/* Copyright (C) 2009 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. 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.
 *
 * 0 A.D. 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 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 * Water settings (speed, height) and texture management
 */

#include "precompiled.h"

#include "lib/bits.h"
#include "lib/timer.h"
#include "lib/tex/tex.h"
#include "lib/res/graphics/ogl_tex.h"

#include "maths/MathUtil.h"

#include "ps/CLogger.h"
#include "ps/Loader.h"

#include "renderer/WaterManager.h"
#include "renderer/Renderer.h"

#define LOG_CATEGORY "graphics"


///////////////////////////////////////////////////////////////////////////////////////////////
// WaterManager implementation


///////////////////////////////////////////////////////////////////
// Construction/Destruction
WaterManager::WaterManager()
{
	// water
	m_RenderWater = false; // disabled until textures are successfully loaded
	m_WaterHeight = 5.0f;
	m_WaterColor = CColor(0.3f, 0.35f, 0.7f, 1.0f);
	m_WaterFullDepth = 4.0f;
	m_WaterMaxAlpha = 0.85f;
	m_WaterAlphaOffset = -0.05f;
	m_SWaterTrans = 0;
	m_TWaterTrans = 0;
	m_SWaterSpeed = 0.0015f;
	m_TWaterSpeed = 0.0015f;
	m_SWaterScrollCounter = 0;
	m_TWaterScrollCounter = 0;
	m_WaterCurrentTex = 0;
	m_ReflectionTexture = 0;
	m_RefractionTexture = 0;
	m_ReflectionTextureSize = 0;
	m_RefractionTextureSize = 0;
	m_WaterTexTimer = 0.0;
	m_Shininess = 150.0f;
	m_SpecularStrength = 0.4f;
	m_Waviness = 8.0f;
	m_ReflectionTint = CColor(0.28f, 0.3f, 0.59f, 1.0f);
	m_ReflectionTintStrength = 0.0f;
	m_WaterTint = CColor(0.28f, 0.3f, 0.59f, 1.0f);
	m_Murkiness = 0.45f;
	m_RepeatPeriod = 16.0f;

	for (size_t i = 0; i < ARRAY_SIZE(m_WaterTexture); i++)
		m_WaterTexture[i] = 0;

	for (size_t i = 0; i < ARRAY_SIZE(m_NormalMap); i++)
		m_NormalMap[i] = 0;

	cur_loading_water_tex = 0;
	cur_loading_normal_map = 0;
}

WaterManager::~WaterManager()
{
	// Cleanup if the caller messed up
	UnloadWaterTextures();
}


///////////////////////////////////////////////////////////////////
// Progressive load of water textures
int WaterManager::LoadWaterTextures()
{
	const size_t num_textures = ARRAY_SIZE(m_WaterTexture);
	const size_t num_normal_maps = ARRAY_SIZE(m_NormalMap);

	// TODO: add a member variable and setter for this. (can't make this
	// a parameter because this function is called via delay-load code)
	static const char* const water_type = "default";

	// yield after this time is reached. balances increased progress bar
	// smoothness vs. slowing down loading.
	const double end_time = timer_Time() + 100e-3;

	char filename[PATH_MAX];

	// Load diffuse grayscale images (for non-fancy water)
	while (cur_loading_water_tex < num_textures)
	{
		snprintf(filename, ARRAY_SIZE(filename), "art/textures/animated/water/%s/diffuse%02d.dds", 
			water_type, (int)cur_loading_water_tex+1);
		Handle ht = ogl_tex_load(filename);
		if (ht <= 0)
		{
			LOG(CLogger::Error, LOG_CATEGORY, "LoadWaterTextures failed on \"%s\"", filename);
			return ht;
		}
		m_WaterTexture[cur_loading_water_tex] = ht;
		RETURN_ERR(ogl_tex_upload(ht));
		cur_loading_water_tex++;
		LDR_CHECK_TIMEOUT(cur_loading_water_tex, num_textures + num_normal_maps);
	}

	// Load normalmaps (for fancy water)
	while (cur_loading_normal_map < num_normal_maps)
	{
		snprintf(filename, ARRAY_SIZE(filename), "art/textures/animated/water/%s/normal%02d.dds", 
			water_type, (int)cur_loading_normal_map+1);
		Handle ht = ogl_tex_load(filename);
		if (ht <= 0)
		{
			LOG(CLogger::Error, LOG_CATEGORY, "LoadWaterTextures failed on \"%s\"", filename);
			return ht;
		}
		m_NormalMap[cur_loading_normal_map] = ht;
		RETURN_ERR(ogl_tex_upload(ht));
		cur_loading_normal_map++;
		LDR_CHECK_TIMEOUT(num_textures + cur_loading_normal_map, num_textures + num_normal_maps);
	}

	// Set the size to the largest power of 2 that is <= to the window height, so
	// the reflection/reflaction images will fit within the window 
	// (alternative: use FBO's, which can have arbitrary size - but do we need
	// the reflection/refraction textures to be that large?)
	int size = round_up_to_pow2(g_Renderer.GetHeight());
	if(size > g_Renderer.GetHeight()) size /= 2;
	m_ReflectionTextureSize = size;
	m_RefractionTextureSize = size;

	// Create reflection texture
	glGenTextures(1, &m_ReflectionTexture);
	glBindTexture(GL_TEXTURE_2D, m_ReflectionTexture);
	glTexImage2D( GL_TEXTURE_2D, 0, GL_RGB,
		(GLsizei)m_ReflectionTextureSize, (GLsizei)m_ReflectionTextureSize,
		0,  GL_RGB, GL_UNSIGNED_BYTE, 0);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
	
	// Create refraction texture
	glGenTextures(1, &m_RefractionTexture);
	glBindTexture(GL_TEXTURE_2D, m_RefractionTexture);
	glTexImage2D( GL_TEXTURE_2D, 0, GL_RGB, 
		(GLsizei)m_RefractionTextureSize, (GLsizei)m_RefractionTextureSize,
		0,  GL_RGB, GL_UNSIGNED_BYTE, 0);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

	// Enable rendering, now that we've succeeded this far
	m_RenderWater = true;

	return 0;
}


///////////////////////////////////////////////////////////////////
// Unload water textures
void WaterManager::UnloadWaterTextures()
{
	for(size_t i = 0; i < ARRAY_SIZE(m_WaterTexture); i++)
	{
		ogl_tex_free(m_WaterTexture[i]);
		m_WaterTexture[i] = 0;
	}


	for(size_t i = 0; i < ARRAY_SIZE(m_NormalMap); i++)
	{
		ogl_tex_free(m_NormalMap[i]);
		m_NormalMap[i] = 0;
	}

	cur_loading_water_tex = 0; // so they will be reloaded if LoadWaterTextures is called again
	cur_loading_normal_map = 0;
}