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针对 Java 移动设备的 3D 图形，第 1 部分: M3G 的快速模式
使用 JSR 184 创建 3D 场景
package m3gsamples1;
import java.util.*;
import javax.microedition.lcdui.*;
import javax.microedition.m3g.*;
/**
* Sample displaying a lit cube with material properties.
*
* @author Claus Hoefele
*/
public class TexturesSample extends Canvas implements Sample
{
/** The cube"s vertex positions (x, y, z). */
private static final byte[] VERTEX_POSITIONS = {
-1, -1, 1, 1, -1, 1, -1, 1, 1, 1, 1, 1, // front
1, -1, -1, -1, -1, -1, 1, 1, -1, -1, 1, -1, // back
1, -1, 1, 1, -1, -1, 1, 1, 1, 1, 1, -1, // right
-1, -1, -1, -1, -1, 1, -1, 1, -1, -1, 1, 1, // left
-1, 1, 1, 1, 1, 1, -1, 1, -1, 1, 1, -1, // top
-1, -1, -1, 1, -1, -1, -1, -1, 1, 1, -1, 1 // bottom
};
/** Indices that define how to connect the vertices to build
* triangles. */
private static final int[] TRIANGLE_INDICES = {
0, 1, 2, 3, // front
4, 5, 6, 7, // back
8, 9, 10, 11, // right
12, 13, 14, 15, // left
16, 17, 18, 19, // top
20, 21, 22, 23, // bottom
};
/** Lengths of triangle strips in TRIANGLE_INDICES. */
private static int[] TRIANGLE_LENGTHS = {
4, 4, 4, 4, 4, 4
};
/** File name of the texture. */
private static final String TEXTURE_FILE = "/texture.png";
/** The texture coordinates (s, t) that define how to map the
* texture to the cube. */
private static final byte[] VERTEX_TEXTURE_COORDINATES = {
0, 1, 1, 1, 0, 0, 1, 0, // front
0, 1, 1, 1, 0, 0, 1, 0, // back
0, 1, 1, 1, 0, 0, 1, 0, // right
0, 1, 1, 1, 0, 0, 1, 0, // left
0, 1, 1, 1, 0, 0, 1, 0, // top
0, 1, 1, 1, 0, 0, 1, 0, // bottom
};
/** First color for blending. */
private static final int COLOR_0 = 0x000000FF;
/** Second color for blending. */
private static final int COLOR_1 = 0x0000FF00;
/** The cube"s vertex data. */
private VertexBuffer _cubeVertexData;
/** The cube"s triangles defined as triangle strips. */
private TriangleStripArray _cubeTriangles;
/** The cube"s transformation. */
private Transform _cubeTransform;
/** Our cube"s appearance. */
private Appearance _cubeAppearance;
/** Polygon mode component of appearance that encapsulates per-face
* attributes. */
private PolygonMode _polygonMode;
/** Stores whether perspective correction is enabled or not. */
private boolean _isPerspectiveCorrectionEnabled;
/** The cube"s texture. */
private Texture2D _cubeTexture;
/** Graphics singleton used for rendering. */
private Graphics3D _graphics3d;
/**
* Called when this sample is displayed.
*/
public void showNotify()
{
init();
}
/**
* Initializes the sample.
*/
protected void init()
{
// Get the singleton for 3D rendering.
_graphics3d = Graphics3D.getInstance();
// Create vertex data.
_cubeVertexData = new VertexBuffer();
VertexArray vertexPositions =
new VertexArray(VERTEX_POSITIONS.length/3, 3, 1);
vertexPositions.set(0, VERTEX_POSITIONS.length/3, VERTEX_POSITIONS);
_cubeVertexData.setPositions(vertexPositions, 1.0f, null);
VertexArray vertexTextureCoordinates =
new VertexArray(VERTEX_TEXTURE_COORDINATES.length/2, 2, 1);
vertexTextureCoordinates.set(0,
VERTEX_TEXTURE_COORDINATES.length/2, VERTEX_TEXTURE_COORDINATES);
_cubeVertexData.setTexCoords(0, vertexTextureCoordinates, 2.0f, null);
// Set default color for cube.
_cubeVertexData.setDefaultColor(COLOR_0);
// Create the triangles that define the cube; the indices point to
// vertices in VERTEX_POSITIONS.
_cubeTriangles = new TriangleStripArray(TRIANGLE_INDICES,
TRIANGLE_LENGTHS);
// Create a camera with perspective projection.
Camera camera = new Camera();
float aspect = (float) getWidth() / (float) getHeight();
camera.setPerspective(30.0f, aspect, 1.0f, 1000.0f);
Transform cameraTransform = new Transform();
cameraTransform.postTranslate(0.0f, 0.0f, 10.0f);
_graphics3d.setCamera(camera, cameraTransform);
// Rotate the cube so we can see three sides.
_cubeTransform = new Transform();
_cubeTransform.postRotate(20.0f, 1.0f, 0.0f, 0.0f);
_cubeTransform.postRotate(45.0f, 0.0f, 1.0f, 0.0f);
// Define an appearance object and set the polygon mode.
