r_lightmap.cpp

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/*
Copyright (C) 1997-2001 Id Software, Inc.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/

#include "r_local.h"
#include "r_error.h"
#include "r_entity.h"
#include "r_lightmap.h"

lightmaps_t r_lightmaps;

static void R_UploadLightmapPage (void)
{
#ifdef GL_VERSION_ES_CM_1_0
    const int texFormat = GL_RGB;
#else
    const int texFormat = r_config.gl_compressed_solid_format ? r_config.gl_compressed_solid_format : r_config.gl_solid_format;
#endif
    GLuint texid;
    if (r_lightmaps.lightmap_count >= MAX_GL_LIGHTMAPS) {
        Com_Printf("R_UploadLightmapPage: MAX_GL_LIGHTMAPS reached.\n");
        return;
    }

    if (!r_lightmaps.incomplete_atlas) {
        glGenTextures(1, &texid);
        r_lightmaps.lightmap_texnums[r_lightmaps.lightmap_count++] = texid;
    } else {
        texid = r_lightmaps.lightmap_texnums[r_lightmaps.lightmap_count];
    }

    R_BindTexture(texid);

    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    glTexImage2D(GL_TEXTURE_2D, 0, texFormat, r_lightmaps.size, r_lightmaps.size,
        0, GL_RGB, GL_UNSIGNED_BYTE, r_lightmaps.sample_buffer);

    R_CheckError();

    if (r_lightmaps.deluxemap_count >= MAX_GL_DELUXEMAPS) {
        Com_Printf("R_UploadLightmapPage: MAX_GL_DELUXEMAPS reached.\n");
        return;
    }

    if (!r_lightmaps.incomplete_atlas) {
        glGenTextures(1, &texid);
        r_lightmaps.deluxemap_texnums[r_lightmaps.deluxemap_count++] = texid;
    } else {
        texid = r_lightmaps.deluxemap_texnums[r_lightmaps.deluxemap_count];
    }

    R_BindTexture(texid);

    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    glTexImage2D(GL_TEXTURE_2D, 0, texFormat, r_lightmaps.size, r_lightmaps.size,
        0, GL_RGB, GL_UNSIGNED_BYTE, r_lightmaps.direction_buffer);

    /* clear the allocation heightmap and buffers */
    memset(r_lightmaps.allocated, 0, r_lightmaps.size * sizeof(unsigned));
    memset(r_lightmaps.sample_buffer, 0, r_lightmaps.size * r_lightmaps.size * LIGHTMAP_SAMPLE_SIZE);
    memset(r_lightmaps.direction_buffer, 0, r_lightmaps.size * r_lightmaps.size * DELUXEMAP_SAMPLE_SIZE);

    r_lightmaps.incomplete_atlas = false;
}

static bool R_AllocLightmapBlock (int w, int h, int* x, int* y)
{
    if (!r_lightmaps.incomplete_atlas) {
        r_lightmaps.incomplete_atlas = true;
        glGenTextures(1, &r_lightmaps.lightmap_texnums[++r_lightmaps.lightmap_count]);
        glGenTextures(1, &r_lightmaps.deluxemap_texnums[++r_lightmaps.deluxemap_count]);
    }

    /* the height to store the data in the atlas */
    int best = r_lightmaps.size;

    int i;
    for (i = 0; i < r_lightmaps.size - w; i++) {
        int best2 = 0;
        int j;

        for (j = 0; j < w; j++) {
            if (r_lightmaps.allocated[i + j] >= best)
                break;
            if (r_lightmaps.allocated[i + j] > best2)
                best2 = r_lightmaps.allocated[i + j];
        }
        /* this is a valid spot */
        if (j == w) {
            *x = i;
            *y = best = best2;
        }
    }

    if (best + h > r_lightmaps.size)
        return false;

    for (i = 0; i < w; i++)
        r_lightmaps.allocated[*x + i] = best + h;

    return true;
}

static void R_BuildDefaultLightmap (mBspSurface_t* surf, byte* sout, byte* dout, int stride)
{
    const int smax = (surf->stextents[0] / surf->lightmap_scale) + 1;
    const int tmax = (surf->stextents[1] / surf->lightmap_scale) + 1;

