Java tutorial
/* * Copyright LWJGL. All rights reserved. * License terms: http://lwjgl.org/license.php */ package org.lwjgl.demo.opengl.textures; import org.lwjgl.BufferUtils; import org.lwjgl.PointerBuffer; import org.lwjgl.glfw.*; import org.lwjgl.opengl.GL; import org.lwjgl.opengl.GLCapabilities; import org.lwjgl.opengl.GLUtil; import org.lwjgl.system.Callback; import org.joml.Matrix4f; import java.io.IOException; import java.nio.ByteBuffer; import java.nio.FloatBuffer; import java.nio.IntBuffer; import static org.lwjgl.opengl.ARBShaderObjects.*; import static org.lwjgl.opengl.ARBVertexShader.*; import static org.lwjgl.opengl.ARBFragmentShader.*; import static org.lwjgl.demo.opengl.util.DemoUtils.*; import static org.lwjgl.glfw.GLFW.*; import static org.lwjgl.opengl.GL11.*; import static org.lwjgl.stb.STBImage.*; import static org.lwjgl.system.MemoryUtil.*; /** * Shows how to render a spherical/equirectangular texture as environment map using a single fullscreen quad. * <p> * This uses the same technique as the {@link BillboardCubemapDemo}, {@link FullscreenCubemapDemo} and all raytracing demos, * which is to unproject the NDC corner positions into world-space using the inverse of the combined view-projection matrix. * This demo then transforms the obtained cartesian coordinates on the unit sphere (which would otherwise be used for * cubemap lookup) into spherical coordinates (longitude, latitude) to sample the texture using equirectangular projection. * * @author Kai Burjack */ public class EnvironmentDemo { long window; int width = 1024; int height = 768; float fov = 60, rotX, rotY; ByteBuffer vertices; int invViewProjUniform; Matrix4f projMatrix = new Matrix4f(); Matrix4f viewMatrix = new Matrix4f(); Matrix4f invViewProjMatrix = new Matrix4f(); FloatBuffer matrixBuffer = BufferUtils.createFloatBuffer(16); GLCapabilities caps; GLFWKeyCallback keyCallback; GLFWFramebufferSizeCallback fbCallback; GLFWCursorPosCallback cpCallback; GLFWScrollCallback sCallback; Callback debugProc; void init() throws IOException { if (!glfwInit()) throw new IllegalStateException("Unable to initialize GLFW"); glfwDefaultWindowHints(); glfwWindowHint(GLFW_VISIBLE, GLFW_FALSE); glfwWindowHint(GLFW_RESIZABLE, GLFW_TRUE); window = glfwCreateWindow(width, height, "Spherical environment mapping demo", NULL, NULL); if (window == NULL) throw new AssertionError("Failed to create the GLFW window"); System.out.println("Move the mouse to look around"); System.out.println("Zoom in/out with mouse wheel"); glfwSetFramebufferSizeCallback(window, fbCallback = new GLFWFramebufferSizeCallback() { @Override public void invoke(long window, int width, int height) { if (width > 0 && height > 0 && (EnvironmentDemo.this.width != width || EnvironmentDemo.this.height != height)) { EnvironmentDemo.this.width = width; EnvironmentDemo.this.height = height; } } }); 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); } } }); glfwSetCursorPosCallback(window, cpCallback = new GLFWCursorPosCallback() { @Override public void invoke(long window, double x, double y) { float nx = (float) x / width * 2.0f - 1.0f; float ny = (float) y / height * 2.0f - 1.0f; rotX = ny * (float) Math.PI * 0.5f; rotY = nx * (float) Math.PI; } }); glfwSetScrollCallback(window, sCallback = new GLFWScrollCallback() { @Override public void invoke(long window, double xoffset, double yoffset) { if (yoffset < 0) fov *= 1.05f; else fov *= 1f / 1.05f; if (fov < 10.0f) fov = 10.0f; else if (fov > 120.0f) fov = 120.0f; } }); GLFWVidMode vidmode = glfwGetVideoMode(glfwGetPrimaryMonitor()); glfwSetWindowPos(window, (vidmode.width() - width) / 2, (vidmode.height() - height) / 2); glfwMakeContextCurrent(window); glfwSwapInterval(0); glfwShowWindow(window); glfwSetCursorPos(window, width / 2, height / 2); IntBuffer framebufferSize = BufferUtils.createIntBuffer(2); nglfwGetFramebufferSize(window, memAddress(framebufferSize), memAddress(framebufferSize) + 4); width = framebufferSize.get(0); height = framebufferSize.get(1); caps = GL.createCapabilities(); if (!caps.GL_ARB_shader_objects) throw new AssertionError("This demo requires the ARB_shader_objects extension."); if (!caps.GL_ARB_vertex_shader) throw new AssertionError("This demo requires the ARB_vertex_shader extension."); if (!caps.GL_ARB_fragment_shader) throw new AssertionError("This demo requires the ARB_fragment_shader extension."); debugProc = GLUtil.setupDebugMessageCallback(); /* Create all needed GL resources */ createTexture(); createFullScreenQuad(); createProgram(); } void createFullScreenQuad() { vertices = BufferUtils.createByteBuffer(4 * 2 * 6); FloatBuffer fv = vertices.