tr_shade.c

quakeIII源码这个不用我多说吧

/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.

This file is part of Quake III Arena source code.

Quake III Arena 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 2 of the License,
or (at your option) any later version.

Quake III Arena 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 Foobar; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/
// tr_shade.c

#include "tr_local.h"

/*

  THIS ENTIRE FILE IS BACK END

  This file deals with applying shaders to surface data in the tess struct.
*/

/*
================
R_ArrayElementDiscrete

This is just for OpenGL conformance testing, it should never be the fastest
================
*/
static void APIENTRY R_ArrayElementDiscrete( GLint index ) {
	qglColor4ubv( tess.svars.colors[ index ] );
	if ( glState.currenttmu ) {
		qglMultiTexCoord2fARB( 0, tess.svars.texcoords[ 0 ][ index ][0], tess.svars.texcoords[ 0 ][ index ][1] );
		qglMultiTexCoord2fARB( 1, tess.svars.texcoords[ 1 ][ index ][0], tess.svars.texcoords[ 1 ][ index ][1] );
	} else {
		qglTexCoord2fv( tess.svars.texcoords[ 0 ][ index ] );
	}
	qglVertex3fv( tess.xyz[ index ] );
}

/*
===================
R_DrawStripElements

===================
*/
static int		c_vertexes;		// for seeing how long our average strips are
static int		c_begins;
static void R_DrawStripElements( int numIndexes, const glIndex_t *indexes, void ( APIENTRY *element )(GLint) ) {
	int i;
	int last[3] = { -1, -1, -1 };
	qboolean even;

	c_begins++;

	if ( numIndexes <= 0 ) {
		return;
	}

	qglBegin( GL_TRIANGLE_STRIP );

	// prime the strip
	element( indexes[0] );
	element( indexes[1] );
	element( indexes[2] );
	c_vertexes += 3;

	last[0] = indexes[0];
	last[1] = indexes[1];
	last[2] = indexes[2];

	even = qfalse;

	for ( i = 3; i < numIndexes; i += 3 )
	{
		// odd numbered triangle in potential strip
		if ( !even )
		{
			// check previous triangle to see if we're continuing a strip
			if ( ( indexes[i+0] == last[2] ) && ( indexes[i+1] == last[1] ) )
			{
				element( indexes[i+2] );
				c_vertexes++;
				assert( indexes[i+2] < tess.numVertexes );
				even = qtrue;
			}
			// otherwise we're done with this strip so finish it and start
			// a new one
			else
			{
				qglEnd();

				qglBegin( GL_TRIANGLE_STRIP );
				c_begins++;

				element( indexes[i+0] );
				element( indexes[i+1] );
				element( indexes[i+2] );

				c_vertexes += 3;

				even = qfalse;
			}
		}
		else
		{
			// check previous triangle to see if we're continuing a strip
			if ( ( last[2] == indexes[i+1] ) && ( last[0] == indexes[i+0] ) )
			{
				element( indexes[i+2] );
				c_vertexes++;

				even = qfalse;
			}
			// otherwise we're done with this strip so finish it and start
			// a new one
			else
			{
				qglEnd();

				qglBegin( GL_TRIANGLE_STRIP );
				c_begins++;

				element( indexes[i+0] );
				element( indexes[i+1] );
				element( indexes[i+2] );
				c_vertexes += 3;

				even = qfalse;
			}
		}

		// cache the last three vertices
		last[0] = indexes[i+0];
		last[1] = indexes[i+1];
		last[2] = indexes[i+2];
	}

	qglEnd();
}



/*
==================
R_DrawElements

Optionally performs our own glDrawElements that looks for strip conditions
instead of using the single glDrawElements call that may be inefficient
without compiled vertex arrays.
==================
*/
static void R_DrawElements( int numIndexes, const glIndex_t *indexes ) {
	int		primitives;

	primitives = r_primitives->integer;

