viz1) * (y2 - y1) - (viz2 - viz1) * (y3 - y1)) * denom; |
| 111 |
|
|
|
| 112 |
|
|
dizdy = ((iz2 - iz1) * (x3 - x1) - (iz3 - iz1) * (x2 - x1)) * denom; |
| 113 |
|
|
duizdy = ((uiz2 - uiz1) * (x3 - x1) - (uiz3 - uiz1) * (x2 - x1)) * denom; |
| 114 |
|
|
dvizdy = ((viz2 - viz1) * (x3 - x1) - (viz3 - viz1) * (x2 - x1)) * denom; |
| 115 |
|
|
|
| 116 |
|
|
// Calculate X-slopes along the edges |
| 117 |
|
|
|
| 118 |
|
|
if (y2 > y1) |
| 119 |
|
|
dxdy1 = (x2 - x1) / (y2 - y1); |
| 120 |
|
|
if (y3 > y1) |
| 121 |
|
|
dxdy2 = (x3 - x1) / (y3 - y1); |
| 122 |
|
|
if (y3 > y2) |
| 123 |
|
|
dxdy3 = (x3 - x2) / (y3 - y2); |
| 124 |
|
|
|
| 125 |
|
|
// Determine which side of the poly the longer edge is on |
| 126 |
|
|
|
| 127 |
|
|
side = dxdy2 > dxdy1; |
| 128 |
|
|
|
| 129 |
|
|
if (y1 == y2) |
| 130 |
|
|
side = x1 > x2; |
| 131 |
|
|
if (y2 == y3) |
| 132 |
|
|
side = x3 > x2; |
| 133 |
|
|
|
| 134 |
|
|
if (!side) // Longer edge is on the left side |
| 135 |
|
|
{ |
| 136 |
|
|
// Calculate slopes along left edge |
| 137 |
|
|
|
| 138 |
|
|
dxdya = dxdy2; |
| 139 |
|
|
dizdya = dxdy2 * dizdx + dizdy; |
| 140 |
|
|
duizdya = dxdy2 * duizdx + duizdy; |
| 141 |
|
|
dvizdya = dxdy2 * dvizdx + dvizdy; |
| 142 |
|
|
|
| 143 |
|
|
// Perform subpixel pre-stepping along left edge |
| 144 |
|
|
|
| 145 |
|
|
dy = 1 - (y1 - y1i); |
| 146 |
|
|
xa = x1 + dy * dxdya; |
| 147 |
|
|
iza = iz1 + dy * dizdya; |
| 148 |
|
|
uiza = uiz1 + dy * duizdya; |
| 149 |
|
|
viza = viz1 + dy * dvizdya; |
| 150 |
|
|
|
| 151 |
|
|
if (y1i < y2i) // Draw upper segment if possibly visible |
| 152 |
|
|
{ |
| 153 |
|
|
// Set right edge X-slope and perform subpixel pre- |
| 154 |
|
|
// stepping |
| 155 |
|
|
|
| 156 |
|
|
xb = x1 + dy * dxdy1; |
| 157 |
|
|
dxdyb = dxdy1; |
| 158 |
|
|
|
| 159 |
|
|
drawtpolyperspsubtriseg(y1i, y2i); |
| 160 |
|
|
}
|
| 161 |
|
|
|
| 162 |
|
|
if (y2i < y3i) // Draw lower segment if possibly visible |
| 163 |
|
|
{ |
| 164 |
|
|
// Set right edge X-slope and perform subpixel pre- |
| 165 |
|
|
// stepping |
| 166 |
|
|
|
| 167 |
|
|
xb = x2 + (1 - (y2 - y2i)) * dxdy3; |
| 168 |
|
|
dxdyb = dxdy3; |
| 169 |
|
|
|
| 170 |
|
|
drawtpolyperspsubtriseg(y2i, y3i); |
| 171 |
|
|
} |
| 172 |
|
|
} |
| 173 |
|
|
else // Longer edge is on the right side |
| 174 |
|
|
{ |
| 175 |
|
|
// Set right edge X-slope and perform subpixel pre-stepping |
| 176 |
|
|
|
| 177 |
|
|
dxdyb = dxdy2; |
| 178 |
|
|
dy = 1 - (y1 - y1i); |
| 179 |
|
|
xb = x1 + dy * dxdyb; |
| 180 |
|
|
|
| 181 |
|
|
if (y1i < y2i) // Draw upper segment if possibly visible |
| 182 |
|
|
{ |
| 183 |
|
|
// Set slopes along left edge and perform subpixel |
| 184 |
|
|
// pre-stepping |
| 185 |
