glowscript/shaders/peel_depth_fragmentD2.shader at master · vpython/glowscript

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#version 300 es

# ifdef GL_FRAGMENT_PRECISION_HIGH

precision highp float;

# else

precision mediump float;

# endif

// Construct depth maps for depth peeling handling of opacity

uniform vec2 canvas_size;

uniform sampler2D D0; // TEXTURE3 - opaque depth map (minormode 5)

uniform sampler2D D1; // TEXTURE5 - 1st transparency depth map (minormode 7)

out vec4 output_color;

// minormode = 0 render, 1 pick, 2 autoscale, 4 C0, 5 D0, 6 C1, 7 D1, 8 C2, 9 D2, 10 C3, 11 D3, 12 C4

ivec4 encode(float k) { // assumes k is >= 0

if (k <= 0.0) return ivec4(0, 0, 0, 0);

k = 3.0*128.0*k;

int b1 = int(k);

int b2 = int(256.0*fract(k));

return ivec4(

b1,

b2,

0);

}

int decode(ivec4 d) {

return int(256*d[0] + d[1]);

}

int fdecode(vec4 d) {

return int(255.0*(256.0*d[0] + d[1]));

}

void main(void) {

// create depth map D2 (7)

ivec4 c = encode(1.0 - gl_FragCoord.z);

int z = decode(c);

vec2 loc = vec2(gl_FragCoord.x/canvas_size.x, gl_FragCoord.y/canvas_size.y);

int zmin = fdecode(texture(D0, loc));

int zmax = fdecode(texture(D1, loc));

if (zmin < z && z < zmax) {

output_color = vec4(float(c.r)/255.0, float(c.g)/255.0, 0, 0);

} else {

discard;

}