/*
** shader.cpp
**
** This file is part of mkxp.
**
** Copyright (C) 2013 Jonas Kulla <Nyocurio@gmail.com>
**
** mkxp 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.
**
** mkxp 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 mkxp.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "shader.h"
#include "globalstate.h"
#include "glstate.h"

#include "GL/glew.h"

#include <QFile>

#include "../sprite.frag.xxd"
#include "../hue.frag.xxd"
#include "../trans.frag.xxd"
#include "../transSimple.frag.xxd"
#include "../bitmapBlit.frag.xxd"
#include "../plane.frag.xxd"
#include "../simple.frag.xxd"
#include "../simpleColor.frag.xxd"
#include "../simpleAlpha.frag.xxd"
#include "../simple.vert.xxd"
#include "../simpleColor.vert.xxd"
#include "../sprite.vert.xxd"


#define INIT_SHADER(vert, frag) \
	Shader::init(shader_##vert##_vert, shader_##vert##_vert_len, shader_##frag##_frag, shader_##frag##_frag_len)
#define GET_U(name) u_##name = glGetUniformLocation(program, #name)

Shader::Shader()
{
	vertShader = glCreateShader(GL_VERTEX_SHADER);
	fragShader = glCreateShader(GL_FRAGMENT_SHADER);

	program = glCreateProgram();
}

Shader::~Shader()
{
	glUseProgram(0);
	glDeleteProgram(program);
	glDeleteShader(vertShader);
	glDeleteShader(fragShader);
}

void Shader::bind()
{
	glUseProgram(program);
}

void Shader::unbind()
{
	glActiveTexture(GL_TEXTURE0);
	glUseProgram(0);
}

void Shader::init(const unsigned char *vert, int vertSize,
                  const unsigned char *frag, int fragSize)
{
	GLint success;

	/* Compile vertex shader */
	glShaderSource(vertShader, 1, (const GLchar**) &vert, (const GLint*) &vertSize);
	glCompileShader(vertShader);

	glGetObjectParameterivARB(vertShader, GL_COMPILE_STATUS, &success);
	Q_ASSERT(success);

	/* Compile fragment shader */
	glShaderSource(fragShader, 1, (const GLchar**) &frag, (const GLint*) &fragSize);
	glCompileShader(fragShader);

	glGetObjectParameterivARB(fragShader, GL_COMPILE_STATUS, &success);
	Q_ASSERT(success);

	/* Link shader program */
	glAttachShader(program, vertShader);
	glAttachShader(program, fragShader);

	glBindAttribLocation(program, Position, "position");
	glBindAttribLocation(program, TexCoord, "texCoord");
	glBindAttribLocation(program, Color, "color");

	glLinkProgram(program);

	glGetObjectParameterivARB(program, GL_LINK_STATUS, &success);
	Q_ASSERT(success);
}

void Shader::initFromFile(const char *_vertFile, const char *_fragFile)
{
	QFile vertFile(_vertFile);
	vertFile.open(QFile::ReadOnly);
	QByteArray vertContents = vertFile.readAll();
	vertFile.close();

	QFile fragFile(_fragFile);
	fragFile.open(QFile::ReadOnly);
	QByteArray fragContents = fragFile.readAll();
	fragFile.close();

	init((const unsigned char*) vertContents.constData(), vertContents.size(),
	     (const unsigned char*) fragContents.constData(), fragContents.size());
}

void Shader::setVec4Uniform(GLint location, const Vec4 &vec)
{
	glUniform4f(location, vec.x, vec.y, vec.z, vec.w);
}

void Shader::setTexUniform(GLint location, unsigned unitIndex, TEX::ID texture)
{
	GLenum texUnit = GL_TEXTURE0 + unitIndex;

	glActiveTexture(texUnit);
	glBindTexture(GL_TEXTURE_2D, texture.gl);
	glUniform1i(location, unitIndex);
	glActiveTexture(GL_TEXTURE0);
}

void ShaderBase::GLProjMat::apply(const Vec2i &value)
{
	/* glOrtho replacement */
	const float a = 2.f / value.x;
	const float b = 2.f / value.y;
	const float c = -2.f;

	GLfloat mat[16] =
	{
		 a,  0,  0,  0,
		 0,  b,  0,  0,
		 0,  0,  c,  0,
		-1, -1, -1,  1
	};

	glUniformMatrix4fv(u_mat, 1, GL_FALSE, mat);
}

void ShaderBase::init()
{
	GET_U(texSizeInv);
	GET_U(translation);

	projMat.u_mat = glGetUniformLocation(program, "projMat");
}

void ShaderBase::applyViewportProj()
{
	const IntRect &vp = glState.viewport.get();
	projMat.set(Vec2i(vp.w, vp.h));
}

void ShaderBase::setTexSize(const Vec2i &value)
{
	glUniform2f(u_texSizeInv, 1.f / value.x, 1.f / value.y);
}

void ShaderBase::setTranslation(const Vec2i &value)
{
	glUniform2f(u_translation, value.x, value.y);
}


