OpenGl基本頂點着色器

Question

我是着色器概念的新手，我試圖在OpenGL ES中實現一個8x8的精靈。

我想移動紋理在頂點着色器，但我不能弄清楚如何這一點，我的代碼可能是錯的，隨時糾正我

如果我更改了頂點着色器這一行，紋理規模，但我想移動無法形成規模!:

v_TexCoordinate = a_TexCoordinate*vec2(1.5,1.5); 

所以我應該申請ADITION但我不知道該怎麼做（也許還有另一種途徑）

頂點着色器：

uniform mat4 u_MVPMatrix;  // A constant representing the combined model/view/projection matrix.     
uniform mat4 u_MVMatrix;  // A constant representing the combined model/view matrix.    
uniform mat4 u_TextureMatrix; 


attribute vec4 a_Position;  // Per-vertex position information we will pass in.        
attribute vec3 a_Normal;  // Per-vertex normal information we will pass in.  
attribute vec2 a_TexCoordinate; // Per-vertex texture coordinate information we will pass in.  

varying vec3 v_Position;  // This will be passed into the fragment shader.        
varying vec3 v_Normal;   // This will be passed into the fragment shader. 
varying vec2 v_TexCoordinate; // This will be passed into the fragment shader.    

// The entry point for our vertex shader. 
void main()              
{               
// Transform the vertex into eye space.  
    v_Position = vec3(u_MVMatrix * a_Position);     

// Pass through the texture coordinate. 
    v_TexCoordinate = a_TexCoordinate;          

// Transform the normal's orientation into eye space. 
    v_Normal = vec3(u_MVMatrix * vec4(a_Normal, 0.0)); 

// gl_Position is a special variable used to store the final position. 
// Multiply the vertex by the matrix to get the final point in normalized screen coordinates. 
    gl_Position = u_MVPMatrix * a_Position;        
} 

這是我畫機能的研究

private void drawMagia() 
{ 
    GLES20.glUseProgram(mMagiaProgramHandle); 
    mTextureMatrixHandle = GLES20.glGetUniformLocation(mMagiaProgramHandle, "u_TextureMatrix"); 
    mMagiaTextureCoordinateHandle = GLES20.glGetAttribLocation(mMagiaProgramHandle, "a_TexCoordinate"); 



    mMagiaPositions.position(0);   
    GLES20.glVertexAttribPointer(mPositionHandle, mPositionDataSize, GLES20.GL_FLOAT, false, 
      0, mMagiaPositions);   

    GLES20.glEnableVertexAttribArray(mPositionHandle);   


    // Pass in the normal information 
    mMagiaNormals.position(0); 
    GLES20.glVertexAttribPointer(mNormalHandle, mNormalDataSize, GLES20.GL_FLOAT, false, 
      0, mMagiaNormals); 

    GLES20.glEnableVertexAttribArray(mNormalHandle); 

    // Pass in the texture coordinate information 
    mMagiaTextureCoordinates.position(0); 
    GLES20.glVertexAttribPointer(mTextureCoordinateHandle, mTextureCoordinateDataSize, GLES20.GL_FLOAT, false, 
      0, mMagiaTextureCoordinates); 

    GLES20.glEnableVertexAttribArray(mTextureCoordinateHandle); 

    // This multiplies the view matrix by the model matrix, and stores the 
    // result in the MVP matrix 
    // (which currently contains model * view). 
    Matrix.multiplyMM(mMVPMatrix, 0, mViewMatrix, 0, mModelMatrix, 0); 

    // Pass in the modelview matrix. 
    GLES20.glUniformMatrix4fv(mMVMatrixHandle, 1, false, mMVPMatrix, 0); 

    GLES20.glUniformMatrix4fv(mTextureMatrixHandle, 1, false, mTextureMatrix, 0); 

    // This multiplies the modelview matrix by the projection matrix, and 
    // stores the result in the MVP matrix 
    // (which now contains model * view * projection). 
    Matrix.multiplyMM(mMVPMatrix, 0, mProjectionMatrix, 0, mMVPMatrix, 0); 

    // Pass in the combined matrix. 
    GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mMVPMatrix, 0); 

    // Pass in the light position in eye space. 
    GLES20.glUniform3f(mLightPosHandle, mLightPosInEyeSpace[0], mLightPosInEyeSpace[1], mLightPosInEyeSpace[2]); 


    // Draw the square. 
    GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, 6); 
} 

Answer 1

您可以添加的，而不是乘以一定的偏移。

v_TexCoordinate = a_TexCoordinate + vec2(1.5,1.5); 

而且你的紋理應鎖定