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dxx-rebirth/common/texmap/ntmap.cpp

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/*
* Portions of this file are copyright Rebirth contributors and licensed as
* described in COPYING.txt.
* Portions of this file are copyright Parallax Software and licensed
* according to the Parallax license below.
* See COPYING.txt for license details.
THE COMPUTER CODE CONTAINED HEREIN IS THE SOLE PROPERTY OF PARALLAX
SOFTWARE CORPORATION ("PARALLAX"). PARALLAX, IN DISTRIBUTING THE CODE TO
END-USERS, AND SUBJECT TO ALL OF THE TERMS AND CONDITIONS HEREIN, GRANTS A
ROYALTY-FREE, PERPETUAL LICENSE TO SUCH END-USERS FOR USE BY SUCH END-USERS
IN USING, DISPLAYING, AND CREATING DERIVATIVE WORKS THEREOF, SO LONG AS
SUCH USE, DISPLAY OR CREATION IS FOR NON-COMMERCIAL, ROYALTY OR REVENUE
FREE PURPOSES. IN NO EVENT SHALL THE END-USER USE THE COMPUTER CODE
CONTAINED HEREIN FOR REVENUE-BEARING PURPOSES. THE END-USER UNDERSTANDS
AND AGREES TO THE TERMS HEREIN AND ACCEPTS THE SAME BY USE OF THIS FILE.
COPYRIGHT 1993-1998 PARALLAX SOFTWARE CORPORATION. ALL RIGHTS RESERVED.
*/
/*
*
* Start of conversion to new texture mapper.
*
*/
#include "pstypes.h"
#include "maths.h"
#include "vecmat.h"
#include "gr.h"
#include "3d.h"
#include "dxxerror.h"
#include "render.h"
#include "texmap.h"
#include "texmapl.h"
#include "rle.h"
#include "scanline.h"
#include "u_mem.h"
#include "d_zip.h"
#include "dxxsconf.h"
#include "dsx-ns.h"
#include <utility>
namespace dcx {
#if DXX_USE_EDITOR
#define EDITOR_TMAP 1 //if in, include extra stuff
#endif
// Temporary texture map, interface from Matt's 3d system to Mike's texture mapper.
int Lighting_on=1; // initialize to no lighting
unsigned Current_seg_depth; // HACK INTERFACE: how far away the current segment (& thus texture) is
// These variables are the interface to assembler. They get set for each texture map, which is a real waste of time.
// They should be set only when they change, which is generally when the window bounds change. And, even still, it's
// a pretty bad interface.
int bytes_per_row=-1;
unsigned char *write_buffer;
fix fx_l, fx_u, fx_v, fx_z, fx_du_dx, fx_dv_dx, fx_dz_dx, fx_dl_dx;
int fx_xleft, fx_xright, fx_y;
const color_palette_index *pixptr;
uint8_t Transparency_on = 0;
uint8_t tmap_flat_color;
int Interpolation_method; // 0 = choose best method
// -------------------------------------------------------------------------------------
template <std::size_t... N>
static inline constexpr const std::array<fix, 1 + sizeof...(N)> init_fix_recip_table(std::index_sequence<0, N...>)
{
/* gcc 4.5 fails on bare initializer list */
return std::array<fix, 1 + sizeof...(N)>{{F1_0, (F1_0 / N)...}};
}
constexpr std::array<fix, FIX_RECIP_TABLE_SIZE> fix_recip_table = init_fix_recip_table(std::make_index_sequence<FIX_RECIP_TABLE_SIZE>());
// -------------------------------------------------------------------------------------
// Initialize interface variables to assembler.
// These things used to be constants. This routine is now (10/6/93) getting called for
// every texture map. It should get called whenever the window changes, or, preferably,
// not at all. I'm pretty sure these variables are only being used for range checking.
void init_interface_vars_to_assembler(void)
{
grs_bitmap *bp;
bp = &grd_curcanv->cv_bitmap;
Assert(bp!=NULL);
Assert(bp->bm_data!=NULL);
// If bytes_per_row has changed, create new table of pointers.
if (bytes_per_row != static_cast<int>(bp->bm_rowsize)) {
bytes_per_row = static_cast<int>(bp->bm_rowsize);
}
write_buffer = bp->bm_mdata;
Window_clip_left = 0;
Window_clip_right = static_cast<int>(bp->bm_w)-1;
Window_clip_top = 0;
Window_clip_bot = static_cast<int>(bp->bm_h)-1;
}
static int Lighting_enabled;
// -------------------------------------------------------------------------------------
// VARIABLES
// -------------------------------------------------------------------------------------
// Returns number preceding val modulo modulus.
