Differential D2889 Diff 10411 source/blender/draw/engines/gpencil/shaders/gpencil_swirl_frag.glsl

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source/blender/draw/engines/gpencil/shaders/gpencil_swirl_frag.glsl

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				uniform mat4 ProjectionMatrix;
				uniform mat4 ViewMatrix;

				uniform sampler2D strokeColor;
				uniform sampler2D strokeDepth;

				uniform vec2 Viewport;
				uniform vec3 loc;
				uniform float radius;
				uniform float angle;
				uniform int transparent;

				uniform float pixsize; /* rv3d->pixsize */
				uniform float pixelsize; /* U.pixelsize */
				uniform float pixfactor;

				out vec4 FragColor;

				float defaultpixsize = pixsize * pixelsize * (1000.0 / pixfactor);

				/* project 3d point to 2d on screen space */
				vec2 toScreenSpace(vec4 vertex)
				{
				/* need to calculate ndc because this is not done by vertex shader */
				vec3 ndc = vec3(vertex).xyz / vertex.w;

				vec2 sc;
				sc.x = ((ndc.x + 1.0) / 2.0) * Viewport.x;
				sc.y = ((ndc.y + 1.0) / 2.0) * Viewport.y;

				return sc;
				}

				/* This swirl shader is a modified version of original Geeks3d.com code */
				void main()
				{
				vec2 uv = vec2(gl_FragCoord.xy);
				float stroke_depth;
				vec4 outcolor;

				vec4 center3d = ProjectionMatrix * ViewMatrix * vec4(loc.xyz, 1.0);
				vec2 center = toScreenSpace(center3d);
				vec2 tc = uv - center;

				float dist = length(tc);
				float pxradius = (ProjectionMatrix[3][3] == 0.0) ? (radius / (loc.z * defaultpixsize)) : (radius / defaultpixsize);
				pxradius = max(pxradius, 1);

				if (dist <= pxradius) {
				float percent = (pxradius - dist) / pxradius;
				float theta = percent * percent * angle * 8.0;
				float s = sin(theta);
				float c = cos(theta);
				tc = vec2(dot(tc, vec2(c, -s)), dot(tc, vec2(s, c)));
				tc += center;

				stroke_depth = texelFetch(strokeDepth, ivec2(tc), 0).r;
				outcolor = texelFetch(strokeColor, ivec2(tc), 0);
				}
				else {
				if (transparent == 1) {
				discard;
				}
				stroke_depth = texelFetch(strokeDepth, ivec2(uv), 0).r;
				outcolor = texelFetch(strokeColor, ivec2(uv), 0);
				}

				gl_FragDepth = stroke_depth;
				FragColor = outcolor;
				}