org.lwjgl.demo.opengl.textures.SimpleProceduralTextureDemo.java Source code

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Here is the source code for org.lwjgl.demo.opengl.textures.SimpleProceduralTextureDemo.java

Source

/*
 * 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.glfw.*;
import org.lwjgl.opengl.GL;
import org.lwjgl.opengl.GLCapabilities;
import org.lwjgl.opengl.GLUtil;
import org.lwjgl.system.Callback;

import java.nio.IntBuffer;

import static org.lwjgl.glfw.GLFW.*;
import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.system.MemoryUtil.*;

public class SimpleProceduralTextureDemo {

    long window;
    int width = 1024;
    int height = 768;

    GLCapabilities caps;
    GLFWErrorCallback errCallback;
    GLFWKeyCallback keyCallback;
    GLFWFramebufferSizeCallback fbCallback;
    Callback debugProc;
    boolean isCrappyIntel;

    private void init() {
        glfwSetErrorCallback(errCallback = GLFWErrorCallback.createPrint(System.err));

        if (!glfwInit())
            throw new IllegalStateException("Unable to initialize GLFW");

        glfwDefaultWindowHints();
        glfwWindowHint(GLFW_VISIBLE, GLFW_FALSE);
        glfwWindowHint(GLFW_RESIZABLE, GLFW_TRUE);

        window = glfwCreateWindow(width, height, "Simple texture demo", NULL, NULL);
        if (window == NULL) {
            throw new AssertionError("Failed to create the GLFW window");
        }
        glfwSetFramebufferSizeCallback(window, fbCallback = new GLFWFramebufferSizeCallback() {
            @Override
            public void invoke(long window, int width, int height) {
                if (width > 0 && height > 0 && (SimpleProceduralTextureDemo.this.width != width
                        || SimpleProceduralTextureDemo.this.height != height)) {
                    SimpleProceduralTextureDemo.this.width = width;
                    SimpleProceduralTextureDemo.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);
                }
            }
        });

        GLFWVidMode vidmode = glfwGetVideoMode(glfwGetPrimaryMonitor());
        glfwSetWindowPos(window, (vidmode.width() - width) / 2, (vidmode.height() - height) / 2);
        glfwMakeContextCurrent(window);
        glfwShowWindow(window);

        IntBuffer framebufferSize = BufferUtils.createIntBuffer(2);
        nglfwGetFramebufferSize(window, memAddress(framebufferSize), memAddress(framebufferSize) + 4);
        width = framebufferSize.get(0);
        height = framebufferSize.get(1);

        caps = GL.createCapabilities();
        debugProc = GLUtil.setupDebugMessageCallback();

        String vendor = glGetString(GL_VENDOR);
        isCrappyIntel = vendor != null && vendor.toLowerCase().contains("intel");

        /* Set state and create all needed GL resources */
        glEnable(GL_TEXTURE_2D);
        int 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_RGB8, 4, 4, 0, GL_RGB, GL_UNSIGNED_BYTE, (IntBuffer) null);
        glBindTexture(GL_TEXTURE_2D, tex);
        IntBuffer bb = BufferUtils.createIntBuffer(4 * 4);
        bb.put(new int[] { 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF,
                0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF,
                0xFFFFFFFF }).rewind();
        glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 1, 4, GL_RGBA, GL_UNSIGNED_BYTE, bb);
    }

    private void loop() {
        while (!glfwWindowShouldClose(window)) {
            glfwPollEvents();
            glViewport(0, 0, width, height);

            /*
             * Workaround an apparent bug in Intel's drivers:
             * Even though we don't need to clear the color buffer because every frame we render to the entire viewport,
             * we have to clear it, because otherwise if the window is being minimized and restored there is nothing rendered
             * anymore (just pure black).
             */
            if (isCrappyIntel)
                glClear(GL_COLOR_BUFFER_BIT);

            glBegin(GL_QUADS);
            glTexCoord2f(0.0f, 0.0f);
            glVertex2f(-1.0f, -1.0f);
            glTexCoord2f(1.0f, 0.0f);
            glVertex2f(1.0f, -1.0f);
            glTexCoord2f(1.0f, 1.0f);
            glVertex2f(1.0f, 1.0f);
            glTexCoord2f(0.0f, 1.0f);
            glVertex2f(-1.0f, 1.0f);
            glEnd();

            glfwSwapBuffers(window);
        }
    }

    private 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 SimpleProceduralTextureDemo().run();
    }

}