// -------------------------------------------------------------------------------------
// Render a texture map with lighting using perspective interpolation in inner and outer loops.
// -------------------------------------------------------------------------------------
void ntexture_map_lighted_linear(grs_bitmap *srcb, g3ds_tmap *t)
{
int vlt,vrt,vlb,vrb; // vertex left top, vertex right top, vertex left bottom, vertex right bottom
int topy,boty,y, dy;
fix dx_dy_left,dx_dy_right;
fix du_dy_left,du_dy_right;
fix dv_dy_left,dv_dy_right;
fix dl_dy_left,dl_dy_right;
int max_y_vertex;
fix xleft,xright,uleft,vleft,uright,vright,lleft,lright;
int next_break_left, next_break_right;
fix recip_dyl, recip_dyr;
g3ds_vertex *v3d;
//remove stupid warnings in compile
dl_dy_left = F1_0;
dl_dy_right = F1_0;
lleft = F1_0;
lright = F1_0;
v3d = t->verts;
// Determine top and bottom y coords.
compute_y_bounds(t,&vlt,&vlb,&vrt,&vrb,&max_y_vertex);
// Set top and bottom (of entire texture map) y coordinates.
topy = f2i(v3d[vlt].y2d);
boty = f2i(v3d[max_y_vertex].y2d);
if (topy > Window_clip_bot)
return;
if (boty > Window_clip_bot)
boty = Window_clip_bot;
dy = f2i(t->verts[vlb].y2d) - f2i(t->verts[vlt].y2d);
if (dy < FIX_RECIP_TABLE_SIZE)
recip_dyl = fix_recip[dy];
else
recip_dyl = F1_0/dy;
dy = f2i(t->verts[vrb].y2d) - f2i(t->verts[vrt].y2d);
if (dy < FIX_RECIP_TABLE_SIZE)
recip_dyr = fix_recip[dy];
else
recip_dyr = F1_0/dy;
// Set amount to change x coordinate for each advance to next scanline.
dx_dy_left = compute_dx_dy(t,vlt,vlb, recip_dyl);
dx_dy_right = compute_dx_dy(t,vrt,vrb, recip_dyr);
du_dy_left = compute_du_dy_lin(t,vlt,vlb, recip_dyl);
du_dy_right = compute_du_dy_lin(t,vrt,vrb, recip_dyr);
dv_dy_left = compute_dv_dy_lin(t,vlt,vlb, recip_dyl);
dv_dy_right = compute_dv_dy_lin(t,vrt,vrb, recip_dyr);
if (Lighting_enabled) {
dl_dy_left = compute_dl_dy_lin(t,vlt,vlb, recip_dyl);
dl_dy_right = compute_dl_dy_lin(t,vrt,vrb, recip_dyr);
lleft = v3d[vlt].l;
lright = v3d[vrt].l;
}
// Set initial values for x, u, v
xleft = v3d[vlt].x2d;
xright = v3d[vrt].x2d;
uleft = v3d[vlt].u;
uright = v3d[vrt].u;
vleft = v3d[vlt].v;
vright = v3d[vrt].v;
// scan all rows in texture map from top through first break.
next_break_left = f2i(v3d[vlb].y2d);
next_break_right = f2i(v3d[vrb].y2d);
for (y = topy; y < boty; y++) {
// See if we have reached the end of the current left edge, and if so, set
// new values for dx_dy and x,u,v
if (y == next_break_left) {
fix recip_dy;
// Handle problem of double points. Search until y coord is different. Cannot get
// hung in an infinite loop because we know there is a vertex with a lower y coordinate
// because in the for loop, we don't scan all spanlines.
while (y == f2i(v3d[vlb].y2d)) {
vlt = vlb;
vlb = prevmod(vlb,t->nv);
}
next_break_left = f2i(v3d[vlb].y2d);
dy = f2i(t->verts[vlb].y2d) - f2i(t->verts[vlt].y2d);
if (dy < FIX_RECIP_TABLE_SIZE)
recip_dy = fix_recip[dy];
else
recip_dy = F1_0/dy;
dx_dy_left = compute_dx_dy(t,vlt,vlb, recip_dy);
xleft = v3d[vlt].x2d;
uleft = v3d[vlt].u;
vleft = v3d[vlt].v;
lleft = v3d[vlt].l;
du_dy_left = compute_du_dy_lin(t,vlt,vlb, recip_dy);
dv_dy_left = compute_dv_dy_lin(t,vlt,vlb, recip_dy);
if (Lighting_enabled) {
dl_dy_left = compute_dl_dy_lin(t,vlt,vlb, recip_dy);
lleft = v3d[vlt].l;
}
}
// See if we have reached the end of the current left edge, and if so, set
// new values for dx_dy and x. Not necessary to set new values for u,v.