    /* Allocatate attached-to-surface cache for fast point lighting lookups */
    byte* l = surf->lightmap = Mem_PoolAllocTypeN(byte, smax * tmax * LIGHTMAP_SAMPLE_SIZE, vid_lightPool);

    for (int t = 0; t < tmax; t++) {
        byte* lmPtr = sout, *dmPtr = dout;
        for (int s = 0; s < smax; s++) {
            /* fill lightmap samples */
            l[0] = lmPtr[0] = 255;
            l[1] = lmPtr[1] = 255;
            l[2] = lmPtr[2] = 255;
            /* fill deluxemap samples */
            dmPtr[0] = 127;
            dmPtr[1] = 127;
            dmPtr[2] = 255;
            /* advance pointers */
            lmPtr += LIGHTMAP_SAMPLE_SIZE;
            dmPtr += DELUXEMAP_SAMPLE_SIZE;
            l += LIGHTMAP_SAMPLE_SIZE;
        }
        sout += stride * LIGHTMAP_SAMPLE_SIZE;
        dout += stride * DELUXEMAP_SAMPLE_SIZE;
    }

    Vector4Set(surf->lightColor, 1.0, 1.0, 1.0, 1.0);
}

static void R_BuildLightmap (mBspSurface_t* surf, byte* sout, byte* dout, int stride)
{
    const int smax = (surf->stextents[0] / surf->lightmap_scale) + 1;
    const int tmax = (surf->stextents[1] / surf->lightmap_scale) + 1;
    const int area = smax * tmax;

    int color[3] = {0, 0, 0};
    byte* src = surf->samples;

    /* Allocatate attached-to-surface cache for fast point lighting lookups and keep the pointer to fill it  a bit later */
    byte* l = surf->lightmap = Mem_PoolAllocTypeN(byte, area * LIGHTMAP_SAMPLE_SIZE, vid_lightPool);

    for (int t = 0; t < tmax; t++) {
        byte* lmPtr = sout, *dmPtr = dout;
        for (int s = 0; s < smax; s++) {
            /* process lightmap samples and accumulate the average color */
            color[0] += l[0] = lmPtr[0] = src[0];
            color[1] += l[1] = lmPtr[1] = src[1];
            color[2] += l[2] = lmPtr[2] = src[2];
            /* process deluxemap samples */
            dmPtr[0] = src[3];
            dmPtr[1] = src[4];
            dmPtr[2] = src[5];
            /* advance pointers */
            lmPtr += LIGHTMAP_SAMPLE_SIZE;
            dmPtr += DELUXEMAP_SAMPLE_SIZE;
            l += LIGHTMAP_SAMPLE_SIZE;
            src += 6;
        }
        sout += stride * LIGHTMAP_SAMPLE_SIZE;
        dout += stride * DELUXEMAP_SAMPLE_SIZE;
    }

    /* store average lightmap color and surface alpha */
    surf->lightColor[0] = color[0] / (255.0 * area);
    surf->lightColor[1] = color[1] / (255.0 * area);
    surf->lightColor[2] = color[2] / (255.0 * area);

    if (surf->texinfo->flags & (SURF_BLEND33 | SURF_ALPHATEST))
        surf->lightColor[3] = 0.25;
    else if (surf->texinfo->flags & SURF_BLEND66)
        surf->lightColor[3] = 0.50;
    else
        surf->lightColor[3] = 1.0;
}

void R_CreateSurfaceLightmap (mBspSurface_t* surf)
{
    int smax, tmax;
    byte* samples, *directions;

    if (!(surf->flags & MSURF_LIGHTMAP))
        return;

    smax = (surf->stextents[0] / surf->lightmap_scale) + 1;
    tmax = (surf->stextents[1] / surf->lightmap_scale) + 1;

    if (!R_AllocLightmapBlock(smax, tmax, &surf->light_s, &surf->light_t)) {
        /* upload the last page */
        R_UploadLightmapPage();
        if (!R_AllocLightmapBlock(smax, tmax, &surf->light_s, &surf->light_t))
            Com_Error(ERR_DROP, "R_CreateSurfaceLightmap: Consecutive calls to R_AllocLightmapBlock(%d,%d) failed (lightmap_scale: %i, stextents: %f %f)\n",
                    smax, tmax, surf->lightmap_scale, surf->stextents[0], surf->stextents[1]);
    }

