// -------------------------------------------------------------------------------------
// 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);
}
// -------------------------------------------------------------------------------------
// 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);
}