#version 150

uniform mat4 modelViewProjectionMatrix;
uniform float gridSize;
uniform vec2 resolution;
uniform vec2 threshold;
uniform sampler2DRect tex1;
uniform float depth_mult;

in vec2 texcoord;
in vec4 position;


out vec2 tex_c;

void main()
{
    tex_c = texcoord;

    //float depth = pow(texture(tex1, tex_c).r, 2);

    vec2 depthCoord = texcoord * vec2(1920.0/2.0, 1080.0);
    float depth = texture(tex1, depthCoord).r;

    // Apply a contrast adjustment only to the range [0.5, 1.0]
    // if (depth > 0.4) {
    //     // Shift the range to [0, 1] and apply pow() for more contrast, then shift it back
    //     depth = pow((depth - 0.4) / (1.0 - 0.4), 4.0) * (1.0 - 0.4) + 0.4;
    // }

    // Normalize the depth value between 0 and 1 based on min/max
    float normalizedDepth = (depth);

    vec4 displaced = position;

    displaced.z = normalizedDepth * depth_mult;

    // Transform the vertex position to clip space
    vec4 clipPos = modelViewProjectionMatrix * displaced;
    
    // Perform perspective division
    vec3 ndcPos = clipPos.xyz / clipPos.w;
    
    // Convert to screen space
    vec2 screenPos = (ndcPos.xy + 1.0) * 0.5 * resolution;
    
    // Snap to grid
    screenPos = floor(screenPos / gridSize) * gridSize;
    
    // Convert back to NDC space
    ndcPos.xy = (screenPos / resolution) * 2.0 - 1.0;
    
    // Reconstruct the clip space position
    clipPos = vec4(ndcPos * clipPos.w, clipPos.w);
    
    gl_Position = clipPos;
}