    surf->lightmap_texnum = r_lightmaps.lightmap_texnums[r_lightmaps.lightmap_count];
    surf->deluxemap_texnum = r_lightmaps.deluxemap_texnums[r_lightmaps.deluxemap_count];

    samples = r_lightmaps.sample_buffer;
    samples += (surf->light_t*  r_lightmaps.size + surf->light_s) * LIGHTMAP_SAMPLE_SIZE;

    directions = r_lightmaps.direction_buffer;
    directions += (surf->light_t*  r_lightmaps.size + surf->light_s) * DELUXEMAP_SAMPLE_SIZE;

    if (!surf->samples)  /* make it fullbright */
        R_BuildDefaultLightmap(surf, samples, directions, r_lightmaps.size);
    else  /* or light it properly */
        R_BuildLightmap(surf, samples, directions, r_lightmaps.size);
}

static void R_DisposeLightmaps (void)
{
    if (r_lightmaps.lightmap_count) {
        glDeleteTextures(r_lightmaps.lightmap_count, r_lightmaps.lightmap_texnums);
        r_lightmaps.lightmap_count = 0;
    }
    if (r_lightmaps.deluxemap_count) {
        glDeleteTextures(r_lightmaps.deluxemap_count, r_lightmaps.deluxemap_texnums);
        r_lightmaps.deluxemap_count = 0;
    }
}

void R_BeginBuildingLightmaps (void)
{
    static bool gotAllocatedLightmaps = false;

    if (gotAllocatedLightmaps)
        R_DisposeLightmaps();

    gotAllocatedLightmaps = true;

    /* users can tune lightmap size for their card */
    r_lightmaps.size = r_maxlightmap->integer;

    r_lightmaps.allocated        = Mem_PoolAllocTypeN(unsigned, r_lightmaps.size, vid_lightPool);
    r_lightmaps.sample_buffer    = Mem_PoolAllocTypeN(byte, r_lightmaps.size * r_lightmaps.size * LIGHTMAP_SAMPLE_SIZE, vid_lightPool);
    r_lightmaps.direction_buffer = Mem_PoolAllocTypeN(byte, r_lightmaps.size * r_lightmaps.size * DELUXEMAP_SAMPLE_SIZE, vid_lightPool);

    r_lightmaps.lightmap_count = 0;
    r_lightmaps.deluxemap_count = 0;
    r_lightmaps.incomplete_atlas = false;
}

void R_EndBuildingLightmaps (void)
{
    /* upload the pending lightmap page */
    R_UploadLightmapPage();
    Mem_Free(r_lightmaps.allocated);
    Mem_Free(r_lightmaps.sample_buffer);
    Mem_Free(r_lightmaps.direction_buffer);
    r_lightmaps.allocated = nullptr;
    r_lightmaps.sample_buffer = nullptr;
    r_lightmaps.direction_buffer = nullptr;
}


void R_Trace (const Line& trLine, float size, int contentmask)
{
    r_locals.tracenum++;

    if (r_locals.tracenum > 0xffff)  /* avoid overflows */
        r_locals.tracenum = 0;

    AABB box;
    box.expand(size);

    refdef.trace = CM_CompleteBoxTrace(refdef.mapTiles, trLine, box, TRACE_ALL_LEVELS, contentmask, 0);
    refdef.traceEntity = nullptr;

    float frac = refdef.trace.fraction;

    /* check bsp models */
    for (int i = 0; i < refdef.numEntities; i++) {
        entity_t* ent = R_GetEntity(i);
        const model_t* m = ent->model;

        if (!m || m->type != mod_bsp_submodel)
            continue;

        trace_t tr = CM_TransformedBoxTrace(refdef.mapTiles->mapTiles[m->bsp.maptile], trLine, box, m->bsp.firstnode,
                contentmask, 0, ent->origin, ent->angles);

        if (tr.fraction < frac) {
            refdef.trace = tr;
            refdef.traceEntity = ent;

            frac = tr.fraction;
        }
    }

    assert(refdef.trace.mapTile >= 0);
    assert(refdef.trace.mapTile < r_numMapTiles);
}