r_bsp.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_lightmap.h"
#include "r_material.h"
#include "r_light.h"
#include "r_draw.h"

/*
=============================================================
BRUSH MODELS
=============================================================
*/

#define BACKFACE_EPSILON 0.01

#define MAX_BSPS_TO_RENDER 1024

typedef struct bspRenderRef_s {
    const mBspModel_t* bsp;
    vec3_t origin;
    vec3_t angles;
} bspRenderRef_t;

static bspRenderRef_t bspRRefs[MAX_BSPS_TO_RENDER];
static int numBspRRefs;

static int R_CullBox (const vec3_t mins, const vec3_t maxs)
{
    int i;
    int cullState = 0;

    if (r_nocull->integer)
        return PSIDE_FRONT;

    for (i = lengthof(r_locals.frustum) - 1; i >= 0; i--) {
        int planeSide = TR_BoxOnPlaneSide(mins, maxs, &r_locals.frustum[i]);
        if (planeSide == PSIDE_BACK)
            return PSIDE_BACK; /* completely culled away */
        cullState |= planeSide;
    }

    return cullState;
}


bool R_CullSphere (const vec3_t centre, const float radius, const unsigned int clipflags)
{
    unsigned int i;
    unsigned int bit;
    const cBspPlane_t* p;

    if (r_nocull->integer)
        return false;

    for (i = lengthof(r_locals.frustum), bit = 1, p = r_locals.frustum; i > 0; i--, bit <<= 1, p++) {
        if (!(clipflags & bit))
            continue;
        if (DotProduct(centre, p->normal) - p->dist <= -radius)
            return true;
    }

    return false;
}

bool R_CullBspModel (const entity_t* e)
{
    /* no surfaces */
    if (!e->model->bsp.nummodelsurfaces)
        return true;

    AABB modBox = e->model->modBox;
    if (e->isOriginBrushModel) {
        modBox.expand(e->model->radius);
    } else {
        modBox.shift(e->origin);
    }

    return R_CullBox(modBox.getMins(), modBox.getMaxs()) == PSIDE_BACK;
}

/*
=============================================================
WORLD MODEL
=============================================================
*/

void R_DrawBspNormals (int tile)
{
    const vec4_t color = {1.0, 0.0, 0.0, 1.0};

    if (!r_shownormals->integer)
        return;

    R_EnableTexture(&texunit_diffuse, false);

    R_ResetArrayState();  /* default arrays */

    R_Color(color);

    int k = 0;
    const mBspModel_t* bsp = &r_mapTiles[tile]->bsp;
    const mBspSurface_t* surf = bsp->surfaces;
    for (int i = 0; i < bsp->numsurfaces; i++, surf++) {
        if (surf->frame != r_locals.frame)
            continue; /* not visible */

        if (surf->texinfo->flags & SURF_WARP)
            continue;  /* don't care */

        if (r_shownormals->integer > 1 && !(surf->texinfo->flags & SURF_PHONG))
            continue;  /* don't care */

        /* avoid overflows, draw in batches */
        if (k > r_state.array_size - 512) {
            glDrawArrays(GL_LINES, 0, k / 3);
            k = 0;

            refdef.batchCount++;
        }

        for (int j = 0; j < surf->numedges; j++) {
            vec3_t end;
            const GLfloat* vertex = &bsp->verts[(surf->index + j) * 3];
            const GLfloat* normal = &bsp->normals[(surf->index + j) * 3];

            VectorMA(vertex, 12.0, normal, end);

            memcpy(&r_state.vertex_array_3d[k], vertex, sizeof(vec3_t));
            memcpy(&r_state.vertex_array_3d[k + 3], end, sizeof(vec3_t));
            k += sizeof(vec3_t) / sizeof(vec_t) * 2;
            R_ReallocateStateArrays(k);
        }
    }

    glDrawArrays(GL_LINES, 0, k / 3);

    refdef.batchCount++;

    R_EnableTexture(&texunit_diffuse, true);

