Java tutorial
/* * Copyright LWJGL. All rights reserved. * License terms: http://lwjgl.org/license.php */ package org.lwjgl.demo.opengl.fbo; import static org.lwjgl.demo.opengl.util.DemoUtils.createShader; 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.EXTFramebufferObject.*; import static org.lwjgl.system.MemoryUtil.NULL; import java.io.IOException; import java.nio.FloatBuffer; import org.joml.Matrix3f; import org.joml.Matrix4f; import org.lwjgl.BufferUtils; import org.lwjgl.demo.opengl.util.WavefrontMeshLoader; import org.lwjgl.demo.opengl.util.WavefrontMeshLoader.Mesh; import org.lwjgl.glfw.GLFWErrorCallback; import org.lwjgl.glfw.GLFWFramebufferSizeCallback; import org.lwjgl.glfw.GLFWKeyCallback; import org.lwjgl.glfw.GLFWVidMode; import org.lwjgl.opengl.GL; import org.lwjgl.opengl.GLCapabilities; import org.lwjgl.opengl.GLUtil; import org.lwjgl.system.Callback; /** * Uses a Sobel edge detection filter to render the edges/outline of a mesh. * <p> * The edges are detected based on the view-space normals of the mesh. * The outlines are detected based on a simple mask written to the color alpha channel. * * @author Kai Burjack */ public class EdgeShaderDemo20 { long window; int width = 1024; int height = 768; boolean resize; int fbo; int rbo; int tex; int cubeVbo; long normalsOffset; int numVertices; int quadVbo; int normalProgram; int viewMatrixUniform; int projMatrixUniform; int normalMatrixUniform; int edgeProgram; int outlineProgram; int normalTexUniform; int invWidthUniform; int invHeightUniform; int edgeShowEdgeUniform; int outlineShowEdgeUniform; boolean outlineOnly; boolean showEdge = true; Matrix4f viewMatrix = new Matrix4f(); Matrix4f projMatrix = new Matrix4f(); Matrix3f normalMatrix = new Matrix3f(); FloatBuffer matrixBuffer = BufferUtils.createFloatBuffer(16); GLCapabilities caps; GLFWErrorCallback errCallback; GLFWKeyCallback keyCallback; GLFWFramebufferSizeCallback fbCallback; Callback debugProc; void init() throws IOException { glfwSetErrorCallback(errCallback = new GLFWErrorCallback() { 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 2.0 or higher."); delegate.invoke(error, description); } @Override public void free() { delegate.free(); } }); if (!glfwInit()) throw new IllegalStateException("Unable to initialize GLFW"); glfwDefaultWindowHints(); glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2); glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0); glfwWindowHint(GLFW_VISIBLE, GLFW_FALSE); glfwWindowHint(GLFW_RESIZABLE, GLFW_TRUE); window = glfwCreateWindow(width, height, "Silhouette rendering with Sobel edge detection shader", NULL, NULL); if (window == NULL) { throw new AssertionError("Failed to create the GLFW window"); } System.out.println("Press letter 'O' to toggle between outline/edges."); System.out.println("Press spacebar to show/hide edges."); glfwSetFramebufferSizeCallback(window, fbCallback = new GLFWFramebufferSizeCallback() { @Override public void invoke(long window, int width, int height) { if (width > 0 && height > 0 && (EdgeShaderDemo20.this.width != width || EdgeShaderDemo20.this.height != height)) { EdgeShaderDemo20.this.width = width; EdgeShaderDemo20.this.height = height; EdgeShaderDemo20.this.resize = true; } } }); 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_O) { outlineOnly = !outlineOnly; } else if (key == GLFW_KEY_SPACE) { showEdge = !showEdge; } } }); GLFWVidMode vidmode = glfwGetVideoMode(glfwGetPrimaryMonitor()); glfwSetWindowPos(window, (vidmode.width() - width) / 2, (vidmode.height() - height) / 2); glfwMakeContextCurrent(window); glfwSwapInterval(0); glfwShowWindow(window); caps = GL.createCapabilities(); if (!caps.GL_EXT_framebuffer_object) { throw new AssertionError("This demo requires the EXT_framebuffer_object extension"); } debugProc = GLUtil.setupDebugMessageCallback(); glClearColor(1.0f, 