移動紋理OpenGL ES 2.0

Question

我正在嘗試在OpenGL ES 2.0中實現8列8行的精靈
我出現了第一個圖像，但是我不知道如何在OpenGL ES 2.0中轉換紋理矩陣，相當於我正在尋找的OpenGL 1.0中的代碼

        gl.glMatrixMode(GL10.GL_TEXTURE);
        gl.glLoadIdentity();
        gl.glPushMatrix();
        gl.glTranslatef(0.0f, 0.2f, 0f);
        gl.glPopMatrix();

這是我正在使用atm的矩陣

/**
 * Store the model matrix. This matrix is used to move models from object space (where each model can be thought
 * of being located at the center of the universe) to world space.
 */
private float[] mModelMatrix = new float[16];

/**
 * Store the view matrix. This can be thought of as our camera. This matrix transforms world space to eye space;
 * it positions things relative to our eye.
 */
private float[] mViewMatrix = new float[16];

/** Store the projection matrix. This is used to project the scene onto a 2D viewport. */
private float[] mProjectionMatrix = new float[16];

/** Allocate storage for the final combined matrix. This will be passed into the shader program. */
private float[] mMVPMatrix = new float[16];

/** 
 * Stores a copy of the model matrix specifically for the light position.
 */
private float[] mLightModelMatrix = new float[16];  

我的頂點着色器

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.              

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;                               
}

我的片段着色器：

precision mediump float;        // Set the default precision to medium. We don't need as high of a 
                            // precision in the fragment shader.
    uniform vec3 u_LightPos;        // The position of the light in eye space.
    uniform sampler2D u_Texture;    // The input texture.

    varying vec3 v_Position;        // Interpolated position for this fragment.
    varying vec3 v_Normal;          // Interpolated normal for this fragment.
    varying vec2 v_TexCoordinate;   // Interpolated texture coordinate per fragment.

    // The entry point for our fragment shader.
    void main()                         
    {                              
        // Will be used for attenuation.
      float distance = length(u_LightPos - v_Position);                  

        // Get a lighting direction vector from the light to the vertex.
     vec3 lightVector = normalize(u_LightPos - v_Position);                 

        // Calculate the dot product of the light vector and vertex normal. If the normal and light vector are
        // pointing in the same direction then it will get max illumination.
     float diffuse = max(dot(v_Normal, lightVector), 0.0);                                                                                

        // Add attenuation. 
     diffuse = diffuse * (1.0 / (1.0 + (0.25 * distance)));

     // Add ambient lighting
     diffuse = diffuse + 0.7;  

        // Multiply the color by the diffuse illumination level and texture value to get final output color.
     gl_FragColor = (diffuse * texture2D(u_Texture, v_TexCoordinate));                                          
     }                                                                      

Answer 1

您將需要自己對紋理坐標進行轉換，可以在以下四個位置之一進行：

• 將轉換應用於原始模型數據。
• 在CPU中應用轉換（除非您有充分的理由，否則不建議這樣做，因為這是頂點着色器的作用）。
• 在頂點着色器中應用變換（推薦）。
• 在片段着色器中應用轉換。

如果要對紋理坐標應用平移，最靈活的方法是使用數學庫創建平移矩陣並將新矩陣均勻地傳遞到頂點着色器（與傳遞mMVPMatrix和mLightModelMatrix的方法相同） ）。 然后，您可以將轉換矩陣乘以頂點着色器中的紋理坐標，並將結果輸出為變化的向量。

頂點着色器：

texture_coordinate_varying = texture_matrix_uniform * texture_coordinate_attribute;

片段着色器：

gl_FragColor = texture2D(texture_sampler, texture_coordinate_varying);

請注意：您的GLES 1.0代碼實際上沒有執行翻譯，因為您將其包圍了推入式彈出式操作。