r_entity.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_matrix.h"
#include "r_entity.h"
#include "r_mesh.h"
#include "r_mesh_anim.h"
#include "r_draw.h"
#include "r_matrix.h"

#define MAX_ENTITIES    2048*2

static entity_t r_entities[MAX_ENTITIES];

entity_t* r_opaque_mesh_entities;
entity_t* r_blend_mesh_entities;
entity_t* r_null_entities;
entity_t* r_special_entities;

void R_EntitySetOrigin (entity_t* ent, const vec3_t origin)
{
    VectorCopy(origin, ent->origin);
}

void R_EntityAddToOrigin (entity_t* ent, const vec3_t offset)
{
    VectorAdd(ent->origin, offset, ent->origin);
}

static void R_DrawBox (const entity_t* e)
{
    const vec4_t color = {e->color[0], e->color[1], e->color[2], e->alpha};

    if (e->texture) {
        R_Color(color);
        R_BindTexture(e->texture->texnum);
        if (VectorNotEmpty(e->eBox.mins) && VectorNotEmpty(e->eBox.maxs)) {
            R_DrawTexturedBox(e->eBox.mins, e->eBox.maxs);
        } else {
            R_DrawTexturedBox(e->oldorigin, e->origin);
        }
        R_Color(nullptr);
        return;
    }

    glDisable(GL_TEXTURE_2D);

    R_Color(color);

    if (VectorNotEmpty(e->eBox.mins) && VectorNotEmpty(e->eBox.maxs)) {
        R_DrawBoundingBox(e->eBox);
    } else {
        vec3_t points[] = { { e->oldorigin[0], e->oldorigin[1], e->oldorigin[2] }, { e->oldorigin[0], e->origin[1],
                e->oldorigin[2] }, { e->origin[0], e->origin[1], e->oldorigin[2] }, { e->origin[0], e->oldorigin[1],
                e->oldorigin[2] } };

        glLineWidth(2.0f);
        R_BindArray(GL_VERTEX_ARRAY, GL_FLOAT, points);

        glDrawArrays(GL_LINE_LOOP, 0, 4);
        refdef.batchCount++;
        points[0][2] = e->origin[2];
        points[1][2] = e->origin[2];
        points[2][2] = e->origin[2];
        points[3][2] = e->origin[2];
        glDrawArrays(GL_LINE_LOOP, 0, 4);
        refdef.batchCount++;
        points[0][2] = e->oldorigin[2];
        points[1][1] = e->oldorigin[1];
        points[2][2] = e->oldorigin[2];
        points[3][1] = e->origin[1];
        glDrawArrays(GL_LINES, 0, 4);
        refdef.batchCount++;
        points[0][0] = e->origin[0];
        points[1][0] = e->origin[0];
        points[2][0] = e->oldorigin[0];
        points[3][0] = e->oldorigin[0];
        glDrawArrays(GL_LINES, 0, 4);
        refdef.batchCount++;
        R_BindDefaultArray(GL_VERTEX_ARRAY);
    }
    glEnable(GL_TEXTURE_2D);

    R_Color(nullptr);
}


static void R_DrawFloor (const entity_t* e)
{
    GLint oldDepthFunc;
    glGetIntegerv(GL_DEPTH_FUNC, &oldDepthFunc);

    image_t* cellIndicator = R_FindImage("pics/sfx/cell", it_pic);
    const float dx = PLAYER_WIDTH * 2;
    const vec4_t color = {e->color[0], e->color[1], e->color[2], e->alpha};
    const float size = 4.0;
    const vec2_t texcoords[] = { { 0.0, 1.0 }, { 1.0, 1.0 }, { 1.0, 0.0 }, { 0.0, 0.0 } };
    const vec3_t points[] = { { e->origin[0] - size, e->origin[1] + dx + size, e->origin[2] }, { e->origin[0] + dx
            + size, e->origin[1] + dx + size, e->origin[2] }, { e->origin[0] + dx + size, e->origin[1] - size,
            e->origin[2] }, { e->origin[0] - size, e->origin[1] - size, e->origin[2] } };

