draw_nv10.cpp

Go to the documentation of this file.

/*
===========================================================================

Doom 3 GPL Source Code
Copyright (C) 1999-2011 id Software LLC, a ZeniMax Media company. 

This file is part of the Doom 3 GPL Source Code (?Doom 3 Source Code?).  

Doom 3 Source Code 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 3 of the License, or
(at your option) any later version.

Doom 3 Source Code 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 Doom 3 Source Code.  If not, see <http://www.gnu.org/licenses/>.

In addition, the Doom 3 Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU General Public License which accompanied the Doom 3 Source Code.  If not, please request a copy in writing from id Software at the address below.

If you have questions concerning this license or the applicable additional terms, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.

===========================================================================
*/
#include "../idlib/precompiled.h"
#pragma hdrstop

#include "tr_local.h"


/*
==================
RB_RenderInteraction

backEnd.vLight
backEnd.lightScale


backEnd.depthFunc must be equal for alpha tested surfaces to work right,
it is set to lessThan for blended transparent surfaces

This expects a bumpmap stage before a diffuse stage before a specular stage
The material code is responsible for guaranteeing that, but conditional stages
can still make it invalid.

you can't blend two bumpmaps, but you can change bump maps between
blended diffuse / specular maps to get the same effect


==================
*/
static void RB_RenderInteraction( const drawSurf_t *surf ) {
        const idMaterial        *surfaceShader = surf->material;
        const float                     *surfaceRegs = surf->shaderRegisters;
        const viewLight_t       *vLight = backEnd.vLight;
        const idMaterial        *lightShader = vLight->lightShader;
        const float                     *lightRegs = vLight->shaderRegisters;
        static idPlane          lightProject[4];        // reused across function calls
        const srfTriangles_t    *tri = surf->geo;
        const shaderStage_t     *lastBumpStage = NULL;

        RB_LogComment( "---------- RB_RenderInteraction %s on %s ----------\n", 
                lightShader->GetName(), surfaceShader->GetName() );

        // change the matrix and light projection vectors if needed
        if ( surf->space != backEnd.currentSpace ) {
                backEnd.currentSpace = surf->space;
                qglLoadMatrixf( surf->space->modelViewMatrix );

                for ( int i = 0 ; i < 4 ; i++ ) {
                        R_GlobalPlaneToLocal( surf->space->modelMatrix, backEnd.vLight->lightProject[i], lightProject[i] );
                }
        }

        // change the scissor if needed
        if ( r_useScissor.GetBool() && !backEnd.currentScissor.Equals( surf->scissorRect ) ) {
                backEnd.currentScissor = surf->scissorRect;
                qglScissor( backEnd.viewDef->viewport.x1 + backEnd.currentScissor.x1, 
                        backEnd.viewDef->viewport.y1 + backEnd.currentScissor.y1,
                        backEnd.currentScissor.x2 + 1 - backEnd.currentScissor.x1,
                        backEnd.currentScissor.y2 + 1 - backEnd.currentScissor.y1 );
        }

        // hack depth range if needed
        if ( surf->space->weaponDepthHack ) {
                RB_EnterWeaponDepthHack();
        }

        if ( surf->space->modelDepthHack != 0.0f ) {
                RB_EnterModelDepthHack( surf->space->modelDepthHack );
        }


        // set the vertex arrays, which may not all be enabled on a given pass
        idDrawVert      *ac = (idDrawVert *)vertexCache.Position(tri->ambientCache);
        qglVertexPointer( 3, GL_FLOAT, sizeof( idDrawVert ), ac->xyz.ToFloatPtr() );
        GL_SelectTexture( 0 );
        qglTexCoordPointer( 2, GL_FLOAT, sizeof( idDrawVert ), ac->st.ToFloatPtr() );
        qglColorPointer( 4, GL_UNSIGNED_BYTE, sizeof( idDrawVert ), ac->color );