// prevmod(3,4) = 2
// prevmod(0,4) = 3
int prevmod(int val,int modulus)
{
if (val > 0)
return val-1;
else
return modulus-1;
// return (val + modulus - 1) % modulus;
}
// Returns number succeeding val modulo modulus.
// succmod(3,4) = 0
// succmod(0,4) = 1
int succmod(int val,int modulus)
{
if (val < modulus-1)
return val+1;
else
return 0;
// return (val + 1) % modulus;
}
// -------------------------------------------------------------------------------------
// 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(const g3ds_tmap &t, int &vlt, int &vlb, int &vrt, int &vrb,int &bottom_y_ind)
{
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 (int 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
vlb = prevmod(vlt = min_y_ind,t.nv);
vrb = succmod(vrt = vlt,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);
}
}
// -------------------------------------------------------------------------------------
// Returns dx/dy given two vertices.
// If dy == 0, returns 0.0
// -------------------------------------------------------------------------------------
//--fix compute_dx_dy_lin(g3ds_tmap *t, int top_vertex,int bottom_vertex)
//--{
//-- int dy;
//--
//-- // compute delta x with respect to y for any edge
//-- dy = f2i(t->verts[bottom_vertex].y2d - t->verts[top_vertex].y2d) + 1;
//-- if (dy)
//-- return (t->verts[bottom_vertex].x2d - t->verts[top_vertex].x2d) / dy;
//-- else
//-- return 0;
//--
//--}
//#if !DXX_USE_OGL
static fix compute_du_dy_lin(const g3ds_tmap &t, int top_vertex,int bottom_vertex, fix recip_dy)
{
return fixmul(t.verts[bottom_vertex].u - t.verts[top_vertex].u, recip_dy);
}
static fix compute_dv_dy_lin(const g3ds_tmap &t, int top_vertex,int bottom_vertex, fix recip_dy)
{
return fixmul(t.verts[bottom_vertex].v - t.verts[top_vertex].v, recip_dy);
}
static fix compute_dl_dy_lin(const g3ds_tmap &t, int top_vertex,int bottom_vertex, fix recip_dy)
{
return fixmul(t.verts[bottom_vertex].l - t.verts[top_vertex].l, recip_dy);
}
fix compute_dx_dy(const g3ds_tmap &t, int top_vertex,int bottom_vertex, fix recip_dy)
{
return fixmul(t.verts[bottom_vertex].x2d - t.verts[top_vertex].x2d, recip_dy);
}
static fix compute_du_dy(const g3ds_tmap &t, int top_vertex,int bottom_vertex, fix recip_dy)
{
return fixmul(fixmul(t.verts[bottom_vertex].u,t.verts[bottom_vertex].z) - fixmul(t.verts[top_vertex].u,t.verts[top_vertex].z), recip_dy);
}
static fix compute_dv_dy(const g3ds_tmap &t, int top_vertex,int bottom_vertex, fix recip_dy)
{
return fixmul(fixmul(t.verts[bottom_vertex].v,t.verts[bottom_vertex].z) - fixmul(t.verts[top_vertex].v,t.verts[top_vertex].z), recip_dy);
}
static fix compute_dz_dy(const g3ds_tmap &t, int top_vertex,int bottom_vertex, fix recip_dy)
{
return fixmul(t.verts[bottom_vertex].z - t.verts[top_vertex].z, recip_dy);
}
// -------------------------------------------------------------------------------------
// Texture map current scanline in perspective.
// -------------------------------------------------------------------------------------
static void ntmap_scanline_lighted(const grs_bitmap &srcb, int y, fix xleft, fix xright, fix uleft, fix uright, fix vleft, fix vright, fix zleft, fix zright, fix lleft, fix lright)
{
fix dx,recip_dx;
fx_xright = f2i(xright);
//edited 06/27/99 Matt Mueller - moved these tests up from within the switch so as not to do a bunch of needless calculations when we are just gonna return anyway. Slight fps boost?
