Android 纹理定距离移动

效果图：右边的文字栏上下移动，没有文字会自动停止移动。这和之前我写的纹理移动不同，之前的是循环移动，这次是定位移动。

顶点着色器：

uniform mat4 uMVPMatrix;
attribute vec3 aPosition;
attribute vec2 aTexCoor;
varying vec2 vTextureCoord;
void main()
{
   gl_Position=uMVPMatrix*vec4(aPosition,1);
   vTextureCoord=aTexCoor;
}

片元着色器：

precision mediump float;
varying vec2 vTextureCoord;
uniform sampler2D sTexture;
uniform float uSpan;
void main()
{
   vec2 st_Result=vec2(0,0);
   st_Result.x=vTextureCoord.x;
   st_Result.y=vTextureCoord.y+uSpan;
   gl_FragColor=texture2D(sTexture,st_Result);
}

java代码：（这里是核心）

package com.hl.paints;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;

import com.hl.utils.MatrixState;

import android.opengl.GLES20;

public class DrawRectMoveStop {

	int mProgram;
	int muMVPMatrixHandle;
	int maPositionHandle;
	int maTexCoorHandle;
	int muSpanHandle;

	FloatBuffer mVertexBuffer;
	FloatBuffer mTexCoorBuffer;

	int vCount=0;

	public DrawRectMoveStop(float width,float height,float s,float t,int mProgram) {
		// TODO Auto-generated constructor stub
		initVertex(width,height,s,t);
		initShader(mProgram);
	}

	private void initVertex(float width, float height,<span style="color:#ff0000;">float s,float t</span>) {// 纹理的传入，目的是在最开始是不是将整个图片放进矩形框中，而是一部分
		// TODO Auto-generated method stub
		vCount = 6;
		float w = width / 2;
		float h = height / 2;
		float vertices[] = new float[] {
		-w,  h, 0,
		-w, -h, 0,
		 w, -h, 0,
		 w, -h, 0,
		 w,  h, 0,
		-w,  h, 0,

		};
		ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length * 4);
		vbb.order(ByteOrder.nativeOrder());
		mVertexBuffer = vbb.asFloatBuffer();
		mVertexBuffer.put(vertices);
		mVertexBuffer.position(0);

		float texCoor[] = new float[] {
				0, 0,
				0, t,
				s, t,
				s, t,
				s, 0,
				0, 0 };
		ByteBuffer cbb = ByteBuffer.allocateDirect(texCoor.length * 4);
		cbb.order(ByteOrder.nativeOrder());
		mTexCoorBuffer = cbb.asFloatBuffer();
		mTexCoorBuffer.put(texCoor);
		mTexCoorBuffer.position(0);
	}

	private void initShader(int mProgram) {
		// TODO Auto-generated method stub
		this.mProgram = mProgram;
		muMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix");
		maPositionHandle = GLES20.glGetAttribLocation(mProgram, "aPosition");
		maTexCoorHandle = GLES20.glGetAttribLocation(mProgram, "aTexCoor");
		muSpanHandle=GLES20.glGetUniformLocation(mProgram, "uSpan");
	}

	public void drawSelf(int texId,float currStart){
		GLES20.glUseProgram(mProgram);
		GLES20.glUniformMatrix4fv(muMVPMatrixHandle, 1, false, MatrixState.getFinalMatrix(), 0);
		GLES20.glVertexAttribPointer(maPositionHandle, 3, GLES20.GL_FLOAT, false, 3*4, mVertexBuffer);
		GLES20.glVertexAttribPointer(maTexCoorHandle, 2, GLES20.GL_FLOAT, false, 2*4, mTexCoorBuffer);
		GLES20.glEnableVertexAttribArray(maPositionHandle);
		GLES20.glEnableVertexAttribArray(maTexCoorHandle);
		GLES20.glUniform1f(muSpanHandle, currStart);
		GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
		GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, texId);
		GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, vCount);
	}
}

使用代码：

        private DrawRectMoveStop benRightText;
        BUTTON_BEN_RIGHT3_WIDTH = 2.0f * ratio * 0.23f;
	BUTTON_BEN_RIGHT3_HEIGHT = 1.4f;
	BUTTON_BEN_RIGHT3_XOFFSET = ratio - 2.0f * ratio * 0.23f / 2;
	BUTTON_BEN_RIGHT3_YOFFSET = 1.0f - 0.15f - 0.37f - 0.02f - 0.7f;
	benRightText = new DrawRectMoveStop(BUTTON_BEN_RIGHT3_WIDTH, BUTTON_BEN_RIGHT3_HEIGHT,<span style="color:#ff0000;"> 1.0f, 0.7f</span>, ShaderManager.getMoveTextureShaderProgram());

       //1.0f and 0.7f 是根据纹理图片和宽度计算的。效果图中的右边文字部分，是图片形式的。

        <pre name="code" class="java">        MatrixState.pushMatrix();
	MatrixState.translate(BUTTON_BEN_RIGHT3_XOFFSET, BUTTON_BEN_RIGHT3_YOFFSET, 0);
	benRightText.drawSelf(rText[condition], textYOffset);
	MatrixState.popMatrix();

private float textYOffset = 0;

        <span style="color:#ff0000;">if (UtilConfigArea.isInArea(x, y, AREA_BEN_RIGHT3)) {//onTouchEvent ACTION_MOVE:
					textYOffset -= dy * TOUCH_SCALE_FACTOR * 0.002f;
					if (textYOffset > 0.3f) {
						textYOffset = 0.3f;
					}
					if (textYOffset < 0.0f) {
						textYOffset = 0.0f;
					}
				}</span>

注：本文里面用到一些方法，在我的其它博文中有提到，若用到，请查相关博文。