1.0f, 1.0f, 0.0f); // using alpha = 0.0 is important here for the outline to work! glEnable(GL_DEPTH_TEST); glEnable(GL_CULL_FACE); /* Create all needed GL resources */ createCube(); createQuad(); createNormalProgram(); createEdgeProgram(); createOutlineProgram(); createTex(); createFbo(); } void createTex() { if (tex != 0) { glDeleteTextures(tex); } tex = glGenTextures(); glBindTexture(GL_TEXTURE_2D, tex); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0L); glBindTexture(GL_TEXTURE_2D, 0); } void createFbo() { if (fbo != 0) { glDeleteFramebuffersEXT(fbo); glDeleteRenderbuffersEXT(rbo); } fbo = glGenFramebuffersEXT(); glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo); rbo = glGenRenderbuffersEXT(); glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, rbo); glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT, width, height); glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, rbo); glBindTexture(GL_TEXTURE_2D, tex); glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, tex, 0); int status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT); if (status != GL_FRAMEBUFFER_COMPLETE_EXT) { throw new AssertionError("Incomplete framebuffer: " + status); } glBindTexture(GL_TEXTURE_2D, 0); glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0); glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, 0); } void createQuad() { FloatBuffer pb = BufferUtils.createFloatBuffer(2 * 6); pb.put(-1).put(-1); pb.put(1).put(-1); pb.put(1).put(1); pb.put(1).put(1); pb.put(-1).put(1); pb.put(-1).put(-1); pb.flip(); this.quadVbo = glGenBuffers(); glBindBuffer(GL_ARRAY_BUFFER, this.quadVbo); glBufferData(GL_ARRAY_BUFFER, pb, GL_STATIC_DRAW); glBindBuffer(GL_ARRAY_BUFFER, 0); } void createCube() throws IOException { WavefrontMeshLoader loader = new WavefrontMeshLoader(); Mesh mesh = loader.loadMesh("org/lwjgl/demo/opengl/models/cube.obj.zip"); this.numVertices = mesh.numVertices; long bufferSize = 4 * (3 + 3) * mesh.numVertices; this.normalsOffset = 4L * 3 * mesh.numVertices; this.cubeVbo = glGenBuffers(); glBindBuffer(GL_ARRAY_BUFFER, this.cubeVbo); glBufferData(GL_ARRAY_BUFFER, bufferSize, GL_STATIC_DRAW); glBufferSubData(GL_ARRAY_BUFFER, 0L, mesh.positions); glBufferSubData(GL_ARRAY_BUFFER, normalsOffset, mesh.normals); glBindBuffer(GL_ARRAY_BUFFER, 0); } void createNormalProgram() throws IOException { int program = glCreateProgram(); int vshader = createShader("org/lwjgl/demo/opengl/fbo/normal-vs.glsl", GL_VERTEX_SHADER); int fshader = createShader("org/lwjgl/demo/opengl/fbo/normal-fs.glsl", GL_FRAGMENT_SHADER); glAttachShader(program, vshader); glAttachShader(program, fshader); glBindAttribLocation(program, 0, "position"); glBindAttribLocation(program, 1, "normal"); 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.normalProgram = program; glUseProgram(this.normalProgram); viewMatrixUniform = glGetUniformLocation(this.normalProgram, "viewMatrix"); projMatrixUniform = glGetUniformLocation(this.normalProgram, "projMatrix"); normalMatrixUniform = glGetUniformLocation(this.normalProgram, "normalMatrix"); glUseProgram(0); } void createEdgeProgram() throws IOException { int program = glCreateProgram(); int vshader = createShader("org/lwjgl/demo/opengl/fbo/sobel-edge-vs.glsl", GL_VERTEX_SHADER); int fshader = createShader("org/lwjgl/demo/opengl/fbo/sobel-edge-fs.glsl", GL_FRAGMENT_SHADER); int fshader2 = createShader("org/lwjgl/demo/opengl/fbo/color.glsl", GL_FRAGMENT_SHADER); glAttachShader(program, vshader); glAttachShader(program, fshader); glAttachShader(program, fshader2); glBindAttribLocation(program, 0, "position"); 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.edgeProgram = program; glUseProgram(this.edgeProgram); normalTexUniform = glGetUniformLocation(this.edgeProgram, "normalTex"); invWidthUniform = glGetUniformLocation(this.edgeProgram, "invWidth"); invHeightUniform = glGetUniformLocation(this.edgeProgram, "invHeight"); edgeShowEdgeUniform = glGetUniformLocation(this.edgeProgram, "showEdge"); glUseProgram(0); } void createOutlineProgram() throws IOException { int program = glCreateProgram(); int vshader = createShader("org/lwjgl/demo/opengl/fbo/sobel-outline-vs.glsl", GL_VERTEX_SHADER); int fshader = createShader("org/lwjgl/demo/opengl/fbo/sobel-outline-fs.glsl", GL_FRAGMENT_SHADER); int fshader2 = createShader("org/lwjgl/demo/opengl/fbo/color.glsl", GL_FRAGMENT_SHADER); glAttachShader(program, vshader); glAttachShader(program, fshader); glAttachShader(program, fshader2); glBindAttribLocation(program, 0, "position"); 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.outlineProgram = program; glUseProgram(this.outlineProgram); normalTexUniform = glGetUniformLocation(this.outlineProgram, "normalTex"); invWidthUniform = glGetUniformLocation(this.outlineProgram, "invWidth"); invHeightUniform = glGetUniformLocation(this.outlineProgram, "invHeight"); outlineShowEdgeUniform = glGetUniformLocation(this.edgeProgram, "showEdge"); glUseProgram(0); } float angle = 0.0f; long lastTime = System.nanoTime(); void update() { long thisTime = System.nanoTime(); float diff = (thisTime - lastTime) / 1E9f; angle += diff; lastTime = thisTime; projMatrix.setPerspective((float) Math.toRadians(30), (float) width / height, 0.01f, 50.0f); viewMatrix.setLookAt(0.0f, 2.0f, 7.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f).rotateY(angle / 2.0f) .rotateX(angle / 8.0f); viewMatrix.normal(normalMatrix); if (resize) { createTex(); createFbo(); resize = false; } } /** * Render the normals into a texture. */ void renderNormal() { glEnable(GL_DEPTH_TEST); glUseProgram(this.normalProgram); glUniformMatrix4fv(viewMatrixUniform, false, viewMatrix.get(matrixBuffer)); glUniformMatrix4fv(projMatrixUniform, false, projMatrix.get(matrixBuffer)); glUniformMatrix3fv(normalMatrixUniform, false, normalMatrix.get(matrixBuffer)); glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glBindBuffer(GL_ARRAY_BUFFER, this.cubeVbo); glEnableVertexAttribArray(0); glVertexAttribPointer(0, 3, GL_FLOAT, false, 0, 0L); glEnableVertexAttribArray(1); glVertexAttribPointer(1, 3, GL_FLOAT, false, 0, normalsOffset); glDrawArrays(GL_TRIANGLES, 0, numVertices); glDisableVertexAttribArray(0); glDisableVertexAttribArray(1); glBindBuffer(GL_ARRAY_BUFFER, 0); glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0); glUseProgram(0); } /** * Render the edges using the Sobel edge filter and blend that with the normals. */ void renderEdge() { glDisable(GL_DEPTH_TEST); if (outlineOnly) { glUseProgram(this.outlineProgram); glUniform1i(outlineShowEdgeUniform, showEdge ? 1 : 0); } else { glUseProgram(this.edgeProgram); glUniform1i(edgeShowEdgeUniform, showEdge ? 1 : 0); } glClear(GL_COLOR_BUFFER_BIT); glUniform1f(invWidthUniform, 1.0f / width); glUniform1f(invHeightUniform, 1.0f / height); glUniform1i(normalTexUniform, 0); glBindTexture(GL_TEXTURE_2D, tex); glBindBuffer(GL_ARRAY_BUFFER, this.quadVbo); glEnableVertexAttribArray(0); glVertexAttribPointer(0, 2, GL_FLOAT, false, 0, 0L); glDrawArrays(GL_TRIANGLES, 0, 6); glDisableVertexAttribArray(0); glBindBuffer(GL_ARRAY_BUFFER, 0); glBindTexture(GL_TEXTURE_2D, 0); glUseProgram(0); } void loop() { while (!glfwWindowShouldClose(window)) { glfwPollEvents(); glViewport(0, 0, width, height); update(); renderNormal(); renderEdge(); glfwSwapBuffers(window); } } void run() { try { init(); loop(); if (debugProc != null) { debugProc.free(); } errCallback.free(); keyCallback.free(); fbCallback.free(); glfwDestroyWindow(window); } catch (Throwable t) { t.printStackTrace(); } finally { glfwTerminate(); } } public static void main(String[] args) { new EdgeShaderDemo20().run(); } }