/*
===========================================================================
Copyright (C) 2011 Andrei Drexler, Richard Allen, James Canete

This file is part of Reaction source code.

Reaction 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.

Reaction 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 Reaction source code; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/

#include "tr_local.h"

void RB_ToneMap(FBO_t *hdrFbo, int autoExposure)
{
	vec4i_t srcBox, dstBox;
	vec4_t color;
	static int lastFrameCount = 0;

	if (autoExposure)
	{
		if (lastFrameCount == 0 || tr.frameCount < lastFrameCount || tr.frameCount - lastFrameCount > 5)
		{
			// determine average log luminance
			FBO_t *srcFbo, *dstFbo, *tmp;
			int size = 256;

			lastFrameCount = tr.frameCount;

			VectorSet4(dstBox, 0, 0, size, size);

			srcFbo = hdrFbo;
			dstFbo = tr.textureScratchFbo[0];
			FBO_Blit(srcFbo, NULL, NULL, dstFbo, dstBox, &tr.calclevels4xShader[0], NULL, 0);

			srcFbo = tr.textureScratchFbo[0];
			dstFbo = tr.textureScratchFbo[1];

			// downscale to 1x1 texture
			while (size > 1)
			{
				VectorSet4(srcBox, 0, 0, size, size);
				//size >>= 2;
				size >>= 1;
				VectorSet4(dstBox, 0, 0, size, size);

				if (size == 1)
					dstFbo = tr.targetLevelsFbo;

				//FBO_Blit(targetFbo, srcBox, NULL, tr.textureScratchFbo[nextScratch], dstBox, &tr.calclevels4xShader[1], NULL, 0);
				FBO_FastBlit(srcFbo, srcBox, dstFbo, dstBox, GL_COLOR_BUFFER_BIT, GL_LINEAR);

				tmp = srcFbo;
				srcFbo = dstFbo;
				dstFbo = tmp;
			}
		}

		// blend with old log luminance for gradual change
		VectorSet4(srcBox, 0, 0, 0, 0);

		color[0] = 
		color[1] =
		color[2] = 1.0f;
		if (glRefConfig.textureFloat)
			color[3] = 0.03f;
		else
			color[3] = 0.1f;

		FBO_Blit(tr.targetLevelsFbo, srcBox, NULL, tr.calcLevelsFbo, NULL,  NULL, color, GLS_SRCBLEND_SRC_ALPHA | GLS_DSTBLEND_ONE_MINUS_SRC_ALPHA);
	}

	// tonemap
	color[0] =
	color[1] =
	color[2] = pow(2, r_cameraExposure->value); //exp2(r_cameraExposure->value);
	color[3] = 1.0f;

	if (autoExposure)
		GL_BindToTMU(tr.calcLevelsImage,  TB_LEVELSMAP);
	else
		GL_BindToTMU(tr.fixedLevelsImage, TB_LEVELSMAP);

	FBO_Blit(hdrFbo, NULL, NULL, tr.screenScratchFbo, NULL, &tr.tonemapShader, color, 0);
}


void RB_BokehBlur(float blur)
{
//	vec4i_t srcBox, dstBox;
	vec4_t color;
	
	blur *= 10.0f;

	if (blur < 0.004f)
		return;

	if (glRefConfig.framebufferObject)
	{
		// bokeh blur
		if (blur > 0.0f)
		{
			// create a quarter texture
			//FBO_Blit(NULL, NULL, NULL, tr.quarterFbo[0], NULL, NULL, NULL, 0);
			FBO_FastBlit(tr.screenScratchFbo, NULL, tr.quarterFbo[0], NULL, GL_COLOR_BUFFER_BIT, GL_LINEAR);
		}

#ifndef HQ_BLUR
		if (blur > 1.0f)
		{
			// create a 1/16th texture
			//FBO_Blit(tr.quarterFbo[0], NULL, NULL, tr.textureScratchFbo[0], NULL, NULL, NULL, 0);
			FBO_FastBlit(tr.quarterFbo[0], NULL, tr.textureScratchFbo[0], NULL, GL_COLOR_BUFFER_BIT, GL_LINEAR);
		}
#endif

		if (blur > 0.0f && blur <= 1.0f)
		{
			// Crossfade original with quarter texture
			VectorSet4(color, 1, 1, 1, blur);

			FBO_Blit(tr.quarterFbo[0], NULL, NULL, tr.screenScratchFbo, NULL, NULL, color, GLS_SRCBLEND_SRC_ALPHA | GLS_DSTBLEND_ONE_MINUS_SRC_ALPHA);
		}
#ifndef HQ_BLUR
		// ok blur, but can see some pixelization
		else if (blur > 1.0f && blur <= 2.0f)
		{
			// crossfade quarter texture with 1/16th texture
			FBO_Blit(tr.quarterFbo[0], NULL, NULL, tr.screenScratchFbo, NULL, NULL, NULL, 0);

