name.martingeisse.swtlib.canvas.OpenGlImageBlockCanvas.java Source code

Introduction

Here is the source code for name.martingeisse.swtlib.canvas.OpenGlImageBlockCanvas.java

Source

/**
 * Copyright (c) 2011 Martin Geisse
 *
 * This file is distributed under the terms of the MIT license.
 */

package name.martingeisse.swtlib.canvas;

import org.eclipse.swt.widgets.Composite;
import org.lwjgl.opengl.GL11;

/**
 * This class keeps an array of block values and a block palette. It draws its
 * blocks by drawing the image from the palette that corresponds to the block
 * value of the respective block.
 * 
 * If an invalid value is stored in a block, block 0 is drawn instead.
 */
public class OpenGlImageBlockCanvas extends AbstractOpenGlBlockCanvas {

    /**
     * the blocks
     */
    private final int[] blocks;

    /**
     * the palette
     */
    private OpenGlImageBlockPalette palette;

    /**
     * Constructor
     * @param parent the parent composite
     * @param blockWidth the width of a single block
     * @param blockHeight the height of a single block
     * @param horizontalBlockCount the number of blocks in a horizontal row
     * @param verticalBlockCount the number of blocks in a vertical column
     * @param palette the block palette
     */
    public OpenGlImageBlockCanvas(final Composite parent, final int blockWidth, final int blockHeight,
            final int horizontalBlockCount, final int verticalBlockCount, final OpenGlImageBlockPalette palette) {
        super(parent, blockWidth, blockHeight, horizontalBlockCount, verticalBlockCount);
        this.blocks = new int[horizontalBlockCount * verticalBlockCount];
        this.palette = palette;
    }

    /**
     * Getter method for the palette.
     * @return the palette
     */
    public OpenGlImageBlockPalette getPalette() {
        return palette;
    }

    /**
     * Setter method for the palette.
     * @param palette the palette to set
     */
    public void setPalette(final OpenGlImageBlockPalette palette) {
        this.palette = palette;
    }

    /**
     * Returns the index of the specified block, throwing an {@link IndexOutOfBoundsException}
     * if the position is invalid.
     * @param x the x position
     * @param y the y position
     * @return the block index
     */
    private int getBlockIndex(final int x, final int y) {
        if (x < 0 || x >= getHorizontalBlockCount()) {
            throw new IndexOutOfBoundsException("invalid x value");
        }
        if (y < 0 || y >= getVerticalBlockCount()) {
            throw new IndexOutOfBoundsException("invalid y value");
        }
        return y * getHorizontalBlockCount() + x;
    }

    /**
     * Returns the value of a block.
     * @param x the x position
     * @param y the y position
     * @return the block value
     */
    public int getBlock(final int x, final int y) {
        return blocks[getBlockIndex(x, y)];
    }

    /**
     * Sets the value of a block.
     * @param x the x position
     * @param y the y position
     * @param value the value to set
     */
    public void setBlock(final int x, final int y, final int value) {
        blocks[getBlockIndex(x, y)] = value;
    }

    /* (non-Javadoc)
     * @see name.martingeisse.swtlib.canvas.AbstractOpenGlBlockCanvas#onBeforeDraw()
     */
    @Override
    protected void onBeforeDraw() {
        GL11.glEnable(GL11.GL_TEXTURE_2D);
        GL11.glColor3f(1.0f, 1.0f, 1.0f);
    }

    /* (non-Javadoc)
     * @see name.martingeisse.swtlib.canvas.AbstractOpenGlBlockCanvas#drawBlock(int, int)
     */
    @Override
    protected void drawBlock(final int x, final int y) {
        palette.safeBind(getBlock(x, y));
        GL11.glTexParameterf(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MAG_FILTER, GL11.GL_NEAREST);

        // glBegin/glEnd must be called per block because of changing textures
        GL11.glBegin(GL11.GL_QUADS);
        GL11.glTexCoord2f(0.0f, 0.0f);
        GL11.glVertex2i(x, y);
        GL11.glTexCoord2f(1.0f, 0.0f);
        GL11.glVertex2i(x + 1, y);
        GL11.glTexCoord2f(1.0f, 1.0f);
        GL11.glVertex2i(x + 1, y + 1);
        GL11.glTexCoord2f(0.0f, 1.0f);
        GL11.glVertex2i(x, y + 1);
        GL11.glEnd();

    }

    /* (non-Javadoc)
     * @see name.martingeisse.swtlib.canvas.AbstractOpenGlBlockCanvas#onAfterDraw()
     */
    @Override
    protected void onAfterDraw() {
    }

}