#33 - Texture Class C++

Date: 2018-11-03 12:00 - C++

Simple OpenGL Texture Wrapper class for 2D textures.

// Texture.h
#pragma once

#include <string>
#include <memory>
#include "../OpenGL.h"

namespace YourNamespace {
	namespace Rendering {
		class Texture {
		public:
			static std::shared_ptr<Texture> getTexture(const std::string& file);
			static void unbind(GLenum target = GL_TEXTURE_2D) { glBindTexture(target, NULL); }
		private:
			GLuint _texId;
			GLuint _width;
			GLuint _height;
		public:
			Texture(GLuint texID, GLuint width, GLuint height);
			GLuint textureID() const { return _texId; }
			GLuint width() const { return _width; }
			GLuint height() const { return _height; }
			void bind(GLenum target = GL_TEXTURE_2D) const { glBindTexture(target, _texId); }
			~Texture() { glDeleteTextures(1, &_texId); }
		};
	}
}
// Texture.cpp
#include "Texture.h"

#include <SDL/SDL_image.h>

#include "../Logging/Logger.h"

using namespace Texture::Rendering;

std::shared_ptr<Texture> Texture::getTexture(const std::string& file) {
	GLuint textureID;
	SDL_Surface* surface = IMG_Load(file.c_str());
	if (surface == NULL) {
		LOG_ERROR("Unable to load texture: " + file);
		return nullptr;
	}

	if (SDL_SetSurfaceAlphaMod(surface, 0) == -1) {
		LOG_ERROR("Unable to load texture: " + file + ", surface alpha error.");
		return nullptr;
	}

	GLenum internalFormat = GL_RGBA;
	GLenum format;
	if (surface->format->BitsPerPixel == 8 && surface->format->Amask == 0) {
		format = GL_RED;
		internalFormat = GL_RED;
	}
	else if (surface->format->BitsPerPixel == 24 && surface->format->Amask == 0)
		format = GL_RGB;
	else if (surface->format->BitsPerPixel == 32 && surface->format->Amask != 0)
		format = GL_RGBA;
	else {
		LOG_ERROR("Unable to load texture: " + file + ", format error!");
		return nullptr;
	}

	glGenTextures(1, &textureID);
	glBindTexture(GL_TEXTURE_2D, textureID);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	glTexImage2D(GL_TEXTURE_2D, 0, internalFormat, surface->w, surface->h, 0, format, GL_UNSIGNED_BYTE, surface->pixels);

	std::shared_ptr<Texture> tex = std::make_shared<Texture>(textureID, surface->w, surface->h);
	SDL_FreeSurface(surface);
	return tex;
}

Texture::Texture(GLuint texID, GLuint width, GLuint height) : _texId(texID), _width(width), _height(height) {
}

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