oculus1: sdr.glsl annotate

oculus1

annotate sdr.glsl @ 13:464e1d135d68

hurraaaay!

author	John Tsiombikas <nuclear@member.fsf.org>
date	Sat, 21 Sep 2013 03:00:47 +0300
parents
children	cceffea995a4

rev	line source
nuclear@13	1 uniform sampler2D tex;
nuclear@13	2 uniform float aspect, scale;
nuclear@13	3 uniform float lens_center_offset;
nuclear@13	4 uniform vec4 dist_factors;
nuclear@13	5
nuclear@13	6 vec2 distort_texcoords(in vec2 tc, out float dbgrad);
nuclear@13	7 float barrel_scale(float x, in vec4 k);
nuclear@13	8
nuclear@13	9 void main()
nuclear@13	10 {
nuclear@13	11 float dbgrad;
nuclear@13	12 vec2 tc = distort_texcoords(gl_TexCoord[0].xy, dbgrad);
nuclear@13	13
nuclear@13	14 gl_FragColor.rgb = texture2D(tex, tc).rgb;
nuclear@13	15 gl_FragColor.rgb += mix(vec3(1.0, 1.0, 0.0), vec3(0.0), smoothstep(0.01, 0.05, dbgrad));
nuclear@13	16 gl_FragColor.a = 1.0;
nuclear@13	17 }
nuclear@13	18
nuclear@13	19 vec2 distort_texcoords(in vec2 tc, out float dbgrad)
nuclear@13	20 {
nuclear@13	21 // map tc [0, 1] -> [-1, 1]
nuclear@13	22 vec2 pt = tc * 2.0 - 1.0;
nuclear@13	23
nuclear@13	24 pt.x += lens_center_offset * 2.0;
nuclear@13	25 pt.y /= aspect; // correct for aspect ratio
nuclear@13	26
nuclear@13	27 float rad = barrel_scale(dot(pt, pt), dist_factors);
nuclear@13	28 pt *= rad; // scale the point by the computer distortion radius
nuclear@13	29
nuclear@13	30 dbgrad = length(pt) * rad;
nuclear@13	31
nuclear@13	32 pt.y *= aspect;
nuclear@13	33 pt.x -= lens_center_offset * 2.0;
nuclear@13	34
nuclear@13	35 // map back to range [0, 1]
nuclear@13	36 return pt * 0.5 + 0.5;
nuclear@13	37 }
nuclear@13	38
nuclear@13	39 float barrel_scale(float rad, in vec4 k)
nuclear@13	40 {
nuclear@13	41 float radsq = rad * rad;
nuclear@13	42 float radquad = radsq * radsq;
nuclear@13	43 return k.x + k.y * radsq + k.z * radquad + k.w * radquad * radsq;
nuclear@13	44 }