3Dterrain-OpenGL/Skybox.cpp at master · sarahayu/3Dterrain-OpenGL · GitHub

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#include "Skybox.h"
#include <glad\glad.h>
#define STB_IMAGE_STATIC
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"
#include <iostream>

const float skyboxVertices[] = {
	// positions
	-1.0f,  1.0f, -1.0f,
	-1.0f, -1.0f, -1.0f,
	1.0f, -1.0f, -1.0f,
	1.0f, -1.0f, -1.0f,
	1.0f,  1.0f, -1.0f,
	-1.0f,  1.0f, -1.0f,

	-1.0f, -1.0f,  1.0f,
	-1.0f, -1.0f, -1.0f,
	-1.0f,  1.0f, -1.0f,
	-1.0f,  1.0f, -1.0f,
	-1.0f,  1.0f,  1.0f,
	-1.0f, -1.0f,  1.0f,

	1.0f, -1.0f, -1.0f,
	1.0f, -1.0f,  1.0f,
	1.0f,  1.0f,  1.0f,
	1.0f,  1.0f,  1.0f,
	1.0f,  1.0f, -1.0f,
	1.0f, -1.0f, -1.0f,

	-1.0f, -1.0f,  1.0f,
	-1.0f,  1.0f,  1.0f,
	1.0f,  1.0f,  1.0f,
	1.0f,  1.0f,  1.0f,
	1.0f, -1.0f,  1.0f,
	-1.0f, -1.0f,  1.0f,

	-1.0f,  1.0f, -1.0f,
	1.0f,  1.0f, -1.0f,
	1.0f,  1.0f,  1.0f,
	1.0f,  1.0f,  1.0f,
	-1.0f,  1.0f,  1.0f,
	-1.0f,  1.0f, -1.0f,

	-1.0f, -1.0f, -1.0f,
	-1.0f, -1.0f,  1.0f,
	1.0f, -1.0f, -1.0f,
	1.0f, -1.0f, -1.0f,
	-1.0f, -1.0f,  1.0f,
	1.0f, -1.0f,  1.0f
};

void Skybox::initialize(const std::vector<std::string>& faceFiles)
{

	glGenVertexArrays(1, &m_skyboxVAO);
	glGenBuffers(1, &m_skyboxVBO);
	glBindVertexArray(m_skyboxVAO);
	glBindBuffer(GL_ARRAY_BUFFER, m_skyboxVBO);
	glBufferData(GL_ARRAY_BUFFER, sizeof(skyboxVertices), &skyboxVertices, GL_STATIC_DRAW);
	glEnableVertexAttribArray(0);
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);

	glGenTextures(1, &m_cubeTex);
	glBindTexture(GL_TEXTURE_CUBE_MAP, m_cubeTex);
	stbi_set_flip_vertically_on_load(false);
	int width, height, nrChannels;
	for (unsigned int i = 0; i < faceFiles.size(); i++)
	{
		unsigned char *data = stbi_load(faceFiles[i].c_str(), &width, &height, &nrChannels, 0);
		if (data)
		{
			std::cout << "\n" << width << "x" << height;
			glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
			stbi_image_free(data);
		}
		else
		{
			std::cout << "Cubemap texture failed to load at path: " << faceFiles[i].c_str() << std::endl;
			stbi_image_free(data);
		}
	}
	glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_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);
}

void Skybox::draw() const
{
	glBindVertexArray(m_skyboxVAO);
	glBindTexture(GL_TEXTURE_CUBE_MAP, m_cubeTex);
	glActiveTexture(GL_TEXTURE0);
	glDrawArrays(GL_TRIANGLES, 0, 36);
}