/*
Copyright (C) 1996-2001 Id Software, Inc.
Copyright (C) 2002-2009 John Fitzgibbons and others
Copyright (C) 2010-2014 QuakeSpasm developers

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.

*/

//r_alias.c -- alias model rendering

#include "q_defs.h"

extern cvar_t r_drawflat, gl_overbright_models, gl_fullbrights, r_lerpmodels, r_lerpmove; //johnfitz

//up to 16 color translated skins
gltexture_t *playertextures[MAX_SCOREBOARD]; //johnfitz -- changed to an array of pointers

#define NUMVERTEXNORMALS        162

float   r_avertexnormals[NUMVERTEXNORMALS][3] =
{
#include "anorms.h"
};

extern vec3_t   lightcolor; //johnfitz -- replaces "float shadelight" for lit support

// precalculated dot products for quantized angles
#define SHADEDOT_QUANT 16
float   r_avertexnormal_dots[SHADEDOT_QUANT][256] =
{
#include "anorm_dots.h"
};

extern  vec3_t                  lightspot;

float   *shadedots = r_avertexnormal_dots[0];
vec3_t  shadevector;

float   entalpha; //johnfitz

bool    overbright; //johnfitz

bool shading = true; //johnfitz -- if false, disable vertex shading for various reasons (fullbright, r_lightmap, showtris, etc)

//johnfitz -- struct for passing lerp information to drawing functions
typedef struct
{
	int16_t pose1;
	int16_t pose2;
	float blend;
	vec3_t origin;
	vec3_t angles;
} lerpdata_t;
//johnfitz

static GLuint r_alias_program;

// uniforms used in vert shader
static GLuint blendLoc;
static GLuint shadevectorLoc;
static GLuint lightColorLoc;

// uniforms used in frag shader
static GLuint texLoc;
static GLuint fullbrightTexLoc;
static GLuint useFullbrightTexLoc;
static GLuint useOverbrightLoc;
static GLuint useAlphaTestLoc;

#define pose1VertexAttrIndex 0
#define pose1NormalAttrIndex 1
#define pose2VertexAttrIndex 2
#define pose2NormalAttrIndex 3
#define texCoordsAttrIndex 4

/*
=============
GLARB_GetXYZOffset

Returns the offset of the first vertex's meshxyz_t.xyz in the vbo for the given
model and pose.
=============
*/
static void *GLARB_GetXYZOffset(aliashdr_t *hdr, int32_t pose)
{
	const int32_t xyzoffs = offsetof(meshxyz_t, xyz);
	return (void *)(currententity->model->vboxyzofs + (hdr->numverts_vbo * pose * sizeof(meshxyz_t)) + xyzoffs);
}

/*
=============
GLARB_GetNormalOffset

Returns the offset of the first vertex's meshxyz_t.normal in the vbo for the
given model and pose.
=============
*/
static void *GLARB_GetNormalOffset(aliashdr_t *hdr, int32_t pose)
{
	const int32_t normaloffs = offsetof(meshxyz_t, normal);
	return (void *)(currententity->model->vboxyzofs + (hdr->numverts_vbo * pose * sizeof(meshxyz_t)) + normaloffs);
}

/*
=============
GLAlias_CreateShaders
=============
*/
void GLAlias_CreateShaders(void)
{
	const glsl_attrib_binding_t bindings[] =
	{
		{ "TexCoords", texCoordsAttrIndex },
		{ "Pose1Vert", pose1VertexAttrIndex },
		{ "Pose1Normal", pose1NormalAttrIndex },
		{ "Pose2Vert", pose2VertexAttrIndex },
		{ "Pose2Normal", pose2NormalAttrIndex }
	};

	const GLchar *vertSource = \
	                           "#version 110\n"
	                           "\n"
	                           "uniform float Blend;\n"
	                           "uniform vec3 ShadeVector;\n"
	                           "uniform vec4 LightColor;\n"
	                           "attribute vec4 TexCoords; // only xy are used \n"
	                           "attribute vec4 Pose1Vert;\n"
	                           "attribute vec3 Pose1Normal;\n"
	                           "attribute vec4 Pose2Vert;\n"
	                           "attribute vec3 Pose2Normal;\n"
	                           "\n"
	                           "varying float FogFragCoord;\n"
	                           "\n"
	                           "float r_avertexnormal_dot(vec3 vertexnormal) // from MH \n"
	                           "{\n"
	                           "        float dot = dot(vertexnormal, ShadeVector);\n"
	                           "        // wtf - this reproduces anorm_dots within as reasonable a degree of tolerance as the >= 0 case\n"
	                           "        if (dot < 0.0)\n"
	                           "            return 1.0 + dot * (13.0 / 44.0);\n"
	                           "        else\n"
	                           "            return 1.0 + dot;\n"
	                           "}\n"
	                           "void main()\n"
	                           "{\n"
	                           "	gl_TexCoord[0] = TexCoords;\n"
	                           "	vec4 lerpedVert = mix(vec4(Pose1Vert.xyz, 1.0), vec4(Pose2Vert.xyz, 1.0), Blend);\n"
	                           "	gl_Position = gl_ModelViewProjectionMatrix * lerpedVert;\n"
	                           "	FogFragCoord = gl_Position.w;\n"
	                           "	float dot1 = r_avertexnormal_dot(Pose1Normal);\n"
	                           "	float dot2 = r_avertexnormal_dot(Pose2Normal);\n"
	                           "	gl_FrontColor = LightColor * vec4(vec3(mix(dot1, dot2, Blend)), 1.0);\n"
	                           "}\n";

	const GLchar *fragSource = \
	                           "#version 110\n"
	                           "\n"
	                           "uniform sampler2D Tex;\n"
	                           "uniform sampler2D FullbrightTex;\n"
	                           "uniform bool UseFullbrightTex;\n"
	                           "uniform bool UseOverbright;\n"
	                           "uniform bool UseAlphaTest;\n"
	                           "\n"
	                           "varying float FogFragCoord;\n"
	                           "\n"
	                           "void main()\n"
	                           "{\n"
	                           "	vec4 result = texture2D(Tex, gl_TexCoord[0].xy);\n"
	                           "	if (UseAlphaTest && (result.a < 0.666))\n"
	                           "		discard;\n"
	                           "	result *= gl_Color;\n"
	                           "	if (UseOverbright)\n"
	                           "		result.rgb *= 2.0;\n"
	                           "	if (UseFullbrightTex)\n"
	                           "		result += texture2D(FullbrightTex, gl_TexCoord[0].xy);\n"
	                           "	result = clamp(result, 0.0, 1.0);\n"
	                           "	float fog = exp(-gl_Fog.density * gl_Fog.density * FogFragCoord * FogFragCoord);\n"
	                           "	fog = clamp(fog, 0.0, 1.0);\n"
	                           "	result = mix(gl_Fog.color, result, fog);\n"
	                           "	result.a = gl_Color.a;\n" // FIXME: This will make almost transparent things cut holes though heavy fog
	                           "	gl_FragColor = result;\n"
	                           "}\n";

	if(!gl_glsl_alias_able)
		return;

	r_alias_program = GL_CreateProgram(vertSource, fragSource, arraysizeof(bindings), bindings);

	if(r_alias_program != 0)
	{
		// get uniform locations
		blendLoc = GL_GetUniformLocation(&r_alias_program, "Blend");
		shadevectorLoc = GL_GetUniformLocation(&r_alias_program, "ShadeVector");
		lightColorLoc = GL_GetUniformLocation(&r_alias_program, "LightColor");
		texLoc = GL_GetUniformLocation(&r_alias_program, "Tex");
		fullbrightTexLoc = GL_GetUniformLocation(&r_alias_program, "FullbrightTex");
		useFullbrightTexLoc = GL_GetUniformLocation(&r_alias_program, "UseFullbrightTex");
		useOverbrightLoc = GL_GetUniformLocation(&r_alias_program, "UseOverbright");
		useAlphaTestLoc = GL_GetUniformLocation(&r_alias_program, "UseAlphaTest");
	}
}

/*
=============
GL_DrawAliasFrame_GLSL -- ericw

Optimized alias model drawing codepath.
Compared to the original GL_DrawAliasFrame, this makes 1 draw call,
no vertex data is uploaded (it's already in the r_meshvbo and r_meshindexesvbo
static VBOs), and lerping and lighting is done in the vertex shader.

Supports optional overbright, optional fullbright pixels.

Based on code by MH from RMQEngine
=============
*/
void GL_DrawAliasFrame_GLSL(aliashdr_t *paliashdr, lerpdata_t lerpdata, gltexture_t *tx, gltexture_t *fb)
{
	float   blend;

	if(lerpdata.pose1 != lerpdata.pose2)
	{
		blend = lerpdata.blend;
	}
	else // poses the same means either 1. the entity has paused its animation, or 2. r_lerpmodels is disabled
	{
		blend = 0;
	}

	GL_UseProgramFunc(r_alias_program);

	GL_BindBuffer(GL_ARRAY_BUFFER, currententity->model->meshvbo);
	GL_BindBuffer(GL_ELEMENT_ARRAY_BUFFER, currententity->model->meshindexesvbo);

