#include "SkyBox.h"
#include "Shader.h"

#include <glad/glad.h>
#include <stb_image.h>

using namespace std;

SkyBox::SkyBox() {
	glGenTextures(1, &textureId);
}

SkyBox::~SkyBox() {
	glDeleteTextures(1, &textureId);
}

bool SkyBox::Load(const std::string basename) {
	glBindTexture(GL_TEXTURE_CUBE_MAP, textureId);

	Load(GL_TEXTURE_CUBE_MAP_POSITIVE_X, basename + "_right1.png");
	Load(GL_TEXTURE_CUBE_MAP_NEGATIVE_X, basename + "_left2.png");
	Load(GL_TEXTURE_CUBE_MAP_POSITIVE_Y, basename + "_top3.png");
	Load(GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, basename + "_bottom4.png");
	Load(GL_TEXTURE_CUBE_MAP_POSITIVE_Z, basename + "_front5.png");
	Load(GL_TEXTURE_CUBE_MAP_NEGATIVE_Z, basename + "_back6.png");

	programId = loadProgram("skybox");

	return true;
}

bool SkyBox::Load(GLuint target, const std::string filename) {
	int x, y, comp;
	unsigned char *data = stbi_load(filename.c_str(), &x, &y, &comp, 4);

	glTexImage2D(target, 0, GL_RGBA, x, y, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
	glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S,
	GL_CLAMP_TO_EDGE);
	glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T,
	GL_CLAMP_TO_EDGE);
	glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R,
	GL_CLAMP_TO_EDGE);

	stbi_image_free(data);
	return true;
}

void SkyBox::Render() {
	GLint OldCullFaceMode;
	glGetIntegerv(GL_CULL_FACE_MODE, &OldCullFaceMode);
	GLint OldDepthFuncMode;
	glGetIntegerv(GL_DEPTH_FUNC, &OldDepthFuncMode);

	glCullFace(GL_FRONT);
	glDepthFunc(GL_LEQUAL);
/*
	Pipeline p;
	p.Scale(20.0f, 20.0f, 20.0f);
	p.Rotate(0.0f, 0.0f, 0.0f);
	p.WorldPos(m_pCamera->GetPos().x, m_pCamera->GetPos().y,
			m_pCamera->GetPos().z);
	p.SetCamera(m_pCamera->GetPos(), m_pCamera->GetTarget(),
			m_pCamera->GetUp());
	p.SetPerspectiveProj(m_persProjInfo);
	m_pSkyboxTechnique->SetWVP(p.GetWVPTrans());
	m_pCubemapTex->Bind(GL_TEXTURE0);
	m_pMesh->Render();
*/
	glCullFace(OldCullFaceMode);
	glDepthFunc(OldDepthFuncMode);
}

void SkyBox::Bind(GLenum unit) {
	glActiveTexture(unit);
	glBindTexture(GL_TEXTURE_CUBE_MAP, textureId);
}