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); glEnableClientState(GL_VERTEX_ARRAY); glVertexPointer(2, GL_FLOAT, 0, vertices); } static int createShader(String resource, int type) throws IOException { int shader = glCreateShaderObjectARB(type); ByteBuffer source = ioResourceToByteBuffer(resource, 1024); PointerBuffer strings = BufferUtils.createPointerBuffer(1); IntBuffer lengths = BufferUtils.createIntBuffer(1); strings.put(0, source); lengths.put(0, source.remaining()); glShaderSourceARB(shader, strings, lengths); glCompileShaderARB(shader); int compiled = glGetObjectParameteriARB(shader, GL_OBJECT_COMPILE_STATUS_ARB); String shaderLog = glGetInfoLogARB(shader); if (shaderLog.trim().length() > 0) { System.err.println(shaderLog); } if (compiled == 0) { throw new AssertionError("Could not compile shader"); } return shader; } void createProgram() throws IOException { int program = glCreateProgramObjectARB(); int vshader = createShader("org/lwjgl/demo/opengl/textures/environment.vs", GL_VERTEX_SHADER_ARB); int fshader = createShader("org/lwjgl/demo/opengl/textures/environment.fs", GL_FRAGMENT_SHADER_ARB); glAttachObjectARB(program, vshader); glAttachObjectARB(program, fshader); glLinkProgramARB(program); int linked = glGetObjectParameteriARB(program, GL_OBJECT_LINK_STATUS_ARB); String programLog = glGetInfoLogARB(program); if (programLog.trim().length() > 0) { System.err.println(programLog); } if (linked == 0) { throw new AssertionError("Could not link program"); } glUseProgramObjectARB(program); int texLocation = glGetUniformLocationARB(program, "tex"); glUniform1iARB(texLocation, 0); invViewProjUniform = glGetUniformLocationARB(program, "invViewProj"); } static void createTexture() throws IOException { int tex = glGenTextures(); glBindTexture(GL_TEXTURE_2D, tex); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); ByteBuffer imageBuffer; IntBuffer w = BufferUtils.createIntBuffer(1); IntBuffer h = BufferUtils.createIntBuffer(1); IntBuffer comp = BufferUtils.createIntBuffer(1); ByteBuffer image; imageBuffer = ioResourceToByteBuffer("org/lwjgl/demo/opengl/textures/environment.jpg", 8 * 1024); if (!stbi_info_from_memory(imageBuffer, w, h, comp)) throw new IOException("Failed to read image information: " + stbi_failure_reason()); image = stbi_load_from_memory(imageBuffer, w, h, comp, 3); if (image == null) throw new IOException("Failed to load image: " + stbi_failure_reason()); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB8, w.get(0), h.get(0), 0, GL_RGB, GL_UNSIGNED_BYTE, image); stbi_image_free(image); } void update() { projMatrix.setPerspective((float) Math.toRadians(fov), (float) width / height, 0.01f, 100.0f); viewMatrix.rotationX(rotX).rotateY(rotY); projMatrix.invertPerspectiveView(viewMatrix, invViewProjMatrix); glUniformMatrix4fvARB(invViewProjUniform, false, invViewProjMatrix.get(matrixBuffer)); } static void render() { glClear(GL_COLOR_BUFFER_BIT); glDrawArrays(GL_TRIANGLES, 0, 6); } void loop() { while (!glfwWindowShouldClose(window)) { glfwPollEvents(); glViewport(0, 0, width, height); update(); render(); glfwSwapBuffers(window); } } void run() { try { init(); loop(); if (debugProc != null) { debugProc.free(); } cpCallback.free(); keyCallback.free(); fbCallback.free(); glfwDestroyWindow(window); } catch (Throwable t) { t.printStackTrace(); } finally { glfwTerminate(); } } public static void main(String[] args) { new EnvironmentDemo().run(); } }