			VectorSet4(color, 1, 1, 1, blur - 1.0f);

			FBO_Blit(tr.textureScratchFbo[0], NULL, NULL, tr.screenScratchFbo, NULL, NULL, color, GLS_SRCBLEND_SRC_ALPHA | GLS_DSTBLEND_ONE_MINUS_SRC_ALPHA);
		}
		else if (blur > 2.0f)
		{
			// blur 1/16th texture then replace
			int i;

			for (i = 0; i < 2; i++)
			{
				vec2_t blurTexScale;
				float subblur;

				subblur = ((blur - 2.0f) / 2.0f) / 3.0f * (float)(i + 1);

				blurTexScale[0] =
				blurTexScale[1] = subblur;

				color[0] =
				color[1] =
				color[2] = 0.5f;
				color[3] = 1.0f;

				if (i != 0)
					FBO_Blit(tr.textureScratchFbo[0], NULL, blurTexScale, tr.textureScratchFbo[1], NULL, &tr.bokehShader, color, GLS_SRCBLEND_ONE | GLS_DSTBLEND_ONE);
				else
					FBO_Blit(tr.textureScratchFbo[0], NULL, blurTexScale, tr.textureScratchFbo[1], NULL, &tr.bokehShader, color, 0);
			}

			FBO_Blit(tr.textureScratchFbo[1], NULL, NULL, tr.screenScratchFbo, NULL, &tr.textureColorShader, NULL, 0);
		}
#else // higher quality blur, but slower
		else if (blur > 1.0f)
		{
			// blur quarter texture then replace
			int i;

			src = tr.quarterFbo[0];
			dst = tr.quarterFbo[1];

			VectorSet4(color, 0.5f, 0.5f, 0.5f, 1);

			for (i = 0; i < 2; i++)
			{
				vec2_t blurTexScale;
				float subblur;

				subblur = (blur - 1.0f) / 2.0f * (float)(i + 1);

				blurTexScale[0] =
				blurTexScale[1] = subblur;

				color[0] =
				color[1] =
				color[2] = 1.0f;
				if (i != 0)
					color[3] = 1.0f;
				else
					color[3] = 0.5f;

				FBO_Blit(tr.quarterFbo[0], NULL, blurTexScale, tr.quarterFbo[1], NULL, &tr.bokehShader, color, GLS_SRCBLEND_SRC_ALPHA | GLS_DSTBLEND_ONE_MINUS_SRC_ALPHA);
			}

			FBO_Blit(tr.quarterFbo[1], NULL, NULL, tr.screenScratchFbo, NULL, &tr.textureColorShader, NULL, 0);
		}
#endif
	}
}


#ifdef REACTION
static void RB_RadialBlur(FBO_t *srcFbo, FBO_t *dstFbo, int passes, float stretch, float x, float y, float w, float h, float xcenter, float ycenter, float alpha)
{
	vec4i_t srcBox, dstBox;
	vec4_t color;
	const float inc = 1.f / passes;
	const float mul = powf(stretch, inc);
	float scale;

	{
		vec2_t texScale;

		texScale[0] = 
		texScale[1] = 1.0f;

		alpha *= inc;
		VectorSet4(color, alpha, alpha, alpha, 1.0f);

		VectorSet4(srcBox, 0, 0, srcFbo->width, srcFbo->height);
		VectorSet4(dstBox, x, y, w, h);
		FBO_Blit(srcFbo, srcBox, texScale, dstFbo, dstBox, &tr.textureColorShader, color, 0);

		--passes;
		scale = mul;
		while (passes > 0)
		{
			float iscale = 1.f / scale;
			float s0 = xcenter * (1.f - iscale);
			float t0 = (1.0f - ycenter) * (1.f - iscale);
			float s1 = iscale + s0;
			float t1 = iscale + t0;

			srcBox[0] = s0 * srcFbo->width;
			srcBox[1] = t0 * srcFbo->height;
			srcBox[2] = (s1 - s0) * srcFbo->width;
			srcBox[3] = (t1 - t0) * srcFbo->height;
			
			FBO_Blit(srcFbo, srcBox, texScale, dstFbo, dstBox, &tr.textureColorShader, color, GLS_SRCBLEND_ONE | GLS_DSTBLEND_ONE );

			scale *= mul;
			--passes;
		}
	}
}


static qboolean RB_UpdateSunFlareVis(void)
{
	GLuint sampleCount = 0;
	if (!glRefConfig.occlusionQuery)
		return qtrue;

	tr.sunFlareQueryIndex ^= 1;
	if (!tr.sunFlareQueryActive[tr.sunFlareQueryIndex])
		return qtrue;

