Java tutorial
/* * Copyright LWJGL. All rights reserved. * License terms: http://lwjgl.org/license.php */ package org.lwjgl.demo.opengl.raytracing; import org.lwjgl.BufferUtils; import org.lwjgl.PointerBuffer; import org.lwjgl.glfw.*; import org.lwjgl.opengl.ARBShaderAtomicCounters; import org.lwjgl.opengl.GL; import org.lwjgl.opengl.GLUtil; import org.lwjgl.system.Callback; import org.joml.Matrix4f; import org.joml.Vector3f; import java.io.IOException; import java.nio.ByteBuffer; import java.nio.FloatBuffer; import java.nio.IntBuffer; import static java.lang.Math.*; import static org.lwjgl.demo.opengl.util.DemoUtils.*; import static org.lwjgl.glfw.GLFW.*; import static org.lwjgl.opengl.GL11.*; import static org.lwjgl.opengl.GL15.*; import static org.lwjgl.opengl.GL20.*; import static org.lwjgl.opengl.GL30.*; import static org.lwjgl.opengl.GL33.*; import static org.lwjgl.opengl.GL42.*; import static org.lwjgl.opengl.GL43.*; import static org.lwjgl.system.MathUtil.*; import static org.lwjgl.system.MemoryUtil.*; /** * Same as {@link Demo} but it uses a pseudo-random number generator based on * {@link ARBShaderAtomicCounters}. * <p> * This should showcase the use of atomic counter buffers in GLSL shaders. In * detail, there is a new <code>random()</code> GLSL function which implicitly * takes an atomic counter and increments it everytime the function is called. * What was once the combination of screen coordinate parameterization and time * to achieve variance of the generated random value over each pixel is now a * single atomic counter. * <p> * In later demos (especially with correct "by the book" photon mapping), which * use rays originating from the light source we are going to need this * approach, since otherwise we cannot have different random reflection * directions, since the direction will always depend on constant "random" * values. This will be explained in later demos! * * @author Kai Burjack */ public class AtomicDemo { private long window; private int width = 1024; private int height = 768; private boolean resetFramebuffer = true; private int tex; private int vao; private int computeProgram; private int quadProgram; private int sampler; private int eyeUniform; private int ray00Uniform; private int ray10Uniform; private int ray01Uniform; private int ray11Uniform; private int blendFactorUniform; private int bounceCountUniform; private int framebufferImageBinding; private int atomicBuffer; private int workGroupSizeX; private int workGroupSizeY; private float mouseDownX; private float mouseX; private boolean mouseDown; private float currRotationAboutY = 0.0f; private float rotationAboutY = 0.8f; private int frameNumber; private int bounceCount = 1; private IntBuffer intBuffer = BufferUtils.createIntBuffer(1); private Matrix4f projMatrix = new Matrix4f(); private Matrix4f viewMatrix = new Matrix4f(); private Matrix4f invViewProjMatrix = new Matrix4f(); private Vector3f tmpVector = new Vector3f(); private Vector3f cameraPosition = new Vector3f(); private Vector3f cameraLookAt = new Vector3f(0.0f, 0.5f, 0.0f); private Vector3f cameraUp = new Vector3f(0.0f, 1.0f, 0.0f); GLFWErrorCallback errCallback; GLFWKeyCallback keyCallback; GLFWFramebufferSizeCallback fbCallback; GLFWCursorPosCallback cpCallback; GLFWMouseButtonCallback mbCallback; Callback debugProc; private void init() throws IOException { glfwSetErrorCallback(errCallback = new GLFWErrorCallback() { private GLFWErrorCallback delegate = GLFWErrorCallback.createPrint(System.err); @Override