        // go through the individual stages
        for ( int i = 0 ; i < surfaceShader->GetNumStages() ; i++ ) {
                const shaderStage_t     *surfaceStage = surfaceShader->GetStage( i );

                // ignore ambient stages while drawing interactions
                if ( surfaceStage->lighting == SL_AMBIENT ) {
                        continue;
                }

                // ignore stages that fail the condition
                if ( !surfaceRegs[ surfaceStage->conditionRegister ] ) {
                        continue;
                }

                //-----------------------------------------------------
                //
                // bump / falloff
                //
                //-----------------------------------------------------
                if ( surfaceStage->lighting == SL_BUMP ) {
                        // render light falloff * bumpmap lighting

                        if ( surfaceStage->vertexColor != SVC_IGNORE ) {
                                common->Printf( "shader %s: vertexColor on a bump stage\n",
                                        surfaceShader->GetName() );
                        }

                        // check for RGBA modulations in the stage, which are also illegal?

                        // save the bump map stage for the specular calculation and diffuse
                        // error checking
                        lastBumpStage = surfaceStage;

                        //
                        // ambient lights combine non-directional bump and falloff
                        // and write to the alpha channel
                        //
                        if ( lightShader->IsAmbientLight() ) {
                                GL_State( GLS_COLORMASK | GLS_DEPTHMASK | backEnd.depthFunc );

                                // texture 0 will be the per-surface bump map
                                GL_SelectTexture( 0 );
                                qglEnableClientState( GL_TEXTURE_COORD_ARRAY );

                                RB_BindStageTexture( surfaceRegs, &surfaceStage->texture, surf );
                                // development aid
                                if ( r_skipBump.GetBool() ) {
                                        globalImages->flatNormalMap->Bind();
                                }

                                // texture 1 will be the light falloff
                                GL_SelectTexture( 1 );

                                qglEnable( GL_TEXTURE_GEN_S );
                                qglTexGenfv( GL_S, GL_OBJECT_PLANE, lightProject[3].ToFloatPtr() );
                                qglTexCoord2f( 0, 0.5 );
                                vLight->falloffImage->Bind();

                                qglCombinerParameteriNV( GL_NUM_GENERAL_COMBINERS_NV, 2 );

                                // set the constant color to a bit of an angle
                                qglCombinerParameterfvNV( GL_CONSTANT_COLOR0_NV, tr.ambientLightVector.ToFloatPtr() );

                                // stage 0 sets primary_color = bump dot constant color
                                qglCombinerInputNV( GL_COMBINER0_NV, GL_RGB, GL_VARIABLE_A_NV, 
                                        GL_CONSTANT_COLOR0_NV, GL_EXPAND_NORMAL_NV, GL_RGB );
                                qglCombinerInputNV( GL_COMBINER0_NV, GL_RGB, GL_VARIABLE_B_NV, 
                                        GL_TEXTURE0_ARB, GL_EXPAND_NORMAL_NV, GL_RGB );
                                qglCombinerOutputNV( GL_COMBINER0_NV, GL_RGB, 
                                        GL_PRIMARY_COLOR_NV, GL_DISCARD_NV, GL_DISCARD_NV,
                                        GL_NONE, GL_NONE, GL_TRUE, GL_FALSE, GL_FALSE );

                                // stage 1 alpha sets primary_color = primary_color * falloff
                                qglCombinerInputNV( GL_COMBINER1_NV, GL_ALPHA, GL_VARIABLE_A_NV, 
                                        GL_PRIMARY_COLOR_NV, GL_UNSIGNED_IDENTITY_NV, GL_BLUE );
                                qglCombinerInputNV( GL_COMBINER1_NV, GL_ALPHA, GL_VARIABLE_B_NV, 
                                        GL_TEXTURE1_ARB, GL_UNSIGNED_IDENTITY_NV, GL_ALPHA );
                                qglCombinerOutputNV( GL_COMBINER1_NV, GL_ALPHA, 
                                        GL_PRIMARY_COLOR_NV, GL_DISCARD_NV, GL_DISCARD_NV,
                                        GL_NONE, GL_NONE, GL_FALSE, GL_FALSE, GL_FALSE );

