|
This example shows how to load .RAW image files and how to write your own blitter routine to modify textures after they have been loaded.
This is the Java port of the one of the NeHe OpenGL tutorials.
You can get complete IntelliJ IDEA project structure (all source, resources, build script, …) by downloading the source distribution from here.
The original post of the programmer who ported the examples can be found here.
package demos.nehe.lesson29;
import demos.common.GLDisplay;
/**
* @author Pepijn Van Eeckhoudt
*/
public class Lesson29 {
public static void main(String[] args) {
GLDisplay neheGLDisplay = GLDisplay.createGLDisplay(
"Lesson 29: RAW Files and blitter function");
Renderer renderer = new Renderer();
neheGLDisplay.addGLEventListener(renderer);
neheGLDisplay.start();
}
}
package demos.nehe.lesson29;
import demos.common.ResourceRetriever;
import javax.media.opengl.GL;
import javax.media.opengl.GLAutoDrawable;
import javax.media.opengl.GLEventListener;
import javax.media.opengl.glu.GLU;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import com.sun.opengl.util.BufferUtil;
class Renderer implements GLEventListener {
private class TextureImage {
int width; // Width Of Image In Pixels
int height; // Height Of Image In Pixels
int format; // Number Of Bytes Per Pixel
ByteBuffer data; // Texture Data
}
private float xrot = 0f; // X Rotation
private float yrot = 0f; // Y Rotation
private float zrot = 0f; // Y Rotation
private int textures[] = new int[1]; // Storage For 6 Textures (Modified)
private GLU glu = new GLU();
public Renderer() {
}
// Allocate An Image Structure And Inside Allocate Its Memory Requirements
private TextureImage allocateTextureBuffer(int w, int h, int f) {
TextureImage ti = new TextureImage(); // Pointer To Image Struct
ti.width = w; // Set Width
ti.height = h; // Set Height
ti.format = f; // Set Format
ti.data = BufferUtil.newByteBuffer(w * h * f);
ti.data.position(0);
ti.data.limit(ti.data.capacity());
return ti; // Return Pointer To Image Struct
}
private void readTextureData(String filename, TextureImage buffer) throws IOException {
int i,j,k,done = 0;
// Size Of A Row (Width * Bytes Per Pixel)
int stride = buffer.width * buffer.format;
InputStream inputStream = ResourceRetriever.getResourceAsStream(filename);
// Loop Through Height (Bottoms Up - Flip Image)
for (i = buffer.height - 1; i >= 0; i--) {
int p = i * stride;
for (j = 0; j < buffer.width; j++) { // Loop Through Width
for (k = 0; k < buffer.format - 1; k++, p++, done++) {
// Read Value From File And Store In Memory
buffer.data.put(p, (byte) inputStream.read());
}
buffer.data.put(p, (byte) 255);
p++; // Store 255 In Alpha Channel And Increase Pointer
}
}
inputStream.close(); // Close The File
}
private void buildTexture(GL gl, GLU glu, TextureImage tex) {
gl.glGenTextures(1, textures, 0);
gl.glBindTexture(GL.GL_TEXTURE_2D, textures[0]);
gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MAG_FILTER, GL.GL_LINEAR);
gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MIN_FILTER, GL.GL_LINEAR);
glu.gluBuild2DMipmaps(GL.GL_TEXTURE_2D, GL.GL_RGB, tex.width, tex.height,
GL.GL_RGBA, GL.GL_UNSIGNED_BYTE, tex.data);
}
void blit(TextureImage src, TextureImage dst, int src_xstart, int src_ystart,
int src_width, int src_height,
int dst_xstart, int dst_ystart, boolean blend, int alpha) {
int i,j,k;
int s, d; // Source & Destination
// Clamp Alpha If Value Is Out Of Range
if (alpha > 255) alpha = 255;
if (alpha < 0) alpha = 0;
// Start Row - dst (Row * Width In Pixels * Bytes Per Pixel)
d = (dst_ystart * dst.width * dst.format);
// Start Row - src (Row * Width In Pixels * Bytes Per Pixel)
s = (src_ystart * src.width * src.format);
for (i = 0; i < src_height; i++) // Height Loop
{
// Move Through Src Data By Bytes Per Pixel
s = s + (src_xstart * src.format);
// Move Through Dst Data By Bytes Per Pixel
d = d + (dst_xstart * dst.format);
for (j = 0; j < src_width; j++) // Width Loop
{
for (k = 0; k < src.format; k++, d++, s++) // "n" Bytes At A Time
{
if (blend) // If Blending Is On
// Multiply Src Data*alpha Add Dst Data*(255-alpha)
dst.data.put(d, (byte) (((src.data.get(s) * alpha) +
(dst.data.get(d) * (255 - alpha))) >> 8));
else // Keep in 0-255 Range With >> 8
// No Blending Just Do A Straight Copy
dst.data.put(d, src.data.get(s));
}
}
// Add End Of Row */
d = d + (dst.width - (src_width + dst_xstart)) * dst.format;
// Add End Of Row */
s = s + (src.width - (src_width + src_xstart)) * src.format;
}
}
public void init(GLAutoDrawable glDrawable) {
GL gl = glDrawable.getGL();
TextureImage t1 = allocateTextureBuffer(256, 256, 4); // Get An Image Structure
try {
// Fill The Image Structure With Data
readTextureData("demos/data/images/monitor.raw", t1);
} catch (IOException e) { // Nothing Read?
System.out.println("Could not read data/monitor.raw");
throw new RuntimeException(e);
}
TextureImage t2 = allocateTextureBuffer(256, 256, 4); // Second Image Structure
try {
// Fill The Image Structure With Data
readTextureData("demos/data/images/gl.raw", t2);
} catch (IOException e) { // Nothing Read?
System.out.println("Could not read data/gl.raw");
throw new RuntimeException(e);
}
// Image To Blend In, Original Image, Src Start X & Y, Src Width & Height,
// Dst Location X & Y, Blend Flag, Alpha Value
// Call The Blitter Routine
blit(t2, t1, 127, 127, 128, 128, 64, 64, true, 127);
buildTexture(gl, glu, t1); // Load The Texture Map Into Texture Memory
gl.glEnable(GL.GL_TEXTURE_2D); // Enable Texture Mapping
gl.glShadeModel(GL.GL_SMOOTH); // Enables Smooth Color Shading
// This Will Clear The Background Color To Black
gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
gl.glClearDepth(1.0); // Enables Clearing Of The Depth Buffer
gl.glEnable(GL.GL_DEPTH_TEST); // Enables Depth Testing
gl.glDepthFunc(GL.GL_LESS); // The Type Of Depth Test To Do
}
public void display(GLAutoDrawable glDrawable) {
GL gl = glDrawable.getGL();
// Clear The Screen And The Depth Buffer
gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);
gl.glLoadIdentity(); // Reset The View
gl.glTranslatef(0.0f, 0.0f, -5.0f);
gl.glRotatef(xrot, 1.0f, 0.0f, 0.0f);
gl.glRotatef(yrot, 0.0f, 1.0f, 0.0f);
gl.glRotatef(zrot, 0.0f, 0.0f, 1.0f);
gl.glBindTexture(GL.GL_TEXTURE_2D, textures[0]);
gl.glBegin(GL.GL_QUADS);
// Front Face
gl.glNormal3f(0.0f, 0.0f, 1.0f);
gl.glTexCoord2f(1.0f, 1.0f);
gl.glVertex3f(1.0f, 1.0f, 1.0f);
gl.glTexCoord2f(0.0f, 1.0f);
gl.glVertex3f(-1.0f, 1.0f, 1.0f);
gl.glTexCoord2f(0.0f, 0.0f);
gl.glVertex3f(-1.0f, -1.0f, 1.0f);
gl.glTexCoord2f(1.0f, 0.0f);
gl.glVertex3f(1.0f, -1.0f, 1.0f);
// Back Face
gl.glNormal3f(0.0f, 0.0f, -1.0f);
gl.glTexCoord2f(1.0f, 1.0f);
gl.glVertex3f(-1.0f, 1.0f, -1.0f);
gl.glTexCoord2f(0.0f, 1.0f);
gl.glVertex3f(1.0f, 1.0f, -1.0f);
gl.glTexCoord2f(0.0f, 0.0f);
gl.glVertex3f(1.0f, -1.0f, -1.0f);
gl.glTexCoord2f(1.0f, 0.0f);
gl.glVertex3f(-1.0f, -1.0f, -1.0f);
// Top Face
gl.glNormal3f(0.0f, 1.0f, 0.0f);
gl.glTexCoord2f(1.0f, 1.0f);
gl.glVertex3f(1.0f, 1.0f, -1.0f);
gl.glTexCoord2f(0.0f, 1.0f);
gl.glVertex3f(-1.0f, 1.0f, -1.0f);
gl.glTexCoord2f(0.0f, 0.0f);
gl.glVertex3f(-1.0f, 1.0f, 1.0f);
gl.glTexCoord2f(1.0f, 0.0f);
gl.glVertex3f(1.0f, 1.0f, 1.0f);
// Bottom Face
gl.glNormal3f(0.0f, -1.0f, 0.0f);
gl.glTexCoord2f(0.0f, 0.0f);
gl.glVertex3f(1.0f, -1.0f, 1.0f);
gl.glTexCoord2f(1.0f, 0.0f);
gl.glVertex3f(-1.0f, -1.0f, 1.0f);
gl.glTexCoord2f(1.0f, 1.0f);
gl.glVertex3f(-1.0f, -1.0f, -1.0f);
gl.glTexCoord2f(0.0f, 1.0f);
gl.glVertex3f(1.0f, -1.0f, -1.0f);
// Right Face
gl.glNormal3f(1.0f, 0.0f, 0.0f);
gl.glTexCoord2f(1.0f, 0.0f);
gl.glVertex3f(1.0f, -1.0f, -1.0f);
gl.glTexCoord2f(1.0f, 1.0f);
gl.glVertex3f(1.0f, 1.0f, -1.0f);
gl.glTexCoord2f(0.0f, 1.0f);
gl.glVertex3f(1.0f, 1.0f, 1.0f);
gl.glTexCoord2f(0.0f, 0.0f);
gl.glVertex3f(1.0f, -1.0f, 1.0f);
// Left Face
gl.glNormal3f(-1.0f, 0.0f, 0.0f);
gl.glTexCoord2f(0.0f, 0.0f);
gl.glVertex3f(-1.0f, -1.0f, -1.0f);
gl.glTexCoord2f(1.0f, 0.0f);
gl.glVertex3f(-1.0f, -1.0f, 1.0f);
gl.glTexCoord2f(1.0f, 1.0f);
gl.glVertex3f(-1.0f, 1.0f, 1.0f);
gl.glTexCoord2f(0.0f, 1.0f);
gl.glVertex3f(-1.0f, 1.0f, -1.0f);
gl.glEnd();
xrot += 0.3f;
yrot += 0.2f;
zrot += 0.4f;
}
public void reshape(GLAutoDrawable glDrawable, int x, int y, int w, int h) {
if (h == 0) h = 1;
GL gl = glDrawable.getGL();
// Reset The Current Viewport And Perspective Transformation
gl.glViewport(0, 0, w, h);
gl.glMatrixMode(GL.GL_PROJECTION); // Select The Projection Matrix
gl.glLoadIdentity(); // Reset The Projection Matrix
// Calculate The Aspect Ratio Of The Window
glu.gluPerspective(45.0f, (float) w / (float) h, 0.1f, 100.0f);
gl.glMatrixMode(GL.GL_MODELVIEW); // Select The Modelview Matrix
gl.glLoadIdentity(); // Reset The ModalView Matrix
}
public void displayChanged(GLAutoDrawable glDrawable, boolean b, boolean b1) {
}
}
|
Related Tips
|
Other API Tips 
You can share your information about this topic using the form below!
Please do not post your questions with this form! Thanks.