org.lwjgl.demo.system.jawt.LWJGLCanvas.java Source code

Introduction

Here is the source code for org.lwjgl.demo.system.jawt.LWJGLCanvas.java

Source

/*
 * Copyright LWJGL. All rights reserved.
 * License terms: https://www.lwjgl.org/license
 */
package org.lwjgl.demo.system.jawt;

import org.lwjgl.demo.opengl.*;
import org.lwjgl.opengl.*;
import org.lwjgl.system.jawt.JAWT;
import org.lwjgl.system.jawt.*;
import org.lwjgl.system.windows.*;

import java.awt.*;

import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.opengl.WGL.*;
import static org.lwjgl.system.MemoryUtil.*;
import static org.lwjgl.system.jawt.JAWTFunctions.*;
import static org.lwjgl.system.windows.GDI32.*;

/**
 * A Canvas component that uses OpenGL for rendering.
 *
 * <p>This implementation supports Windows only and is no way complete or robust enough for production use.</p>
 */
@SuppressWarnings("serial")
public class LWJGLCanvas extends Canvas {

    private final JAWT awt;

    private final AbstractGears gears;

    private long hglrc;

    private GLCapabilities caps;

    public LWJGLCanvas() {
        awt = JAWT.calloc();
        awt.version(JAWT_VERSION_1_4);
        if (!JAWT_GetAWT(awt)) {
            throw new IllegalStateException("GetAWT failed");
        }

        gears = new AbstractGears();
    }

    @Override
    public void update(Graphics g) {
        paint(g);
    }

    @Override
    public void paint(Graphics g) {
        // Get the drawing surface
        JAWTDrawingSurface ds = JAWT_GetDrawingSurface(awt.GetDrawingSurface(), this);
        if (ds == null) {
            throw new IllegalStateException("awt->GetDrawingSurface() failed");
        }

        try {
            // Lock the drawing surface
            int lock = JAWT_DrawingSurface_Lock(ds.Lock(), ds);
            if ((lock & JAWT_LOCK_ERROR) != 0) {
                throw new IllegalStateException("ds->Lock() failed");
            }

            try {
                // Get the drawing surface info
                JAWTDrawingSurfaceInfo dsi = JAWT_DrawingSurface_GetDrawingSurfaceInfo(ds.GetDrawingSurfaceInfo(),
                        ds);
                if (dsi == null) {
                    throw new IllegalStateException("ds->GetDrawingSurfaceInfo() failed");
                }

                try {
                    // Get the platform-specific drawing info
                    JAWTWin32DrawingSurfaceInfo dsi_win = JAWTWin32DrawingSurfaceInfo.create(dsi.platformInfo());
                    long hdc = dsi_win.hdc();
                    if (hdc != NULL) {
                        if (hglrc == NULL) {
                            createContext(dsi_win);
                            gears.initGLState();
                        } else {
                            if (!wglMakeCurrent(hdc, hglrc)) {
                                throw new IllegalStateException("wglMakeCurrent() failed");
                            }

                            GL.setCapabilities(caps);
                        }

                        glViewport(0, 0, getWidth(), getHeight());

                        float f = getHeight() / (float) getWidth();

                        glMatrixMode(GL_PROJECTION);
                        glLoadIdentity();
                        glFrustum(-1.0f, 1.0f, -f, f, 5.0f, 100.0f);
                        glMatrixMode(GL_MODELVIEW);

                        gears.renderLoop();
                        SwapBuffers(hdc);

                        wglMakeCurrent(NULL, NULL);
                        GL.setCapabilities(null);
                    }
                } finally {
                    // Free the drawing surface info
                    JAWT_DrawingSurface_FreeDrawingSurfaceInfo(ds.FreeDrawingSurfaceInfo(), dsi);
                }
            } finally {
                // Unlock the drawing surface
                JAWT_DrawingSurface_Unlock(ds.Unlock(), ds);
            }
        } finally {
            // Free the drawing surface
            JAWT_FreeDrawingSurface(awt.FreeDrawingSurface(), ds);
        }

        repaint();
    }

    // Simplest possible context creation.
    private void createContext(JAWTWin32DrawingSurfaceInfo dsi_win) {
        long hdc = dsi_win.hdc();

        try (PIXELFORMATDESCRIPTOR pfd = PIXELFORMATDESCRIPTOR.calloc().nSize((byte) PIXELFORMATDESCRIPTOR.SIZEOF)
                .nVersion((short) 1).dwFlags(PFD_SUPPORT_OPENGL | PFD_DRAW_TO_WINDOW | PFD_DOUBLEBUFFER)
                .iPixelType(PFD_TYPE_RGBA).cColorBits((byte) 32).cAlphaBits((byte) 8).cDepthBits((byte) 24)
                .iLayerType(PFD_MAIN_PLANE)) {
            int pixelFormat = GetPixelFormat(hdc);
            if (pixelFormat != 0) {
                if (DescribePixelFormat(hdc, pixelFormat, pfd) == 0) {
                    throw new IllegalStateException("DescribePixelFormat() failed: " + WinBase.getLastError());
                }
            } else {
                pixelFormat = ChoosePixelFormat(hdc, pfd);
                if (pixelFormat < 1) {
                    throw new IllegalStateException("ChoosePixelFormat() failed: " + WinBase.getLastError());
                }

                if (!SetPixelFormat(hdc, pixelFormat, null)) {
                    throw new IllegalStateException("SetPixelFormat() failed: " + WinBase.getLastError());
                }
            }
        }

        hglrc = wglCreateContext(hdc);

        if (hglrc == NULL) {
            throw new IllegalStateException("wglCreateContext() failed");
        }

        if (!wglMakeCurrent(hdc, hglrc)) {
            throw new IllegalStateException("wglMakeCurrent() failed");
        }

        caps = GL.createCapabilities();
    }

    public void destroy() {
        awt.free();

        if (hglrc != NULL) {
            wglDeleteContext(hglrc);
        }
    }

}