	/* debug code */
	if (0)
	{
		int iter;
		for (iter=0 ; ; ++iter)
		{
			GLint available = 0;
			qglGetQueryObjectivARB(tr.sunFlareQuery[tr.sunFlareQueryIndex], GL_QUERY_RESULT_AVAILABLE_ARB, &available);
			if (available)
				break;
		}

		ri.Printf(PRINT_DEVELOPER, "Waited %d iterations\n", iter);
	}
	
	qglGetQueryObjectuivARB(tr.sunFlareQuery[tr.sunFlareQueryIndex], GL_QUERY_RESULT_ARB, &sampleCount);
	return sampleCount > 0;
}

void RB_GodRays(void)
{
	vec4i_t srcBox, dstBox;
	vec4_t color;
	vec3_t dir;
	float dot;
	const float cutoff = 0.25f;
	qboolean colorize = qtrue;

//	float w, h, w2, h2;
	matrix_t mvp;
	vec4_t pos, hpos;

	if (!backEnd.viewHasSunFlare)
		return;

	VectorSubtract(backEnd.sunFlarePos, backEnd.viewParms.or.origin, dir);
	VectorNormalize(dir);

	dot = DotProduct(dir, backEnd.viewParms.or.axis[0]);
	if (dot < cutoff)
		return;

	if (!RB_UpdateSunFlareVis())
		return;

	VectorCopy(backEnd.sunFlarePos, pos);
	pos[3] = 1.f;

	// project sun point
	Matrix16Multiply(backEnd.viewParms.projectionMatrix, backEnd.viewParms.world.modelMatrix, mvp);
	Matrix16Transform(mvp, pos, hpos);
		
	// transform to UV coords
	hpos[3] = 0.5f / hpos[3];

	pos[0] = 0.5f + hpos[0] * hpos[3];
	pos[1] = 0.5f - hpos[1] * hpos[3];
	
	// viewport dimensions
	// JBravo: Apparently not used
/*	w = glConfig.vidWidth;
	h = glConfig.vidHeight;
	w2 = glConfig.vidWidth / 2;
	h2 = glConfig.vidHeight / 2; */

	// initialize quarter buffers
	{
		float mul = 1.f;
		vec2_t texScale;

		texScale[0] = 
		texScale[1] = 1.0f;

		VectorSet4(color, mul, mul, mul, 1);

		// first, downsample the framebuffer
		if (colorize)
		{
			FBO_FastBlit(tr.screenScratchFbo, NULL, tr.quarterFbo[0], NULL, GL_COLOR_BUFFER_BIT, GL_LINEAR);
			FBO_Blit(tr.godRaysFbo, NULL, NULL, tr.quarterFbo[0], NULL, NULL, color, GLS_SRCBLEND_DST_COLOR | GLS_DSTBLEND_ZERO);
		}
		else
		{
			FBO_FastBlit(tr.godRaysFbo, NULL, tr.quarterFbo[0], NULL, GL_COLOR_BUFFER_BIT, GL_LINEAR);
		}
	}

	// radial blur passes, ping-ponging between the two quarter-size buffers
	{
		const float stretch_add = 2.f/3.f;
		float stretch = 1.f + stretch_add;
		int i;
		for (i=0; i<2; ++i)
		{
			RB_RadialBlur(tr.quarterFbo[i&1], tr.quarterFbo[(~i) & 1], 5, stretch, 0.f, 0.f, tr.quarterFbo[0]->width, tr.quarterFbo[0]->height, pos[0], pos[1], 1.125f);
			stretch += stretch_add;
		}
	}
	
	// add result back on top of the main buffer
	{
		float mul = 1.f;
		vec2_t texScale;

		texScale[0] = 
		texScale[1] = 1.0f;

		VectorSet4(color, mul, mul, mul, 1);

		VectorSet4(srcBox, 0, 0, tr.quarterFbo[0]->width, tr.quarterFbo[0]->height);
		VectorSet4(dstBox, 0, 0, glConfig.vidWidth, glConfig.vidHeight);
		FBO_Blit(tr.quarterFbo[0], srcBox, texScale, tr.screenScratchFbo, dstBox, &tr.textureColorShader, color, GLS_SRCBLEND_ONE | GLS_DSTBLEND_ONE);
	}
}
#endif

static void RB_BlurAxis(FBO_t *srcFbo, FBO_t *dstFbo, float strength, qboolean horizontal)
{
	float dx, dy;
	float xmul, ymul;
	float weights[3] = {
		0.227027027f,
		0.316216216f,
		0.070270270f,
	};
	float offsets[3] = {
		0.f,
		1.3846153846f,
		3.2307692308f,
	};

	xmul = horizontal;
	ymul = 1.f - xmul;

	xmul *= strength;
	ymul *= strength;