if (fx_xright < Window_clip_left)
return;
fx_xleft = f2i(xleft);
if (fx_xleft > Window_clip_right)
return;
//end edit -MM
dx = fx_xright - fx_xleft;
if ((dx < 0) || (xright < 0) || (xleft > xright)) // the (xleft > xright) term is not redundant with (dx < 0) because dx is computed using integers
return;
// setup to call assembler scanline renderer
recip_dx = fix_recip(dx);
fx_u = uleft;
fx_v = vleft;
fx_z = zleft;
fx_du_dx = fixmul(uright - uleft,recip_dx);
fx_dv_dx = fixmul(vright - vleft,recip_dx);
fx_dz_dx = fixmul(zright - zleft,recip_dx);
fx_y = y;
pixptr = srcb.bm_data;
switch (Lighting_enabled) {
case 0:
//added 05/17/99 Matt Mueller - prevent writing before the buffer
if ((fx_y == 0) && (fx_xleft < 0))
fx_xleft = 0;
//end addition -MM
if (fx_xright > Window_clip_right)
fx_xright = Window_clip_right;
cur_tmap_scanline_per();
break;
case 1: {
fix mul_thing;
if (lleft < 0) lleft = 0;
if (lright < 0) lright = 0;
if (lleft > (NUM_LIGHTING_LEVELS*F1_0-F1_0/2)) lleft = (NUM_LIGHTING_LEVELS*F1_0-F1_0/2);
if (lright > (NUM_LIGHTING_LEVELS*F1_0-F1_0/2)) lright = (NUM_LIGHTING_LEVELS*F1_0-F1_0/2);
fx_l = lleft;
fx_dl_dx = fixmul(lright - lleft,recip_dx);
// This is a pretty ugly hack to prevent lighting overflows.
mul_thing = dx * fx_dl_dx;
if (lleft + mul_thing < 0)
fx_dl_dx += 12;
else if (lleft + mul_thing > (NUM_LIGHTING_LEVELS*F1_0-F1_0/2))
fx_dl_dx -= 12;
//added 05/17/99 Matt Mueller - prevent writing before the buffer
if ((fx_y == 0) && (fx_xleft < 0))
fx_xleft = 0;
//end addition -MM
if (fx_xright > Window_clip_right)
fx_xright = Window_clip_right;
cur_tmap_scanline_per();
break;
}
case 2:
#ifdef EDITOR_TMAP
fx_xright = f2i(xright);
fx_xleft = f2i(xleft);
tmap_flat_color = 1;
c_tmap_scanline_flat();
#else
Int3(); // Illegal, called an editor only routine!
#endif
break;
}
}
// -------------------------------------------------------------------------------------
// Render a texture map with lighting using perspective interpolation in inner and outer loops.
// -------------------------------------------------------------------------------------
static void ntexture_map_lighted(const grs_bitmap &srcb, const g3ds_tmap &t)
{
int vlt,vrt,vlb,vrb; // vertex left top, vertex right top, vertex left bottom, vertex right bottom
int topy,boty,dy;
fix dx_dy_left,dx_dy_right;
fix du_dy_left,du_dy_right;
fix dv_dy_left,dv_dy_right;
fix dz_dy_left,dz_dy_right;
fix dl_dy_left,dl_dy_right;
fix recip_dyl, recip_dyr;
int max_y_vertex;
fix xleft,xright,uleft,vleft,uright,vright,zleft,zright,lleft,lright;
int next_break_left, next_break_right;
//remove stupid warnings in compile
dl_dy_left = F1_0;
dl_dy_right = F1_0;
lleft = F1_0;
lright = F1_0;
auto &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;
// Set amount to change x coordinate for each advance to next scanline.
dy = f2i(t.verts[vlb].y2d) - f2i(t.verts[vlt].y2d);
recip_dyl = fix_recip(dy);
dx_dy_left = compute_dx_dy(t,vlt,vlb, recip_dyl);
du_dy_left = compute_du_dy(t,vlt,vlb, recip_dyl);
dv_dy_left = compute_dv_dy(t,vlt,vlb, recip_dyl);
dz_dy_left = compute_dz_dy(t,vlt,vlb, recip_dyl);
dy = f2i(t.verts[vrb].y2d) - f2i(t.verts[vrt].y2d);
recip_dyr = fix_recip(dy);
du_dy_right = compute_du_dy(t,vrt,vrb, recip_dyr);
dx_dy_right = compute_dx_dy(t,vrt,vrb, recip_dyr);
dv_dy_right = compute_dv_dy(t,vrt,vrb, recip_dyr);
dz_dy_right = compute_dz_dy(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;
zleft = v3d[vlt].z;
zright = v3d[vrt].z;
uleft = fixmul(v3d[vlt].u,zleft);
uright = fixmul(v3d[vrt].u,zright);
vleft = fixmul(v3d[vlt].v,zleft);
vright = fixmul(v3d[vrt].v,zright);
// 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 (int 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);
recip_dy = fix_recip(dy);
dx_dy_left = compute_dx_dy(t,vlt,vlb, recip_dy);
xleft = v3d[vlt].x2d;
zleft = v3d[vlt].z;
uleft = fixmul(v3d[vlt].u,zleft);
vleft = fixmul(v3d[vlt].v,zleft);
lleft = v3d[vlt].l;
du_dy_left = compute_du_dy(t,vlt,vlb, recip_dy);
dv_dy_left = compute_dv_dy(t,vlt,vlb, recip_dy);
dz_dy_left = compute_dz_dy(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);
}
next_break_right = f2i(v3d[vrb].y2d);
dy = f2i(t.verts[vrb].y2d) - f2i(t.verts[vrt].y2d);
recip_dy = fix_recip(dy);
dx_dy_right = compute_dx_dy(t,vrt,vrb, recip_dy);
xright = v3d[vrt].x2d;
zright = v3d[vrt].z;
uright = fixmul(v3d[vrt].u,zright);
vright = fixmul(v3d[vrt].v,zright);
du_dy_right = compute_du_dy(t,vrt,vrb, recip_dy);
dv_dy_right = compute_dv_dy(t,vrt,vrb, recip_dy);
dz_dy_right = compute_dz_dy(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) {
if (y >= Window_clip_top)
ntmap_scanline_lighted(srcb,y,xleft,xright,uleft,uright,vleft,vright,zleft,zright,lleft,lright);
lleft += dl_dy_left;
lright += dl_dy_right;
} else
if (y >= Window_clip_top)
ntmap_scanline_lighted(srcb,y,xleft,xright,uleft,uright,vleft,vright,zleft,zright,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;
zleft += dz_dy_left;
zright += dz_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(srcb,boty,xleft,xright,uleft,uright,vleft,vright,zleft,zright,lleft,lright);
}
// -------------------------------------------------------------------------------------
// Texture map current scanline using linear interpolation.
// -------------------------------------------------------------------------------------
static void ntmap_scanline_lighted_linear(const grs_bitmap &srcb, int y, fix xleft, fix xright, fix uleft, fix uright, fix vleft, fix vright, fix lleft, fix lright)
{
fix dx,recip_dx,du_dx,dv_dx,dl_dx;
dx = f2i(xright) - f2i(xleft);
if ((dx < 0) || (xright < 0) || (xleft > xright)) // the (xleft > xright) term is not redundant with (dx < 0) because dx is computed using integers
return;
// setup to call assembler scanline renderer
recip_dx = fix_recip(dx);
du_dx = fixmul(uright - uleft,recip_dx);
dv_dx = fixmul(vright - vleft,recip_dx);
fx_u = uleft;
fx_v = vleft;
fx_du_dx = du_dx;
fx_dv_dx = dv_dx;
fx_y = y;
fx_xright = f2i(xright);
fx_xleft = f2i(xleft);
pixptr = srcb.bm_data;
switch (Lighting_enabled) {
case 0:
//added 07/11/99 adb - prevent writing before the buffer
if (fx_xleft < 0)
fx_xleft = 0;
//end addition -adb
c_tmap_scanline_lin_nolight();
break;
case 1:
if (lleft < F1_0/2)
lleft = F1_0/2;
if (lright < F1_0/2)
lright = F1_0/2;
if (lleft > MAX_LIGHTING_VALUE*NUM_LIGHTING_LEVELS)
lleft = MAX_LIGHTING_VALUE*NUM_LIGHTING_LEVELS;
if (lright > MAX_LIGHTING_VALUE*NUM_LIGHTING_LEVELS)
lright = MAX_LIGHTING_VALUE*NUM_LIGHTING_LEVELS;
//added 07/11/99 adb - prevent writing before the buffer
if (fx_xleft < 0)
fx_xleft = 0;
//end addition -adb
{
fix mul_thing;
fx_l = lleft;
fx_dl_dx = fixmul(lright - lleft,recip_dx);
// This is a pretty ugly hack to prevent lighting overflows.
