#include "quakedef.h"

#define LERPSPRITES

#ifdef LERPSPRITES
void R_ClipSpriteImage (vec3_t origin, vec3_t left, vec3_t up)
{
	int i;
	mspriteframe_t *frame;
	vec3_t points[4];
	float fleft, fright, fdown, fup;
	frame = currentrenderentity->model->sprdata_frames + currentrenderentity->frameblend[0].frame;
	fleft  = frame->left;
	fdown  = frame->down;
	fright = frame->right;
	fup    = frame->up;
	for (i = 1;i < 4 && currentrenderentity->frameblend[i].lerp;i++)
	{
		frame = currentrenderentity->model->sprdata_frames + currentrenderentity->frameblend[i].frame;
		fleft  = min(fleft , frame->left );
		fdown  = min(fdown , frame->down );
		fright = max(fright, frame->right);
		fup    = max(fup   , frame->up   );
	}
	// FIXME: reverse these in loader to save time
	fleft = -fleft;
	fright = -fright;
	points[0][0] = origin[0] + fdown * up[0] + fleft  * left[0];points[0][1] = origin[1] + fdown * up[1] + fleft  * left[1];points[0][2] = origin[2] + fdown * up[2] + fleft  * left[2];
	points[1][0] = origin[0] + fup   * up[0] + fleft  * left[0];points[1][1] = origin[1] + fup   * up[1] + fleft  * left[1];points[1][2] = origin[2] + fup   * up[2] + fleft  * left[2];
	points[2][0] = origin[0] + fup   * up[0] + fright * left[0];points[2][1] = origin[1] + fup   * up[1] + fright * left[1];points[2][2] = origin[2] + fup   * up[2] + fright * left[2];
	points[3][0] = origin[0] + fdown * up[0] + fright * left[0];points[3][1] = origin[1] + fdown * up[1] + fright * left[1];points[3][2] = origin[2] + fdown * up[2] + fright * left[2];
	R_Clip_AddPolygon(&points[0][0], 4, sizeof(float[3]), false, R_Entity_Callback, currentrenderentity, NULL, NULL);
}
#else
void R_ClipSpriteImage (vec3_t origin, vec3_t left, vec3_t up)
{
	int i;
	mspriteframe_t *frame;
	vec3_t points[4];
	float fleft, fright, fdown, fup;
	frame = NULL;
	for (i = 0;i < 4 && currentrenderentity->frameblend[i].lerp;i++)
		frame = currentrenderentity->model->sprdata_frames + currentrenderentity->frameblend[i].frame;
	fleft  = frame->left;
	fdown  = frame->down;
	fright = frame->right;
	fup    = frame->up;
	// FIXME: reverse these in loader to save time
	fleft = -fleft;
	fright = -fright;
	points[0][0] = origin[0] + fdown * up[0] + fleft  * left[0];points[0][1] = origin[1] + fdown * up[1] + fleft  * left[1];points[0][2] = origin[2] + fdown * up[2] + fleft  * left[2];
	points[1][0] = origin[0] + fup   * up[0] + fleft  * left[0];points[1][1] = origin[1] + fup   * up[1] + fleft  * left[1];points[1][2] = origin[2] + fup   * up[2] + fleft  * left[2];
	points[2][0] = origin[0] + fup   * up[0] + fright * left[0];points[2][1] = origin[1] + fup   * up[1] + fright * left[1];points[2][2] = origin[2] + fup   * up[2] + fright * left[2];
	points[3][0] = origin[0] + fdown * up[0] + fright * left[0];points[3][1] = origin[1] + fdown * up[1] + fright * left[1];points[3][2] = origin[2] + fdown * up[2] + fright * left[2];
	R_Clip_AddPolygon(&points[0][0], 4, sizeof(float[3]), false, R_Entity_Callback, currentrenderentity, NULL, NULL);
}
#endif

int R_SpriteSetup (int type, float org[3], float left[3], float up[3])
{
	float matrix1[3][3], matrix2[3][3], matrix3[3][3];

