SkyboxRenderer.cpp

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//
// Created by denzel on 14/06/2025.
//
 
#include "hellfire/graphics/renderer/SkyboxRenderer.h"
 
#include <glm/gtc/type_ptr.hpp>
 
#include "../core/Application.h"
#include <GL/glew.h>
#include "Skybox.h"
#include "hellfire/utilities/ServiceLocator.h"
 
namespace hellfire {
    // skyboxes cube vertices
    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
    };
 
    SkyboxRenderer::~SkyboxRenderer() {
        if (skybox_vao_ != 0)
            glDeleteVertexArrays(1, &skybox_vao_);
        if (skybox_vbo_ != 0)
            glDeleteBuffers(1, &skybox_vbo_);
        if (skybox_shader_ != 0)
            glDeleteProgram(skybox_shader_);
    }
 
    void SkyboxRenderer::initialize() {
        if (!initialized_) {
            setup_skybox_geometry();
            load_skybox_shader();
        }
    }
 
    void SkyboxRenderer::setup_skybox_geometry() {
        glGenVertexArrays(1, &skybox_vao_);
        glGenBuffers(1, &skybox_vbo_);
 
        glBindVertexArray(skybox_vao_);
        glBindBuffer(GL_ARRAY_BUFFER, skybox_vbo_);
        glBufferData(GL_ARRAY_BUFFER, sizeof(skyboxVertices), &skyboxVertices, GL_STATIC_DRAW);
 
        glEnableVertexAttribArray(0);
        glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), static_cast<void *>(nullptr));
 
        glBindVertexArray(0);
    }
 
    void SkyboxRenderer::load_skybox_shader() {
        skybox_shader_ = ServiceLocator::get_service<ShaderManager>()->load_shader_from_files(
            "assets/shaders/skybox.vert", "assets/shaders/skybox.frag");
    }
 
    void SkyboxRenderer::render(const Skybox &skybox, const CameraComponent *camera) const {
        if (!skybox.is_loaded()) return;
 
        // Save current depth state
        glDepthFunc(GL_LEQUAL);
 
        glUseProgram(skybox_shader_);
 
        // Remove translation from view matrix
        glm::mat4 view = glm::mat4(glm::mat3(camera->get_view_matrix()));
        glm::mat4 projection = camera->get_projection_matrix();
 
        glUniformMatrix4fv(glGetUniformLocation(skybox_shader_, "view"), 1, GL_FALSE, glm::value_ptr(view));
        glUniformMatrix4fv(glGetUniformLocation(skybox_shader_, "projection"), 1, GL_FALSE, glm::value_ptr(projection));
 
        // Set tint and exposure
        glUniform3fv(glGetUniformLocation(skybox_shader_, "tint"), 1, glm::value_ptr(skybox.get_tint()));
        glUniform1f(glGetUniformLocation(skybox_shader_, "exposure"), skybox.get_exposure());
 
        // Bind cubemap
        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_CUBE_MAP, skybox.get_cubemap());
        glUniform1i(glGetUniformLocation(skybox_shader_, "skyboxes"), 0);
 
        // Draw skyboxes cube
        glBindVertexArray(skybox_vao_);
        glDrawArrays(GL_TRIANGLES, 0, 36);
        glBindVertexArray(0);
 
        // Restore depth state
        glDepthFunc(GL_LESS);
    }
}