                                // final combiner takes the result for the alpha channel
                                qglFinalCombinerInputNV( GL_VARIABLE_A_NV, GL_ZERO,
                                        GL_UNSIGNED_IDENTITY_NV, GL_RGB );
                                qglFinalCombinerInputNV( GL_VARIABLE_B_NV, GL_ZERO,
                                        GL_UNSIGNED_IDENTITY_NV, GL_RGB );
                                qglFinalCombinerInputNV( GL_VARIABLE_C_NV, GL_ZERO,
                                        GL_UNSIGNED_IDENTITY_NV, GL_RGB );
                                qglFinalCombinerInputNV( GL_VARIABLE_D_NV, GL_ZERO,
                                        GL_UNSIGNED_IDENTITY_NV, GL_RGB );
                                qglFinalCombinerInputNV( GL_VARIABLE_G_NV, GL_PRIMARY_COLOR_NV,
                                        GL_UNSIGNED_IDENTITY_NV, GL_ALPHA );

                                // draw it
                                RB_DrawElementsWithCounters( tri );

                                globalImages->BindNull();
                                qglDisable( GL_TEXTURE_GEN_S );

                                GL_SelectTexture( 0 );
                                RB_FinishStageTexture( &surfaceStage->texture, surf );
                                continue;
                        }

                        //
                        // draw light falloff to the alpha channel
                        //
                        GL_State( GLS_COLORMASK | GLS_DEPTHMASK | backEnd.depthFunc );
                        qglDisableClientState( GL_TEXTURE_COORD_ARRAY );
                        qglDisableClientState( GL_COLOR_ARRAY );
                        qglEnable( GL_TEXTURE_GEN_S );
                        qglTexGenfv( GL_S, GL_OBJECT_PLANE, lightProject[3].ToFloatPtr() );
                        qglTexCoord2f( 0, 0.5 );
                        vLight->falloffImage->Bind();

                        // make sure a combiner output doesn't step on the texture
                        qglCombinerParameteriNV( GL_NUM_GENERAL_COMBINERS_NV, 1 );
                        qglCombinerOutputNV( GL_COMBINER0_NV, GL_ALPHA, 
                                GL_DISCARD_NV, GL_DISCARD_NV, GL_DISCARD_NV,
                                GL_NONE, GL_NONE, GL_FALSE, GL_FALSE, GL_FALSE );

                        // final combiner
                        qglFinalCombinerInputNV( GL_VARIABLE_A_NV, GL_ZERO,
                                GL_UNSIGNED_IDENTITY_NV, GL_RGB );
                        qglFinalCombinerInputNV( GL_VARIABLE_B_NV, GL_ZERO,
                                GL_UNSIGNED_IDENTITY_NV, GL_RGB );
                        qglFinalCombinerInputNV( GL_VARIABLE_C_NV, GL_ZERO,
                                GL_UNSIGNED_IDENTITY_NV, GL_RGB );
                        qglFinalCombinerInputNV( GL_VARIABLE_D_NV, GL_ZERO,
                                GL_UNSIGNED_IDENTITY_NV, GL_RGB );
                        qglFinalCombinerInputNV( GL_VARIABLE_G_NV, GL_TEXTURE0_ARB,
                                GL_UNSIGNED_IDENTITY_NV, GL_ALPHA );

                        // draw it
                        RB_DrawElementsWithCounters( tri );

                        qglDisable( GL_TEXTURE_GEN_S );

                        //
                        // draw the bump map result onto the alpha channel
                        //
                        GL_State( GLS_SRCBLEND_DST_ALPHA | GLS_DSTBLEND_ZERO | GLS_COLORMASK | GLS_DEPTHMASK 
                                | backEnd.depthFunc );

