/*
    QGLView
    Copyright (C) 2012  Ivan Pelipenko peri4ko@gmail.com

    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 3 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, see <http://www.gnu.org/licenses/>.
*/

#include "renderer_deferred_shading.h"


RendererDeferredShading::RendererDeferredShading(QGLView * view_): GLRendererBase(view_), fbo(5, true, GL_RGBA16F) {
	shader_fxaa = shader_ds_0 = shader_ds_1 = 0;
}


void RendererDeferredShading::renderScene() {
	int passes = (view.lightsCount() - 1) / 8 + 1;
	QMatrix4x4 pm = getGLMatrix(GL_PROJECTION_MATRIX);//, mvm = getGLMatrix(GL_MODELVIEW_MATRIX), pmvm = pm * mvm, lpm, lmvm, lpmvm;
	if (passes < 1) passes = 1;
	fbo.bind();
	int buffs[] = {0, 1, 2};
	fbo.setWriteBuffers(buffs);
	glClearFramebuffer(QColor(0, 0, 0, 0));
	//glEnable(GL_TEXTURE_2D);
	glEnable(GL_DEPTH_TEST);
	glDepthFunc(GL_LESS);
	glDepthMask(GL_TRUE);
	shader_ds_0->bind();
	shader_ds_0->setUniformValue("t0", 0);
	shader_ds_0->setUniformValue("t1", 1);
	shader_ds_0->setUniformValue("t2", 2);
	shader_ds_0->setUniformValue("dt", QVector2D(1. / view.viewport()->width(), 1. / view.viewport()->height()));
	renderObjects(GLObjectBase::Solid, 0, 0, true, false, false);
	//glReleaseShaders();
	//fbo.release();

	glSetLightEnabled(false);
	glDisable(GL_BLEND);
	//glBlendFunc(GL_ONE, GL_ONE);
	glDisable(GL_DEPTH_TEST);
	glDepthMask(GL_FALSE);
	shader_ds_1->bind();
	shader_ds_1->setUniformValue("t0", 0);
	shader_ds_1->setUniformValue("t1", 1);
	shader_ds_1->setUniformValue("t2", 2);
	shader_ds_1->setUniformValue("back_color", view.backColor());
	shader_ds_1->setUniformValue("mat", pm.inverted());
	shader_ds_1->setUniformValue("dt", QVector2D(1. / view.viewport()->width(), 1. / view.viewport()->height()));
	fbo.setWriteBuffer(3);
	fbo.bindColorTextures();
	glClearFramebuffer(Qt::black, false);
	QVector<QVector4D> lpos;
	GLfloat glmvm[16];
	glGetFloatv(GL_MODELVIEW_MATRIX, glmvm);
	//glResetAllTransforms();
	for (int l = 0; l < passes; ++l) {
		fbo.setWriteBuffer(4 - l % 2);
		shader_ds_1->setUniformValue("tb", 3 + l % 2);
		glMatrixMode(GL_MODELVIEW);
		glLoadMatrixf(glmvm);
		setupLights(l, 8);
		shader_ds_1->setUniformValue("lightsCount", cplc);
		glDrawQuad();
		//renderObjects(GLObjectBase::Solid, l, 0, true, true, view.isFogEnabled());
		//renderObjects(GLObjectBase::Transparent, l, 0, true, true, view.isFogEnabled());
		glFinish();
	}
	fbo.release();
	glReleaseShaders();
	glActiveTextureChannel(0);
	glBindTexture(GL_TEXTURE_2D, fbo.colorTexture(3 + passes % 2));
	if (view.isFXAAEnabled()) {
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
		shader_fxaa->bind();
		shader_fxaa->setUniformValue("dt", QVector2D(1. / view.viewport()->width(), 1. / view.viewport()->height()));
	} else {
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
	}
	glDrawQuad();
	if (view.isFXAAEnabled())
		shader_fxaa->release();
}


void RendererDeferredShading::reloadShaders() {
	if (shader_fxaa == 0) shader_fxaa = new QGLShaderProgram(view.context());
	if (shader_ds_0 == 0) shader_ds_0 = new QGLShaderProgram(view.context());
	if (shader_ds_1 == 0) shader_ds_1 = new QGLShaderProgram(view.context());
	//if (shader_ds_0 == 0) shader_ds_0 = new QGLShaderProgram(view.context());
	loadShaders(shader_fxaa, "FXAA", "shaders");
	loadShaders(shader_ds_0, "dsl_pass_0", "shaders");
	loadShaders(shader_ds_1, "dsl_pass_1", "shaders");
}


void RendererDeferredShading::setupShadersTextures(GLObjectBase & object, GLRendererBase::RenderingParameters & rp) {
	shader_ds_0->setUniformValue("has_diffuse", object.material().diffuse.bitmap_id != 0);
	shader_ds_0->setUniformValue("has_bump", object.material().bump.bitmap_id != 0);
	shader_ds_0->setUniformValue("has_height", object.material().relief.bitmap_id != 0);
	shader_ds_0->setUniformValue("bump_scale", object.material().bump_scale);
	shader_ds_0->setUniformValue("height_scale", object.material().relief_scale);
}