	GL_EnableVertexAttribArrayFunc(texCoordsAttrIndex);
	GL_EnableVertexAttribArrayFunc(pose1VertexAttrIndex);
	GL_EnableVertexAttribArrayFunc(pose2VertexAttrIndex);
	GL_EnableVertexAttribArrayFunc(pose1NormalAttrIndex);
	GL_EnableVertexAttribArrayFunc(pose2NormalAttrIndex);

	GL_VertexAttribPointerFunc(texCoordsAttrIndex, 2, GL_FLOAT, GL_FALSE, 0, (void *)(intptr_t)currententity->model->vbostofs);
	GL_VertexAttribPointerFunc(pose1VertexAttrIndex, 4, GL_UNSIGNED_BYTE, GL_FALSE, sizeof(meshxyz_t), GLARB_GetXYZOffset(paliashdr, lerpdata.pose1));
	GL_VertexAttribPointerFunc(pose2VertexAttrIndex, 4, GL_UNSIGNED_BYTE, GL_FALSE, sizeof(meshxyz_t), GLARB_GetXYZOffset(paliashdr, lerpdata.pose2));
// GL_TRUE to normalize the signed bytes to [-1 .. 1]
	GL_VertexAttribPointerFunc(pose1NormalAttrIndex, 4, GL_BYTE, GL_TRUE, sizeof(meshxyz_t), GLARB_GetNormalOffset(paliashdr, lerpdata.pose1));
	GL_VertexAttribPointerFunc(pose2NormalAttrIndex, 4, GL_BYTE, GL_TRUE, sizeof(meshxyz_t), GLARB_GetNormalOffset(paliashdr, lerpdata.pose2));

// set uniforms
	GL_Uniform1fFunc(blendLoc, blend);
	GL_Uniform3fFunc(shadevectorLoc, shadevector[0], shadevector[1], shadevector[2]);
	GL_Uniform4fFunc(lightColorLoc, lightcolor[0], lightcolor[1], lightcolor[2], entalpha);
	GL_Uniform1iFunc(texLoc, 0);
	GL_Uniform1iFunc(fullbrightTexLoc, 1);
	GL_Uniform1iFunc(useFullbrightTexLoc, (fb != NULL) ? 1 : 0);
	GL_Uniform1fFunc(useOverbrightLoc, overbright ? 1 : 0);
	GL_Uniform1iFunc(useAlphaTestLoc, (currententity->model->flags & MF_HOLEY) ? 1 : 0);

// set textures
	GL_SelectTexture(GL_TEXTURE0);
	GL_Bind(tx);

	if(fb)
	{
		GL_SelectTexture(GL_TEXTURE1);
		GL_Bind(fb);
	}

// draw
	glDrawElements(GL_TRIANGLES, paliashdr->numindexes, GL_UNSIGNED_SHORT, (void *)(intptr_t)currententity->model->vboindexofs);

// clean up
	GL_DisableVertexAttribArrayFunc(texCoordsAttrIndex);
	GL_DisableVertexAttribArrayFunc(pose1VertexAttrIndex);
	GL_DisableVertexAttribArrayFunc(pose2VertexAttrIndex);
	GL_DisableVertexAttribArrayFunc(pose1NormalAttrIndex);
	GL_DisableVertexAttribArrayFunc(pose2NormalAttrIndex);

	GL_UseProgramFunc(0);
	GL_SelectTexture(GL_TEXTURE0);

	rs_aliaspasses += paliashdr->numtris;
}

/*
=============
GL_DrawAliasFrame -- johnfitz -- rewritten to support colored light, lerping, entalpha, multitexture, and r_drawflat
=============
*/
void GL_DrawAliasFrame(aliashdr_t *paliashdr, lerpdata_t lerpdata)
{
	float   vertcolor[4];
	trivertx_t *verts1, *verts2;
	int32_t         *commands;
	int32_t         count;
	float   u, v;
	float   blend, iblend;
	bool lerping;

	if(lerpdata.pose1 != lerpdata.pose2)
	{
		lerping = true;
		verts1  = (trivertx_t *)((byte *)paliashdr + paliashdr->posedata);
		verts2  = verts1;
		verts1 += lerpdata.pose1 * paliashdr->poseverts;
		verts2 += lerpdata.pose2 * paliashdr->poseverts;
		blend = lerpdata.blend;
		iblend = 1.0f - blend;
	}
	else // poses the same means either 1. the entity has paused its animation, or 2. r_lerpmodels is disabled
	{
		lerping = false;
		verts1  = (trivertx_t *)((byte *)paliashdr + paliashdr->posedata);
		verts2  = verts1; // avoid bogus compiler warning
		verts1 += lerpdata.pose1 * paliashdr->poseverts;
		blend = iblend = 0; // avoid bogus compiler warning
	}

	commands = (int32_t *)((byte *)paliashdr + paliashdr->commands);

	vertcolor[3] = entalpha; //never changes, so there's no need to put this inside the loop