                        // texture 0 will be the per-surface bump map
                        GL_SelectTexture( 0 );
                        qglEnableClientState( GL_TEXTURE_COORD_ARRAY );
                        RB_BindStageTexture( surfaceRegs, &surfaceStage->texture, surf );

                        // texture 1 is the normalization cube map
                        // the texccords are the non-normalized vector towards the light origin
                        GL_SelectTexture( 1 );
                        globalImages->normalCubeMapImage->Bind();
                        qglEnableClientState( GL_TEXTURE_COORD_ARRAY );
                        qglTexCoordPointer( 3, GL_FLOAT, sizeof( lightingCache_t ), ((lightingCache_t *)vertexCache.Position(tri->lightingCache))->localLightVector.ToFloatPtr() );

                        qglDisableClientState( GL_COLOR_ARRAY );

                        // program the nvidia register combiners
                        // I just want alpha = Dot( texture0, texture1 )
                        qglCombinerParameteriNV( GL_NUM_GENERAL_COMBINERS_NV, 1 );

                        // stage 0 rgb performs the dot product
                        // SPARE0 = TEXTURE0 dot TEXTURE1
                        qglCombinerInputNV( GL_COMBINER0_NV, GL_RGB, GL_VARIABLE_A_NV, 
                                GL_TEXTURE1_ARB, GL_EXPAND_NORMAL_NV, GL_RGB );
                        qglCombinerInputNV( GL_COMBINER0_NV, GL_RGB, GL_VARIABLE_B_NV, 
                                GL_TEXTURE0_ARB, GL_EXPAND_NORMAL_NV, GL_RGB );
                        qglCombinerOutputNV( GL_COMBINER0_NV, GL_RGB, 
                                GL_SPARE0_NV, GL_DISCARD_NV, GL_DISCARD_NV,
                                GL_NONE, GL_NONE, GL_TRUE, GL_FALSE, GL_FALSE );

                        // final combiner just takes the dot result and puts it in alpha
                        qglFinalCombinerInputNV( GL_VARIABLE_G_NV, GL_SPARE0_NV,
                                GL_UNSIGNED_IDENTITY_NV, GL_BLUE );

                        // draw it
                        RB_DrawElementsWithCounters( tri );

                        globalImages->BindNull();
                        qglDisableClientState( GL_TEXTURE_COORD_ARRAY );

                        GL_SelectTexture( 0 );
                        RB_FinishStageTexture( &surfaceStage->texture, surf );
                        continue;
                }

                if ( surfaceStage->lighting == SL_DIFFUSE ) {
                        if ( !lastBumpStage ) {
                                common->Printf( "shader %s: diffuse stage without a preceeding bumpmap stage\n",
                                        surfaceShader->GetName() );
                                continue;
                        }
                }

                //-----------------------------------------------------
                //
                // specular exponent modification of the bump / falloff
                //
                //-----------------------------------------------------
                if ( surfaceStage->lighting == SL_SPECULAR ) {
                        // put specular bump map into alpha channel, then treat as a diffuse

                        // allow the specular to be skipped as a user speed optimization
                        if ( r_skipSpecular.GetBool() ) {
                                continue;
                        }

                        // ambient lights don't have specular
                        if ( lightShader->IsAmbientLight() ) {
                                continue;
                        }

                        if ( !lastBumpStage ) {
                                common->Printf( "shader %s: specular stage without a preceeding bumpmap stage\n",
                                        surfaceShader->GetName() );
                                continue;
                        }

                        GL_State( GLS_SRCBLEND_DST_ALPHA | GLS_DSTBLEND_SRC_ALPHA | GLS_COLORMASK | GLS_DEPTHMASK 
                                | backEnd.depthFunc );

                        // texture 0 will be the per-surface bump map
                        GL_SelectTexture( 0 );
                        qglEnableClientState( GL_TEXTURE_COORD_ARRAY );
                        RB_BindStageTexture( surfaceRegs, &lastBumpStage->texture, surf );

                        // development aid
                        if ( r_skipBump.GetBool() ) {
                                globalImages->flatNormalMap->Bind();
                        }