	VectorCopy(currentrenderentity->origin, org);
	switch(type)
	{
	case SPR_VP_PARALLEL_UPRIGHT:
		// flames and such
		// vertical beam sprite, faces view plane
		VectorNegate(vpn, matrix3[0]);
		matrix3[0][2] = 0;
		VectorNormalizeFast(matrix3[0]);
		matrix3[1][0] = matrix3[0][1];
		matrix3[1][1] = -matrix3[0][0];
		matrix3[1][2] = 0;
		matrix3[2][0] = 0;
		matrix3[2][1] = 0;
		matrix3[2][2] = 1;
		break;
	case SPR_FACING_UPRIGHT:
		// flames and such
		// vertical beam sprite, faces viewer's origin (not the view plane)
		VectorSubtract(currentrenderentity->origin, r_origin, matrix3[0]);
		matrix3[0][2] = 0;
		VectorNormalizeFast(matrix3[0]);
		matrix3[1][0] = matrix3[0][1];
		matrix3[1][1] = -matrix3[0][0];
		matrix3[1][2] = 0;
		matrix3[2][0] = 0;
		matrix3[2][1] = 0;
		matrix3[2][2] = 1;
		break;
	default:
		Con_Printf("R_SpriteSetup: unknown sprite type %i\n", type);
		// fall through to normal sprite
	case SPR_VP_PARALLEL:
		// normal sprite
		// faces view plane
		VectorCopy(vpn, matrix3[0]);
		VectorNegate(vright, matrix3[1]);
		VectorCopy(vup, matrix3[2]);
		break;
	case SPR_ORIENTED:
		// bullet marks on walls
		// ignores viewer entirely
		AngleVectorsFLU (currentrenderentity->angles, matrix3[0], matrix3[1], matrix3[2]);
		// nudge it toward the view, so it will be infront of the wall
		VectorSubtract(org, vpn, org);
		break;
	case SPR_VP_PARALLEL_ORIENTED:
		// I have no idea what people would use this for
		// oriented relative to view space
		// FIXME: test this and make sure it mimicks software
		AngleVectorsFLU (currentrenderentity->angles, matrix1[0], matrix1[1], matrix1[2]);
		VectorCopy(vpn, matrix2[0]);
		VectorNegate(vright, matrix2[1]);
		VectorCopy(vup, matrix2[2]);
		R_ConcatRotations (matrix1[0], matrix2[0], matrix3[0]);
		break;
	}

	if (currentrenderentity->scale != 1)
	{
		VectorScale(matrix3[1], currentrenderentity->scale, left);
		VectorScale(matrix3[2], currentrenderentity->scale, up);
	}
	else
	{
		VectorCopy(matrix3[1], left);
		VectorCopy(matrix3[2], up);
	}
	return false;
}

void R_ClipSprite (void)
{
	vec3_t org, left, up;

	if (currentrenderentity->frameblend[0].frame < 0)
		return;

	if (R_SpriteSetup(currentrenderentity->model->sprnum_type, org, left, up))
		return;

	// LordHavoc: interpolated sprite rendering
	R_ClipSpriteImage(org, left, up);
}

int spritepolyindex[6] = {0, 1, 2, 0, 2, 3};

void GL_DrawSpriteImage (int fog, mspriteframe_t *frame, int texture, vec3_t origin, vec3_t up, vec3_t left, float red, float green, float blue, float alpha)
{
	rmeshinfo_t m;
	float v[4][4], st[4][2];
	memset(&m, 0, sizeof(m));
	m.transparent = true;
	m.blendfunc1 = GL_SRC_ALPHA;
	m.blendfunc2 = GL_ONE_MINUS_SRC_ALPHA;
	if ((currentrenderentity->effects & EF_ADDITIVE)
	 || (currentrenderentity->model->flags & EF_ADDITIVE)
	 || fog)
		m.blendfunc2 = GL_ONE;
	m.numtriangles = 2;
	m.index = spritepolyindex;
	m.numverts = 4;
	m.vertex = &v[0][0];
	m.vertexstep = sizeof(float[4]);
	m.cr = red;
	m.cg = green;
	m.cb = blue;
	m.ca = alpha;
	m.tex[0] = texture;
	m.texcoords[0] = &st[0][0];
	m.texcoordstep[0] = sizeof(float[2]);