if (y == next_break_right) {
fix recip_dy;
while (y == f2i(v3d[vrb].y2d)) {
vrt = vrb;
vrb = succmod(vrb,t->nv);
}
dy = f2i(t->verts[vrb].y2d) - f2i(t->verts[vrt].y2d);
if (dy < FIX_RECIP_TABLE_SIZE)
recip_dy = fix_recip[dy];
else
recip_dy = F1_0/dy;
next_break_right = f2i(v3d[vrb].y2d);
dx_dy_right = compute_dx_dy(t,vrt,vrb, recip_dy);
xright = v3d[vrt].x2d;
uright = v3d[vrt].u;
vright = v3d[vrt].v;
du_dy_right = compute_du_dy_lin(t,vrt,vrb, recip_dy);
dv_dy_right = compute_dv_dy_lin(t,vrt,vrb, recip_dy);
if (Lighting_enabled) {
dl_dy_right = compute_dl_dy_lin(t,vrt,vrb, recip_dy);
lright = v3d[vrt].l;
}
}
if (Lighting_enabled) {
ntmap_scanline_lighted_linear(srcb,y,xleft,xright,uleft,uright,vleft,vright,lleft,lright);
lleft += dl_dy_left;
lright += dl_dy_right;
} else
ntmap_scanline_lighted_linear(srcb,y,xleft,xright,uleft,uright,vleft,vright,lleft,lright);
uleft += du_dy_left;
vleft += dv_dy_left;
uright += du_dy_right;
vright += dv_dy_right;
xleft += dx_dy_left;
xright += dx_dy_right;
}
// We can get lleft or lright out of bounds here because we compute dl_dy using fixed point values,
// but we plot an integer number of scanlines, therefore doing an integer number of additions of the delta.
ntmap_scanline_lighted_linear(srcb,y,xleft,xright,uleft,uright,vleft,vright,lleft,lright);
}
// -------------------------------------------------------------------------------------
// Render a texture map.
// Linear in outer loop, linear in inner loop.
// -------------------------------------------------------------------------------------
void texture_map_flat(g3ds_tmap *t, int color)
{
int vlt,vrt,vlb,vrb; // vertex left top, vertex right top, vertex left bottom, vertex right bottom
int topy,boty,y, dy;
fix dx_dy_left,dx_dy_right;
int max_y_vertex;
fix xleft,xright;
fix recip_dy;
g3ds_vertex *v3d;
v3d = t->verts;
tmap_flat_color = color;
// Determine top and bottom y coords.
compute_y_bounds(t,&vlt,&vlb,&vrt,&vrb,&max_y_vertex);
// Set top and bottom (of entire texture map) y coordinates.
topy = f2i(v3d[vlt].y2d);
boty = f2i(v3d[max_y_vertex].y2d);
// Set amount to change x coordinate for each advance to next scanline.
dy = f2i(t->verts[vlb].y2d) - f2i(t->verts[vlt].y2d);
if (dy < FIX_RECIP_TABLE_SIZE)
recip_dy = fix_recip[dy];
else
recip_dy = F1_0/dy;
dx_dy_left = compute_dx_dy(t,vlt,vlb, recip_dy);
dy = f2i(t->verts[vrb].y2d) - f2i(t->verts[vrt].y2d);
if (dy < FIX_RECIP_TABLE_SIZE)
recip_dy = fix_recip[dy];
else
recip_dy = F1_0/dy;
dx_dy_right = compute_dx_dy(t,vrt,vrb, recip_dy);
// Set initial values for x, u, v
xleft = v3d[vlt].x2d;
xright = v3d[vrt].x2d;
// scan all rows in texture map from top through first break.
// @mk: Should we render the scanline for y==boty? This violates Matt's spec.
for (y = topy; y < boty; y++) {
// See if we have reached the end of the current left edge, and if so, set
// new values for dx_dy and x,u,v
if (y == f2i(v3d[vlb].y2d)) {
// Handle problem of double points. Search until y coord is different. Cannot get
// hung in an infinite loop because we know there is a vertex with a lower y coordinate
// because in the for loop, we don't scan all spanlines.
while (y == f2i(v3d[vlb].y2d)) {
vlt = vlb;
vlb = prevmod(vlb,t->nv);
}
dy = f2i(t->verts[vlb].y2d) - f2i(t->verts[vlt].y2d);
if (dy < FIX_RECIP_TABLE_SIZE)
recip_dy = fix_recip[dy];
else
recip_dy = F1_0/dy;
dx_dy_left = compute_dx_dy(t,vlt,vlb, recip_dy);
xleft = v3d[vlt].x2d;
}
// See if we have reached the end of the current left edge, and if so, set
// new values for dx_dy and x. Not necessary to set new values for u,v.
if (y == f2i(v3d[vrb].y2d)) {
while (y == f2i(v3d[vrb].y2d)) {
vrt = vrb;
vrb = succmod(vrb,t->nv);
}
dy = f2i(t->verts[vrb].y2d) - f2i(t->verts[vrt].y2d);
if (dy < FIX_RECIP_TABLE_SIZE)
recip_dy = fix_recip[dy];
else
recip_dy = F1_0/dy;
dx_dy_right = compute_dx_dy(t,vrt,vrb, recip_dy);
xright = v3d[vrt].x2d;
}
//tmap_scanline_flat(y, xleft, xright);
(*scanline_func)(y, xleft, xright);
xleft += dx_dy_left;
xright += dx_dy_right;
}
//tmap_scanline_flat(y, xleft, xright);
(*scanline_func)(y, xleft, xright);
}
// -------------------------------------------------------------------------------------
// Select topmost vertex (minimum y coordinate) and bottommost (maximum y coordinate) in
// texture map. If either is part of a horizontal edge, then select leftmost vertex for
// top, rightmost vertex for bottom.
