我在android设备上运行了vulkan渲染器,生成的图像颠倒了。我不想在VkViewport定义中设置负高度,因为有代码和注释建议将矩阵倒置为Y。
我尝试在以下代码中反转mvp [5]矩阵数组的符号,但在渲染的图像中出现了剔除问题。
// update opengl projection matrix to vulkan conventions:
// Vulkan clip space has inverted Y and half Z ( Z - [0, 1] instead of [-1, 1])
float zNear = r_znear->value;
float m10 = -zFar / (zFar - zNear);
float py = tan(fovY * (M_PI / 360.0f));
float px = tan(fovX * (M_PI / 360.0f));
mvp[0] = 1.0f / px;
mvp[1] = 0;
mvp[2] = 0;
mvp[3] = 0;
mvp[4] = 0;
mvp[5] = -1.0f / py;
mvp[6] = 0;
mvp[7] = 0;
mvp[8] = 0;
mvp[9] = 0;
mvp[10] = m10;
mvp[11] = -1.0f;
mvp[12] = 0;
mvp[13] = 0;
mvp[14] = zNear * m10;
mvp[15] = 0;
我知道z轴会以某种方式反转,但目前我不知道该如何解决。
要在Y轴上翻转矩阵:
mvp[5] = -mvp[5];
mvp[7] = -mvp[7];
然后,可以在VkPipelineRasterizationStateCreateInfo结构中反转剔除顺序:
// with frontFace field, replace:
createInfo.frontFace = VK_FRONT_FACE_CLOCKWISE;
// by:
createInfo.frontFace = VK_FRONT_FACE_COUNTER_CLOCKWISE;
// OR with cullMode field, replace:
createInfo.cullMode = VK_CULL_MODE_FRONT_BIT;
// by:
createInfo.cullMode = VK_CULL_MODE_BACK_BIT;