	while(1)
	{
		// get the vertex count and primitive type
		count = *commands++;
		if(!count)
			break;          // done

		if(count < 0)
		{
			count = -count;
			glBegin(GL_TRIANGLE_FAN);
		}
		else
			glBegin(GL_TRIANGLE_STRIP);

		do
		{
			u = ((float *)commands)[0];
			v = ((float *)commands)[1];
			if(mtexenabled)
			{
				GL_MTexCoord2fFunc(GL_TEXTURE0_ARB, u, v);
				GL_MTexCoord2fFunc(GL_TEXTURE1_ARB, u, v);
			}
			else
				glTexCoord2f(u, v);

			commands += 2;

			if(shading)
			{
				if(r_drawflat_cheatsafe)
				{
					srand(count * (uint32_t)(src_offset_t)commands);
					glColor3f(rand() % 256 / 255.0, rand() % 256 / 255.0, rand() % 256 / 255.0);
				}
				else if(lerping)
				{
					vertcolor[0] = (shadedots[verts1->lightnormalindex] * iblend + shadedots[verts2->lightnormalindex] * blend) * lightcolor[0];
					vertcolor[1] = (shadedots[verts1->lightnormalindex] * iblend + shadedots[verts2->lightnormalindex] * blend) * lightcolor[1];
					vertcolor[2] = (shadedots[verts1->lightnormalindex] * iblend + shadedots[verts2->lightnormalindex] * blend) * lightcolor[2];
					glColor4fv(vertcolor);
				}
				else
				{
					vertcolor[0] = shadedots[verts1->lightnormalindex] * lightcolor[0];
					vertcolor[1] = shadedots[verts1->lightnormalindex] * lightcolor[1];
					vertcolor[2] = shadedots[verts1->lightnormalindex] * lightcolor[2];
					glColor4fv(vertcolor);
				}
			}

			if(lerping)
			{
				glVertex3f(verts1->v[0]*iblend + verts2->v[0]*blend,
				           verts1->v[1]*iblend + verts2->v[1]*blend,
				           verts1->v[2]*iblend + verts2->v[2]*blend);
				verts1++;
				verts2++;
			}
			else
			{
				glVertex3f(verts1->v[0], verts1->v[1], verts1->v[2]);
				verts1++;
			}
		}
		while(--count);

		glEnd();
	}

	rs_aliaspasses += paliashdr->numtris;
}

/*
=================
R_SetupAliasFrame -- johnfitz -- rewritten to support lerping
=================
*/
void R_SetupAliasFrame(aliashdr_t *paliashdr, int32_t frame, lerpdata_t *lerpdata)
{
	entity_t                *e = currententity;
	int32_t                         posenum, numposes;

	if((frame >= paliashdr->numframes) || (frame < 0))
	{
		Con_DPrintf("R_AliasSetupFrame: no such frame %" PRIi32 " for '%s'\n", frame, e->model->name);
		frame = 0;
	}

	posenum = paliashdr->frames[frame].firstpose;
	numposes = paliashdr->frames[frame].numposes;

	if(numposes > 1)
	{
		e->lerptime = paliashdr->frames[frame].interval;
		posenum += (int32_t)(cl.time / e->lerptime) % numposes;
	}
	else
		e->lerptime = 0.1;

	if(e->lerpflags & LERP_RESETANIM)  //kill any lerp in progress
	{
		e->lerpstart = 0;
		e->previouspose = posenum;
		e->currentpose = posenum;
		e->lerpflags -= LERP_RESETANIM;
	}
	else if(e->currentpose != posenum)  // pose changed, start new lerp
	{
		if(e->lerpflags & LERP_RESETANIM2)  //defer lerping one more time
		{
			e->lerpstart = 0;
			e->previouspose = posenum;
			e->currentpose = posenum;
			e->lerpflags -= LERP_RESETANIM2;
		}
		else
		{
			e->lerpstart = cl.time;
			e->previouspose = e->currentpose;
			e->currentpose = posenum;
		}
	}

	//set up values
	if(r_lerpmodels.value && !(e->model->flags & MOD_NOLERP && r_lerpmodels.value != 2))
	{
		if(e->lerpflags & LERP_FINISH && numposes == 1)
			lerpdata->blend = CLAMP(0, (cl.time - e->lerpstart) / (e->lerpfinish - e->lerpstart), 1);
		else
			lerpdata->blend = CLAMP(0, (cl.time - e->lerpstart) / e->lerptime, 1);
		lerpdata->pose1 = e->previouspose;
		lerpdata->pose2 = e->currentpose;
	}
	else //don't lerp
	{
		lerpdata->blend = 1;
		lerpdata->pose1 = posenum;
		lerpdata->pose2 = posenum;
	}
}