	{
		vec4i_t srcBox, dstBox;
		vec4_t color;
		vec2_t texScale;

		texScale[0] = 
		texScale[1] = 1.0f;

		VectorSet4(color, weights[0], weights[0], weights[0], 1.0f);
		VectorSet4(srcBox, 0, 0, srcFbo->width, srcFbo->height);
		VectorSet4(dstBox, 0, 0, dstFbo->width, dstFbo->height);
		FBO_Blit(srcFbo, srcBox, texScale, dstFbo, dstBox, &tr.textureColorShader, color, 0 );

		VectorSet4(color, weights[1], weights[1], weights[1], 1.0f);
		dx = offsets[1] * xmul;
		dy = offsets[1] * ymul;
		VectorSet4(srcBox, dx, dy, srcFbo->width, srcFbo->height);
		FBO_Blit(srcFbo, srcBox, texScale, dstFbo, dstBox, &tr.textureColorShader, color, GLS_SRCBLEND_ONE | GLS_DSTBLEND_ONE );
		VectorSet4(srcBox, -dx, -dy, srcFbo->width, srcFbo->height);
		FBO_Blit(srcFbo, srcBox, texScale, dstFbo, dstBox, &tr.textureColorShader, color, GLS_SRCBLEND_ONE | GLS_DSTBLEND_ONE );

		VectorSet4(color, weights[2], weights[2], weights[2], 1.0f);
		dx = offsets[2] * xmul;
		dy = offsets[2] * ymul;
		VectorSet4(srcBox, dx, dy, srcFbo->width, srcFbo->height);
		FBO_Blit(srcFbo, srcBox, texScale, dstFbo, dstBox, &tr.textureColorShader, color, GLS_SRCBLEND_ONE | GLS_DSTBLEND_ONE );
		VectorSet4(srcBox, -dx, -dy, srcFbo->width, srcFbo->height);
		FBO_Blit(srcFbo, srcBox, texScale, dstFbo, dstBox, &tr.textureColorShader, color, GLS_SRCBLEND_ONE | GLS_DSTBLEND_ONE );
	}
}

static void RB_HBlur(FBO_t *srcFbo, FBO_t *dstFbo, float strength)
{
	RB_BlurAxis(srcFbo, dstFbo, strength, qtrue);
}

static void RB_VBlur(FBO_t *srcFbo, FBO_t *dstFbo, float strength)
{
	RB_BlurAxis(srcFbo, dstFbo, strength, qfalse);
}

void RB_GaussianBlur(float blur)
{
	//float mul = 1.f;
	float factor = Com_Clamp(0.f, 1.f, blur);

	if (factor <= 0.f)
		return;

	{
		vec4i_t srcBox, dstBox;
		vec4_t color;
		vec2_t texScale;

		texScale[0] = 
		texScale[1] = 1.0f;

		VectorSet4(color, 1, 1, 1, 1);

		// first, downsample the framebuffer
		FBO_FastBlit(tr.screenScratchFbo, NULL, tr.quarterFbo[0], NULL, GL_COLOR_BUFFER_BIT, GL_LINEAR);
		FBO_FastBlit(tr.quarterFbo[0], NULL, tr.textureScratchFbo[0], NULL, GL_COLOR_BUFFER_BIT, GL_LINEAR);

		// set the alpha channel
		VectorSet4(srcBox, 0, 0, tr.whiteImage->width, tr.whiteImage->height);
		VectorSet4(dstBox, 0, 0, tr.textureScratchFbo[0]->width, tr.textureScratchFbo[0]->height);
		qglColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_TRUE);
		FBO_BlitFromTexture(tr.whiteImage, srcBox, texScale, tr.textureScratchFbo[0], dstBox, &tr.textureColorShader, color, GLS_DEPTHTEST_DISABLE);
		qglColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);

		// blur the tiny buffer horizontally and vertically
		RB_HBlur(tr.textureScratchFbo[0], tr.textureScratchFbo[1], factor);
		RB_VBlur(tr.textureScratchFbo[1], tr.textureScratchFbo[0], factor);

		// finally, merge back to framebuffer
		VectorSet4(srcBox, 0, 0, tr.textureScratchFbo[0]->width, tr.textureScratchFbo[0]->height);
		VectorSet4(dstBox, 0, 0, glConfig.vidWidth,              glConfig.vidHeight);
		color[3] = factor;
		FBO_Blit(tr.textureScratchFbo[0], srcBox, texScale, tr.screenScratchFbo, dstBox, &tr.textureColorShader, color, GLS_SRCBLEND_SRC_ALPHA | GLS_DSTBLEND_ONE_MINUS_SRC_ALPHA);
	}
}