|
|
|
| 186 |
|
|
dxdya = dxdy1; |
| 187 |
|
|
dizdya = dxdy1 * dizdx + dizdy; |
| 188 |
|
|
duizdya = dxdy1 * duizdx + duizdy; |
| 189 |
|
|
dvizdya = dxdy1 * dvizdx + dvizdy; |
| 190 |
|
|
xa = x1 + dy * dxdya; |
| 191 |
|
|
iza = iz1 + dy * dizdya; |
| 192 |
|
|
uiza = uiz1 + dy * duizdya; |
| 193 |
|
|
viza = viz1 + dy * dvizdya; |
| 194 |
|
|
|
| 195 |
|
|
drawtpolyperspsubtriseg(y1i, y2i); |
| 196 |
|
|
} |
| 197 |
|
|
|
| 198 |
|
|
if (y2i < y3i) // Draw lower segment if possibly visible |
| 199 |
|
|
{ |
| 200 |
|
|
// Set slopes along left edge and perform subpixel |
| 201 |
|
|
// pre-stepping |
| 202 |
|
|
|
| 203 |
|
|
dxdya = dxdy3; |
| 204 |
|
|
dizdya = dxdy3 * dizdx + dizdy; |
| 205 |
|
|
duizdya = dxdy3 * duizdx + duizdy; |
| 206 |
|
|
dvizdya = dxdy3 * dvizdx + dvizdy; |
| 207 |
|
|
dy = 1 - (y2 - y2i); |
| 208 |
|
|
xa = x2 + dy * dxdya; |
| 209 |
|
|
iza = iz2 + dy * dizdya; |
| 210 |
|
|
uiza = uiz2 + dy * duizdya; |
| 211 |
|
|
viza = viz2 + dy * dvizdya; |
| 212 |
|
|
|
| 213 |
|
|
drawtpolyperspsubtriseg(y2i, y3i); |
| 214 |
|
|
} |
| 215 |
|
|
} |
| 216 |
|
|
} |
| 217 |
|
|
|
| 218 |
|
|
void TMapare::drawtpolyperspsubtriseg(int y1, int y2) |
| 219 |
|
|
{ |
| 220 |
|
|
int *scr; |
| 221 |
|
|
int x1, x2; |
| 222 |
|
|
float z, u, v, dx; |
| 223 |
|
|
float iz, uiz, viz; |
| 224 |
|
|
|
| 225 |
|
|
while (y1 < y2) // Loop through all lines in the segment |
| 226 |
|
|
{ |
| 227 |
|
|
x1 = (int) xa; |
| 228 |
|
|
x2 = (int) xb; |
| 229 |
|
|
|
| 230 |
|
|
// Perform subtexel pre-stepping on 1/Z, U/Z and V/Z |
| 231 |
|
|
|
| 232 |
|
|
dx = 1 - (xa - x1); |
| 233 |
|
|
iz = iza + dx * dizdx; |
| 234 |
|
|
uiz = uiza + dx * duizdx; |
| 235 |
|
|
viz = viza + dx * dvizdx; |
| 236 |
|
|
|
| 237 |
|
|
scr = &screen[(screenheight-y1) * screenwidth + x1]; |
| 238 |
|
|
|
| 239 |
|
|
while (x1++ < x2) // Draw horizontal line |
| 240 |
|
|
{ |
| 241 |
|
|
// Calculate U and V from 1/Z, U/Z and V/Z |
| 242 |
|
|
|
| 243 |
|
|
z = 1 / iz; |
| 244 |
|
|
u = uiz * z; |
| 245 |
|
|
v = viz * z; |
| 246 |
|
|
|
| 247 |
|
|
// Copy pixel from texture to screen |
| 248 |
|
|
|
| 249 |
|
|
*(scr++) = texture[((((int) v) & 0xff) << 8) + (((int) u) & 0xff)]; |
| 250 |
|
|
|
| 251 |
|
|
// Step 1/Z, U/Z and V/Z horizontally |
| 252 |
|
|
|
| 253 |
|
|
iz += dizdx; |
| 254 |
|
|
uiz += duizdx; |
| 255 |
|
|
viz += dvizdx; |
| 256 |
|
|
} |
| 257 |
|
|
|
| 258 |
|
|
// Step along both edges |
| 259 |
|
|
|
| 260 |
|
|
xa += dxdya; |
| 261 |
|
|
xb += dxdyb; |
| 262 |
|
|
iza += dizdya; |
| 263 |
|
|
uiza += duizdya; |
| 264 |
|
|
viza += dvizdya; |
| 265 |
|
|
|
| 266 |
|
|
y1++; |
| 267 |
|
|
} |
| 268 |
|
|
} |
Parent Directory
| 
Revision Log