openGL es2.0 创建可移动的纹理平面

深藏阁楼爱情的钟 2022-08-06 11:20 173阅读 0赞

一、Java部分代码

package com.gzdxid.utils;
    
    import java.nio.ByteBuffer;
    import java.nio.ByteOrder;
    import java.nio.FloatBuffer;
    
    import android.opengl.GLES20;
    
    
    public class DrawRectMove {
    
    	int mProgram;
    	int muMVPMatrixHandle;
    	int maPositionHandle;
    	int maTexCoorHandle;
    	int muSpanHandle;
    	
    	FloatBuffer mVertexBuffer;
    	FloatBuffer mTexCoorBuffer;
    	
    	int vCount=0;
    	
    	public DrawRectMove(float width,float height,int mProgram) {
    		// TODO Auto-generated constructor stub
    		initVertex(width,height);
    		initShader(mProgram);
    	}
    
    	private void initVertex(float width, float height) {
    		// 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, 1, 1, 1, 1, 1, 1, 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);
    	}
    	
    }

二、定点着色器：

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

三、片源着色器：  
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);  
\}

这里面是移动y轴参数，当然也可以移动x轴的。在Java代码中的drawSelf()中，currStart参数改变影响图片在指定大小平面上移动。