light/Engine/src/Platform/GraphicsAPI/OpenGL/glTexture.cpp

#include "ltpch.h"
#include "glTexture.h"

#include <glad/glad.h>

namespace Light {

	glTexture::glTexture(unsigned int width, unsigned int height, unsigned int components, unsigned char* pixels)
	{
		// create texture
		glCreateTextures(GL_TEXTURE_2D, 1, &m_TextureID);
		
		// set texture parameters
		glTextureParameteri(m_TextureID, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
		glTextureParameteri(m_TextureID, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
		glTextureParameteri(m_TextureID, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
		glTextureParameteri(m_TextureID, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

		// determine formats
		unsigned int format = components == 4u ? GL_RGBA :
		                      components == 3u ? GL_RGB  :
		                      components == 2u ? GL_RG   :
		                      components == 1u ? GL_RED  : NULL;

		unsigned int internalFormat = format == GL_RGBA ? GL_RGBA8 :
		                              format == GL_RGB  ? GL_RGB8  :
		                              format == GL_RG   ? GL_RG8   :
		                              format == GL_RED  ? GL_R8    : NULL;

		// check
		LT_ENGINE_ASSERT(format, "glTexture::glTexture: invalid number of components: {}", components);
		


		// #todo: isn't there something like glTextureImage2D ???
		// create texture and mipsmaps
		Bind();
		glTexImage2D(GL_TEXTURE_2D, 0, internalFormat, width, height, 0, format, GL_UNSIGNED_BYTE, pixels);
		glGenerateMipmap(GL_TEXTURE_2D);
	}

	glTexture::~glTexture()
	{
		glDeleteTextures(1, &m_TextureID);
	}

	void glTexture::Bind(unsigned int slot /* = 0u */)
	{
		glActiveTexture(GL_TEXTURE0 + slot);
		glBindTexture(GL_TEXTURE_2D, m_TextureID);
	}

}