/*
=================
R_SetupEntityTransform -- johnfitz -- set up transform part of lerpdata
=================
*/
void R_SetupEntityTransform(entity_t *e, lerpdata_t *lerpdata)
{
	float blend;
	vec3_t d;
	int32_t i;

	// if LERP_RESETMOVE, kill any lerps in progress
	if(e->lerpflags & LERP_RESETMOVE)
	{
		e->movelerpstart = 0;
		VectorCopy(e->origin, e->previousorigin);
		VectorCopy(e->origin, e->currentorigin);
		VectorCopy(e->angles, e->previousangles);
		VectorCopy(e->angles, e->currentangles);
		e->lerpflags -= LERP_RESETMOVE;
	}
	else if(!VectorCompare(e->origin, e->currentorigin) || !VectorCompare(e->angles, e->currentangles))    // origin/angles changed, start new lerp
	{
		e->movelerpstart = cl.time;
		VectorCopy(e->currentorigin, e->previousorigin);
		VectorCopy(e->origin,  e->currentorigin);
		VectorCopy(e->currentangles, e->previousangles);
		VectorCopy(e->angles,  e->currentangles);
	}

	//set up values
	if(r_lerpmove.value && e != &cl.viewent && e->lerpflags & LERP_MOVESTEP)
	{
		if(e->lerpflags & LERP_FINISH)
			blend = CLAMP(0, (cl.time - e->movelerpstart) / (e->lerpfinish - e->movelerpstart), 1);
		else
			blend = CLAMP(0, (cl.time - e->movelerpstart) / 0.1, 1);

		//translation
		VectorSubtract(e->currentorigin, e->previousorigin, d);
		lerpdata->origin[0] = e->previousorigin[0] + d[0] * blend;
		lerpdata->origin[1] = e->previousorigin[1] + d[1] * blend;
		lerpdata->origin[2] = e->previousorigin[2] + d[2] * blend;

		//rotation
		VectorSubtract(e->currentangles, e->previousangles, d);
		for(i = 0; i < 3; i++)
		{
			if(d[i] > 180)  d[i] -= 360;
			if(d[i] < -180) d[i] += 360;
		}
		lerpdata->angles[0] = e->previousangles[0] + d[0] * blend;
		lerpdata->angles[1] = e->previousangles[1] + d[1] * blend;
		lerpdata->angles[2] = e->previousangles[2] + d[2] * blend;
	}
	else //don't lerp
	{
		VectorCopy(e->origin, lerpdata->origin);
		VectorCopy(e->angles, lerpdata->angles);
	}
}

/*
=================
R_SetupAliasLighting -- johnfitz -- broken out from R_DrawAliasModel and rewritten
=================
*/
void R_SetupAliasLighting(entity_t     *e)
{
	vec3_t          dist;
	float           add;
	int32_t                 i;
	int32_t         quantizedangle;
	float           radiansangle;

	R_LightPoint(e->origin);

	//add dlights
	for(i = 0 ; i < cl_max_dlights ; i++)
	{
		if(cl_dlights[i].die >= cl.time)
		{
			VectorSubtract(currententity->origin, cl_dlights[i].origin, dist);
			add = cl_dlights[i].radius - VectorLength(dist);
			if(add > 0)
				VectorMA(lightcolor, add, cl_dlights[i].color, lightcolor);
		}
	}

	// minimum light value on gun (24)
	if(e == &cl.viewent)
	{
		add = 72.0f - (lightcolor[0] + lightcolor[1] + lightcolor[2]);
		if(add > 0.0f)
		{
			lightcolor[0] += add / 3.0f;
			lightcolor[1] += add / 3.0f;
			lightcolor[2] += add / 3.0f;
		}
	}

	// minimum light value on players (8)
	if(currententity > cl_entities && currententity <= cl_entities + cl.maxclients)
	{
		add = 24.0f - (lightcolor[0] + lightcolor[1] + lightcolor[2]);
		if(add > 0.0f)
		{
			lightcolor[0] += add / 3.0f;
			lightcolor[1] += add / 3.0f;
			lightcolor[2] += add / 3.0f;
		}
	}

	// clamp lighting so it doesn't overbright as much (96)
	if(overbright)
	{
		add = 288.0f / (lightcolor[0] + lightcolor[1] + lightcolor[2]);
		if(add < 1.0f)
			VectorScale(lightcolor, add, lightcolor);
	}

	//hack up the brightness when fullbrights but no overbrights (256)
	if(gl_fullbrights.value && !gl_overbright_models.value)
		if(e->model->flags & MOD_FBRIGHTHACK)
		{
			lightcolor[0] = 256.0f;
			lightcolor[1] = 256.0f;
			lightcolor[2] = 256.0f;
		}

	quantizedangle = ((int32_t)(e->angles[1] * (SHADEDOT_QUANT / 360.0))) & (SHADEDOT_QUANT - 1);

