Shader.cpp

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/*
   Copyright 2022 Rishi Challa
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at
 
       http://www.apache.org/licenses/LICENSE-2.0
 
   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/
 
#ifdef KALE_VULKAN
 
#include "Shader.hpp"
 
#include <Kale/Core/Application/Application.hpp>
#include <Kale/Vulkan/Device/Device.hpp>
 
#include <fstream>
#include <stdexcept>
 
using namespace Kale;
using namespace Kale::Vulkan;
 
Shader::Shader() {
    // Empty Body
}
 
Shader::Shader(const std::string& filename, ShaderType type, Device& device) : ChildResource(device), type(type) {
    std::vector<char> code = readFile(filename);
    createShaderModule(code);
}
 
void Shader::init(const std::string& filename, ShaderType type, Device& device) {
    ChildResource::init(device);
    this->type = type;
    std::vector<char> code = readFile(filename);
    createShaderModule(code);
}
 
std::vector<char> Shader::readFile(const std::string& filename) const {
    std::ifstream file(mainApp->getAssetFolderPath() + "shaders/" + filename, std::ios::ate | std::ios::binary);
    if (!file.is_open()) throw std::runtime_error("Unable to open the file "+filename);
    size_t fileSize = static_cast<size_t>(file.tellg());
    std::vector<char> code(fileSize);
    file.seekg(0);
    file.read(code.data(), fileSize);
    file.close();
    return code;
}
 
void Shader::createShaderModule(const std::vector<char>& code) {
    vk::ShaderModuleCreateInfo createInfo(vk::ShaderModuleCreateFlags(), code.size(),
        reinterpret_cast<const uint32_t*>(code.data()));
    shader = parentPtr->logicalDevice->createShaderModuleUnique(createInfo);
}
 
void Shader::freeResources(bool remove) {
    ChildResource::freeResources(remove);
    shader.reset();
}
 
vk::ShaderStageFlagBits Shader::getShaderStage() const {
    switch (type) {
        case ShaderType::Vertex:
            return vk::ShaderStageFlagBits::eVertex;
        case ShaderType::Fragment:
            return vk::ShaderStageFlagBits::eFragment;
        default:
            throw std::runtime_error("Invalid Shader Type");
    }
}
 
vk::PipelineShaderStageCreateInfo Shader::getShaderPipelineInfo() const {
    vk::PipelineShaderStageCreateInfo createInfo;
    createInfo.stage = getShaderStage();
    createInfo.module = shader.get();
    createInfo.pName = "main"; // All kale shaders are REQUIRED to have a main function
    
    return createInfo;
}
 
#endif