    /* Draw it twice, with and without depth check, so it will still be visible if obscured by a wall */
    R_Color(color);
    R_BindTexture(cellIndicator->texnum);

    /* circle points */
    R_BindArray(GL_TEXTURE_COORD_ARRAY, GL_FLOAT, texcoords);
    R_BindArray(GL_VERTEX_ARRAY, GL_FLOAT, points);
    glDrawArrays(GL_TRIANGLE_FAN, 0, 4);

    glDepthFunc(GL_GREATER);
    glColor4f(color[0], color[1], color[2], color[3] * 0.25f);

    glDrawArrays(GL_TRIANGLE_FAN, 0, 4);

    glDepthFunc(oldDepthFunc);

    R_BindDefaultArray(GL_TEXTURE_COORD_ARRAY);
    R_BindDefaultArray(GL_VERTEX_ARRAY);

    refdef.batchCount += 2;

    R_Color(nullptr);
}

static void R_DrawArrow (const entity_t* e)
{
    const vec3_t upper = { e->origin[0] + 2, e->origin[1], e->origin[2] };
    const vec3_t mid = { e->origin[0], e->origin[1] + 2, e->origin[2] };
    const vec3_t lower = { e->origin[0], e->origin[1], e->origin[2] + 2 };
    const vec4_t color = { e->color[0], e->color[1], e->color[2], e->alpha };
    const vec3_t points[] = { { e->oldorigin[0], e->oldorigin[1], e->oldorigin[2] }, { upper[0], upper[1], upper[2] },
            { mid[0], mid[1], mid[2] }, { lower[0], lower[1], lower[2] } };

    R_Color(color);

    glDisable(GL_TEXTURE_2D);
    glEnable(GL_LINE_SMOOTH);

    R_BindArray(GL_VERTEX_ARRAY, GL_FLOAT, points);
    glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
    R_BindDefaultArray(GL_VERTEX_ARRAY);

    refdef.batchCount++;

    glDisable(GL_LINE_SMOOTH);
    glEnable(GL_TEXTURE_2D);

    R_Color(nullptr);
}

static image_t* selectedActorIndicator;
static image_t* actorIndicator;

void R_DrawEntityEffects (void)
{
    const int mask = r_stencilshadows->integer ? RF_BLOOD : (RF_SHADOW | RF_BLOOD);
    GLint oldDepthFunc;
    glGetIntegerv(GL_DEPTH_FUNC, &oldDepthFunc);

    R_EnableBlend(true);

    if (actorIndicator == nullptr) {
        selectedActorIndicator = R_FindImage("pics/sfx/actor_selected", it_effect);
        actorIndicator = R_FindImage("pics/sfx/actor", it_effect);
    }

    for (int i = 0; i < refdef.numEntities; i++) {
        const entity_t* e = &r_entities[i];

        if (e->flags <= RF_BOX)
            continue;

        glPushMatrix();
        glMultMatrixf(e->transform.matrix);

        if (e->flags & mask) {
            const vec3_t points[] = { { -18.0, 14.0, -28.5 }, { 10.0, 14.0, -28.5 }, { 10.0, -14.0, -28.5 }, { -18.0,
                    -14.0, -28.5 } };
            const vec2_t texcoords[] = { { 0.0, 1.0 }, { 1.0, 1.0 }, { 1.0, 0.0 }, { 0.0, 0.0 } };

            if (e->flags & RF_SHADOW) {
                R_BindTexture(shadow->texnum);
            } else {
                assert(e->texture);
                R_BindTexture(e->texture->texnum);
            }

