Differential D2133 Diff 8390 source/blender/gpu/shaders/gpu_shader_fx_lensdistortion_frag.glsl

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source/blender/gpu/shaders/gpu_shader_fx_lensdistortion_frag.glsl

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				//per eye texture to warp for lens distortion
				uniform sampler2D warpTexture;

				//Position of lens center in m (usually eye_w/2, eye_h/2)
				uniform vec2 LensCenter;
				//Scale from texture co-ords to m (usually eye_w, eye_h)
				uniform vec2 ViewportScale;
				//Distortion overall scale in m (usually ~eye_w/2)
				uniform float WarpScale;
				//Distoriton coefficients (PanoTools model) [a,b,c,d]
				uniform vec4 HmdWarpParam;

				//chromatic distortion post scaling
				uniform vec3 aberr;

				void main()
				{
				//output_loc is the fragment location on screen from [0,1]x[0,1]
				vec2 output_loc = vec2(gl_TexCoord[0].s, gl_TexCoord[0].t);
				//Compute fragment location in lens-centered co-ordinates at world scale
				vec2 r = output_loc * ViewportScale - LensCenter;
				//scale for distortion model
				//distortion model has r=1 being the largest circle inscribed (e.g. eye_w/2)
				r /= WarpScale;

				//\|r\|**2
				float r_mag = length(r);
				//offset for which fragment is sourced
				vec2 r_displaced = r * (HmdWarpParam.w + HmdWarpParam.z * r_mag +
				HmdWarpParam.y * r_mag * r_mag +
				HmdWarpParam.x * r_mag * r_mag * r_mag);
				//back to world scale
				r_displaced *= WarpScale;
				//back to viewport co-ord
				vec2 tc_r = (LensCenter + aberr.r * r_displaced) / ViewportScale;
				vec2 tc_g = (LensCenter + aberr.g * r_displaced) / ViewportScale;
				vec2 tc_b = (LensCenter + aberr.b * r_displaced) / ViewportScale;

				float red = texture2D(warpTexture, tc_r).r;
				float green = texture2D(warpTexture, tc_g).g;
				float blue = texture2D(warpTexture, tc_b).b;
				//Black edges off the texture
				gl_FragColor = ((tc_g.x < 0.0) \|\| (tc_g.x > 1.0) \|\| (tc_g.y < 0.0) \|\| (tc_g.y > 1.0)) ? vec4(0.0, 0.0, 0.0, 1.0) : vec4(red, green, blue, 1.0);
				}