	// default is to use triangles if compiled vertex arrays are present
	if ( primitives == 0 ) {
		if ( qglLockArraysEXT ) {
			primitives = 2;
		} else {
			primitives = 1;
		}
	}


	if ( primitives == 2 ) {
		qglDrawElements( GL_TRIANGLES, 
						numIndexes,
						GL_INDEX_TYPE,
						indexes );
		return;
	}

	if ( primitives == 1 ) {
		R_DrawStripElements( numIndexes,  indexes, qglArrayElement );
		return;
	}
	
	if ( primitives == 3 ) {
		R_DrawStripElements( numIndexes,  indexes, R_ArrayElementDiscrete );
		return;
	}

	// anything else will cause no drawing
}


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

SURFACE SHADERS

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

shaderCommands_t	tess;
static qboolean	setArraysOnce;

/*
=================
R_BindAnimatedImage

=================
*/
static void R_BindAnimatedImage( textureBundle_t *bundle ) {
	int		index;

	if ( bundle->isVideoMap ) {
		ri.CIN_RunCinematic(bundle->videoMapHandle);
		ri.CIN_UploadCinematic(bundle->videoMapHandle);
		return;
	}

	if ( bundle->numImageAnimations <= 1 ) {
		GL_Bind( bundle->image[0] );
		return;
	}

	// it is necessary to do this messy calc to make sure animations line up
	// exactly with waveforms of the same frequency
	index = myftol( tess.shaderTime * bundle->imageAnimationSpeed * FUNCTABLE_SIZE );
	index >>= FUNCTABLE_SIZE2;

	if ( index < 0 ) {
		index = 0;	// may happen with shader time offsets
	}
	index %= bundle->numImageAnimations;

	GL_Bind( bundle->image[ index ] );
}

/*
================
DrawTris

Draws triangle outlines for debugging
================
*/
static void DrawTris (shaderCommands_t *input) {
	GL_Bind( tr.whiteImage );
	qglColor3f (1,1,1);

	GL_State( GLS_POLYMODE_LINE | GLS_DEPTHMASK_TRUE );
	qglDepthRange( 0, 0 );

	qglDisableClientState (GL_COLOR_ARRAY);
	qglDisableClientState (GL_TEXTURE_COORD_ARRAY);

	qglVertexPointer (3, GL_FLOAT, 16, input->xyz);	// padded for SIMD

	if (qglLockArraysEXT) {
		qglLockArraysEXT(0, input->numVertexes);
		GLimp_LogComment( "glLockArraysEXT\n" );
	}

	R_DrawElements( input->numIndexes, input->indexes );

	if (qglUnlockArraysEXT) {
		qglUnlockArraysEXT();
		GLimp_LogComment( "glUnlockArraysEXT\n" );
	}
	qglDepthRange( 0, 1 );
}


/*
================
DrawNormals

Draws vertex normals for debugging
================
*/
static void DrawNormals (shaderCommands_t *input) {
	int		i;
	vec3_t	temp;

	GL_Bind( tr.whiteImage );
	qglColor3f (1,1,1);
	qglDepthRange( 0, 0 );	// never occluded
	GL_State( GLS_POLYMODE_LINE | GLS_DEPTHMASK_TRUE );

	qglBegin (GL_LINES);
	for (i = 0 ; i < input->numVertexes ; i++) {
		qglVertex3fv (input->xyz[i]);
		VectorMA (input->xyz[i], 2, input->normal[i], temp);
		qglVertex3fv (temp);
	}
	qglEnd ();

	qglDepthRange( 0, 1 );
}

/*
==============
RB_BeginSurface

We must set some things up before beginning any tesselation,
because a surface may be forced to perform a RB_End due
to overflow.
==============
*/
void RB_BeginSurface( shader_t *shader, int fogNum ) {

	shader_t *state = (shader->remappedShader) ? shader->remappedShader : shader;

	tess.numIndexes = 0;
	tess.numVertexes = 0;
	tess.shader = state;
	tess.fogNum = fogNum;
	tess.dlightBits = 0;		// will be OR'd in by surface functions
	tess.xstages = state->stages;
	tess.numPasses = state->numUnfoggedPasses;
	tess.currentStageIteratorFunc = state->optimalStageIteratorFunc;

	tess.shaderTime = backEnd.refdef.floatTime - tess.shader->timeOffset;
	if (tess.shader->clampTime && tess.shaderTime >= tess.shader->clampTime) {
		tess.shaderTime = tess.shader->clampTime;
	}