                        // texture 1 is the normalization cube map
                        // indexed by the dynamic halfangle texcoords
                        GL_SelectTexture( 1 );
                        globalImages->normalCubeMapImage->Bind();
                        qglEnableClientState( GL_TEXTURE_COORD_ARRAY );
                        qglTexCoordPointer( 4, GL_FLOAT, 0, vertexCache.Position( surf->dynamicTexCoords ) );

                        // program the nvidia register combiners
                        qglCombinerParameteriNV( GL_NUM_GENERAL_COMBINERS_NV, 2 );

                        // stage 0 rgb performs the dot product
                        // GL_PRIMARY_COLOR_NV = ( TEXTURE0 dot TEXTURE1 - 0.5 ) * 2
                        // the scale and bias steepen the specular curve
                        qglCombinerInputNV( GL_COMBINER0_NV, GL_RGB, GL_VARIABLE_A_NV, 
                                GL_TEXTURE1_ARB, GL_EXPAND_NORMAL_NV, GL_RGB );
                        qglCombinerInputNV( GL_COMBINER0_NV, GL_RGB, GL_VARIABLE_B_NV, 
                                GL_TEXTURE0_ARB, GL_EXPAND_NORMAL_NV, GL_RGB );
                        qglCombinerOutputNV( GL_COMBINER0_NV, GL_RGB, 
                                GL_PRIMARY_COLOR_NV, GL_DISCARD_NV, GL_DISCARD_NV,
                                GL_SCALE_BY_TWO_NV, GL_BIAS_BY_NEGATIVE_ONE_HALF_NV, GL_TRUE, GL_FALSE, GL_FALSE );

                        // stage 0 alpha does nothing
                        qglCombinerOutputNV( GL_COMBINER0_NV, GL_ALPHA, 
                                GL_DISCARD_NV, GL_DISCARD_NV, GL_DISCARD_NV,
                                GL_NONE, GL_NONE, GL_FALSE, GL_FALSE, GL_FALSE );

                        // stage 1 rgb does nothing
                        qglCombinerOutputNV( GL_COMBINER1_NV, GL_RGB, 
                                GL_PRIMARY_COLOR_NV, GL_DISCARD_NV, GL_DISCARD_NV,
                                GL_NONE, GL_NONE, GL_FALSE, GL_FALSE, GL_FALSE );

                        // stage 1 alpha takes bump * bump
                        // PRIMARY_COLOR = ( GL_PRIMARY_COLOR_NV * GL_PRIMARY_COLOR_NV - 0.5 ) * 2
                        // the scale and bias steepen the specular curve
                        qglCombinerInputNV( GL_COMBINER1_NV, GL_ALPHA, GL_VARIABLE_A_NV, 
                                GL_PRIMARY_COLOR_NV, GL_UNSIGNED_IDENTITY_NV, GL_BLUE );
                        qglCombinerInputNV( GL_COMBINER1_NV, GL_ALPHA, GL_VARIABLE_B_NV, 
                                GL_PRIMARY_COLOR_NV, GL_UNSIGNED_IDENTITY_NV, GL_BLUE );
                        qglCombinerOutputNV( GL_COMBINER1_NV, GL_ALPHA, 
                                GL_PRIMARY_COLOR_NV, GL_DISCARD_NV, GL_DISCARD_NV,
                                GL_SCALE_BY_TWO_NV, GL_BIAS_BY_NEGATIVE_ONE_HALF_NV, GL_FALSE, GL_FALSE, GL_FALSE );