            R_BindArray(GL_TEXTURE_COORD_ARRAY, GL_FLOAT, texcoords);
            R_BindArray(GL_VERTEX_ARRAY, GL_FLOAT, points);
            glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
            R_BindDefaultArray(GL_TEXTURE_COORD_ARRAY);
            R_BindDefaultArray(GL_VERTEX_ARRAY);

            refdef.batchCount++;
        }

        if (e->flags & RF_ACTOR) {
            const float size = 15.0;
            int texnum;
            /* draw the circles for team-members and allied troops */
            vec4_t color = {1, 1, 1, 1};
            const vec3_t points[] = { { -size, size, -SELECTION_DELTA }, { size, size, -SELECTION_DELTA }, { size, -size,
                    -SELECTION_DELTA }, { -size, -size, -SELECTION_DELTA } };
            const vec2_t texcoords[] = { { 0.0, 1.0 }, { 1.0, 1.0 }, { 1.0, 0.0 }, { 0.0, 0.0 } };

            if (e->flags & RF_SELECTED)
                Vector4Set(color, 0, 1, 0, 0.5);
            else if (e->flags & RF_MEMBER)
                Vector4Set(color, 0, 0.8, 0, 0.5);
            else if (e->flags & RF_ALLIED)
                Vector4Set(color, 0, 1, 0.5, 0.5);
            else if (e->flags & RF_NEUTRAL)
                Vector4Set(color, 1, 1, 0, 0.5);
            else if (e->flags & RF_OPPONENT)
                Vector4Set(color, 1, 0, 0, 0.5);
            else
                Vector4Set(color, 0.3, 0.3, 0.3, 0.5);

            if (e->flags & RF_SELECTED)
                texnum = selectedActorIndicator->texnum;
            else
                texnum = actorIndicator->texnum;

            R_BindTexture(texnum);
            R_Color(color);
            R_EnableDrawAsGlow(true);

            /* circle points */
            R_BindArray(GL_TEXTURE_COORD_ARRAY, GL_FLOAT, texcoords);
            R_BindArray(GL_VERTEX_ARRAY, GL_FLOAT, points);

            glDrawArrays(GL_TRIANGLE_FAN, 0, 4);

            refdef.batchCount++;

            /* add transparency when something is in front of the circle */
            color[3] *= 0.25;
            R_Color(color);
            glDepthFunc(GL_GREATER);
            glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
            glDepthFunc(oldDepthFunc);

            refdef.batchCount++;

            R_BindDefaultArray(GL_TEXTURE_COORD_ARRAY);
            R_BindDefaultArray(GL_VERTEX_ARRAY);

            R_Color(nullptr);
            R_EnableDrawAsGlow(false);
        }
        glPopMatrix();
    }
}

void R_DrawMeshEntities (entity_t* ents)
{
    entity_t* e;

    e = ents;

    while (e) {
        switch (e->model->type) {
        case mod_alias_md2:
        case mod_alias_md3:
        case mod_obj:
            R_DrawAliasModel(e);
            break;
        default:
            break;
        }
        e = e->next;
    }
}

void R_DrawOpaqueMeshEntities (entity_t* ents)
{
    if (!ents)
        return;

    if (!(refdef.rendererFlags & RDF_NOWORLDMODEL)) {
        R_EnableLighting(r_state.model_program, true);
    }
    R_DrawMeshEntities(ents);
    if (!(refdef.rendererFlags & RDF_NOWORLDMODEL)) {
        R_EnableLighting(nullptr, false);
        R_EnableGlowMap(nullptr);
    }
}

static entity_t* R_MergeSortMerge (entity_t* a, entity_t* b)
{
    entity_t* c;

    if (a == nullptr)
        return b;

    if (b == nullptr)
        return a;

    if (a->distanceFromViewOrigin > b->distanceFromViewOrigin) {
        c = a;
        c->next = R_MergeSortMerge(a->next, b);
    } else {
        c = b;
        c->next = R_MergeSortMerge(a, b->next);
    }

    return c;
}

static entity_t* R_MergeSortEntList (entity_t* c)
{
    entity_t* a, *b;

    /* list containing one or no entities is already sorted by definition */
    if (c == nullptr || c->next == nullptr)
        return c;

    /* two element or longer lists are bisected */
    a = c;
    b = c->next;
    while (b != nullptr && b->next != nullptr) {
        c = c->next;
        b = b->next->next;
    }
    b = c->next;
    c->next = nullptr;