SimpleShader::SimpleShader()
{
	INIT_SHADER(simple, simple);

	ShaderBase::init();

	GET_U(texOffsetX);
}

void SimpleShader::setTexOffsetX(int value)
{
	glUniform1f(u_texOffsetX, value);
}


SimpleColorShader::SimpleColorShader()
{
	INIT_SHADER(simpleColor, simpleColor);

	ShaderBase::init();
}


SimpleAlphaShader::SimpleAlphaShader()
{
	INIT_SHADER(simpleColor, simpleAlpha);

	ShaderBase::init();
}


SimpleSpriteShader::SimpleSpriteShader()
{
	INIT_SHADER(sprite, simple);

	ShaderBase::init();

	GET_U(spriteMat);
}

void SimpleSpriteShader::setSpriteMat(const float value[16])
{
	glUniformMatrix4fv(u_spriteMat, 1, GL_FALSE, value);
}


TransShader::TransShader()
{
	INIT_SHADER(simple, trans);

	ShaderBase::init();

	GET_U(currentScene);
	GET_U(frozenScene);
	GET_U(transMap);
	GET_U(prog);
	GET_U(vague);
}

void TransShader::setCurrentScene(TEX::ID tex)
{
	setTexUniform(u_currentScene, 0, tex);
}

void TransShader::setFrozenScene(TEX::ID tex)
{
	setTexUniform(u_frozenScene, 1, tex);
}

void TransShader::setTransMap(TEX::ID tex)
{
	setTexUniform(u_transMap, 2, tex);
}

void TransShader::setProg(float value)
{
	glUniform1f(u_prog, value);
}

void TransShader::setVague(float value)
{
	glUniform1f(u_vague, value);
}


SimpleTransShader::SimpleTransShader()
{
	INIT_SHADER(simple, transSimple);

	ShaderBase::init();

	GET_U(currentScene);
	GET_U(frozenScene);
	GET_U(prog);
}

void SimpleTransShader::setCurrentScene(TEX::ID tex)
{
	setTexUniform(u_currentScene, 0, tex);
}

void SimpleTransShader::setFrozenScene(TEX::ID tex)
{
	setTexUniform(u_frozenScene, 1, tex);
}

void SimpleTransShader::setProg(float value)
{
	glUniform1f(u_prog, value);
}


SpriteShader::SpriteShader()
{
	INIT_SHADER(sprite, sprite);

	ShaderBase::init();

	GET_U(spriteMat);
	GET_U(tone);
	GET_U(color);
	GET_U(opacity);
	GET_U(bushDepth);
	GET_U(bushOpacity);
}

void SpriteShader::setSpriteMat(const float value[16])
{
	glUniformMatrix4fv(u_spriteMat, 1, GL_FALSE, value);
}

void SpriteShader::setTone(const Vec4 &tone)
{
	setVec4Uniform(u_tone, tone);
}

void SpriteShader::setColor(const Vec4 &color)
{
	setVec4Uniform(u_color, color);
}

void SpriteShader::setOpacity(float value)
{
	glUniform1f(u_opacity, value);
}

void SpriteShader::setBushDepth(float value)
{
	glUniform1f(u_bushDepth, value);
}

void SpriteShader::setBushOpacity(float value)
{
	glUniform1f(u_bushOpacity, value);
}


PlaneShader::PlaneShader()
{
	INIT_SHADER(simple, plane);

	ShaderBase::init();

	GET_U(tone);
	GET_U(color);
	GET_U(flash);
	GET_U(opacity);
}

void PlaneShader::setTone(const Vec4 &tone)
{
	setVec4Uniform(u_tone, tone);
}

void PlaneShader::setColor(const Vec4 &color)
{
	setVec4Uniform(u_color, color);
}

void PlaneShader::setFlash(const Vec4 &flash)
{
	setVec4Uniform(u_flash, flash);
}

void PlaneShader::setOpacity(float value)
{
	glUniform1f(u_opacity, value);
}


HueShader::HueShader()
{
	INIT_SHADER(simple, hue);

	ShaderBase::init();

	GET_U(hueAdjust);
	GET_U(inputTexture);
}

void HueShader::setHueAdjust(float value)
{
	glUniform1f(u_hueAdjust, value);
}

void HueShader::setInputTexture(TEX::ID tex)
{
	setTexUniform(u_inputTexture, 0, tex);
}


BltShader::BltShader()
{
	INIT_SHADER(simple, bitmapBlit);

	ShaderBase::init();

	GET_U(source);
	GET_U(destination);
	GET_U(subRect);
	GET_U(opacity);
}

void BltShader::setSource()
{
	glUniform1i(u_source, 0);
}

void BltShader::setDestination(const TEX::ID value)
{
	setTexUniform(u_destination, 1, value);
}

void BltShader::setSubRect(const FloatRect &value)
{
	glUniform4f(u_subRect, value.x, value.y, value.w, value.h);
}

void BltShader::setOpacity(float value)
{
	glUniform1f(u_opacity, value);
}