Android 纹理定距离移动

短命女 2022-08-05 01:30 139阅读 0赞

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。

![20150531084550309][]

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,float s,float t) {// 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, 1.0f, 0.7f, 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;

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;
 					}
 				}

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。

[20150531084550309]: /images/20220805/c319456c7b864cf3969c6b5cd9bcadae.png