我在Python和C中使用OpenCV完成了图像变形,看到可口可乐标志在我选择的角落里扭曲了：

使用以下图像：

还有这个：

我需要做到这一点,但在OpenGL中.我会：

>角落里面我要映射扭曲的图像

>单应矩阵,用于映射徽标图像的变换

进入最终图像内部的徽标图像(使用OpenCV

warpPerspective),像这样：

[[ 2.59952324e+00, 3.33170976e-01, -2.17014066e+02],

[ 8.64133587e-01, 1.82580111e+00, -3.20053715e+02],

[ 2.78910149e-03, 4.47911310e-05, 1.00000000e+00]]

>主图像(此处为跑道图像)

>叠加图像(可口可乐图像在这里)

可能吗 ？我已经阅读了很多并开始了OpenGL基础知识教程,但它可以从我拥有的内容中完成吗？ OpenGL实现会更快,比如大约10ms左右吗？

解决方法:

在尝试了这里和其他地方提出的一些解决方案之后,我通过编写一个复制“warpPerspective”的片段着色器来解决这个问题.

片段着色器代码类似于：

varying highp vec2 textureCoordinate;

uniform sampler2D inputImageTexture;

// NOTE: you will need to pass the INVERSE of the homography matrix, as well as

// the width and height of your image as uniforms!

uniform highp mat3 inverseHomographyMatrix;

uniform highp float width;

uniform highp float height;

void main()

{

// Texture coordinates will run [0,1],[0,1];

// Convert to "real world" coordinates

highp vec3 frameCoordinate = vec3(textureCoordinate.x * width, textureCoordinate.y * height, 1.0);

// Determine what 'z' is

highp vec3 m = inverseHomographyMatrix[2] * frameCoordinate;

highp float zed = 1.0 / (m.x + m.y + m.z);

frameCoordinate = frameCoordinate * zed;

// Determine translated x and y coordinates

highp float xTrans = inverseHomographyMatrix[0][0] * frameCoordinate.x + inverseHomographyMatrix[0][1] * frameCoordinate.y + inverseHomographyMatrix[0][2] * frameCoordinate.z;

highp float yTrans = inverseHomographyMatrix[1][0] * frameCoordinate.x + inverseHomographyMatrix[1][1] * frameCoordinate.y + inverseHomographyMatrix[1][2] * frameCoordinate.z;

// Normalize back to [0,1],[0,1] space

highp vec2 coords = vec2(xTrans / width, yTrans / height);

// Sample the texture if we're mapping within the image, otherwise set color to black

if (coords.x >= 0.0 && coords.x <= 1.0 && coords.y >= 0.0 && coords.y <= 1.0) {

gl_FragColor = texture2D(inputImageTexture, coords);

} else {

gl_FragColor = vec4(0.0,0.0,0.0,0.0);

}

}

请注意,我们在这里传递的单应矩阵是逆向自然矩阵！你必须反转你将传递给’warpPerspective’的单应矩阵 – 否则这段代码将无效.

顶点着色器除了通过坐标外什么都不做：

// Vertex shader

attribute vec4 position;

attribute vec4 inputTextureCoordinate;

varying vec2 textureCoordinate;

void main() {

// Nothing happens in the vertex shader

textureCoordinate = inputTextureCoordinate.xy;

gl_Position = position;

}

传入未改变的纹理坐标和位置坐标(即textureCoordinates = [(0,0),(0,1),(1,0),(1,1)]和positionCoordinates = [(-1,-1),( -1,1),(1,-1),(1,1)],对于三角形条),这应该工作！

标签：c-2,android,opencv,opengl-es,homography

来源： https://codeday.me/bug/20190702/1357650.html