r_surface.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_light.h"
#include "r_error.h"
#include "r_draw.h"

void R_SetSurfaceBumpMappingParameters (const mBspSurface_t* surf, const image_t* normalMap, const image_t* specularMap)
{
    if (!r_state.lighting_enabled)
        return;

    if (!r_bumpmap->value)
        return;

    assert(surf);

    if (normalMap && (surf->flags & MSURF_LIGHTMAP)) {
        const image_t* image = surf->texinfo->image;
        R_BindDeluxemapTexture(surf->deluxemap_texnum);
        R_EnableBumpmap(normalMap);
        R_EnableSpecularMap(specularMap, true);
        R_UseMaterial(&image->material);
    } else {
        R_EnableBumpmap(nullptr);
        R_EnableSpecularMap(nullptr, false);
        R_UseMaterial(nullptr);
    }
}

static void R_SetSurfaceState (const mBspSurface_t* surf)
{
    image_t* image;

    if (r_state.blend_enabled) {  /* alpha blend */
        vec4_t color = {1.0, 1.0, 1.0, 1.0};
        switch (surf->texinfo->flags & (SURF_BLEND33 | SURF_BLEND66)) {
        case SURF_BLEND33:
            color[3] = 0.33;
            break;
        case SURF_BLEND66:
            color[3] = 0.66;
            break;
        }

        R_Color(color);
    }

    image = surf->texinfo->image;
    R_BindTexture(image->texnum);  /* texture */

    if (texunit_lightmap.enabled) {  /* lightmap */
        if (surf->flags & MSURF_LIGHTMAP)
            R_BindLightmapTexture(surf->lightmap_texnum);
    }

    R_SetSurfaceBumpMappingParameters(surf, image->normalmap, image->specularmap);

    R_EnableGlowMap(image->glowmap);

    R_CheckError();
}

void R_DrawSurfaces (const mBspSurfaces_t* surfs, glElementIndex_t* indexPtr)
{
    int numSurfaces = surfs->count;
    mBspSurface_t** surfPtrList = surfs->surfaces;
    const int frame = r_locals.frame;

    int lastLightMap = 0, lastDeluxeMap = 0;
    image_t* lastTexture = nullptr;
    uint32_t lastFlags = ~0;

    int batchStart = 0, batchSize = 0; /* in triangles */

    while (numSurfaces--) {
        const mBspSurface_t* surf = *surfPtrList++;
        const int numTriangles = surf->numTriangles;
        mBspTexInfo_t* texInfo;
        int texFlags;
        bool newBatch = false;

        if (surf->frame != frame)
            continue;
        if (numTriangles <= 0)
            continue;

        refdef.brushCount += numTriangles;

        if (batchStart + batchSize != surf->firstTriangle) {
            /* Cannot continue assembling the batch, draw it and start a new one*/
            if (batchSize > 0) {
                glDrawElements(GL_TRIANGLES, batchSize * 3, GL_ELEMENT_INDEX_TYPE, indexPtr + batchStart * 3);
                refdef.batchCount++;
            }
            batchStart = surf->firstTriangle;
            batchSize = 0;
            newBatch = true;
        }

        texInfo = surf->texinfo;
        texFlags = texInfo->flags & (SURF_BLEND33 | SURF_BLEND66); /* should match flags that affect R_SetSurfaceState behavior */
        if (texInfo->image != lastTexture || surf->lightmap_texnum != lastLightMap || surf->deluxemap_texnum != lastDeluxeMap || texFlags != lastFlags) {
            if (!newBatch) {
                /* changes in texturing require new batch */
                glDrawElements(GL_TRIANGLES, batchSize * 3, GL_ELEMENT_INDEX_TYPE, indexPtr + batchStart * 3);
                refdef.batchCount++;
                batchStart = surf->firstTriangle;
                batchSize = 0;
            }
            lastTexture = texInfo->image;
            lastLightMap = surf->lightmap_texnum;
            lastDeluxeMap = surf->deluxemap_texnum;
            lastFlags = texFlags;
            R_SetSurfaceState(surf);
        }

        batchSize += numTriangles;
    }

    /* finish uncomplete batch, if any */
    if (batchSize > 0) {
        glDrawElements(GL_TRIANGLES, batchSize * 3, GL_ELEMENT_INDEX_TYPE, indexPtr + batchStart * 3);
        refdef.batchCount++;
    }

    /* reset state */
    if (r_state.active_normalmap)
        R_EnableBumpmap(nullptr);

    R_EnableGlowMap(nullptr);

    R_Color(nullptr);
}