// ==============================================================
//	This file is part of Glest Shared Library (www.glest.org)
//
//	Copyright (C) 2001-2008 Martiño Figueroa
//
//	You can redistribute this code 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
// ==============================================================

#include "shader_gl.h"

#include <fstream>

#include "opengl.h"
#include "leak_dumper.h"

using namespace std;

namespace Shared {
	namespace Graphics {
		namespace Gl {

			// =====================================================
			//	class ShaderProgramGl
			// =====================================================

			ShaderProgramGl::ShaderProgramGl() {
				inited = false;
				vertexShader = 0;
				fragmentShader = 0;
				handle = 0;
			}

			void ShaderProgramGl::init() {
				if (!inited) {
					assertGl();
					handle = glCreateProgramObjectARB();
					assertGl();
					inited = true;
				}
			}

			void ShaderProgramGl::end() {
				if (inited) {
					assertGl();
					glDeleteObjectARB(handle);
					assertGl();
					inited = false;
				}
			}

			void ShaderProgramGl::attach(VertexShader *vertexShader, FragmentShader *fragmentShader) {
				this->vertexShader = vertexShader;
				this->fragmentShader = fragmentShader;
			}

			bool ShaderProgramGl::link(string &messages) {
				assertGl();

				VertexShaderGl *vertexShaderGl = static_cast<VertexShaderGl*>(vertexShader);
				FragmentShaderGl *fragmentShaderGl = static_cast<FragmentShaderGl*>(fragmentShader);

				const ShaderSource *vss = vertexShaderGl->getSource();
				const ShaderSource *fss = fragmentShaderGl->getSource();
				messages = "Linking program: " + vss->getPathInfo() + ", " + fss->getPathInfo() + "\n";

				//attach
				glAttachObjectARB(handle, vertexShaderGl->getHandle());
				glAttachObjectARB(handle, fragmentShaderGl->getHandle());

				assertGl();

				//bind attributes
				for (unsigned int i = 0; i < attributes.size(); ++i) {
					//int a= attributes[i].second;
					//string s= attributes[i].first;
					glBindAttribLocationARB(handle, attributes[i].second, attributes[i].first.c_str());
				}

				assertGl();

				//link
				glLinkProgramARB(handle);
				glValidateProgramARB(handle);

				assertGl();

				//log
				GLint logLength = 0;
				glGetObjectParameterivARB(handle, GL_OBJECT_INFO_LOG_LENGTH_ARB, &logLength);
				char *buffer = new char[logLength + 1];
				glGetInfoLogARB(handle, logLength + 1, NULL, buffer);
				messages += buffer;
				delete[] buffer;

				assertGl();

				//status
				GLint status = false;
				glGetObjectParameterivARB(handle, GL_OBJECT_LINK_STATUS_ARB, &status);

				assertGl();

				return status != 0;
			}

			void ShaderProgramGl::activate() {
				assertGl();
				glUseProgramObjectARB(handle);
				assertGl();
			}

			void ShaderProgramGl::deactivate() {
				assertGl();
				glUseProgramObjectARB(0);
				assertGl();
			}

			void ShaderProgramGl::setUniform(const string &name, int value) {
				assertGl();
				glUniform1iARB(getLocation(name), value);
				assertGl();
			}

			void ShaderProgramGl::setUniform(const string &name, float value) {
				assertGl();
				glUniform1fARB(getLocation(name), value);
				assertGl();
			}

			void ShaderProgramGl::setUniform(const string &name, const Vec2f &value) {
				assertGl();
				glUniform2fvARB(getLocation(name), 1, value.ptr());
				assertGl();
			}

			void ShaderProgramGl::setUniform(const string &name, const Vec3f &value) {
				assertGl();
				glUniform3fvARB(getLocation(name), 1, value.ptr());
				assertGl();
			}

			void ShaderProgramGl::setUniform(const string &name, const Vec4f &value) {
				assertGl();
				glUniform4fvARB(getLocation(name), 1, value.ptr());
				assertGl();
			}

			void ShaderProgramGl::setUniform(const string &name, const Matrix3f &value) {
				assertGl();
				glUniformMatrix3fvARB(getLocation(name), 1, GL_FALSE, value.ptr());
				assertGl();
			}

			void ShaderProgramGl::setUniform(const string &name, const Matrix4f &value) {
				assertGl();
				glUniformMatrix4fvARB(getLocation(name), 1, GL_FALSE, value.ptr());
				assertGl();
			}

			void ShaderProgramGl::bindAttribute(const string &name, int index) {
				attributes.push_back(AttributePair(name, index));
			}

			GLint ShaderProgramGl::getLocation(const string &name) {
				GLint location = glGetUniformLocationARB(handle, name.c_str());
				if (location == -1) {
					throw megaglest_runtime_error("Can't locate uniform: " + name);
				}
				return location;
			}

			// ===============================================
			//	class ShaderGl
			// ===============================================

			ShaderGl::ShaderGl() {
				inited = false;
				handle = 0;
			}

			void ShaderGl::load(const string &path) {
				source.load(path);
			}

			bool ShaderGl::compile(string &messages) {

				assertGl();

				messages = "Compiling shader: " + source.getPathInfo() + "\n";

				//load source
				GLint length = (GLint) source.getCode().size();
				const GLcharARB *csource = source.getCode().c_str();
				glShaderSourceARB(handle, 1, &csource, &length);

				//compile
				glCompileShaderARB(handle);

				//log
				GLint logLength = 0;
				glGetObjectParameterivARB(handle, GL_OBJECT_INFO_LOG_LENGTH_ARB, &logLength);
				char *buffer = new char[logLength + 1];
				glGetInfoLogARB(handle, logLength + 1, NULL, buffer);
				messages += buffer;
				delete[] buffer;

				//status
				GLint status = false;
				glGetObjectParameterivARB(handle, GL_OBJECT_COMPILE_STATUS_ARB, &status);
				assertGl();

				return status != 0;
			}

			void ShaderGl::end() {
				if (inited) {
					assertGl();
					glDeleteObjectARB(handle);
					assertGl();
				}
			}

			// ===============================================
			//	class VertexShaderGl
			// ===============================================

			void VertexShaderGl::init() {
				if (!inited) {
					assertGl();
					handle = glCreateShaderObjectARB(GL_VERTEX_SHADER_ARB);
					assertGl();
					inited = true;
				}
			}

			// ===============================================
			//	class FragmentShaderGl
			// ===============================================

			void FragmentShaderGl::init() {
				if (!inited) {
					assertGl();
					handle = glCreateShaderObjectARB(GL_FRAGMENT_SHADER_ARB);
					assertGl();
					inited = true;
				}
			}

		}
	}
}//end namespace