                        // final combiner
                        qglFinalCombinerInputNV( GL_VARIABLE_D_NV, GL_PRIMARY_COLOR_NV,
                                GL_UNSIGNED_IDENTITY_NV, GL_RGB );
                        qglFinalCombinerInputNV( GL_VARIABLE_A_NV, GL_ZERO,
                                GL_UNSIGNED_IDENTITY_NV, GL_RGB );
                        qglFinalCombinerInputNV( GL_VARIABLE_B_NV, GL_ZERO,
                                GL_UNSIGNED_IDENTITY_NV, GL_RGB );
                        qglFinalCombinerInputNV( GL_VARIABLE_C_NV, GL_ZERO,
                                GL_UNSIGNED_IDENTITY_NV, GL_RGB );
                        qglFinalCombinerInputNV( GL_VARIABLE_G_NV, GL_PRIMARY_COLOR_NV,
                                GL_UNSIGNED_IDENTITY_NV, GL_ALPHA );

                        // draw it
                        RB_DrawElementsWithCounters( tri );

                        globalImages->BindNull();
                        qglDisableClientState( GL_TEXTURE_COORD_ARRAY );

                        GL_SelectTexture( 0 );

                        RB_FinishStageTexture( &lastBumpStage->texture, surf );

                        // the bump map in the alpha channel is now corrupted, so a normal diffuse
                        // map can't be drawn unless a new bumpmap is put down
                        lastBumpStage = NULL;

                        // fall through to the common handling of diffuse and specular projected lighting
                }

                //-----------------------------------------------------
                //
                // projected light / surface color for diffuse and specular maps
                //
                //-----------------------------------------------------
                if ( surfaceStage->lighting == SL_DIFFUSE || surfaceStage->lighting == SL_SPECULAR ) {
                        // don't trash alpha
                        GL_State( GLS_SRCBLEND_DST_ALPHA | GLS_DSTBLEND_ONE | GLS_ALPHAMASK | GLS_DEPTHMASK 
                        | backEnd.depthFunc );

                        // texture 0 will get the surface color texture
                        GL_SelectTexture( 0 );
                        qglEnableClientState( GL_TEXTURE_COORD_ARRAY );
                        RB_BindStageTexture( surfaceRegs, &surfaceStage->texture, surf );

                        // development aid
                        if ( ( surfaceStage->lighting == SL_DIFFUSE && r_skipDiffuse.GetBool() )
                                || ( surfaceStage->lighting == SL_SPECULAR && r_skipSpecular.GetBool() ) ) {
                                globalImages->blackImage->Bind();
                        }

                        // texture 1 will get the light projected texture
                        GL_SelectTexture( 1 );
                        qglDisableClientState( GL_TEXTURE_COORD_ARRAY );
                        qglEnable( GL_TEXTURE_GEN_S );
                        qglEnable( GL_TEXTURE_GEN_T );
                        qglEnable( GL_TEXTURE_GEN_Q );
                        qglTexGenfv( GL_S, GL_OBJECT_PLANE, lightProject[0].ToFloatPtr() );
                        qglTexGenfv( GL_T, GL_OBJECT_PLANE, lightProject[1].ToFloatPtr() );
                        qglTexGenfv( GL_Q, GL_OBJECT_PLANE, lightProject[2].ToFloatPtr() );

                        // texture0 * texture1 * primaryColor * constantColor
                        qglCombinerParameteriNV( GL_NUM_GENERAL_COMBINERS_NV, 1 );