}

/*
===================
DrawMultitextured

output = t0 * t1 or t0 + t1

t0 = most upstream according to spec
t1 = most downstream according to spec
===================
*/
static void DrawMultitextured( shaderCommands_t *input, int stage ) {
	shaderStage_t	*pStage;

	pStage = tess.xstages[stage];

	GL_State( pStage->stateBits );

	// this is an ugly hack to work around a GeForce driver
	// bug with multitexture and clip planes
	if ( backEnd.viewParms.isPortal ) {
		qglPolygonMode( GL_FRONT_AND_BACK, GL_FILL );
	}

	//
	// base
	//
	GL_SelectTexture( 0 );
	qglTexCoordPointer( 2, GL_FLOAT, 0, input->svars.texcoords[0] );
	R_BindAnimatedImage( &pStage->bundle[0] );

	//
	// lightmap/secondary pass
	//
	GL_SelectTexture( 1 );
	qglEnable( GL_TEXTURE_2D );
	qglEnableClientState( GL_TEXTURE_COORD_ARRAY );

	if ( r_lightmap->integer ) {
		GL_TexEnv( GL_REPLACE );
	} else {
		GL_TexEnv( tess.shader->multitextureEnv );
	}

	qglTexCoordPointer( 2, GL_FLOAT, 0, input->svars.texcoords[1] );

	R_BindAnimatedImage( &pStage->bundle[1] );

	R_DrawElements( input->numIndexes, input->indexes );

	//
	// disable texturing on TEXTURE1, then select TEXTURE0
	//
	//qglDisableClientState( GL_TEXTURE_COORD_ARRAY );
	qglDisable( GL_TEXTURE_2D );

	GL_SelectTexture( 0 );
}



/*
===================
ProjectDlightTexture

Perform dynamic lighting with another rendering pass
===================
*/
static void ProjectDlightTexture( void ) {
	int		i, l;
#if idppc_altivec
	vec_t	origin0, origin1, origin2;
	float   texCoords0, texCoords1;
	vector float floatColorVec0, floatColorVec1;
	vector float modulateVec, colorVec, zero;
	vector short colorShort;
	vector signed int colorInt;
	vector unsigned char floatColorVecPerm, modulatePerm, colorChar;
	vector unsigned char vSel = (vector unsigned char)(0x00, 0x00, 0x00, 0xff,
							   0x00, 0x00, 0x00, 0xff,
							   0x00, 0x00, 0x00, 0xff,
							   0x00, 0x00, 0x00, 0xff);
#else
	vec3_t	origin;
#endif
	float	*texCoords;
	byte	*colors;
	byte	clipBits[SHADER_MAX_VERTEXES];
	MAC_STATIC float	texCoordsArray[SHADER_MAX_VERTEXES][2];
	byte	colorArray[SHADER_MAX_VERTEXES][4];
	unsigned	hitIndexes[SHADER_MAX_INDEXES];
	int		numIndexes;
	float	scale;
	float	radius;
	vec3_t	floatColor;
	float	modulate;

	if ( !backEnd.refdef.num_dlights ) {
		return;
	}

#if idppc_altivec
	// There has to be a better way to do this so that floatColor 
	// and/or modulate are already 16-byte aligned.
	floatColorVecPerm = vec_lvsl(0,(float *)floatColor);
	modulatePerm = vec_lvsl(0,(float *)&modulate);
	modulatePerm = (vector unsigned char)vec_splat((vector unsigned int)modulatePerm,0);
	zero = (vector float)vec_splat_s8(0);
#endif

	for ( l = 0 ; l < backEnd.refdef.num_dlights ; l++ ) {
		dlight_t	*dl;

		if ( !( tess.dlightBits & ( 1 << l ) ) ) {
			continue;	// this surface definately doesn't have any of this light
		}
		texCoords = texCoordsArray[0];
		colors = colorArray[0];

		dl = &backEnd.refdef.dlights[l];
#if idppc_altivec