//ericw -- shadevector is passed to the shader to compute shadedots inside the
//shader, see GLAlias_CreateShaders()
	radiansangle = (quantizedangle / 16.0) * 2.0 * 3.14159;
	shadevector[0] = cos(-radiansangle);
	shadevector[1] = sin(-radiansangle);
	shadevector[2] = 1;
	VectorNormalize(shadevector);
//ericw --

	shadedots = r_avertexnormal_dots[quantizedangle];
	VectorScale(lightcolor, 1.0f / 200.0f, lightcolor);
}

/*
=================
R_DrawAliasModel -- johnfitz -- almost completely rewritten
=================
*/
void R_DrawAliasModel(entity_t *e)
{
	aliashdr_t      *paliashdr;
	int32_t                 i, anim, skinnum;
	gltexture_t     *tx, *fb;
	lerpdata_t      lerpdata;
	bool    alphatest = !!(e->model->flags & MF_HOLEY);

	//
	// setup pose/lerp data -- do it first so we don't miss updates due to culling
	//
	paliashdr = (aliashdr_t *)Mod_Extradata(e->model);
	R_SetupAliasFrame(paliashdr, e->frame, &lerpdata);
	R_SetupEntityTransform(e, &lerpdata);

	//
	// cull it
	//
	if(R_CullModelForEntity(e))
		return;

	//
	// transform it
	//
	glPushMatrix();
	R_RotateForEntity(lerpdata.origin, lerpdata.angles);
	glTranslatef(paliashdr->scale_origin[0], paliashdr->scale_origin[1], paliashdr->scale_origin[2]);
	glScalef(paliashdr->scale[0], paliashdr->scale[1], paliashdr->scale[2]);

	//
	// random stuff
	//
	if(gl_smoothmodels.value && !r_drawflat_cheatsafe)
		glShadeModel(GL_SMOOTH);
	if(gl_affinemodels.value)
		glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_FASTEST);
	overbright = gl_overbright_models.value;
	shading = true;

	//
	// set up for alpha blending
	//
	if(r_drawflat_cheatsafe || r_lightmap_cheatsafe)  //no alpha in drawflat or lightmap mode
		entalpha = 1;
	else
		entalpha = ENTALPHA_DECODE(e->alpha);
	if(entalpha == 0)
		goto cleanup;
	if(entalpha < 1)
	{
		if(!gl_texture_env_combine) overbright = false;  //overbright can't be done in a single pass without combiners
		glDepthMask(GL_FALSE);
		glEnable(GL_BLEND);
	}
	else if(alphatest)
		glEnable(GL_ALPHA_TEST);

	//
	// set up lighting
	//
	rs_aliaspolys += paliashdr->numtris;
	R_SetupAliasLighting(e);

	//
	// set up textures
	//
	GL_DisableMultitexture();
	anim = (int32_t)(cl.time * 10) & 3;
	skinnum = e->skinnum;
	if((skinnum >= paliashdr->numskins) || (skinnum < 0))
	{
		Con_DPrintf("R_DrawAliasModel: no such skin # %" PRIi32 " for '%s'\n", skinnum, e->model->name);
		// ericw -- display skin 0 for winquake compatibility
		skinnum = 0;
	}
	tx = paliashdr->gltextures[skinnum][anim];
	fb = paliashdr->fbtextures[skinnum][anim];
	if(e->colormap != vid.colormap && !gl_nocolors.value)
	{
		i = e - cl_entities;
		if(i >= 1 && i <= cl.maxclients /* && !strcmp (currententity->model->name, "progs/player.mdl") */)
			tx = playertextures[i - 1];
	}
	if(!gl_fullbrights.value)
		fb = NULL;

