OpenGL：从GLSL中的窗口空间坐标计算出眼睛空间坐标？

// input: x_coord, y_coord, samplerDepth
vec2 xy = vec2(x_coord,y_coord); //in [0,1] range
vec4 v_screen = vec4(xy, texture(samplerDepth,xy), 1.0 );
vec4 v_homo = inverse(gl_ProjectionMatrix) * 2.0*(v_screen-vec4(0.5));
vec3 v_eye = v_homo.xyz / v_homo.w; //transfer from homogeneous coordinates

vec4 unProjectedPosition = invertedModelViewProjection * vec4( 
               2.0 * (gl_FragCoord.x - view[0]) / view[2] - 1.0, 
               2.0 * (gl_FragCoord.y - view[1]) / view[3] - 1.0,
               2.0 * gl_FragCoord.z - 1.0,
               1.0);

uniform sampler2D sceneDepth;
uniform mat4 projectionInverse;
uniform vec2 clipPlanes; // zNear, zFar
uniform vec2 windowSize; // window width, height

#define ZNEAR clipPlanes.x
#define ZFAR clipPlanes.y

#define A (ZNEAR + ZFAR)
#define B (ZNEAR - ZFAR)
#define C (2.0 * ZNEAR * ZFAR)
#define D (ndcPos.z * B)
#define ZEYE -(C / (A + D))

void main() 
{
vec3 ndcPos;
ndcPos.xy = gl_FragCoord.xy / windowSize;
ndcPos.z = texture2D (sceneDepth, ndcPos.xy).r; // or gl_FragCoord.z
ndcPos -= 0.5;
ndcPos *= 2.0;
vec4 clipPos;
clipPos.w = -ZEYE;
clipPos.xyz = ndcPos * clipPos.w;
vec4 eyePos = projectionInverse * clipPos;
}

glDepthRange(0, 1)

glm::vec4 vp(left, right, width, height);
glm::mat4 viewportMat = glm::translate(
    vec3(-2.0 * vp.x / vp.z - 1.0, -2.0 * vp.y / vp.w - 1.0, -1.0))
  * glm::scale(glm::vec3(2.0 / vp.z, 2.0 / vp.w, 2.0));
glm::mat4 mvpInv = inverse(mvp);
glm::mat4 vmvpInv = mvpInv * viewportMat;
shader->uniform(\"vmvpInv\", vmvpInv);

vec4 eyePos = vmvpInv * vec4(gl_FragCoord.xyz, 1);
vec3 pos = eyePos.xyz / eyePos.w;

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