CLK/Outputs/OpenGL/Primitives/Texture.cpp

//
//  Texture.cpp
//  Clock Signal Kiosk
//
//  Created by Thomas Harte on 30/01/2026.
//  Copyright © 2026 Thomas Harte. All rights reserved.
//

#include "Texture.hpp"

using namespace Outputs::Display::OpenGL;

namespace {
constexpr GLint internal_format_for_depth(const std::size_t depth) {
	switch(depth) {
		default: return GL_FALSE;
		case 1: return GL_R8UI;
		case 2: return GL_RG8UI;
		case 3: return GL_RGB8UI;
		case 4: return GL_RGBA8UI;
	}
}

constexpr GLenum format_for_depth(const std::size_t depth) {
	switch(depth) {
		default: return GL_FALSE;
		case 1: return GL_RED_INTEGER;
		case 2: return GL_RG_INTEGER;
		case 3: return GL_RGB_INTEGER;
		case 4: return GL_RGBA_INTEGER;
	}
}
}

Texture::Texture(
	const size_t channels,
	const GLenum texture_unit,
	const GLint mag_filter,
	const GLint min_filter,
	const GLsizei width,
	const GLsizei height
) :
	channels_(channels),
	texture_unit_(texture_unit),
	width_(width),
	height_(height)
{
	test_gl([&]{ glGenTextures(1, &texture_); });
	test_gl([&]{ glActiveTexture(texture_unit); });
	test_gl([&]{ glBindTexture(GL_TEXTURE_2D, texture_); });

	test_gl([&]{
		glTexImage2D(
			GL_TEXTURE_2D,
			0,
			internal_format_for_depth(channels),
			GLsizei(width_),
			GLsizei(height_),
			0,
			format_for_depth(channels),
			GL_UNSIGNED_BYTE,
			nullptr
		);
	});
	test_gl([&]{ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, mag_filter); });
	test_gl([&]{ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, min_filter); });
	test_gl([&]{ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); });
	test_gl([&]{ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); });
}

void Texture::bind() {
	test_gl([&]{ glActiveTexture(texture_unit_); });
	test_gl([&]{ glBindTexture(GL_TEXTURE_2D, texture_); });
}

Texture::~Texture() {
	glDeleteTextures(1, &texture_);
}

Texture::Texture(Texture &&rhs) {
	*this = std::move(rhs);
}

Texture &Texture::operator =(Texture &&rhs) {
	std::swap(channels_, rhs.channels_);
	std::swap(texture_, rhs.texture_);
	std::swap(texture_unit_, rhs.texture_unit_);
	std::swap(width_, rhs.width_);
	std::swap(height_, rhs.height_);
	return *this;
}