public void invoke(int error, long description) { if (error == GLFW_VERSION_UNAVAILABLE) System.err.println( "This demo requires OpenGL 4.3 or higher. The Demo33 version works on OpenGL 3.3 or higher."); delegate.invoke(error, description); } @Override public void free() { delegate.free(); } }); if (!glfwInit()) throw new IllegalStateException("Unable to initialize GLFW"); glfwDefaultWindowHints(); glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GLFW_TRUE); glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4); glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3); glfwWindowHint(GLFW_VISIBLE, GLFW_FALSE); glfwWindowHint(GLFW_RESIZABLE, GLFW_TRUE); window = glfwCreateWindow(width, height, "Raytracing Demo (compute shader + atomic counter)", NULL, NULL); if (window == NULL) { throw new AssertionError("Failed to create the GLFW window"); } System.out.println("Press keypad '+' or 'page up' to increase the number of bounces."); System.out.println("Press keypad '-' or 'page down' to decrease the number of bounces."); glfwSetKeyCallback(window, keyCallback = new GLFWKeyCallback() { @Override public void invoke(long window, int key, int scancode, int action, int mods) { if (action != GLFW_RELEASE) { return; } if (key == GLFW_KEY_ESCAPE) { glfwSetWindowShouldClose(window, true); } else if (key == GLFW_KEY_KP_ADD || key == GLFW_KEY_PAGE_UP) { int newBounceCount = Math.min(4, AtomicDemo.this.bounceCount + 1); if (newBounceCount != AtomicDemo.this.bounceCount) { AtomicDemo.this.bounceCount = newBounceCount; System.out.println("Ray bounce count is now: " + AtomicDemo.this.bounceCount); AtomicDemo.this.frameNumber = 0; } } else if (key == GLFW_KEY_KP_SUBTRACT || key == GLFW_KEY_PAGE_DOWN) { int newBounceCount = Math.max(1, AtomicDemo.this.bounceCount - 1); if (newBounceCount != AtomicDemo.this.bounceCount) { AtomicDemo.this.bounceCount = newBounceCount; System.out.println("Ray bounce count is now: " + AtomicDemo.this.bounceCount); AtomicDemo.this.frameNumber = 0; } } } }); glfwSetFramebufferSizeCallback(window, fbCallback = new GLFWFramebufferSizeCallback() { @Override public void invoke(long window, int width, int height) { if (width > 0 && height > 0 && (AtomicDemo.this.width != width || AtomicDemo.this.height != height)) { AtomicDemo.this.width = width; AtomicDemo.this.height = height; AtomicDemo.this.resetFramebuffer = true; AtomicDemo.this.frameNumber = 0; } } }); glfwSetCursorPosCallback(window, cpCallback = new GLFWCursorPosCallback() { @Override public void invoke(long window, double x, double y) { AtomicDemo.this.mouseX = (float) x; if (mouseDown) { AtomicDemo.this.frameNumber = 0; } } }); glfwSetMouseButtonCallback(window, mbCallback = new GLFWMouseButtonCallback() { @Override public void invoke(long window, int button, int action, int mods) { if (action == GLFW_PRESS) { AtomicDemo.this.mouseDownX = AtomicDemo.this.mouseX; AtomicDemo.this.mouseDown = true; } else if (action == GLFW_RELEASE) { AtomicDemo.this.mouseDown = false; AtomicDemo.this.rotationAboutY = AtomicDemo.this.currRotationAboutY; } } }); GLFWVidMode vidmode = glfwGetVideoMode(glfwGetPrimaryMonitor()); glfwSetWindowPos(window, (vidmode.width() - width) / 2, (vidmode.height() - height) / 2); glfwMakeContextCurrent(window); glfwSwapInterval(0); glfwShowWindow(window); IntBuffer framebufferSize = BufferUtils.createIntBuffer(2); nglfwGetFramebufferSize(window, memAddress(framebufferSize), memAddress(framebufferSize) + 4); width = framebufferSize.get(0); height = framebufferSize.get(1); GL.createCapabilities(); debugProc = GLUtil.setupDebugMessageCallback(); /* Create all needed GL resources */ createFramebufferTexture(); createSampler(); quadFullScreenVao(); createComputeProgram(); initComputeProgram(); createQuadProgram(); initQuadProgram(); createAtomicBuffer(); } /** * Create a VAO with a full-screen quad VBO. */ private void quadFullScreenVao() { this.vao = glGenVertexArrays(); int vbo = glGenBuffers(); glBindVertexArray(vao); glBindBuffer(GL_ARRAY_BUFFER, vbo); ByteBuffer bb = BufferUtils.createByteBuffer(4 * 2 * 6); FloatBuffer fv = bb.asFloatBuffer(); fv.put(-1.0f).put(-1.0f); fv.put(1.0f).put(-1.0f); fv.put(1.0f).put(1.0f); fv.put(1.0f).put(1.0f); fv.put(-1.0f).put(1.0f); fv.put(-1.0f).put(-1.0f); glBufferData(GL_ARRAY_BUFFER, bb, GL_STATIC_DRAW); glEnableVertexAttribArray(0); glVertexAttribPointer(0, 2, GL_FLOAT, false, 0, 0L); glBindBuffer(GL_ARRAY_BUFFER, 0); glBindVertexArray(0); } /** * Create a shader object from the given classpath resource. * * @param resource * the class path * @param type * the shader type * * @return the shader object id * * @throws IOException */ static int createShader(String resource, int type) throws IOException { return createShader(resource, type, null); } /** * Create a shader object from the given classpath resource. * * @param resource * the class path * @param type * the shader type * @param version * the GLSL version to prepend to the shader source, or null * * @return the shader object id * * @throws IOException */ static int createShader(String resource, int type, String version) throws IOException { int shader = glCreateShader(type); ByteBuffer source = ioResourceToByteBuffer(resource, 8192); if (version == null) { PointerBuffer strings = BufferUtils.createPointerBuffer(1); IntBuffer lengths = BufferUtils.createIntBuffer(1); strings.put(0, source); lengths.put(0, source.remaining()); glShaderSource(shader, strings, lengths); } else { PointerBuffer strings = BufferUtils.createPointerBuffer(2); IntBuffer lengths = BufferUtils.createIntBuffer(2); ByteBuffer preamble = memUTF8("#version " + version + "\n", false); strings.put(0, preamble); lengths.put(0, preamble.remaining()); strings.put(1, source); lengths.put(1, source.remaining()); glShaderSource(shader, strings, lengths); } glCompileShader(shader); int compiled = glGetShaderi(shader, GL_COMPILE_STATUS); String shaderLog = glGetShaderInfoLog(shader); if (shaderLog.trim().length() > 0) { System.err.println(shaderLog); } if (compiled == 0) { throw new AssertionError("Could not compile shader"); } return shader; } private void createAtomicBuffer() { atomicBuffer = glGenBuffers(); glBindBuffer(GL_ATOMIC_COUNTER_BUFFER, atomicBuffer); glBufferData(GL_ATOMIC_COUNTER_BUFFER, 4, GL_DYNAMIC_DRAW); glBindBuffer(GL_ATOMIC_COUNTER_BUFFER, 0); } /** * Create the full-scren quad shader. * * @throws IOException */ private void createQuadProgram() throws IOException { int program = glCreateProgram(); int vshader = AtomicDemo.createShader("org/lwjgl/demo/opengl/raytracing/quad.vs", GL_VERTEX_SHADER, "330"); int fshader = AtomicDemo.createShader("org/lwjgl/demo/opengl/raytracing/quad.fs", GL_FRAGMENT_SHADER, "330"); glAttachShader(program, vshader); glAttachShader(program, fshader); glBindAttribLocation(program, 0, "vertex"); glBindFragDataLocation(program, 0, "color"); glLinkProgram(program); int linked = glGetProgrami(program, GL_LINK_STATUS); String programLog = glGetProgramInfoLog(program); if (programLog.trim().length() > 