// Important: Vertex is selected with integer precision. So, if there are vertices at
// (0.0,0.7) and (0.5,0.3), the first vertex is selected, because they y coordinates are
// considered the same, so the smaller x is favored.
// Parameters:
// nv number of vertices
// v3d pointer to 3d vertices containing u,v,x2d,y2d coordinates
// Results in:
// *min_y_ind
// *max_y_ind
// -------------------------------------------------------------------------------------
void compute_y_bounds(g3ds_tmap *t, int *vlt, int *vlb, int *vrt, int *vrb,int *bottom_y_ind)
{
int i;
int min_y,max_y;
int min_y_ind;
int original_vrt;
fix min_x;
// Scan all vertices, set min_y_ind to vertex with smallest y coordinate.
min_y = f2i(t->verts[0].y2d);
max_y = min_y;
min_y_ind = 0;
min_x = f2i(t->verts[0].x2d);
*bottom_y_ind = 0;
for (i=1; i<t->nv; i++) {
if (f2i(t->verts[i].y2d) < min_y) {
min_y = f2i(t->verts[i].y2d);
min_y_ind = i;
min_x = f2i(t->verts[i].x2d);
} else if (f2i(t->verts[i].y2d) == min_y) {
if (f2i(t->verts[i].x2d) < min_x) {
min_y_ind = i;
min_x = f2i(t->verts[i].x2d);
}
}
if (f2i(t->verts[i].y2d) > max_y) {
max_y = f2i(t->verts[i].y2d);
*bottom_y_ind = i;
}
}
//--removed mk, 11/27/94-- // Check for a non-upright-hourglass polygon and fix, if necessary, by bashing a y coordinate.
//--removed mk, 11/27/94-- // min_y_ind = index of minimum y coordinate, *bottom_y_ind = index of maximum y coordinate
//--removed mk, 11/27/94--{
//--removed mk, 11/27/94-- int max_temp, min_temp;
//--removed mk, 11/27/94--
//--removed mk, 11/27/94-- max_temp = *bottom_y_ind;
//--removed mk, 11/27/94-- if (*bottom_y_ind < min_y_ind)
//--removed mk, 11/27/94-- max_temp += t->nv;
//--removed mk, 11/27/94--
//--removed mk, 11/27/94-- for (i=min_y_ind; i<max_temp; i++) {
//--removed mk, 11/27/94-- if (f2i(t->verts[i%t->nv].y2d) > f2i(t->verts[(i+1)%t->nv].y2d)) {
//--removed mk, 11/27/94-- Int3();
//--removed mk, 11/27/94-- t->verts[(i+1)%t->nv].y2d = t->verts[i%t->nv].y2d;
//--removed mk, 11/27/94-- }
//--removed mk, 11/27/94-- }
//--removed mk, 11/27/94--
//--removed mk, 11/27/94-- min_temp = min_y_ind;
//--removed mk, 11/27/94-- if (min_y_ind < *bottom_y_ind)
//--removed mk, 11/27/94-- min_temp += t->nv;
//--removed mk, 11/27/94--
//--removed mk, 11/27/94-- for (i=*bottom_y_ind; i<min_temp; i++) {
//--removed mk, 11/27/94-- if (f2i(t->verts[i%t->nv].y2d) < f2i(t->verts[(i+1)%t->nv].y2d)) {
//--removed mk, 11/27/94-- Int3();
//--removed mk, 11/27/94-- t->verts[(i+1)%t->nv].y2d = t->verts[i%t->nv].y2d;
//--removed mk, 11/27/94-- }
//--removed mk, 11/27/94-- }
//--removed mk, 11/27/94--}
// Set "vertex left top", etc. based on vertex with topmost y coordinate
*vlt = min_y_ind;
*vrt = *vlt;
*vlb = prevmod(*vlt,t->nv);
*vrb = succmod(*vrt,t->nv);
// If right edge is horizontal, then advance along polygon bound until it no longer is or until all
// vertices have been examined.
// (Left edge cannot be horizontal, because *vlt is set to leftmost point with highest y coordinate.)
original_vrt = *vrt;
while (f2i(t->verts[*vrt].y2d) == f2i(t->verts[*vrb].y2d)) {
if (succmod(*vrt,t->nv) == original_vrt) {
break;
}
*vrt = succmod(*vrt,t->nv);
*vrb = succmod(*vrt,t->nv);
}
}