_cubeAppearance = new Appearance();
_polygonMode = new PolygonMode();
_isPerspectiveCorrectionEnabled = false;
_cubeAppearance.setPolygonMode(_polygonMode);
try
{
// Load image for texture and assign it to the appearance. The
// default values are: WRAP_REPEAT, FILTER_BASE_LEVEL/
// FILTER_NEAREST, and FUNC_MODULATE.
Image2D image2D = (Image2D) Loader.load(TEXTURE_FILE)[0];
_cubeTexture = new Texture2D(image2D);
_cubeTexture.setBlending(Texture2D.FUNC_DECAL);
// Index 0 is used because we have only one texture.
_cubeAppearance.setTexture(0, _cubeTexture);
}
catch (Exception e)
{
System.out.println("Error loading image " + TEXTURE_FILE);
e.printStackTrace();
}
}
/**
* Renders the sample on the screen.
*
* @param graphics the graphics object to draw on.
*/
protected void paint(Graphics graphics)
{
_graphics3d.bindTarget(graphics);
_graphics3d.clear(null);
_graphics3d.render(_cubeVertexData, _cubeTriangles,
_cubeAppearance, _cubeTransform);
_graphics3d.releaseTarget();
drawMenu(graphics);
}
/**
* Draws a menu on the screen.
*
* @param graphics graphics context.
*/
protected void drawMenu(Graphics graphics)
{
graphics.setColor(0xFFFFFFFF);
int fontHeight = graphics.getFont().getHeight();
// Upper half menu.
int height = 0;
graphics.drawString(getKeyName(getKeyCode(FIRE)) + ": Reset", 0, height, 0);
height += fontHeight;
graphics.drawString(
getKeyName(getKeyCode(LEFT)) + "/" +
getKeyName(getKeyCode(RIGHT)) + ": Rotate y ", 0, height, 0);
// Lower half menu.
height = getHeight() - fontHeight;
if (_cubeVertexData.getDefaultColor() == COLOR_0)
{
graphics.drawString(getKeyName(getKeyCode(GAME_C)) +
": Color: blue", 0, height, 0);
}
else
{
graphics.drawString(getKeyName(getKeyCode(GAME_C)) +
": Color: green", 0, height, 0);
}
height -= fontHeight;
if (_cubeTexture.getWrappingS() == Texture2D.WRAP_CLAMP)
{
graphics.drawString(getKeyName(getKeyCode(GAME_B)) +
": Wrapping: clamp", 0, height, 0);
}
else
{
graphics.drawString(getKeyName(getKeyCode(GAME_B)) +
": Wrapping: repeat", 0, height, 0);
}
height -= fontHeight;
if (isPerspectiveCorrectionSupported())
{
if (_isPerspectiveCorrectionEnabled)
{
graphics.drawString(getKeyName(getKeyCode(GAME_A)) +
": Persp. correction: on", 0, height, 0);
}
else
{
graphics.drawString(getKeyName(getKeyCode(GAME_A)) +
": Persp. correction: off", 0, height, 0);
}
}
else
{
graphics.drawString(getKeyName(getKeyCode(GAME_A)) +
": Persp. correction: not supported", 0, height, 0);
}
}
/**
* Checks whether perspective correction is supported.
*
* @return true if persepctive correction is supported, false otherwise.
*/
protected boolean isPerspectiveCorrectionSupported()
{
Hashtable properties = Graphics3D.getProperties();
Boolean supportPerspectiveCorrection =
(Boolean) properties.get("supportPerspectiveCorrection");
return supportPerspectiveCorrection.booleanValue();
}
/**
* Handles key presses.
*
* @param keyCode key code.
*/
protected void keyPressed(int keyCode)
{
switch (getGameAction(keyCode))
{
case LEFT:
_cubeTransform.postRotate(-10.0f, 0.0f, 1.0f, 0.0f);
break;
case RIGHT:
_cubeTransform.postRotate(10.0f, 0.0f, 1.0f, 0.0f);
break;
case FIRE:
init();
break;
case GAME_A:
if (isPerspectiveCorrectionSupported())
{
_isPerspectiveCorrectionEnabled = !_isPerspectiveCorrectionEnabled;
_polygonMode.setPerspectiveCorrectionEnable(
_isPerspectiveCorrectionEnabled);
}
break;
case GAME_B:
if (_cubeTexture.getWrappingS() == Texture2D.WRAP_CLAMP)
{
_cubeTexture.setWrapping(Texture2D.WRAP_REPEAT,
Texture2D.WRAP_REPEAT);
}
else
{
_cubeTexture.setWrapping(Texture2D.WRAP_CLAMP,
Texture2D.WRAP_CLAMP);
}
break;
case GAME_C:
if (_cubeVertexData.getDefaultColor() == COLOR_0)
{
_cubeVertexData.setDefaultColor(COLOR_1);
}
else
{
_cubeVertexData.setDefaultColor(COLOR_0);
}
break;
// no default
}
repaint();
}
/**
* Handles key repeat events for phones that support them. Redirects
* all key input to <code>keyPressed()</code>.
*
* @param keyCode key code.
*/
protected void keyRepeated(int keyCode)
{
keyPressed(keyCode);
}
/**
* Returns the <code>Displayable</code> used to display this sample.
*
* @return display
*/
public Displayable getDisplayable()
{
return this;
}
/**
* Returns the display name of this sample.
*
* @return name
*/
public String getName()
{
return "Textures";
}
}
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发表于 2005-12-3 15:48:00