OmniShadowMap.cpp

#include "OmniShadowMap.h"

OmniShadowMap::OmniShadowMap() : ShadowMap()
{

}

bool OmniShadowMap::Init(GLuint width, GLuint height)
{
	shadowWidth = width;		shadowHeight = height;

	glGenFramebuffers(1, &FBO);

	glGenTextures(1, &shadowMap);
	glBindTexture(GL_TEXTURE_CUBE_MAP, shadowMap);

	//go through and set up each parts of the cubemap
	for (size_t i = 0; i < 6; i++)
	{
		glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, GL_DEPTH_COMPONENT, shadowWidth, shadowHeight, 0, GL_DEPTH_COMPONENT, GL_FLOAT, nullptr);			//the positive x side is the side of our cube on the far left
		
	}

	glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);		//GL_LINEAR means when you zoom in to the image, if you zoom in or zoom out of the image, it will try and blend the pixels together
	glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	glTexParameterf(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);	//GL_TEXTURE_WRAP_S specifies how to handle the image when it's around the border. S refers to the x-axis
	glTexParameterf(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
	glTexParameterf(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
	
	glBindFramebuffer(GL_FRAMEBUFFER, FBO);
	glFramebufferTexture(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, shadowMap, 0);

	glDrawBuffer(GL_NONE);
	glReadBuffer(GL_NONE);				//we are setting these two values to none since we don't wan't to draw or read any sort of color 

	GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);			//check for errors

	if (status != GL_FRAMEBUFFER_COMPLETE)
	{		//If the frame buffer failed
		printf("Framebuffer Error: %i\n", status);
		return false;
	}

	glBindFramebuffer(GL_FRAMEBUFFER, 0);			//unbind the framebuffer

	return true;
}

void OmniShadowMap::write()
{
	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, FBO);
}

void OmniShadowMap::Read(GLenum texUnit)
{
	glActiveTexture(texUnit);
	glBindTexture(GL_TEXTURE_CUBE_MAP, shadowMap);
}

OmniShadowMap::~OmniShadowMap()
{

}