Java tutorial
/******************************************************************************* * Copyright 2011 See AUTHORS file. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. ******************************************************************************/ package com.badlogic.gdx.graphics; import com.badlogic.gdx.graphics.VertexAttributes.Usage; import com.badlogic.gdx.graphics.glutils.ShaderProgram; /** A single vertex attribute defined by its {@link Usage}, its number of components and its shader alias. The Usage is needed for * the fixed function pipeline of OpenGL ES 1.x. Generic attributes are not supported in the fixed function pipeline. The number * of components defines how many components the attribute has. The alias defines to which shader attribute this attribute should * bind. The alias is used by a {@link Mesh} when drawing with a {@link ShaderProgram}. The alias can be changed at any time. * * @author mzechner */ public final class VertexAttribute { /** the attribute {@link Usage} **/ public final int usage; /** the number of components this attribute has **/ public final int numComponents; /** whether the values are normalized to either -1f and +1f (signed) or 0f and +1f (unsigned) */ public final boolean normalized; /** the OpenGL type of each component, e.g. {@link GL20#GL_FLOAT} or {@link GL20#GL_UNSIGNED_BYTE} */ public final int type; /** the offset of this attribute in bytes, don't change this! **/ public int offset; /** the alias for the attribute used in a {@link ShaderProgram} **/ public String alias; /** optional unit/index specifier, used for texture coordinates and bone weights **/ public int unit; private final int usageIndex; /** Constructs a new VertexAttribute. * * @param usage the usage, used for the fixed function pipeline. Generic attributes are not supported in the fixed function * pipeline. * @param numComponents the number of components of this attribute, must be between 1 and 4. * @param alias the alias used in a shader for this attribute. Can be changed after construction. */ public VertexAttribute(int usage, int numComponents, String alias) { this(usage, numComponents, alias, 0); } /** Constructs a new VertexAttribute. * * @param usage the usage, used for the fixed function pipeline. Generic attributes are not supported in the fixed function * pipeline. * @param numComponents the number of components of this attribute, must be between 1 and 4. * @param alias the alias used in a shader for this attribute. Can be changed after construction. * @param index unit/index of the attribute, used for boneweights and texture coordinates. */ public VertexAttribute(int usage, int numComponents, String alias, int index) { this(usage, numComponents, usage == Usage.ColorPacked ? GL20.GL_UNSIGNED_BYTE : GL20.GL_FLOAT, usage == Usage.ColorPacked, alias, index); } private VertexAttribute(int usage, int numComponents, int type, boolean normalized, String alias) { this(usage, numComponents, type, normalized, alias, 0); } private VertexAttribute(int usage, int numComponents, int type, boolean normalized, String alias, int index) { this.usage = usage; this.numComponents = numComponents; this.type = type; this.normalized = normalized; this.alias = alias; this.unit = index; this.usageIndex = Integer.numberOfTrailingZeros(usage); } public static VertexAttribute Position() { return new VertexAttribute(Usage.Position, 3, ShaderProgram.POSITION_ATTRIBUTE); } public static VertexAttribute TexCoords(int unit) { return new VertexAttribute(Usage.TextureCoordinates, 2, ShaderProgram.TEXCOORD_ATTRIBUTE + unit, unit); } public static VertexAttribute Normal() { return new VertexAttribute(Usage.Normal, 3, ShaderProgram.NORMAL_ATTRIBUTE); } /** @deprecated use {@link #ColorPacked()} */ @Deprecated public static VertexAttribute Color() { return ColorPacked(); } public static VertexAttribute ColorPacked() { return new VertexAttribute(Usage.ColorPacked, 4, GL20.GL_UNSIGNED_BYTE, true, ShaderProgram.COLOR_ATTRIBUTE); } public static VertexAttribute ColorUnpacked() { return new VertexAttribute(Usage.Color, 4, GL20.GL_FLOAT, false, ShaderProgram.COLOR_ATTRIBUTE); } public static VertexAttribute Tangent() { return new VertexAttribute(Usage.Tangent, 3, ShaderProgram.TANGENT_ATTRIBUTE); } public static VertexAttribute Binormal() { return new VertexAttribute(Usage.BiNormal, 3, ShaderProgram.BINORMAL_ATTRIBUTE); } public static VertexAttribute BoneWeight(int unit) { return new VertexAttribute(Usage.BoneWeight, 2, "a_boneWeight" + unit, unit); } /** Tests to determine if the passed object was created with the same parameters */ @Override public boolean equals(final Object obj) { if (!(obj instanceof VertexAttribute)) { return false; } return equals((VertexAttribute) obj); } public boolean equals(final VertexAttribute other) { return other != null && usage == other.usage && numComponents == other.numComponents && alias.equals(other.alias) && unit == other.unit; } /** @return A unique number specifying the usage index (3 MSB) and unit (1 LSB). */ public int getKey() { return (usageIndex << 8) + (unit & 0xFF); } @Override public int hashCode() { int result = getKey(); result = 541 * result + numComponents; result = 541 * result + alias.hashCode(); return result; } }