/**
 * @file
 *
 * Illumination stage stencil masking optimization passes
 */
#include "Renderer.h"
#include "Light.h"


//======================================================================================================================
// Statics                                                                                                             =
//======================================================================================================================
float Renderer::Is::Smo::sMOUvSCoords[] = { -0.000000, 0.000000, -1.000000, 0.500000, 0.500000, -0.707107, 0.707107, 0.000000, -0.707107, 0.500000, 0.500000, 0.707107, 0.000000, 0.000000, 1.000000, 0.707107, 0.000000, 0.707107, -0.000000, 0.707107, 0.707107, 0.000000, 0.000000, 1.000000, 0.500000, 0.500000, 0.707107, -0.000000, 0.000000, -1.000000, -0.000000, 0.707107, -0.707107, 0.500000, 0.500000, -0.707107, -0.000000, 0.000000, -1.000000, -0.500000, 0.500000, -0.707107, -0.000000, 0.707107, -0.707107, -0.500000, 0.500000, 0.707107, 0.000000, 0.000000, 1.000000, -0.000000, 0.707107, 0.707107, -0.707107, -0.000000, 0.707107, 0.000000, 0.000000, 1.000000, -0.500000, 0.500000, 0.707107, -0.000000, 0.000000, -1.000000, -0.707107, -0.000000, -0.707107, -0.500000, 0.500000, -0.707107, -0.000000, 0.000000, -1.000000, -0.500000, -0.500000, -0.707107, -0.707107, -0.000000, -0.707107, -0.500000, -0.500000, 0.707107, 0.000000, 0.000000, 1.000000, -0.707107, -0.000000, 0.707107, 0.000000, -0.707107, 0.707107, 0.000000, 0.000000, 1.000000, -0.500000, -0.500000, 0.707107, -0.000000, 0.000000, -1.000000, 0.000000, -0.707107, -0.707107, -0.500000, -0.500000, -0.707107, -0.000000, 0.000000, -1.000000, 0.500000, -0.500000, -0.707107, 0.000000, -0.707107, -0.707107, 0.500000, -0.500000, 0.707107, 0.000000, 0.000000, 1.000000, 0.000000, -0.707107, 0.707107, 0.707107, 0.000000, 0.707107, 0.000000, 0.000000, 1.000000, 0.500000, -0.500000, 0.707107, -0.000000, 0.000000, -1.000000, 0.707107, 0.000000, -0.707107, 0.500000, -0.500000, -0.707107, 0.500000, -0.500000, -0.707107, 0.707107, 0.000000, -0.707107, 1.000000, 0.000000, -0.000000, 0.500000, -0.500000, -0.707107, 1.000000, 0.000000, -0.000000, 0.707107, -0.707107, 0.000000, 0.707107, -0.707107, 0.000000, 1.000000, 0.000000, -0.000000, 0.707107, 0.000000, 0.707107, 0.707107, -0.707107, 0.000000, 0.707107, 0.000000, 0.707107, 0.500000, -0.500000, 0.707107, 0.000000, -1.000000, 0.000000, 0.707107, -0.707107, 0.000000, 0.500000, -0.500000, 0.707107, 0.000000, -1.000000, 0.000000, 0.500000, -0.500000, 0.707107, 0.000000, -0.707107, 0.707107, 0.000000, -0.707107, -0.707107, 0.500000, -0.500000, -0.707107, 0.707107, -0.707107, 0.000000, 0.000000, -0.707107, -0.707107, 0.707107, -0.707107, 0.000000, 0.000000, -1.000000, 0.000000, -0.500000, -0.500000, -0.707107, 0.000000, -0.707107, -0.707107, -0.707107, -0.707107, 0.000000, 0.000000, -0.707107, -0.707107, 0.000000, -1.000000, 0.000000, -0.707107, -0.707107, 0.000000, -0.707107, -0.707107, 0.000000, 0.000000, -1.000000, 0.000000, 0.000000, -0.707107, 0.707107, -0.707107, -0.707107, 0.000000, 0.000000, -0.707107, 0.707107, -0.500000, -0.500000, 0.707107, -1.000000, -0.000000, 0.000000, -0.707107, -0.707107, 0.000000, -0.500000, -0.500000, 0.707107, -1.000000, -0.000000, 0.000000, -0.500000, -0.500000, 0.707107, -0.707107, -0.000000, 0.707107, -0.707107, -0.000000, -0.707107, -0.500000, -0.500000, -0.707107, -0.707107, -0.707107, 0.000000, -0.707107, -0.000000, -0.707107, -0.707107, -0.707107, 0.000000, -1.000000, -0.000000, 0.000000, -0.500000, 0.500000, -0.707107, -0.707107, -0.000000, -0.707107, -1.000000, -0.000000, 0.000000, -0.500000, 0.500000, -0.707107, -1.000000, -0.000000, 0.000000, -0.707107, 0.707107, 0.000000, -0.707107, 0.707107, 0.000000, -1.000000, -0.000000, 0.000000, -0.707107, -0.000000, 0.707107, -0.707107, 0.707107, 0.000000, -0.707107, -0.000000, 0.707107, -0.500000, 0.500000, 0.707107, -0.000000, 1.000000, 0.000000, -0.707107, 0.707107, 0.000000, -0.500000, 0.500000, 0.707107, -0.000000, 1.000000, 0.000000, -0.500000, 0.500000, 0.707107, -0.000000, 0.707107, 0.707107, -0.000000, 0.707107, -0.707107, -0.500000, 0.500000, -0.707107, -0.707107, 0.707107, 0.000000, -0.000000, 0.707107, -0.707107, -0.707107, 0.707107, 0.000000, -0.000000, 1.000000, 0.000000, 0.500000, 0.500000, -0.707107, -0.000000, 0.707107, -0.707107, -0.000000, 1.000000, 0.000000, 0.500000, 0.500000, -0.707107, -0.000000, 1.000000, 0.000000, 0.707107, 0.707107, 0.000000, 0.707107, 0.707107, 0.000000, -0.000000, 1.000000, 0.000000, -0.000000, 0.707107, 0.707107, 0.707107, 0.707107, 0.000000, -0.000000, 0.707107, 0.707107, 0.500000, 0.500000, 0.707107, 1.000000, 0.000000, -0.000000, 0.707107, 0.707107, 0.000000, 0.500000, 0.500000, 0.707107, 1.000000, 0.000000, -0.000000, 0.500000, 0.500000, 0.707107, 0.707107, 0.000000, 0.707107, 0.707107, 0.000000, -0.707107, 0.500000, 0.500000, -0.707107, 0.707107, 0.707107, 0.000000, 0.707107, 0.000000, -0.707107, 0.707107, 0.707107, 0.000000, 1.000000, 0.000000, -0.000000 };
Vbo Renderer::Is::Smo::sMOUvSVbo;
Renderer::Is::Smo::SmoShaderProg Renderer::Is::Smo::sProg;