	//
	// draw it
	//
	if(r_drawflat_cheatsafe)
	{
		glDisable(GL_TEXTURE_2D);
		GL_DrawAliasFrame(paliashdr, lerpdata);
		glEnable(GL_TEXTURE_2D);
		srand((int32_t)(cl.time * 1000));  //restore randomness
	}
	else if(r_fullbright_cheatsafe)
	{
		GL_Bind(tx);
		shading = false;
		glColor4f(1, 1, 1, entalpha);
		GL_DrawAliasFrame(paliashdr, lerpdata);
		if(fb)
		{
			glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
			GL_Bind(fb);
			glEnable(GL_BLEND);
			glBlendFunc(GL_ONE, GL_ONE);
			glDepthMask(GL_FALSE);
			glColor3f(entalpha, entalpha, entalpha);
			Fog_StartAdditive();
			GL_DrawAliasFrame(paliashdr, lerpdata);
			Fog_StopAdditive();
			glDepthMask(GL_TRUE);
			glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
			glDisable(GL_BLEND);
		}
	}
	else if(r_lightmap_cheatsafe)
	{
		glDisable(GL_TEXTURE_2D);
		shading = false;
		glColor3f(1, 1, 1);
		GL_DrawAliasFrame(paliashdr, lerpdata);
		glEnable(GL_TEXTURE_2D);
	}
// call fast path if possible. if the shader compliation failed for some reason,
// r_alias_program will be 0.
	else if(r_alias_program != 0)
	{
		GL_DrawAliasFrame_GLSL(paliashdr, lerpdata, tx, fb);
	}
	else if(overbright)
	{
		if(gl_texture_env_combine && gl_mtexable && gl_texture_env_add && fb)   //case 1: everything in one pass
		{
			GL_Bind(tx);
			glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_EXT);
			glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_RGB_EXT, GL_MODULATE);
			glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE0_RGB_EXT, GL_TEXTURE);
			glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE1_RGB_EXT, GL_PRIMARY_COLOR_EXT);
			glTexEnvf(GL_TEXTURE_ENV, GL_RGB_SCALE_EXT, 2.0f);
			GL_EnableMultitexture(); // selects TEXTURE1
			GL_Bind(fb);
			glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_ADD);
			glEnable(GL_BLEND);
			GL_DrawAliasFrame(paliashdr, lerpdata);
			glDisable(GL_BLEND);
			GL_DisableMultitexture();
			glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
		}
		else if(gl_texture_env_combine)  //case 2: overbright in one pass, then fullbright pass
		{
			// first pass
			GL_Bind(tx);
			glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_EXT);
			glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_RGB_EXT, GL_MODULATE);
			glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE0_RGB_EXT, GL_TEXTURE);
			glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE1_RGB_EXT, GL_PRIMARY_COLOR_EXT);
			glTexEnvf(GL_TEXTURE_ENV, GL_RGB_SCALE_EXT, 2.0f);
			GL_DrawAliasFrame(paliashdr, lerpdata);
			glTexEnvf(GL_TEXTURE_ENV, GL_RGB_SCALE_EXT, 1.0f);
			glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
			// second pass
			if(fb)
			{
				glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
				GL_Bind(fb);
				glEnable(GL_BLEND);
				glBlendFunc(GL_ONE, GL_ONE);
				glDepthMask(GL_FALSE);
				shading = false;
				glColor3f(entalpha, entalpha, entalpha);
				Fog_StartAdditive();
				GL_DrawAliasFrame(paliashdr, lerpdata);
				Fog_StopAdditive();
				glDepthMask(GL_TRUE);
				glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
				glDisable(GL_BLEND);
				glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
			}
		}
		else //case 3: overbright in two passes, then fullbright pass
		{
			// first pass
			GL_Bind(tx);
			glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
			GL_DrawAliasFrame(paliashdr, lerpdata);
			// second pass -- additive with black fog, to double the object colors but not the fog color
			glEnable(GL_BLEND);
			glBlendFunc(GL_ONE, GL_ONE);
			glDepthMask(GL_FALSE);
			Fog_StartAdditive();
			GL_DrawAliasFrame(paliashdr, lerpdata);
			Fog_StopAdditive();
			glDepthMask(GL_TRUE);
			glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
			glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
			glDisable(GL_BLEND);
			// third pass
			if(fb)
			{
				glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
				GL_Bind(fb);
				glEnable(GL_BLEND);
				glBlendFunc(GL_ONE, GL_ONE);
				glDepthMask(GL_FALSE);
				shading = false;
				glColor3f(entalpha, entalpha, entalpha);
				Fog_StartAdditive();
				GL_DrawAliasFrame(paliashdr, lerpdata);
				Fog_StopAdditive();
				glDepthMask(GL_TRUE);
				glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
				glDisable(GL_BLEND);
				glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
			}
		}
	}
	else
	{
		if(gl_mtexable && gl_texture_env_add && fb)  //case 4: fullbright mask using multitexture
		{
			GL_DisableMultitexture(); // selects TEXTURE0
			GL_Bind(tx);
			glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
			GL_EnableMultitexture(); // selects TEXTURE1
			GL_Bind(fb);
			glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_ADD);
			glEnable(GL_BLEND);
			GL_DrawAliasFrame(paliashdr, lerpdata);
			glDisable(GL_BLEND);
			GL_DisableMultitexture();
			glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
		}
		else //case 5: fullbright mask without multitexture
		{
			// first pass
			GL_Bind(tx);
			glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
			GL_DrawAliasFrame(paliashdr, lerpdata);
			// second pass
			if(fb)
			{
				GL_Bind(fb);
				glEnable(GL_BLEND);
				glBlendFunc(GL_ONE, GL_ONE);
				glDepthMask(GL_FALSE);
				shading = false;
				glColor3f(entalpha, entalpha, entalpha);
				Fog_StartAdditive();
				GL_DrawAliasFrame(paliashdr, lerpdata);
				Fog_StopAdditive();
				glDepthMask(GL_TRUE);
				glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
				glDisable(GL_BLEND);
			}
		}
	}