    /* these halves are sorted recursively, and merged into one sorted list */
    return R_MergeSortMerge(R_MergeSortEntList(a), R_MergeSortEntList(b));
}

void R_DrawBlendMeshEntities (entity_t* ents)
{
    if (!ents)
        return;

    if (!(refdef.rendererFlags & RDF_NOWORLDMODEL)) {
        R_EnableLighting(r_state.model_program, true);
    }
    R_EnableBlend(true);

    R_DrawMeshEntities(R_MergeSortEntList(ents));

    R_EnableBlend(false);
    if (!(refdef.rendererFlags & RDF_NOWORLDMODEL)) {
        R_EnableLighting(nullptr, false);
        R_EnableGlowMap(nullptr);
    }
}

static void R_DrawNullModel (const entity_t* e)
{
    int i;
    vec3_t points[6];

    R_EnableTexture(&texunit_diffuse, false);

    glPushMatrix();
    glMultMatrixf(e->transform.matrix);

    R_BindArray(GL_VERTEX_ARRAY, GL_FLOAT, points);

    VectorSet(points[0], 0, 0, -16);
    for (i = 0; i <= 4; i++) {
        points[i + 1][0] = 16 * cos(i * (M_PI / 2));
        points[i + 1][1] = 16 * sin(i * (M_PI / 2));
        points[i + 1][2] = 0;
    }
    glDrawArrays(GL_TRIANGLE_FAN, 0, 6);

    refdef.batchCount++;

    VectorSet(points[0], 0, 0, 16);
    for (i = 4; i >= 0; i--) {
        points[i + 1][0] = 16 * cos(i * (M_PI / 2));
        points[i + 1][1] = 16 * sin(i * (M_PI / 2));
        points[i + 1][2] = 0;
    }
    glDrawArrays(GL_TRIANGLE_FAN, 0, 6);

    refdef.batchCount++;

    R_BindDefaultArray(GL_VERTEX_ARRAY);

    glPopMatrix();

    R_EnableTexture(&texunit_diffuse, true);
}

void R_DrawSpecialEntities (const entity_t* ents)
{
    const entity_t* e;

    if (!ents)
        return;

    e = ents;

    R_EnableBlend(true);
    R_EnableDrawAsGlow(true);

    while (e) {
        if (e->flags & RF_BOX) {
            R_DrawBox(e);
        } else if (e->flags & RF_PATH) {
            R_DrawFloor(e);
        } else if (e->flags & RF_ARROW) {
            R_DrawArrow(e);
        }
        e = e->next;
    }

    R_EnableDrawAsGlow(false);
    R_EnableBlend(false);
}

void R_DrawNullEntities (const entity_t* ents)
{
    const entity_t* e;

    if (!ents)
        return;

    e = ents;

    while (e) {
        R_DrawNullModel(e);
        e = e->next;
    }
}

void R_TransformForEntity (const entity_t* e, const vec3_t in, vec3_t out)
{
    matrix4x4_t tmp, mat;

    Matrix4x4_CreateFromQuakeEntity(&tmp, e->origin[0], e->origin[1], e->origin[2], e->angles[0], e->angles[1],
            e->angles[2], e->getScaleX());

    Matrix4x4_Invert_Simple(&mat, &tmp);
    Matrix4x4_Transform(&mat, in, out);
}

static float* R_CalcTransform (entity_t* e)
{
    transform_t* t;
    float* mp;
    float mt[16], mc[16];

    /* check if this entity is already transformed */
    t = &e->transform;

    if (t->processing)
        Com_Error(ERR_DROP, "Ring in entity transformations!");

    if (t->done)
        return t->matrix;

    /* process this matrix */
    t->processing = true;
    mp = nullptr;

    /* do parent object transformations first */
    if (e->tagent) {
        /* tag transformation */
        const model_t* model = e->tagent->model;
        const mAliasTagOrientation_t* current = nullptr;
        const mAliasTagOrientation_t* old = nullptr;
        const animState_t* as = &e->tagent->as;