	// FIXME: negate left and right in loader
	v[0][0] = origin[0] + frame->down * up[0] - frame->left  * left[0];
	v[0][1] = origin[1] + frame->down * up[1] - frame->left  * left[1];
	v[0][2] = origin[2] + frame->down * up[2] - frame->left  * left[2];
	v[1][0] = origin[0] + frame->up   * up[0] - frame->left  * left[0];
	v[1][1] = origin[1] + frame->up   * up[1] - frame->left  * left[1];
	v[1][2] = origin[2] + frame->up   * up[2] - frame->left  * left[2];
	v[2][0] = origin[0] + frame->up   * up[0] - frame->right * left[0];
	v[2][1] = origin[1] + frame->up   * up[1] - frame->right * left[1];
	v[2][2] = origin[2] + frame->up   * up[2] - frame->right * left[2];
	v[3][0] = origin[0] + frame->down * up[0] - frame->right * left[0];
	v[3][1] = origin[1] + frame->down * up[1] - frame->right * left[1];
	v[3][2] = origin[2] + frame->down * up[2] - frame->right * left[2];
	st[0][0] = 0;
	st[0][1] = 1;
	st[1][0] = 0;
	st[1][1] = 0;
	st[2][0] = 1;
	st[2][1] = 0;
	st[3][0] = 1;
	st[3][1] = 1;

	R_Mesh_Draw(&m);
}

/*
=================
R_DrawSpriteModel
=================
*/
void R_DrawSpriteModel ()
{
	int			i;
	vec3_t		left, up, org, color;
	mspriteframe_t *frame;
	vec3_t diff;
	float		fog, ifog;

	if (currentrenderentity->frameblend[0].frame < 0)
		return;

	if (R_SpriteSetup(currentrenderentity->model->sprnum_type, org, left, up))
		return;

	c_sprites++;

	if ((currentrenderentity->model->flags & EF_FULLBRIGHT) || (currentrenderentity->effects & EF_FULLBRIGHT))
		color[0] = color[1] = color[2] = 1;
	else
		R_CompleteLightPoint(color, currentrenderentity->origin, true, NULL);

	if (fogenabled)
	{
		VectorSubtract(currentrenderentity->origin, r_origin, diff);
		fog = exp(fogdensity/DotProduct(diff,diff));
		if (fog > 1)
			fog = 1;
	}
	else
		fog = 0;
	ifog = 1 - fog;

#ifdef LERPSPRITES
	// LordHavoc: interpolated sprite rendering
	for (i = 0;i < 4;i++)
	{
		if (currentrenderentity->frameblend[i].lerp >= 0.01f)
		{
			frame = currentrenderentity->model->sprdata_frames + currentrenderentity->frameblend[i].frame;
			GL_DrawSpriteImage(false, frame, R_GetTexture(frame->texture), org, up, left, color[0] * ifog, color[1] * ifog, color[2] * ifog, currentrenderentity->alpha * currentrenderentity->frameblend[i].lerp);
			if (fog * currentrenderentity->frameblend[i].lerp >= 0.01f)
				GL_DrawSpriteImage(true, frame, R_GetTexture(frame->fogtexture), org, up, left, fogcolor[0],fogcolor[1],fogcolor[2], fog * currentrenderentity->alpha * currentrenderentity->frameblend[i].lerp);
		}
	}
#else
	// LordHavoc: no interpolation
	frame = NULL;
	for (i = 0;i < 4 && currentrenderentity->frameblend[i].lerp;i++)
		frame = currentrenderentity->model->sprdata_frames + currentrenderentity->frameblend[i].frame;

	GL_DrawSpriteImage(false, frame, R_GetTexture(frame->texture), org, up, left, color[0] * ifog, color[1] * ifog, color[2] * ifog, currentrenderentity->alpha);
	if (fog * currentrenderentity->frameblend[i].lerp >= 0.01f)
		GL_DrawSpriteImage(true, frame, R_GetTexture(frame->fogtexture), org, up, left, fogcolor[0],fogcolor[1],fogcolor[2], fog * currentrenderentity->alpha);
#endif
}