To implement a Signed Distance Function (SDF) renderer using the provided structure in `rendering.cpp` and `rendering.h`, we'll create a minimal setup for rendering SDFs. Below, I'll provide you with a basic implementation that includes the necessary structures and details for rendering SDFs in OpenGL using a fragment shader.
### Step 1: Creating `rendering.h`
We will define the SDF renderer class, which will handle the initialization of shaders, the SDF function, and render the scene.
```cpp
// rendering.h
#ifndef RENDERING_H
#define RENDERING_H
#include <GL/glew.h>
#include <glm/glm.hpp>
#include <string>
class SDFRenderer {
public:
SDFRenderer();
~SDFRenderer();
void Init();
void Render(const glm::mat4& view, const glm::mat4& projection);
private:
GLuint shaderProgram;
GLuint vao;
void CompileShaders();
GLuint LoadShader(const char* vertexPath, const char* fragmentPath);
float SDFSphere(const glm::vec3& p, float radius);
};
#endif // RENDERING_H
```
### Step 2: Implementing `rendering.cpp`
In this file, we will implement the constructor, destructor, shader compilation, SDF functions, and the render method.
```cpp
// rendering.cpp
#include "rendering.h"
#include <iostream>
#include <fstream>
#include <sstream>
#include <glm/gtc/type_ptr.hpp>
SDFRenderer::SDFRenderer() : vao(0) {}
SDFRenderer::~SDFRenderer() {
if (vao) {
glDeleteVertexArrays(1, &vao);
}
glDeleteProgram(shaderProgram);
}
void SDFRenderer::Init() {
CompileShaders();
// Setup a fullscreen quad
float vertices[] = {
-1.0f, -1.0f, 0.0f,
1.0f, -1.0f, 0.0f,
1.0f, 1.0f, 0.0f,
-1.0f, 1.0f, 0.0f
};
GLuint vbo;
glGenVertexArrays(1, &vao);
glGenBuffers(1, &vbo);
glBindVertexArray(vao);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
}
void SDFRenderer::CompileShaders() {
shaderProgram = LoadShader("shaders/vertex_shader.glsl", "shaders/fragment_shader.glsl");
}
GLuint SDFRenderer::LoadShader(const char* vertexPath, const char* fragmentPath) {
std::string vertexCode, fragmentCode;
std::ifstream vShaderFile(vertexPath);
std::ifstream fShaderFile(fragmentPath);
// Ensure ifstream objects can throw exceptions
vShaderFile.exceptions(std::ifstream::badbit);
fShaderFile.exceptions(std::ifstream::badbit);
try {
std::stringstream vShaderStream, fShaderStream;
vShaderStream << vShaderFile.rdbuf();
fShaderStream << fShaderFile.rdbuf();
vertexCode = vShaderStream.str();
fragmentCode = fShaderStream.str();
} catch (std::ifstream::failure e) {
std::cerr << "ERROR::SHADER::FILE_NOT_SUCCESSFULLY_READ" << std::endl;
}
const char* vShaderCode = vertexCode.c_str();
const char* fShaderCode = fragmentCode.c_str();
GLuint vertex, fragment;
// Vertex shader
vertex = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertex, 1, &vShaderCode, nullptr);
glCompileShader(vertex);
// Fragment shader
fragment = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragment, 1, &fShaderCode, nullptr);
glCompileShader(fragment);
GLuint shaderProgram = glCreateProgram();
glAttachShader(shaderProgram, vertex);
glAttachShader(shaderProgram, fragment);
glLinkProgram(shaderProgram);
glDeleteShader(vertex);
glDeleteShader(fragment);
return shaderProgram;
}
void SDFRenderer::Render(const glm::mat4& view, const glm::mat4& projection) {
glUseProgram(shaderProgram);
// Pass view and projection matrices to the shader
GLuint viewLoc = glGetUniformLocation(shaderProgram, "view");
GLuint projLoc = glGetUniformLocation(shaderProgram, "projection");
glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(view));
glUniformMatrix4fv(projLoc, 1, GL_FALSE, glm::value_ptr(projection));
// Render the fullscreen quad
glBindVertexArray(vao);
glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
glBindVertexArray(0);
}
float SDFRenderer::SDFSphere(const glm::vec3& p, float radius) {
return glm::length(p) - radius;
}
```
### Step 3: Setting up Shaders
Create two shader files in a `shaders` directory.
#### Vertex Shader (`shaders/vertex_shader.glsl`)
```glsl
#version 330 core
layout(location = 0) in vec3 aPos;
uniform mat4 view;
uniform mat4 projection;
void main() {
gl_Position = projection * view * vec4(aPos, 1.0);
}
```
#### Fragment Shader (`shaders/fragment_shader.glsl`)
```glsl
#version 330 core
out vec4 FragColor;
uniform mat4 view;
uniform mat4 projection;
float SDFSphere(vec3 p, float radius) {
return length(p) - radius;
}
void main() {
vec2 uv = (gl_FragCoord.xy / vec2(800, 600)) * 2.0 - 1.0; // Adjust to your viewport size
uv.y *= -1.0; // Flip Y coordinates for correct rendering
// Compute SDF
float dist = SDFSphere(vec3(uv, 0.0), 0.5);
// Simple color based on distance
if (dist < 0.0) {
FragColor = vec4(1.0, 0.0, 0.0, 1.0); // Inside the sphere
} else {
FragColor = vec4(0.0, 0.0, 1.0, 1.0); // Outside the sphere
}
}
```
### Step 4: Integrating into `main.cpp`
In your `main.cpp`, create an instance of `SDFRenderer` and call its `Init` and `Render` methods in the main loop.
```cpp
#include "rendering.h"
// Inside your main, after initializing OpenGL context
SDFRenderer sdfRenderer;
sdfRenderer.Init();
while (!glfwWindowShouldClose(window)) {
...
// Render SDF
glm::mat4 view = camera.GetViewMatrix();
glm::mat4 projection = camera.GetProjectionMatrix(); // Assume you have a method to get it
sdfRenderer.Render(view, projection);
...
}
```
### Summary
This setup will render a simple SDF-based sphere in the scene. Make sure you adapt the methods to fit your existing camera and ECS structure if required. Remember that the SDF functions can be expanded to create more complex shapes as needed!