                        // SPARE0 = TEXTURE0 * PRIMARY_COLOR
                        // SPARE1 = TEXTURE1 * CONSTANT_COLOR
                        qglCombinerInputNV( GL_COMBINER0_NV, GL_RGB, GL_VARIABLE_A_NV, 
                                GL_TEXTURE0_ARB, GL_UNSIGNED_IDENTITY_NV, GL_RGB );
                        // variable B will be overriden based on the stage vertexColor option
                        if ( surfaceStage->vertexColor == SVC_MODULATE ) {
                                qglCombinerInputNV( GL_COMBINER0_NV, GL_RGB, GL_VARIABLE_B_NV, 
                                        GL_PRIMARY_COLOR_NV, GL_UNSIGNED_IDENTITY_NV, GL_RGB );
                                qglEnableClientState( GL_COLOR_ARRAY );
                        } else if ( surfaceStage->vertexColor == SVC_INVERSE_MODULATE ) {
                                qglCombinerInputNV( GL_COMBINER0_NV, GL_RGB, GL_VARIABLE_B_NV, 
                                        GL_PRIMARY_COLOR_NV, GL_UNSIGNED_INVERT_NV, GL_RGB );
                                qglEnableClientState( GL_COLOR_ARRAY );
                        } else {        // SVC_IGNORE
                                qglCombinerInputNV( GL_COMBINER0_NV, GL_RGB, GL_VARIABLE_B_NV, 
                                        GL_ZERO, GL_UNSIGNED_INVERT_NV, GL_RGB );
                                qglDisableClientState( GL_COLOR_ARRAY );
                        }
                        qglCombinerInputNV( GL_COMBINER0_NV, GL_RGB, GL_VARIABLE_C_NV, 
                                GL_TEXTURE1_ARB, GL_UNSIGNED_IDENTITY_NV, GL_RGB );
                        qglCombinerInputNV( GL_COMBINER0_NV, GL_RGB, GL_VARIABLE_D_NV, 
                                GL_CONSTANT_COLOR1_NV, GL_UNSIGNED_IDENTITY_NV, GL_RGB );
                        qglCombinerOutputNV( GL_COMBINER0_NV, GL_RGB, 
                                GL_SPARE0_NV, GL_SPARE1_NV, GL_DISCARD_NV,
                                GL_NONE, GL_NONE, GL_FALSE, GL_FALSE, GL_FALSE );

                        // final combiner
                        qglFinalCombinerInputNV( GL_VARIABLE_A_NV, GL_SPARE1_NV,
                                GL_UNSIGNED_IDENTITY_NV, GL_RGB );
                        qglFinalCombinerInputNV( GL_VARIABLE_B_NV, GL_SPARE0_NV,
                                GL_UNSIGNED_IDENTITY_NV, GL_RGB );
                        qglFinalCombinerInputNV( GL_VARIABLE_C_NV, GL_ZERO,
                                GL_UNSIGNED_IDENTITY_NV, GL_RGB );
                        qglFinalCombinerInputNV( GL_VARIABLE_D_NV, GL_ZERO,
                                GL_UNSIGNED_IDENTITY_NV, GL_RGB );
                        qglFinalCombinerInputNV( GL_VARIABLE_G_NV, GL_ZERO,
                                GL_UNSIGNED_IDENTITY_NV, GL_ALPHA );

                        // for all light stages, multiply the projected color by the surface
                        // color, and blend with the framebuffer
                        for ( int j = 0 ; j < lightShader->GetNumStages() ; j++ ) {
                                const shaderStage_t     *lightStage = lightShader->GetStage( j );
                                float   color[4];

                                // ignore stages that fail the condition
                                if ( !lightRegs[ lightStage->conditionRegister ] ) {
                                        continue;
                                }

                                // set the color to the light color times the surface color
                                color[0] = backEnd.lightScale
                                        * lightRegs[ lightStage->color.registers[0] ]
                                        * surfaceRegs[ surfaceStage->color.registers[0] ];
                                color[1] = backEnd.lightScale
                                        * lightRegs[ lightStage->color.registers[1] ]
                                        * surfaceRegs[ surfaceStage->color.registers[1] ];
                                color[2] = backEnd.lightScale
                                        * lightRegs[ lightStage->color.registers[2] ]
                                        * surfaceRegs[ surfaceStage->color.registers[2] ];
                                color[3] = 1;

                                // don't draw if it would be all black
                                if ( color[0] == 0 && color[1] == 0 && color[2] == 0 ) {
                                        continue;
                                }

                                qglCombinerParameterfvNV( GL_CONSTANT_COLOR1_NV, color );

                                RB_BindStageTexture( lightRegs, &lightStage->texture, surf );

                                RB_DrawElementsWithCounters( tri );

                                RB_FinishStageTexture( &lightStage->texture, surf );
                        }

                        if ( surfaceStage->vertexColor != SVC_IGNORE ) {
                                qglDisableClientState( GL_COLOR_ARRAY );
                        }

