OpenglES阿尔法纹理深度

Question

glClear(GL_COLOR_BUFFER_BIT |GL_DEPTH_BUFFER_BIT); 

glUseProgram(_program); 
GLKVector2 poz= { 0, 0}; 
if (_Sprite2) 
{ 
    float aspect = (GLfloat) _screenWidth/ (GLfloat) _screenHeight; 
    [self esMatrixLoadIdentity : &perspective]; 
    [self esPerspective:&perspective pos_fovy:60.0f pos_aspect:aspect pos_nearZ:1.0f pos_farZ:30.0f]; 


    [self esMatrixLoadIdentity : &modelview]; 
    [self esTranslate : &modelview trans_x:0.0f trans_y:-0.5f trans_z:-5 ]; 
    [self esRotate : &modelview gl_angle:0.0f _x:1.0 _y:0.0 _z:1.0]; 
    [self esMatrixMultiply :&mvpMatrix src_A:&modelview src_B:&perspective]; 

    glUniformMatrix4fv (mvpLoc, 1, GL_FALSE, (GLfloat*) &mvpMatrix.m[0][0]); 

    [_Sprite2 update : poz]; 
    [_Sprite2 draw]; 
}/// crown 

if(_sprite)//bug 
{ 
    float aspect = (GLfloat) _screenWidth/ (GLfloat) _screenHeight; 
    [self esMatrixLoadIdentity : &perspective]; 
    [self esPerspective:&perspective pos_fovy:60.0f pos_aspect:aspect pos_nearZ:1.0f pos_farZ:30.0f]; 

    [self esMatrixLoadIdentity : &modelview]; 
    [self esTranslate : &modelview trans_x:0.0f trans_y:0.0f trans_z:_zPoz + _zPoz_2]; 
    [self esRotate : &modelview gl_angle:0.0f _x:1.0 _y:0.0 _z:1.0]; 

    [self esMatrixMultiply :&mvpMatrix src_A:&modelview src_B:&perspective]; 

    glUniformMatrix4fv (mvpLoc, 1, GL_FALSE, (GLfloat*) &mvpMatrix.m[0][0]); 

    [_sprite update : poz]; 
    [_sprite draw]; 
} 

错误图像改变深度-Z， 和冠的透明度区域现在正常工作。

如何正确地看到后面的错误？

Answer 1

您需要：

1. 排序你的精灵，使他们渲染后端到前端没有深度测试，仅仅依靠混合提供透明。
2. 添加阿尔法测试到您的片段着色器丢弃哪些是透明的片段（例如if (alpha < 0.05) discard;，调整透明度阈值适当时）