Question

当我使用CCTransitionPageTurn时，如何指定场景背面的颜色？在cocos2d-iphone 1.0中，我在CCGrid.m中对blot（）进行了一些修改，如下所示：

NSInteger n = gridSize_.x * gridSize_.y;
// Default GL states: GL_TEXTURE_2D, GL_VERTEX_ARRAY, GL_COLOR_ARRAY, GL_TEXTURE_COORD_ARRAY
    // Needed states: GL_TEXTURE_2D, GL_VERTEX_ARRAY, GL_TEXTURE_COORD_ARRAY
    // Unneeded states: GL_COLOR_ARRAY
    //enable culling, the default cull face is back
    glEnable(GL_CULL_FACE);
    //now only the front facing polygons are drawn
    glDisableClientState(GL_COLOR_ARRAY);
glVertexPointer(3, GL_FLOAT, 0, vertices);
    glTexCoordPointer(2, GL_FLOAT, 0, texCoordinates);
    glDrawElements(GL_TRIANGLES, (GLsizei) n*6, GL_UNSIGNED_SHORT, indices);
// This is very important, otherwise the backside of picture will be random color
    glDisable(GL_TEXTURE_2D);
//change the winding of what OpenGl considers front facing
    //only the back facing polygons will be drawn
    //this works better then changing the cull face
    glFrontFace(GL_CW);
    glDisableClientState(GL_TEXTURE_COORD_ARRAY);
    glColor4ub(255,255,255,255);
    glDrawElements(GL_TRIANGLES, (GLsizei) n*6, GL_UNSIGNED_SHORT, indices);
//restore GL default states
    glFrontFace(GL_CCW);
    glDisable(GL_CULL_FACE);
    glEnableClientState(GL_TEXTURE_COORD_ARRAY);
    glEnableClientState(GL_COLOR_ARRAY);

这是cpp代码，我想我可以在cocos2d-x中使用。但遗憾的是，此代码不适用于2.0。任何人都可以建议如何将其转换为2.0？或者是否有在CCTransitionPageTurn期间在场景背面设置颜色的替代方法？

Answer 1

基于您的代码段和其他Google搜索，我设法实现了这一目标：

void CCGrid3D::blit(void)
{

    CCLOG("CCGrid3D::blit()");
    int n = m_sGridSize.width * m_sGridSize.height;

    ccGLEnableVertexAttribs( kCCVertexAttribFlag_Position | kCCVertexAttribFlag_TexCoords );
    m_pShaderProgram->use();
    m_pShaderProgram->setUniformsForBuiltins();;

    //
    // Attributes
    //
#ifdef EMSCRIPTEN
    // Size calculations from calculateVertexPoints().
    unsigned int numOfPoints = (m_sGridSize.width+1) * (m_sGridSize.height+1);

    // position
    setGLBufferData(m_pVertices, numOfPoints * sizeof(ccVertex3F), 0);
    glVertexAttribPointer(kCCVertexAttrib_Position, 3, GL_FLOAT, GL_FALSE, 0, 0);

    // texCoords
    setGLBufferData(m_pTexCoordinates, numOfPoints * sizeof(ccVertex2F), 1);
    glVertexAttribPointer(kCCVertexAttrib_TexCoords, 2, GL_FLOAT, GL_FALSE, 0, 0);

    setGLIndexData(m_pIndices, n * 12, 0);
    glDrawElements(GL_TRIANGLES, (GLsizei) n*6, GL_UNSIGNED_SHORT, 0);
#else

    glEnable(GL_CULL_FACE);
    glVertexAttribPointer(kCCVertexAttrib_Position, 3, GL_FLOAT, GL_FALSE, 0, m_pVertices);
    glVertexAttribPointer(kCCVertexAttrib_TexCoords, 2, GL_FLOAT, GL_FALSE, 0, m_pTexCoordinates);
    glDrawElements(GL_TRIANGLES, (GLsizei)n*6, GL_UNSIGNED_SHORT, m_pIndices);

    glDisable(GL_TEXTURE_2D);

    glFrontFace(GL_CW);
    ccGLEnableVertexAttribs(kCCVertexAttribFlag_Position);

    glEnable(GL_BLEND);

    glDrawElements(GL_TRIANGLES, (GLsizei)n*6, GL_UNSIGNED_SHORT, m_pIndices);

    glFrontFace(GL_CCW);

    glDisable(GL_BLEND);
    glDisable(GL_CULL_FACE);

#endif // EMSCRIPTEN
    CC_INCREMENT_GL_DRAWS(1);
}

它只有一个缺点：它不允许你指定背面颜色，而是它获得左下角像素的颜色并使用它。我希望这对你来说已经足够了，或者你可以改变它，这样我们就可以指定所需的颜色。

CCTransitionPage的背面颜色转换为Cocos2d-x 2.0

1 个答案: