gzdoom-gles/src/r_sky.cpp

171 lines
5.1 KiB
C++

// Emacs style mode select -*- C++ -*-
//-----------------------------------------------------------------------------
//
// $Id:$
//
// Copyright (C) 1993-1996 by id Software, Inc.
//
// This source is available for distribution and/or modification
// only under the terms of the DOOM Source Code License as
// published by id Software. All rights reserved.
//
// The source is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// FITNESS FOR A PARTICULAR PURPOSE. See the DOOM Source Code License
// for more details.
//
// $Log:$
//
// DESCRIPTION:
// Sky rendering. The DOOM sky is a texture map like any
// wall, wrapping around. 1024 columns equal 360 degrees.
// The default sky map is 256 columns and repeats 4 times
// on a 320 screen.
//
//
//-----------------------------------------------------------------------------
// Needed for FRACUNIT.
#include "m_fixed.h"
#include "c_cvars.h"
#include "g_level.h"
#include "r_sky.h"
#include "r_utility.h"
#include "v_text.h"
#include "gi.h"
#include "g_levellocals.h"
//
// sky mapping
//
FTextureID skyflatnum;
FTextureID sky1texture, sky2texture;
double skytexturemid;
double skyscale;
float skyiscale;
bool skystretch;
fixed_t sky1cyl, sky2cyl;
double sky1pos, sky2pos;
CUSTOM_CVAR(Int, testskyoffset, 0, 0)
{
R_InitSkyMap();
}
// [RH] Stretch sky texture if not taller than 128 pixels?
// Also now controls capped skies. 0 = normal, 1 = stretched, 2 = capped
CUSTOM_CVAR (Int, r_skymode, 2, CVAR_ARCHIVE)
{
R_InitSkyMap ();
}
int freelookviewheight;
//==========================================================================
//
// R_InitSkyMap
//
// Called whenever the view size changes.
//
//==========================================================================
void R_InitSkyMap ()
{
int skyheight;
FTexture *skytex1, *skytex2;
// Do not allow the null texture which has no bitmap and will crash.
if (sky1texture.isNull())
{
sky1texture = TexMan.CheckForTexture("-noflat-", FTexture::TEX_Any);
}
if (sky2texture.isNull())
{
sky2texture = TexMan.CheckForTexture("-noflat-", FTexture::TEX_Any);
}
skytex1 = TexMan(sky1texture, true);
skytex2 = TexMan(sky2texture, true);
if (skytex1 == nullptr)
return;
if ((level.flags & LEVEL_DOUBLESKY) && skytex1->GetHeight() != skytex2->GetHeight())
{
Printf (TEXTCOLOR_BOLD "Both sky textures must be the same height." TEXTCOLOR_NORMAL "\n");
sky2texture = sky1texture;
}
// There are various combinations for sky rendering depending on how tall the sky is:
// h < 128: Unstretched and tiled, centered on horizon
// 128 <= h < 200: Can possibly be stretched. When unstretched, the baseline is
// 28 rows below the horizon so that the top of the texture
// aligns with the top of the screen when looking straight ahead.
// When stretched, it is scaled to 228 pixels with the baseline
// in the same location as an unstretched 128-tall sky, so the top
// of the texture aligns with the top of the screen when looking
// fully up.
// h == 200: Unstretched, baseline is on horizon, and top is at the top of
// the screen when looking fully up.
// h > 200: Unstretched, but the baseline is shifted down so that the top
// of the texture is at the top of the screen when looking fully up.
skyheight = skytex1->GetScaledHeight();
skystretch = false;
skytexturemid = 0;
if (skyheight >= 128 && skyheight < 200)
{
skystretch = (r_skymode == 1
&& skyheight >= 128
&& level.IsFreelookAllowed()
&& !(level.flags & LEVEL_FORCETILEDSKY)) ? 1 : 0;
skytexturemid = -28;
}
else if (skyheight > 200)
{
skytexturemid = (200 - skyheight) * skytex1->Scale.Y +((r_skymode == 2 && !(level.flags & LEVEL_FORCETILEDSKY)) ? skytex1->SkyOffset + testskyoffset : 0);
}
if (viewwidth != 0 && viewheight != 0)
{
skyiscale = float(r_Yaspect / freelookviewheight);
skyscale = freelookviewheight / r_Yaspect;
skyiscale *= float(FieldOfView.Degrees / 90.);
skyscale *= float(90. / FieldOfView.Degrees);
}
if (skystretch)
{
skyscale *= (double)SKYSTRETCH_HEIGHT / skyheight;
skyiscale *= skyheight / (float)SKYSTRETCH_HEIGHT;
skytexturemid *= skyheight / (double)SKYSTRETCH_HEIGHT;
}
// The standard Doom sky texture is 256 pixels wide, repeated 4 times over 360 degrees,
// giving a total sky width of 1024 pixels. So if the sky texture is no wider than 1024,
// we map it to a cylinder with circumfrence 1024. For larger ones, we use the width of
// the texture as the cylinder's circumfrence.
sky1cyl = MAX(skytex1->GetWidth(), fixed_t(skytex1->Scale.X * 1024));
sky2cyl = MAX(skytex2->GetWidth(), fixed_t(skytex2->Scale.Y * 1024));
}
//==========================================================================
//
// R_UpdateSky
//
// Performs sky scrolling
//
//==========================================================================
void R_UpdateSky (DWORD mstime)
{
// Scroll the sky
double ms = (double)mstime * FRACUNIT;
sky1pos = ms * level.skyspeed1;
sky2pos = ms * level.skyspeed2;
}