/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 */

#include "sludge/allfiles.h"
#include "sludge/backdrop.h"
#include "sludge/graphics.h"
#include "sludge/newfatal.h"

namespace Sludge {

extern float snapTexW, snapTexH;

void GraphicsManager::setBrightnessLevel(int brightnessLevel)
{
	if (brightnessLevel < 0)
		_brightnessLevel = 0;
	else if (brightnessLevel > 255)
		_brightnessLevel = 255;
	else
		_brightnessLevel = brightnessLevel;
}

//----------------------------------------------------
// PROPER BRIGHTNESS FADING
//----------------------------------------------------

unsigned lastFrom, lastTo;

void transitionFader() {
#if 0
	glEnable(GL_BLEND);

	const GLfloat vertices[] = {
		0.f, (GLfloat)winHeight, 0.f,
		(GLfloat)winWidth, (GLfloat)winHeight, 0.f,
		0.f, 0.f, 0.f,
		(GLfloat)winWidth, 0.f, 0.f
	};

	glUseProgram(shader.color);

	setPMVMatrix(shader.color);
	setPrimaryColor(0.0f, 0.0f, 0.0f, 1.0f - brightnessLevel / 255.f);
	drawQuad(shader.color, vertices, 0);

	glUseProgram(0);

	glDisable(GL_BLEND);
#endif
}

void transitionCrossFader() {
#if 0
	if (! snapshotTextureName) return;

	glBindTexture(GL_TEXTURE_2D, snapshotTextureName);

	glEnable(GL_BLEND);

	const GLfloat vertices[] = {
		0.f, (GLfloat)winHeight, 0.f,
		(GLfloat)winWidth, (GLfloat)winHeight, 0.f,
		0.f, 0.f, 0.f,
		(GLfloat)winWidth, 0.f, 0.f
	};

	const GLfloat texCoords[] = {
		0.0f, snapTexH,
		snapTexW, snapTexH,
		0.0f, 0.0f,
		snapTexW, 0.0f
	};

	glUseProgram(shader.texture);

	setPMVMatrix(shader.texture);

	glUniform1i(glGetUniformLocation(shader.texture, "modulateColor"), 1);

	setPrimaryColor(1.0f, 1.0f, 1.0f, 1.0f - brightnessLevel / 255.f);

	drawQuad(shader.texture, vertices, 1, texCoords);

	glUniform1i(glGetUniformLocation(shader.texture, "modulateColor"), 0);
	glUseProgram(0);

	glDisable(GL_BLEND);
#endif
}

void transitionSnapshotBox() {
#if 0
	if (! snapshotTextureName) return;

	//glTexEnvf (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
	glBindTexture(GL_TEXTURE_2D, snapshotTextureName);

	float xScale = (float) brightnessLevel * winWidth / 510.f;// 510 = 255*2
	float yScale = (float) brightnessLevel * winHeight / 510.f;

	const GLfloat vertices[] = {
		xScale, winHeight - yScale, 0,
		winWidth - xScale, winHeight - yScale, 0,
		xScale, yScale, 0,
		winWidth - xScale, yScale, 0
	};

	const GLfloat texCoords[] = {
		0.0f, snapTexH,
		snapTexW, snapTexH,
		0.0f, 0.0f,
		snapTexW, 0.0f
	};

	glUseProgram(shader.texture);

	setPMVMatrix(shader.texture);

	drawQuad(shader.texture, vertices, 1, texCoords);

	glUseProgram(0);
#endif
}

//----------------------------------------------------
// FAST PSEUDO-RANDOM NUMBER STUFF FOR DISOLVE EFFECT
//----------------------------------------------------

#define KK 17
uint32 randbuffer[KK][2];  // history buffer
int p1, p2;

void GraphicsManager::resetRandW() {
	int32 seed = 12345;

	for (int i = 0; i < KK; i++) {
		for (int j = 0; j < 2; j++) {
			seed = seed * 2891336453u + 1;
			randbuffer[i][j] = seed;
		}
	}

	p1 = 0;
	p2 = 10;
}

#if 0
GLubyte *transitionTexture = NULL;
GLuint transitionTextureName = 0;
#endif

bool reserveTransitionTexture() {
#if 0
	glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

	if (! transitionTexture) {
		transitionTexture = new GLubyte [256 * 256 * 4];
		if (! checkNew(transitionTexture)) return false;
	}

	if (! transitionTextureName) glGenTextures(1, &transitionTextureName);
	glBindTexture(GL_TEXTURE_2D, transitionTextureName);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

	texImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 256, 256, 0, GL_RGBA, GL_UNSIGNED_BYTE, transitionTexture, transitionTextureName);
#endif
	return true;
}

void transitionDisolve() {

#if 0
	if (! transitionTextureName) reserveTransitionTexture();

	if (! brightnessLevel) {
		transitionFader();
		return;
	}

	uint32 n;
	uint32 y;

	GLubyte *toScreen = transitionTexture;
	GLubyte *end = transitionTexture + (256 * 256 * 4);

	do {
		// generate next number
		n = randbuffer[p1][1];
		y = (n << 27) | ((n >> (32 - 27)) + randbuffer[p2][1]);

		n = randbuffer[p1][0];
		randbuffer[p1][1] = (n << 19) | ((n >> (32 - 19)) + randbuffer[p2][0]);
		randbuffer[p1][0] = y;