cleanup:
	glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
	glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
	glShadeModel(GL_FLAT);
	glDepthMask(GL_TRUE);
	glDisable(GL_BLEND);
	if(alphatest)
		glDisable(GL_ALPHA_TEST);
	glColor3f(1, 1, 1);
	glPopMatrix();
}

//johnfitz -- values for shadow matrix
#define SHADOW_SKEW_X -0.7 //skew along x axis. -0.7 to mimic glquake shadows
#define SHADOW_SKEW_Y 0 //skew along y axis. 0 to mimic glquake shadows
#define SHADOW_VSCALE 0 //0=completely flat
#define SHADOW_HEIGHT 0.1 //how far above the floor to render the shadow
//johnfitz

/*
=============
GL_DrawAliasShadow -- johnfitz -- rewritten

TODO: orient shadow onto "lightplane" (a global mplane_t*)
=============
*/
void GL_DrawAliasShadow(entity_t *e)
{
	float   shadowmatrix[16] = {1,                          0,                              0,                              0,
	                            0,                              1,                              0,                              0,
	                            SHADOW_SKEW_X,  SHADOW_SKEW_Y,  SHADOW_VSCALE,  0,
	                            0,                              0,                              SHADOW_HEIGHT,  1
	                           };
	float           lheight;
	aliashdr_t      *paliashdr;
	lerpdata_t      lerpdata;

	if(R_CullModelForEntity(e))
		return;

	if(e == &cl.viewent || e->model->flags & MOD_NOSHADOW)
		return;

	entalpha = ENTALPHA_DECODE(e->alpha);
	if(entalpha == 0) return;

	paliashdr = (aliashdr_t *)Mod_Extradata(e->model);
	R_SetupAliasFrame(paliashdr, e->frame, &lerpdata);
	R_SetupEntityTransform(e, &lerpdata);
	R_LightPoint(e->origin);
	lheight = currententity->origin[2] - lightspot[2];

// set up matrix
	glPushMatrix();
	glTranslatef(lerpdata.origin[0],  lerpdata.origin[1],  lerpdata.origin[2]);
	glTranslatef(0, 0, -lheight);
	glMultMatrixf(shadowmatrix);
	glTranslatef(0, 0, lheight);
	glRotatef(lerpdata.angles[1],  0, 0, 1);
	glRotatef(-lerpdata.angles[0],  0, 1, 0);
	glRotatef(lerpdata.angles[2],  1, 0, 0);
	glTranslatef(paliashdr->scale_origin[0], paliashdr->scale_origin[1], paliashdr->scale_origin[2]);
	glScalef(paliashdr->scale[0], paliashdr->scale[1], paliashdr->scale[2]);

// draw it
	glDepthMask(GL_FALSE);
	glEnable(GL_BLEND);
	GL_DisableMultitexture();
	glDisable(GL_TEXTURE_2D);
	shading = false;
	glColor4f(0, 0, 0, entalpha * 0.5);
	GL_DrawAliasFrame(paliashdr, lerpdata);
	glEnable(GL_TEXTURE_2D);
	glDisable(GL_BLEND);
	glDepthMask(GL_TRUE);

//clean up
	glPopMatrix();
}

/*
=================
R_DrawAliasModel_ShowTris -- johnfitz
=================
*/
void R_DrawAliasModel_ShowTris(entity_t *e)
{
	aliashdr_t      *paliashdr;
	lerpdata_t      lerpdata;

	if(R_CullModelForEntity(e))
		return;

	paliashdr = (aliashdr_t *)Mod_Extradata(e->model);
	R_SetupAliasFrame(paliashdr, e->frame, &lerpdata);
	R_SetupEntityTransform(e, &lerpdata);

	glPushMatrix();
	R_RotateForEntity(lerpdata.origin, lerpdata.angles);
	glTranslatef(paliashdr->scale_origin[0], paliashdr->scale_origin[1], paliashdr->scale_origin[2]);
	glScalef(paliashdr->scale[0], paliashdr->scale[1], paliashdr->scale[2]);

	shading = false;
	glColor3f(1, 1, 1);
	GL_DrawAliasFrame(paliashdr, lerpdata);

	glPopMatrix();
}