0) { System.err.println(programLog); } if (linked == 0) { throw new AssertionError("Could not link program"); } this.quadProgram = program; } /** * Create the tracing compute shader program. * * @throws IOException */ private void createComputeProgram() throws IOException { int program = glCreateProgram(); int cshader = createShader("org/lwjgl/demo/opengl/raytracing/raytracingAtomic.glslcs", GL_COMPUTE_SHADER); int randomCommon = createShader("org/lwjgl/demo/opengl/raytracing/randomCommon.glsl", GL_COMPUTE_SHADER, "330"); int random = createShader("org/lwjgl/demo/opengl/raytracing/randomAtomic.glsl", GL_COMPUTE_SHADER); glAttachShader(program, cshader); glAttachShader(program, randomCommon); glAttachShader(program, random); glLinkProgram(program); int linked = glGetProgrami(program, GL_LINK_STATUS); String programLog = glGetProgramInfoLog(program); if (programLog.trim().length() > 0) { System.err.println(programLog); } if (linked == 0) { throw new AssertionError("Could not link program"); } this.computeProgram = program; } /** * Initialize the full-screen-quad program. */ private void initQuadProgram() { glUseProgram(quadProgram); int texUniform = glGetUniformLocation(quadProgram, "tex"); glUniform1i(texUniform, 0); glUseProgram(0); } /** * Initialize the compute shader. */ private void initComputeProgram() { glUseProgram(computeProgram); IntBuffer workGroupSize = BufferUtils.createIntBuffer(3); glGetProgramiv(computeProgram, GL_COMPUTE_WORK_GROUP_SIZE, workGroupSize); workGroupSizeX = workGroupSize.get(0); workGroupSizeY = workGroupSize.get(1); eyeUniform = glGetUniformLocation(computeProgram, "eye"); ray00Uniform = glGetUniformLocation(computeProgram, "ray00"); ray10Uniform = glGetUniformLocation(computeProgram, "ray10"); ray01Uniform = glGetUniformLocation(computeProgram, "ray01"); ray11Uniform = glGetUniformLocation(computeProgram, "ray11"); blendFactorUniform = glGetUniformLocation(computeProgram, "blendFactor"); bounceCountUniform = glGetUniformLocation(computeProgram, "bounceCount"); /* Query the "image binding point" of the image uniform */ IntBuffer params = BufferUtils.createIntBuffer(1); int loc = glGetUniformLocation(computeProgram, "framebufferImage"); glGetUniformiv(computeProgram, loc, params); framebufferImageBinding = params.get(0); glUseProgram(0); } /** * Create the texture that will serve as our framebuffer. */ private void createFramebufferTexture() { this.tex = glGenTextures(); glBindTexture(GL_TEXTURE_2D, tex); glTexStorage2D(GL_TEXTURE_2D, 1, GL_RGBA32F, width, height); glBindTexture(GL_TEXTURE_2D, 0); } /** * Create the sampler to sample the framebuffer texture within the shader. */ private void createSampler() { this.sampler = glGenSamplers(); glSamplerParameteri(this.sampler, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glSamplerParameteri(this.sampler, GL_TEXTURE_MAG_FILTER, GL_NEAREST); } /** * Recreate the framebuffer when the window size changes. */ private void resizeFramebufferTexture() { glDeleteTextures(tex); createFramebufferTexture(); } /** * Compute one frame by tracing the scene using our compute shader and * presenting that image on the screen. */ private void trace() { glUseProgram(computeProgram); if (mouseDown) { /* * If mouse is down, compute the camera rotation based on mouse * cursor location. */ currRotationAboutY = rotationAboutY + (mouseX - mouseDownX) * 0.01f; } else { currRotationAboutY = rotationAboutY; } /* Rotate camera about Y axis. */ cameraPosition.set((float) sin(-currRotationAboutY) * 3.0f, 