    R_Color(nullptr);
}

static void R_RecursiveVisibleWorldNode (const mBspNode_t* node, int tile)
{
    /* if a leaf node, nothing to mark */
    if (node->contents > CONTENTS_NODE)
        return;

    /* pathfinding nodes are invalid here */
    assert(node->plane);

    mBspSurface_t* surf = r_mapTiles[tile]->bsp.surfaces + node->firstsurface;
    for (int i = 0; i < node->numsurfaces; i++, surf++)
        surf->frame = r_locals.frame;

    /* recurse down the children */
    R_RecursiveVisibleWorldNode(node->children[0], tile);
    R_RecursiveVisibleWorldNode(node->children[1], tile);
}

static void R_RecursiveWorldNode (const mBspNode_t* node, int tile)
{
    /* if a leaf node, nothing to mark */
    if (node->contents > CONTENTS_NODE)
        return;

    int cullState = R_CullBox(node->minmaxs.mins, node->minmaxs.maxs);

    if (cullState == PSIDE_BACK)
        return;                 /* culled out */

    /* pathfinding nodes are invalid here */
    assert(node->plane);

    mBspSurface_t* surf = r_mapTiles[tile]->bsp.surfaces + node->firstsurface;
    for (int i = 0; i < node->numsurfaces; i++, surf++)
        surf->frame = r_locals.frame;

    /* recurse down the children */
    if (cullState == PSIDE_FRONT) {
        /* completely inside the frustum - no need to do any further checks */
        R_RecursiveVisibleWorldNode(node->children[0], tile);
        R_RecursiveVisibleWorldNode(node->children[1], tile);
    } else {
        /* partially clipped by frustum - recurse to do finer checks */
        R_RecursiveWorldNode(node->children[0], tile);
        R_RecursiveWorldNode(node->children[1], tile);
    }
}

static void R_RecurseWorld (const mBspNode_t* node, int tile)
{
    /* skip special pathfinding nodes */
    if (node->contents == CONTENTS_PATHFINDING_NODE) {
        R_RecurseWorld(node->children[0], tile);
        R_RecurseWorld(node->children[1], tile);
    } else {
        R_RecursiveWorldNode(node, tile);
    }
}


void R_GetLevelSurfaceLists (void)
{
    if (!r_drawworld->integer)
        return;

    const int mask = 1 << refdef.worldlevel;

    for (int tile = 0; tile < r_numMapTiles; tile++) {
        /* don't draw weaponclip, actorclip and stepon */
        for (int i = 0; i <= LEVEL_LASTVISIBLE; i++) {
            /* check the worldlevel flags */
            if (i && !(i & mask))
                continue;

            mBspModel_t* bspModel = &r_mapTiles[tile]->bsp;
            mBspHeader_t* header = &bspModel->submodels[i];
            if (!header->numfaces)
                continue;

            R_RecurseWorld(bspModel->nodes + header->headnode, tile);
        }
    }
}

/*
=============================================================
Deferred rendering
=============================================================
*/

void R_ClearBspRRefs (void)
{
    numBspRRefs = 0;
}

void R_AddBspRRef (const mBspModel_t* model, const vec3_t origin, const vec3_t angles, const bool forceVisibility)
{
    if (numBspRRefs >= MAX_BSPS_TO_RENDER) {
        Com_Printf("Cannot add BSP model rendering reference: MAX_BSPS_TO_RENDER exceeded\n");
        return;
    }

    if (!model) {
        Com_Printf("R_AddBspRRef: null model!\n");
        return;
    }

    bspRenderRef_t* bspRR = &bspRRefs[numBspRRefs++];
    bspRR->bsp = model;
    VectorCopy(origin, bspRR->origin);
    VectorCopy(angles, bspRR->angles);

    if (!forceVisibility)
        return;

    mBspSurface_t* surf = &model->surfaces[model->firstmodelsurface];
    for (int i = 0; i < model->nummodelsurfaces; i++, surf++) {
        /* visible flag for rendering */
        surf->frame = r_locals.frame;
    }
}