//======================================================================================================================
// init                                                                                                                =
//======================================================================================================================
void Renderer::Is::Smo::init()
{
	if(sMOUvSVbo.isCreated()) return;

	sMOUvSVbo.create(GL_ARRAY_BUFFER, sizeof(sMOUvSCoords), sMOUvSCoords, GL_STATIC_DRAW);

	sProg.customLoad("shaders/IsSmo.glsl");
	sProg.uniVars.modelViewProjectionMat = sProg.findUniVar("modelViewProjectionMat");
}


//======================================================================================================================
// run [PointLight]                                                                                                    =
//======================================================================================================================
void Renderer::Is::Smo::run(const PointLight& light)
{
	// set GL
	glClear(GL_STENCIL_BUFFER_BIT);
	glStencilFunc(GL_ALWAYS, 0x1, 0x1);
	glStencilOp(GL_KEEP, GL_KEEP, GL_REPLACE);
	glColorMask(false, false, false, false);


	glDisable(GL_CULL_FACE);

	// set shared prog
	const float scale = 1.2; // we scale the sphere a little
	sProg.bind();
	Mat4 modelMat = Mat4(light.getWorldTransform().getOrigin(), Mat3::getIdentity(), light.radius*scale);
	Mat4 trf = r.cam->getProjectionMatrix() * Mat4::combineTransformations(r.cam->getViewMatrix(), modelMat);
	sProg.uniVars.modelViewProjectionMat->setMat4(&trf);

	// render sphere to the stencil buffer
	sMOUvSVbo.bind();
	const int loc = 0;
	glEnableVertexAttribArray(loc);
	glVertexAttribPointer(loc, 3, GL_FLOAT, GL_FALSE, 0, NULL);
	glDrawArrays(GL_TRIANGLES, 0, sizeof(sMOUvSCoords)/sizeof(float)/3);
	glDisableVertexAttribArray(loc);
	sMOUvSVbo.unbind();

	// restore GL
	glEnable(GL_CULL_FACE);
	glColorMask(true, true, true, true);

	glStencilFunc(GL_EQUAL, 0x1, 0x1);
	glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
}


//======================================================================================================================
// run [SpotLight]                                                                                                     =
//======================================================================================================================
void Renderer::Is::Smo::run(const SpotLight& light)
{
	// set GL state
	glStencilFunc(GL_ALWAYS, 0x1, 0x1);
	glStencilOp(GL_KEEP, GL_KEEP, GL_REPLACE);
	glClear(GL_STENCIL_BUFFER_BIT);

	glColorMask(false, false, false, false);
	glDisable(GL_CULL_FACE);

	// calc camera shape
	const Camera& lcam = light.camera;
	float x = lcam.getZFar() / tan((PI-lcam.getFovX())/2);
	float y = tan(lcam.getFovY()/2) * lcam.getZFar();
	float z = -lcam.getZFar();

	const int trisNum = 6;

	float verts[trisNum][3][3] = {
		{ { 0.0, 0.0, 0.0 }, { x, -y, z }, { x,  y, z } }, // right triangle
		{ { 0.0, 0.0, 0.0 }, { x,  y, z }, {-x,  y, z } }, // top
		{ { 0.0, 0.0, 0.0 }, {-x,  y, z }, {-x, -y, z } }, // left
		{ { 0.0, 0.0, 0.0 }, {-x, -y, z }, { x, -y, z } }, // bottom
		{ { x, -y, z }, {-x,  y, z }, { x,  y, z } }, // front up right
		{ { x, -y, z }, {-x, -y, z }, {-x,  y, z } }, // front bottom left
	};

	// shader prog
	sProg.bind();
	Mat4 modelMat = Mat4(lcam.getWorldTransform());
	Mat4 trf = r.cam->getProjectionMatrix() * Mat4::combineTransformations(r.cam->getViewMatrix(), modelMat);
	sProg.uniVars.modelViewProjectionMat->setMat4(&trf);

	// render camera shape to stencil buffer
	const int loc = 0;
	glEnableVertexAttribArray(loc);
	glVertexAttribPointer(loc, 3, GL_FLOAT, false, 0, verts);
	glDrawArrays(GL_TRIANGLES, 0, trisNum*3);
	glDisableVertexAttribArray(loc);

	// restore GL state
	glEnable(GL_CULL_FACE);
	glColorMask(true, true, true, true);

	glStencilFunc(GL_EQUAL, 0x1, 0x1);
	glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
}