2.0f, (float) cos(-currRotationAboutY) * 3.0f); viewMatrix.setLookAt(cameraPosition, cameraLookAt, cameraUp); if (resetFramebuffer) { projMatrix.setPerspective((float) Math.toRadians(60.0f), (float) width / height, 1f, 2f); resizeFramebufferTexture(); resetFramebuffer = false; } projMatrix.invertPerspectiveView(viewMatrix, invViewProjMatrix); /* Bind atomic counter buffer */ glBindBufferBase(GL_ATOMIC_COUNTER_BUFFER, 0, atomicBuffer); /* * Initialize the atomic counter with a seed (current time) to avoid * uint32 wrap-around patterns when 2^32 is divisible by the framebuffer * pixel count. */ intBuffer.put(0, (int) System.nanoTime()); glBufferSubData(GL_ATOMIC_COUNTER_BUFFER, 0, intBuffer); /* * We are going to average multiple successive frames, so here we * compute the blend factor between old frame and new frame. * = 0.0 - use only the new frame * > 0.0 - blend between old frame and new frame */ float blendFactor = frameNumber / (frameNumber + 1.0f); glUniform1f(blendFactorUniform, blendFactor); glUniform1i(bounceCountUniform, bounceCount); /* Set viewing frustum corner rays in shader */ glUniform3f(eyeUniform, cameraPosition.x, cameraPosition.y, cameraPosition.z); invViewProjMatrix.transformProject(tmpVector.set(-1, -1, 0)).sub(cameraPosition); glUniform3f(ray00Uniform, tmpVector.x, tmpVector.y, tmpVector.z); invViewProjMatrix.transformProject(tmpVector.set(-1, 1, 0)).sub(cameraPosition); glUniform3f(ray01Uniform, tmpVector.x, tmpVector.y, tmpVector.z); invViewProjMatrix.transformProject(tmpVector.set(1, -1, 0)).sub(cameraPosition); glUniform3f(ray10Uniform, tmpVector.x, tmpVector.y, tmpVector.z); invViewProjMatrix.transformProject(tmpVector.set(1, 1, 0)).sub(cameraPosition); glUniform3f(ray11Uniform, tmpVector.x, tmpVector.y, tmpVector.z); /* Bind level 0 of framebuffer texture as writable image in the shader. */ glBindImageTexture(framebufferImageBinding, tex, 0, false, 0, GL_READ_WRITE, GL_RGBA32F); /* Compute appropriate invocation dimension. */ int worksizeX = mathRoundPoT(width); int worksizeY = mathRoundPoT(height); /* Invoke the compute shader. */ glDispatchCompute(worksizeX / workGroupSizeX, worksizeY / workGroupSizeY, 1); /* * Synchronize all writes to the framebuffer image before we let OpenGL * source texels from it afterwards when rendering the final image with * the full-screen quad. */ glMemoryBarrier(GL_SHADER_IMAGE_ACCESS_BARRIER_BIT); /* Reset bindings. */ glBindImageTexture(framebufferImageBinding, 0, 0, false, 0, GL_READ_WRITE, GL_RGBA32F); glBindBufferBase(GL_ATOMIC_COUNTER_BUFFER, 0, 0); glUseProgram(0); frameNumber++; } /** * Present the final image on the screen/viewport. */ private void present() { /* * Draw the rendered image on the screen using textured full-screen * quad. */ glUseProgram(quadProgram); glBindVertexArray(vao); glBindTexture(GL_TEXTURE_2D, tex); glBindSampler(0, this.sampler); glDrawArrays(GL_TRIANGLES, 0, 6); glBindSampler(0, 0); glBindTexture(GL_TEXTURE_2D, 0); glBindVertexArray(0); glUseProgram(0); } private void loop() { while (!glfwWindowShouldClose(window)) { glfwPollEvents(); glViewport(0, 0, width, height); trace(); present(); glfwSwapBuffers(window); } } private void run() { try { init(); loop(); if (debugProc != null) debugProc.free(); errCallback.free(); keyCallback.free(); fbCallback.free(); cpCallback.free(); mbCallback.free(); glfwDestroyWindow(window); } catch (Throwable t) { t.printStackTrace(); } finally { glfwTerminate(); } } public static void main(String[] args) { new AtomicDemo().run(); } }