renderer.java

NeHe用java与OpenGL结合教程源码

package demos.nehe.lesson24;

import demos.common.ResourceRetriever;
import javax.media.opengl.GL;
import javax.media.opengl.GLAutoDrawable;
import javax.media.opengl.GLEventListener;

import java.io.IOException;
import java.util.StringTokenizer;
import java.nio.ByteBuffer;
import java.nio.channels.Channels;
import java.nio.channels.ReadableByteChannel;

import com.sun.opengl.util.BufferUtil;

class Renderer implements GLEventListener {
    private int base;                                        // Base Display List For The Font
    private int scroll;                                      // Used For Scrolling The Screen
    private int swidth;                                     // Scissor Width
    private int sheight;                                     // Scissor Height
    private int maxtokens;                                   // Keeps Track Of The Number Of Extensions Supported
    private TextureImage textures[] = new TextureImage[1];                // Storage For One Texture

    private ByteBuffer stringBuffer = BufferUtil.newByteBuffer(256);

    public int getScroll() {
        return scroll;
    }

    public void setScroll(int scroll) {
        this.scroll = Math.max(0, Math.min(32 * (maxtokens - 9), scroll));
    }

    public void init(GLAutoDrawable drawable) {
        GL gl = drawable.getGL();

        textures[0] = new TextureImage();
        try {
            loadTGA(gl, textures[0], "demos/data/images/font.tga"); // Load The Font Texture
        } catch (IOException e) {
            throw new RuntimeException(e);
        }

        buildFont(gl);                                                     // Build The Font

        gl.glShadeModel(GL.GL_SMOOTH);                                   // Enable Smooth Shading
        gl.glClearColor(0.0f, 0.0f, 0.0f, 0.5f);                         // Black Background
        gl.glClearDepth(1.0f);                                           // Depth Buffer Setup
        gl.glBindTexture(GL.GL_TEXTURE_2D, textures[0].texID[0]);        // Select Our Font Texture
    }

    public void display(GLAutoDrawable drawable) {
        GL gl = drawable.getGL();

        gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);
        int cnt = 0;                                         // Local Counter Variable

        gl.glColor3f(1.0f, 0.5f, 0.5f);                           // Set Color To Bright Red
        glPrint(gl, 50, 16, 1, "Renderer");                            // Display Renderer
        glPrint(gl, 80, 48, 1, "Vendor");                              // Display Vendor Name
        glPrint(gl, 66, 80, 1, "Version");                             // Display Version

        gl.glColor3f(1.0f, 0.7f, 0.4f);                           // Set Color To Orange
        glPrint(gl, 200, 16, 1, gl.glGetString(GL.GL_RENDERER));       // Display Renderer
        glPrint(gl, 200, 48, 1, gl.glGetString(GL.GL_VENDOR));         // Display Vendor Name
        glPrint(gl, 200, 80, 1, gl.glGetString(GL.GL_VERSION));        // Display Version

        gl.glColor3f(0.5f, 0.5f, 1.0f);                           // Set Color To Bright Blue
        glPrint(gl, 192, 432, 1, "NeHe Productions");                  // Write NeHe Productions At The Bottom Of The Screen

        gl.glLoadIdentity();                                    // Reset The ModelView Matrix
        gl.glColor3f(1.0f, 1.0f, 1.0f);                           // Set The Color To White
        gl.glBegin(GL.GL_LINE_STRIP);                           // Start Drawing Line Strips (Something New)
        gl.glVertex2d(639, 417);                               // Top Right Of Bottom Box
        gl.glVertex2d(0, 417);                               // Top Left Of Bottom Box
        gl.glVertex2d(0, 480);                               // Lower Left Of Bottom Box
        gl.glVertex2d(639, 480);                               // Lower Right Of Bottom Box
        gl.glVertex2d(639, 128);                               // Up To Bottom Right Of Top Box
        gl.glEnd();                                             // Done First Line Strip
        gl.glBegin(GL.GL_LINE_STRIP);                           // Start Drawing Another Line Strip
        gl.glVertex2d(0, 128);                               // Bottom Left Of Top Box
        gl.glVertex2d(639, 128);                               // Bottom Right Of Top Box
        gl.glVertex2d(639, 1);                               // Top Right Of Top Box
        gl.glVertex2d(0, 1);                               // Top Left Of Top Box
        gl.glVertex2d(0, 417);                               // Down To Top Left Of Bottom Box
        gl.glEnd();                                             // Done Second Line Strip

        gl.glScissor(1, (int) (0.135416f * sheight), swidth - 2, (int) (0.597916f * sheight)); // Define Scissor Region
        gl.glEnable(GL.GL_SCISSOR_TEST);                                             // Enable Scissor Testing

        String text = gl.glGetString(GL.GL_EXTENSIONS);           // Allocate Memory For Our Extension String
        StringTokenizer tokenizer = new StringTokenizer(text);

        while (tokenizer.hasMoreTokens()) {                         // While The Token Isn't NULL
            cnt++;                                                  // Increase The Counter
            if (cnt > maxtokens) {                                      // Is 'maxtokens' Less Than 'cnt'
                maxtokens = cnt;                                      // If So, Set 'maxtokens' Equal To 'cnt'
            }

            gl.glColor3f(0.5f, 1.0f, 0.5f);                           // Set Color To Bright Green
            glPrint(gl, 0, 96 + (cnt * 32) - scroll, 0, "" + cnt);                // Print Current Extension Number
            gl.glColor3f(1.0f, 1.0f, 0.5f);                           // Set Color To Yellow
            glPrint(gl, 50, 96 + (cnt * 32) - scroll, 0, tokenizer.nextToken()); // Print The Current Token (Parsed Extension Name)
        }
        gl.glDisable(GL.GL_SCISSOR_TEST);                         // Disable Scissor Testing
        gl.glFlush();                                             // Flush The Rendering Pipeline
    }

    public void reshape(GLAutoDrawable drawable,
                        int xstart,
                        int ystart,
                        int width,
                        int height) {
        GL gl = drawable.getGL();

        height = (height == 0) ? 1 : height;
        swidth = width;	                          // Set Scissor Width To Window Width
        sheight = height;                          // Set Scissor Height To Window Height

        gl.glViewport(0, 0, width, height);
        gl.glMatrixMode(GL.GL_PROJECTION);            // Select The Projection Matrix
        gl.glLoadIdentity();                          // Reset The Projection Matrix
        gl.glOrtho(0.0f, 640, 480, 0.0f, -1.0f, 1.0f);     // Create Ortho 640x480 View (0,0 At Top Left)
        gl.glMatrixMode(GL.GL_MODELVIEW);             // Select The Modelview Matrix
        gl.glLoadIdentity();
    }

    public void displayChanged(GLAutoDrawable drawable,
                               boolean modeChanged,
                               boolean deviceChanged) {
    }

    private void loadTGA(GL gl, TextureImage texture, String filename) throws IOException {        // Loads A TGA File Into Memory
        ByteBuffer TGAcompare = BufferUtil.newByteBuffer(12);                           // Used To Compare TGA Header
        byte[] TGAheader = new byte[] {0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0};               // Uncompressed TGA Header
        ByteBuffer header = BufferUtil.newByteBuffer(6);                            // First 6 Useful Bytes From The Header