                        qglDisable( GL_TEXTURE_GEN_S );
                        qglDisable( GL_TEXTURE_GEN_T );
                        qglDisable( GL_TEXTURE_GEN_Q );

                        globalImages->BindNull();
                        GL_SelectTexture( 0 );
                        RB_FinishStageTexture( &surfaceStage->texture, surf );

                        continue;
                }

        }
        // unhack depth range if needed
        if ( surf->space->weaponDepthHack || surf->space->modelDepthHack != 0.0f ) {
                RB_LeaveDepthHack();
        }
}

/*
==================
RB_RenderInteractionList
==================
*/
static void RB_RenderInteractionList( const drawSurf_t *surf ) {
        if ( !surf ) {
                return;
        }

        qglEnable( GL_REGISTER_COMBINERS_NV );

        // force a space calculation for light vectors
        backEnd.currentSpace = NULL;

        for ( const drawSurf_t *s = surf ; s ; s = s->nextOnLight ) {
                RB_RenderInteraction( s );
        }

        qglDisable( GL_REGISTER_COMBINERS_NV );
}



/*
==================
RB_RenderViewLight

==================
*/
static void RB_RenderViewLight( viewLight_t *vLight ) {
        backEnd.vLight = vLight;

        // do fogging later
        if ( vLight->lightShader->IsFogLight() ) {
                return;
        }
        if ( vLight->lightShader->IsBlendLight() ) {
                return;
        }

        RB_LogComment( "---------- RB_RenderViewLight 0x%p ----------\n", vLight );

        // clear the stencil buffer if needed
        if ( vLight->globalShadows || vLight->localShadows ) {
                backEnd.currentScissor = vLight->scissorRect;
                if ( r_useScissor.GetBool() ) {
                        qglScissor( backEnd.viewDef->viewport.x1 + backEnd.currentScissor.x1, 
                                backEnd.viewDef->viewport.y1 + backEnd.currentScissor.y1,
                                backEnd.currentScissor.x2 + 1 - backEnd.currentScissor.x1,
                                backEnd.currentScissor.y2 + 1 - backEnd.currentScissor.y1 );
                }
                qglClear( GL_STENCIL_BUFFER_BIT );
        } else {
                // no shadows, so no need to read or write the stencil buffer
                // we might in theory want to use GL_ALWAYS instead of disabling
                // completely, to satisfy the invarience rules
                qglStencilFunc( GL_ALWAYS, 128, 255 );
        }

        backEnd.depthFunc = GLS_DEPTHFUNC_EQUAL;
        RB_StencilShadowPass( vLight->globalShadows );
        RB_RenderInteractionList( vLight->localInteractions );
        RB_StencilShadowPass( vLight->localShadows );
        RB_RenderInteractionList( vLight->globalInteractions );

        if ( r_skipTranslucent.GetBool() ) {
                return;
        }

        // disable stencil testing for translucent interactions, because
        // the shadow isn't calculated at their point, and the shadow
        // behind them may be depth fighting with a back side, so there
        // isn't any reasonable thing to do
        qglStencilFunc( GL_ALWAYS, 128, 255 );
        backEnd.depthFunc = GLS_DEPTHFUNC_LESS;
        RB_RenderInteractionList( vLight->translucentInteractions );
}


/*
==================
RB_NV10_DrawInteractions
==================
*/
void RB_NV10_DrawInteractions( void ) {
        qglEnable( GL_STENCIL_TEST );

        for ( viewLight_t *vLight = backEnd.viewDef->viewLights ; vLight ; vLight = vLight->next ) {
                RB_RenderViewLight( vLight );
        }
}


/*
==================
R_NV10_Init

==================
*/
void R_NV10_Init( void ) {
        glConfig.allowNV10Path = false;

        if ( !glConfig.registerCombinersAvailable ) {
                return;
        }

        glConfig.allowNV10Path = true;
}