Fixed Stencil test.

third_party/gles2_book/Chapter_11/Stencil_Test/Stencil_Test.c

 //
 // Book:      OpenGL(R) ES 2.0 Programming Guide
 // Authors:   Aaftab Munshi, Dan Ginsburg, Dave Shreiner
 // ISBN-10:   0321502795
 // ISBN-13:   9780321502797
 // Publisher: Addison-Wesley Professional
 // URLs:      http://safari.informit.com/9780321563835
 //            http://www.opengles-book.com
 //
 
@@ skipping 24 matching lines @@
       "void main()               \n"
       "{                         \n"
       "  gl_FragColor = u_color; \n"
       "}                         \n";
 
    GLfloat vVertices[] = { 
        -0.75f,  0.25f,  0.50f, // Quad #0
        -0.25f,  0.25f,  0.50f,
        -0.25f,  0.75f,  0.50f,
        -0.75f,  0.75f,  0.50f,
-        0.25f,  0.25f,  0.90f, // Quad #1
-        0.75f,  0.25f,  0.90f,
-        0.75f,  0.75f,  0.90f,
-        0.25f,  0.75f,  0.90f,
+        0.25f,  0.25f,  0.50f, // Quad #1
+        0.75f,  0.25f,  0.50f,
+        0.75f,  0.75f,  0.50f,
+        0.25f,  0.75f,  0.50f,
        -0.75f, -0.75f,  0.50f, // Quad #2
        -0.25f, -0.75f,  0.50f,
        -0.25f, -0.25f,  0.50f,
        -0.75f, -0.25f,  0.50f,
         0.25f, -0.75f,  0.50f, // Quad #3
         0.75f, -0.75f,  0.50f,
         0.75f, -0.25f,  0.50f,
         0.25f, -0.25f,  0.50f,
        -1.00f, -1.00f,  0.00f, // Big Quad
         1.00f, -1.00f,  0.00f,
@@ skipping 52 matching lines @@
    int  i;
    GLubyte *offset = NULL;
 
    STUserData *userData = esContext->userData;
 
 #define NumTests  4
    GLfloat  colors[NumTests][4] = { 
        { 1.0f, 0.0f, 0.0f, 1.0f },
        { 0.0f, 1.0f, 0.0f, 1.0f },
        { 0.0f, 0.0f, 1.0f, 1.0f },
-       { 1.0f, 1.0f, 0.0f, 0.0f }
+       { 1.0f, 1.0f, 0.0f, 1.0f }
    };
 
-   GLint   numStencilBits = 0;
    GLuint  stencilValues[NumTests] = { 
       0x7, // Result of test 0
       0x0, // Result of test 1
       0x2, // Result of test 2
-      0xff // Result of test 3.  We need to fill this
-           //  value in a run-time
+      0xfe // Result of test 3
    };
 
    // Set the viewport
    glViewport ( 0, 0, esContext->width, esContext->height );
    
    // Clear the color, depth, and stencil buffers.  At this
    //   point, the stencil buffer will be 0x1 for all pixels
    glClear ( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT );
 
    // Use the program object
@@ skipping 66 matching lines @@
    //      ( 0x2 & 0x1 ) == ( 0x1 & 0x1 )
    //
    //   The stencil value here will be set to ~((2^s-1) & 0x1),
    //   (with the 0x1 being from the stencil clear value),
    //   where 's' is the number of bits in the stencil buffer
    //
    glStencilFunc( GL_EQUAL, 0x2, 0x1 );
    glStencilOp( GL_INVERT, GL_KEEP, GL_KEEP );
    offset += 6;
    glDrawElements( GL_TRIANGLES, 6, GL_UNSIGNED_BYTE, offset );
-   
-   // Since we don't know at compile time how many stecil bits are present,
-   //   we'll query, and update the value correct value in the
-   //   stencilValues arrays for the fourth tests.  We'll use this value
-   //   later in rendering.
-   glGetIntegerv( GL_STENCIL_BITS, &numStencilBits );
-   
-   stencilValues[3] = ~(((1 << numStencilBits) - 1) & 0x1) & 0xff;
 
    // Use the stencil buffer for controlling where rendering will
    //   occur.  We diable writing to the stencil buffer so we
    //   can test against them without modifying the values we
    //   generated.
    glStencilMask( 0x0 );
    offset += 6;
    for ( i = 0; i < NumTests; ++i )
    {
       glStencilFunc( GL_EQUAL, stencilValues[i], 0xff );
       glUniform4fv( userData->colorLoc, 1, colors[i] );
       glDrawElements( GL_TRIANGLES, 6, GL_UNSIGNED_BYTE, offset );
    }
 }
 
 ///
 // Cleanup
 //
 void stShutDown ( ESContext *esContext )
 {
    STUserData *userData = esContext->userData;
 
    // Delete program object
    glDeleteProgram ( userData->programObject );
 
    // Delete vertex buffer objects
    glDeleteBuffers ( 2, userData->vboIds );
 }