103 lines
2.7 KiB
GLSL
103 lines
2.7 KiB
GLSL
#version 450 core
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//macros
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#extension GL_ARB_explicit_uniform_location : enable
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//output
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out vec4 fragColor;
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//input
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in vec3 FragPos;
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in vec3 Normal;
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in vec2 TexCoord;
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in vec4 projCoord;
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in vec4 modelCoord;
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//uniforms
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uniform float time;
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uniform mat4 model;
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uniform vec3 viewPos;
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const float CONTACT_TEST_MARGIN = -0.001;
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/*
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Main method
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*/
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void main(){
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float timeS = time * 0.01;
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// Normalized pixel coordinates (from 0 to 1)
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vec3 projCoordNorm = projCoord.xyz / projCoord.w / 2.0 + 0.5;
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//make vec2
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vec2 finalProd = projCoordNorm.xy;
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//get vector that describes the movement through the cube
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vec3 viewDir = normalize(viewPos - FragPos);
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//need to transform to model space
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//get inverse of model transform
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mat4 inverseModel = inverse(model);
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//apply to view dir
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vec4 modelViewDir = normalize(inverseModel * vec4(viewDir,1.0));
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//where the vector first hits the cube
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vec4 contactPoint = modelCoord;
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float red = 1.0;
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float green = 1.0;
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float blue = 1.0;
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red = modelViewDir.x;
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green = modelViewDir.y;
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blue = modelViewDir.z;
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//need to calculate exit point
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//if we hit one of the X edges
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vec4 backPoint = vec4(1.0);
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if(abs(contactPoint.x)-1.0>CONTACT_TEST_MARGIN){
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red = 1.0;
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//discard if backface
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if(sign(contactPoint.x)!=sign(modelViewDir.x)){
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discard;
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}
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//calculate distance to nearest face
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float distX = 2.0;
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//this is some really weird logic that I believe works to calculate distance to nearest face
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float distY = abs(sign(modelViewDir.y) - contactPoint.y);
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float distZ = abs(sign(modelViewDir.z) - contactPoint.z);
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//calculate number of times to add viewDir to get dist
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float scaleX = distX / modelViewDir.x;
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float scaleY = distY / modelViewDir.y;
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float scaleZ = distZ / modelViewDir.z;
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//this is the smallest distance of all of them
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float minScale = min(scaleX,min(scaleY,scaleZ));
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backPoint = contactPoint + (modelViewDir * minScale);
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float dist = length(abs(vec3(contactPoint) - vec3(backPoint)))/1.0;
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red = green = blue = dist;
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} else if(abs(contactPoint.y)-1.0>CONTACT_TEST_MARGIN){
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green = 1.0;
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//discard if backface
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if(sign(contactPoint.y)!=sign(modelViewDir.y)){
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discard;
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}
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} else if(abs(contactPoint.z)-1.0>CONTACT_TEST_MARGIN){
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blue = 1.0;
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//discard if backface
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if(sign(contactPoint.z)!=sign(modelViewDir.z)){
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discard;
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}
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}
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vec4 color = vec4(
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red,
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green,
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blue,
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0.3
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);
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fragColor = color;
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}
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