typedef void (*drawSurfaceFunc)(const mBspSurfaces_t* surfs, glElementIndex_t* indexPtr);

static void R_RenderBspRRefs (drawSurfaceFunc drawFunc, surfaceArrayType_t surfType)
{
    glEnable(GL_CULL_FACE);
    glCullFace(GL_FRONT); /* our triangles are backwards to what OpenGL expects, so tell it to render only back faces */

    for (int i = 0; i < numBspRRefs; i++) {
        const bspRenderRef_t* const bspRR = &bspRRefs[i];
        const mBspModel_t* const bsp = bspRR->bsp;
        const mBspModel_t* const tile = &r_mapTiles[bsp->maptile]->bsp; /* This is required to find the tile (world) bsp model to which arrays belong (submodels do not own arrays, but use world model ones) */
        glElementIndex_t* indexPtr;

        if (!bsp->sorted_surfaces[surfType]->count)
            continue;

        R_SetArrayState(tile);

        /* Vertex buffers are nullptr-based, arrays are not */
        if (qglBindBuffer && r_vertexbuffers->integer)
            indexPtr = nullptr;
        else
            indexPtr = tile->indexes;

        glPushMatrix();

        glTranslatef(bspRR->origin[0], bspRR->origin[1], bspRR->origin[2]);
        glRotatef(bspRR->angles[YAW], 0, 0, 1);
        glRotatef(bspRR->angles[PITCH], 0, 1, 0);
        glRotatef(bspRR->angles[ROLL], 1, 0, 0);

        drawFunc(bsp->sorted_surfaces[surfType], indexPtr);

#if 0
        /* show model bounding box */
        if (r_showbox->integer) {
            const model_t* model = bspRR->bsp;
            R_DrawBoundingBox(model->mins, model->maxs);
        }
#endif

        glPopMatrix();
    }

    /* and restore array pointers */
    R_ResetArrayState();

    glCullFace(GL_BACK);
    glDisable(GL_CULL_FACE);
}

void R_RenderOpaqueBspRRefs (void)
{
    R_EnableTexture(&texunit_lightmap, true);
    R_EnableLighting(r_state.world_program, true);
    R_EnableWorldLights();

    R_RenderBspRRefs(R_DrawSurfaces, S_OPAQUE);

    R_EnableLighting(nullptr, false);
    R_EnableGlowMap(nullptr);
    R_EnableTexture(&texunit_lightmap, false);
}

void R_RenderOpaqueWarpBspRRefs (void)
{
    R_EnableWarp(r_state.warp_program, true);

    R_RenderBspRRefs(R_DrawSurfaces, S_OPAQUE_WARP);

    R_EnableWarp(nullptr, false);
    R_EnableGlowMap(nullptr);
}

void R_RenderAlphaTestBspRRefs (void)
{
    R_EnableAlphaTest(true);
    R_EnableLighting(r_state.world_program, true);
    R_EnableWorldLights();

    R_RenderBspRRefs(R_DrawSurfaces, S_ALPHA_TEST);

    R_EnableLighting(nullptr, false);
    R_EnableGlowMap(nullptr);
    R_EnableAlphaTest(false);
}

void R_RenderMaterialBspRRefs (void)
{
    R_RenderBspRRefs(R_DrawMaterialSurfaces, S_MATERIAL);
}

void R_RenderFlareBspRRefs (void)
{
    R_RenderBspRRefs(R_DrawFlareSurfaces, S_FLARE);
}

void R_RenderBlendBspRRefs (void)
{
    assert(r_state.blend_enabled);
    R_EnableTexture(&texunit_lightmap, true);

    R_RenderBspRRefs(R_DrawSurfaces, S_BLEND);

    R_EnableTexture(&texunit_lightmap, false);
}

void R_RenderBlendWarpBspRRefs (void)
{
    assert(r_state.blend_enabled);
    R_EnableWarp(r_state.warp_program, true);

    R_RenderBspRRefs(R_DrawSurfaces, S_BLEND_WARP);

    R_EnableWarp(nullptr, false);
    R_EnableGlowMap(nullptr);
}