		// rotate list pointers
		if (! p1 --) p1 = KK - 1;
		if (! p2 --) p2 = KK - 1;

		if ((y & 255u) > brightnessLevel) {
			toScreen[0] = toScreen[1] = toScreen[2] = 0;
			toScreen[3] = 255;
		} else {
			toScreen[0] = toScreen[1] = toScreen[2] = toScreen[3] = 0;
		}
		toScreen += 4;
	}while (toScreen < end);

	texImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 256, 256, 0, GL_RGBA, GL_UNSIGNED_BYTE, transitionTexture, transitionTextureName);

	glEnable(GL_BLEND);

	const GLfloat vertices[] = {
		0.f, (GLfloat)winHeight, 0.f,
		(GLfloat)winWidth, (GLfloat)winHeight, 0.f,
		0.f, 0.f, 0.f,
		(GLfloat)winWidth, 0.f, 0.f
	};

	const GLfloat texCoords[] = {
		0.0f, 1.0f,
		1.0f, 1.0f,
		0.0f, 0.0f,
		1.0f, 0.0f
	};

	glUseProgram(shader.texture);

	setPMVMatrix(shader.texture);

	glUniform1i(glGetUniformLocation(shader.texture, "modulateColor"), 1);

	setPrimaryColor(1.0f, 1.0f, 1.0f, 1.0f);

	drawQuad(shader.texture, vertices, 1, texCoords);

	glUniform1i(glGetUniformLocation(shader.texture, "modulateColor"), 0);
	glUseProgram(0);

	glDisable(GL_BLEND);
#endif
}

void transitionTV() {

#if 0
	if (! transitionTextureName) reserveTransitionTexture();

	uint32 n;
	uint32 y;

	GLubyte *toScreen = transitionTexture;
	GLubyte *end = transitionTexture + (256 * 256 * 4);

	do {
		// generate next number
		n = randbuffer[p1][1];
		y = (n << 27) | ((n >> (32 - 27)) + randbuffer[p2][1]);

		n = randbuffer[p1][0];
		randbuffer[p1][1] = (n << 19) | ((n >> (32 - 19)) + randbuffer[p2][0]);
		randbuffer[p1][0] = y;

		// rotate list pointers
		if (! p1 --) p1 = KK - 1;
		if (! p2 --) p2 = KK - 1;

		if ((y & 255u) > brightnessLevel) {
			toScreen[0] = toScreen[1] = toScreen[2] = (n & 255);
			toScreen[3] = (n & 255);
		} else {
			toScreen[0] = toScreen[1] = toScreen[2] = toScreen[3] = 0;
		}
		toScreen += 4;
	}while (toScreen < end);

	texImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 256, 256, 0, GL_RGBA, GL_UNSIGNED_BYTE, transitionTexture, transitionTextureName);

	glEnable(GL_BLEND);

	const GLfloat vertices[] = {
		0.f, (GLfloat)winHeight, 0.f,
		(GLfloat)winWidth, (GLfloat)winHeight, 0.f,
		0.f, 0.f, 0.f,
		(GLfloat)winWidth, 0.f, 0.f
	};

	const GLfloat texCoords[] = {
		0.0f, 1.0f,
		1.0f, 1.0f,
		0.0f, 0.0f,
		1.0f, 0.0f
	};

	glUseProgram(shader.texture);

	setPMVMatrix(shader.texture);

	glUniform1i(glGetUniformLocation(shader.texture, "modulateColor"), 1);

	setPrimaryColor(1.0f, 1.0f, 1.0f, 1.0f);

	drawQuad(shader.texture, vertices, 1, texCoords);

	glUniform1i(glGetUniformLocation(shader.texture, "modulateColor"), 0);
	glUseProgram(0);

	glDisable(GL_BLEND);
#endif
}

void transitionBlinds() {
#if 0
	if (! transitionTextureName) reserveTransitionTexture();

	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

	GLubyte *toScreen = transitionTexture;

	int level = brightnessLevel / 8;

	if (level) memset(toScreen, 0, 256 * 32 * level);
	if (level < 32) memset(toScreen + 256 * 32 * level, 255, 256 * 32 * (32 - level));

	texImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 256, 256, 0, GL_RGBA, GL_UNSIGNED_BYTE, transitionTexture, transitionTextureName);

	glEnable(GL_BLEND);

	const GLfloat vertices[] = {
		0.f, (GLfloat)winHeight, 0.f,
		(GLfloat)winWidth, (GLfloat)winHeight, 0.f,
		0.f, 0.f, 0.f,
		(GLfloat)winWidth, 0.f, 0.f
	};

	const GLfloat texCoords[] = {
		0.0f, 0.0f,
		1.0f, 0.0f,
		0.0f, 25.0f,
		1.0f, 25.0f
	};

	glUseProgram(shader.texture);

	setPMVMatrix(shader.texture);

	glUniform1i(glGetUniformLocation(shader.texture, "modulateColor"), 1);

	setPrimaryColor(0.0f, 0.0f, 0.0f, 1.0f);

	drawQuad(shader.texture, vertices, 1, texCoords);

	glUniform1i(glGetUniformLocation(shader.texture, "modulateColor"), 0);
	glUseProgram(0);

	glDisable(GL_BLEND);
#endif
}

//----------------------------------------------------

void GraphicsManager::fixBrightness() {
	switch (_fadeMode) {
		case 0:
			transitionFader();
			break;
		case 1:
			resetRandW();
			// Fall through!
		case 2:
			transitionDisolve();
			break;
		case 3:
			transitionTV();
			break;
		case 4:
			transitionBlinds();
			break;
		case 5:
			transitionCrossFader();
			break;
		case 6:
			transitionSnapshotBox();
			break;
		default:
			break;
	}
}

} // End of namespace Sludge