mul_thing = dx * fx_dl_dx;
if (lleft + mul_thing < 0)
fx_dl_dx += 12;
else if (lleft + mul_thing > (NUM_LIGHTING_LEVELS*F1_0-F1_0/2))
fx_dl_dx -= 12;
}
fx_l = lleft;
dl_dx = fixmul(lright - lleft,recip_dx);
fx_dl_dx = dl_dx;
c_tmap_scanline_lin();
break;
case 2:
#ifdef EDITOR_TMAP
fx_xright = f2i(xright);
fx_xleft = f2i(xleft);
tmap_flat_color = 1;
c_tmap_scanline_flat();
#else
Int3(); // Illegal, called an editor only routine!
#endif
break;
}
}
// -------------------------------------------------------------------------------------
// Render a texture map with lighting using perspective interpolation in inner and outer loops.
// -------------------------------------------------------------------------------------
static void ntexture_map_lighted_linear(const grs_bitmap &srcb, const g3ds_tmap &t)
{
int vlt,vrt,vlb,vrb; // vertex left top, vertex right top, vertex left bottom, vertex right bottom
int topy,boty,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;
//remove stupid warnings in compile
dl_dy_left = F1_0;
dl_dy_right = F1_0;
lleft = F1_0;
lright = F1_0;
auto &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);
recip_dyl = fix_recip(dy);
dy = f2i(t.verts[vrb].y2d) - f2i(t.verts[vrt].y2d);
recip_dyr = fix_recip(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 (int 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);
recip_dy = fix_recip(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);
recip_dy = fix_recip(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,boty,xleft,xright,uleft,uright,vleft,vright,lleft,lright);
}
// fix DivNum = F1_0*12;
// -------------------------------------------------------------------------------------
// Interface from Matt's data structures to Mike's texture mapper.
// -------------------------------------------------------------------------------------
void draw_tmap(grs_canvas &canvas, const grs_bitmap &rbp, const std::span<const g3s_point *const> vertbuf)
{
// These variables are used in system which renders texture maps which lie on one scanline as a line.
// fix div_numerator;
int lighting_on_save = Lighting_on;
assert(vertbuf.size() <= MAX_TMAP_VERTS);
const grs_bitmap *bp = &rbp;
// If no transparency and seg depth is large, render as flat shaded.
if ((Current_seg_depth > Max_linear_depth) && ((bp->get_flag_mask(3)) == 0)) {
draw_tmap_flat(canvas, rbp, vertbuf);
return;
}
bp = rle_expand_texture(*bp); // Expand if rle'd
Transparency_on = bp->get_flag_mask(BM_FLAG_TRANSPARENT);
if (bp->get_flag_mask(BM_FLAG_NO_LIGHTING))
Lighting_on = 0;
// Setup texture map in Tmap1
g3ds_tmap Tmap1;
Tmap1.nv = vertbuf.size(); // Initialize number of vertices
// div_numerator = DivNum; //f1_0*3;
for (auto &&[vp, tvp] : zip(vertbuf, Tmap1.verts))
{
tvp.x2d = vp->p3_sx;
tvp.y2d = vp->p3_sy;
// Check for overflow on fixdiv. Will overflow on vp->z <= something small. Allow only as low as 256.
auto clipped_p3_z = std::max(256, vp->p3_z);
tvp.z = fixdiv(F1_0*12, clipped_p3_z);
tvp.u = vp->p3_u << 6; //* bp->bm_w;
tvp.v = vp->p3_v << 6; //* bp->bm_h;
Assert(Lighting_on < 3);
if (Lighting_on)
tvp.l = vp->p3_l * NUM_LIGHTING_LEVELS;
}
Lighting_enabled = Lighting_on;
// Now, call my texture mapper.
switch (Interpolation_method) { // 0 = choose, 1 = linear, 2 = /8 perspective, 3 = full perspective
case 0: // choose best interpolation
if (Current_seg_depth > Max_perspective_depth)
{
case 1: // linear interpolation
ntexture_map_lighted_linear(*bp, Tmap1);
}
else
{
[[fallthrough]];
case 2: // perspective every 8th pixel interpolation
case 3: // perspective every pixel interpolation
ntexture_map_lighted(*bp, Tmap1);
}
break;
default:
Assert(0); // Illegal value for Interpolation_method, must be 0,1,2,3
}
Lighting_on = lighting_on_save;
}
}
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