        R_GetTags(model, e->tagname, as->frame, as->oldframe, &current, &old);
        if (current != nullptr && old != nullptr) {
            float interpolated[16];

            /* parent transformation */
            mp = R_CalcTransform(e->tagent);

            /* do interpolation */
            R_InterpolateTransform(as->backlerp, model->alias.num_frames, current, old, interpolated);

            /* transform */
            GLMatrixMultiply(mp, interpolated, mt);
            mp = mt;
        }
    }

    GLMatrixAssemble(e->origin, e->angles, mc);

    /* combine transformations */
    if (mp)
        GLMatrixMultiply(mp, mc, t->matrix);
    else
        memcpy(t->matrix, mc, sizeof(float) * 16);

    /* matrix elements 12..14 contain (forward) translation vector, which is also the origin of model after transform */
    e->distanceFromViewOrigin = VectorDist(&t->matrix[12], refdef.viewOrigin);

    /* we're done */
    t->done = true;
    t->processing = false;

    return t->matrix;
}

static bool R_CullEntity (entity_t* e)
{
    if (refdef.rendererFlags & RDF_NOWORLDMODEL)
        return false;

    if (r_nocull->integer)
        return false;

    if (!e->model)  /* don't bother culling null model ents */
        return false;

    if (e->model->type == mod_bsp_submodel)
        return R_CullBspModel(e);
    else
        return R_CullMeshModel(e);
}

void R_GetEntityLists (void)
{
    int i;
    entity_t** chain;

    if (!r_drawentities->integer)
        return;

    r_opaque_mesh_entities = r_special_entities =
        r_blend_mesh_entities = r_null_entities = nullptr;

    for (i = 0; i < refdef.numEntities; i++) {
        entity_t* e = &r_entities[i];

        /* frustum cull check */
        if (R_CullEntity(e))
            continue;

        R_CalcTransform(e);

        if (!e->model) {
            if ((e->flags & RF_BOX) || (e->flags & RF_PATH) || (e->flags & RF_ARROW))
                chain = &r_special_entities;
            else
                chain = &r_null_entities;
        } else {
            const image_t* skin;
            switch (e->model->type) {
            case mod_bsp_submodel:
                R_AddBspRRef(&(e->model->bsp), e->origin, e->angles, true);
                continue;
            case mod_alias_md2:
            case mod_alias_md3:
            case mod_obj:
                skin = R_AliasModelState(e->model, &e->as.mesh, &e->as.frame, &e->as.oldframe, &e->skinnum);
                if (skin == nullptr || skin->texnum == 0)
                    Com_Error(ERR_DROP, "Model '%s' has no skin assigned", e->model->name);
                if (skin->has_alpha || (e->flags & RF_TRANSLUCENT))
                    chain = &r_blend_mesh_entities;
                else
                    chain = &r_opaque_mesh_entities;
                break;
            default:
                if (e->model->loaded)
                    Com_Error(ERR_DROP, "Unknown model type in R_GetEntityLists entity chain: %i (%s)",
                            e->model->type, e->model->name);
                return;
            }
        }
        e->next = *chain;
        *chain = e;
    }
}

entity_t* R_GetFreeEntity (void)
{
    if (refdef.numEntities >= MAX_ENTITIES)
        Com_Error(ERR_DROP, "R_GetFreeEntity: MAX_ENTITIES exceeded");
    return &r_entities[refdef.numEntities];
}

entity_t* R_GetEntity (int id)
{
    if (id < 0 || id >= refdef.numEntities)
        return nullptr;
    return &r_entities[id];
}

int R_AddEntity (const entity_t* ent)
{
    if (refdef.numEntities >= MAX_ENTITIES)
        Com_Error(ERR_DROP, "R_AddEntity: MAX_ENTITIES exceeded");

    /* don't add the bsp tiles from random map assemblies */
    if (ent->model && ent->model->type == mod_bsp)
        return -1;

    r_entities[refdef.numEntities] = *ent;

    refdef.numEntities++;

    return refdef.numEntities - 1;
}