CezveRender

Status: Experimental

Java Version: 17+

Learning Curve: Steep

Last Release: Active (2025)

CezveRender is a real-time 3D renderer built from scratch in Java using OpenGL 3.3 and LWJGL. Created as a learning-focused personal project, it implements core graphics programming concepts including shadow mapping, physically-based lighting models, and scene management entirely in Java. The renderer supports directional, point, and spot lights — each with their own shadow mapping techniques (orthographic, cubemap, and perspective respectively) — along with Phong shading per material. OBJ model loading is handled via Assimp (through LWJGL bindings), and the project includes a live ImGui-powered editor for adding, removing, and transforming scene objects and lights at runtime. Additional features include a procedural mesh generator, skybox rendering, and an adjustable shadow bias debugger. The tech stack is built on LWJGL for low-level OpenGL/GLFW bindings, JOML for vector and matrix math, imgui-java for the in-scene editor UI, and STB for image loading. While experimental and not production-ready, CezveRender is an excellent reference for Java developers interested in learning how to implement a rendering pipeline from scratch on the JVM.

Code Example


            import org.lwjgl.opengl.*;
            import static org.lwjgl.opengl.GL33.*;
            
            // Basic shader program setup in CezveRender style
            public class ShaderProgram {
                private final int programId;
            
                public ShaderProgram(String vertexSrc, String fragmentSrc) {
                    int vertShader = compileShader(GL_VERTEX_SHADER, vertexSrc);
                    int fragShader = compileShader(GL_FRAGMENT_SHADER, fragmentSrc);
            
                    programId = glCreateProgram();
                    glAttachShader(programId, vertShader);
                    glAttachShader(programId, fragShader);
                    glLinkProgram(programId);
                    if (glGetProgrami(programId, GL_LINK_STATUS) == GL_FALSE) {
                        throw new RuntimeException("Program link error: " + glGetProgramInfoLog(programId));
                    }
            
                    glDeleteShader(vertShader);
                    glDeleteShader(fragShader);
                }
            
                private int compileShader(int type, String src) {
                    int shader = glCreateShader(type);
                    glShaderSource(shader, src);
                    glCompileShader(shader);
                    if (glGetShaderi(shader, GL_COMPILE_STATUS) == GL_FALSE) {
                        throw new RuntimeException("Shader compile error: " + glGetShaderInfoLog(shader));
                    }
                    return shader;
                }
            
                public void bind() { glUseProgram(programId); }
                public void unbind() { glUseProgram(0); }
            
                public void setUniform(String name, float value) {
                    glUniform1f(glGetUniformLocation(programId, name), value);
                }
            
                public void cleanup() { glDeleteProgram(programId); }
            }