New Grease Pencil object for 2D animation

This commit merge the full development done in greasepencil-object branch and include mainly the following features.

- New grease pencil object.
- New drawing engine.
- New grease pencil modes Draw/Sculpt/Edit and Weight Paint.
- New brushes for grease pencil.
- New modifiers for grease pencil.
- New shaders FX.
- New material system (replace old palettes and colors).
- Split of annotations (old grease pencil) and new grease pencil object.
- UI adapted to blender 2.8.

You can get more info here:

https://code.blender.org/2017/12/drawing-2d-animation-in-blender-2-8/
https://code.blender.org/2018/07/grease-pencil-status-update/

This is the result of nearly two years of development and I want thanks firstly the other members of the grease pencil team: Daniel M. Lara, Matias Mendiola and Joshua Leung for their support, ideas and to keep working in the project all the time, without them this project had been impossible.

Also, I want thanks other Blender developers for their help, advices and to be there always to help me, and specially to Clément Foucault, Dalai Felinto, Pablo Vázquez and Campbell Barton.

9 files changed, 578 insertions, 0 deletions

diff --git a/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_blur_frag.glsl b/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_blur_frag.glsl
new file mode 100644
index 00000000000..1d66ba3d4d4
--- /dev/null
+++ b/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_blur_frag.glsl
@@ -0,0 +1,60 @@
+uniform mat4 ProjectionMatrix;
+uniform mat4 ViewMatrix;
+
+uniform sampler2D strokeColor;
+uniform sampler2D strokeDepth;
+
+uniform int blur[2];
+
+uniform vec3 loc;
+uniform float pixsize;   /* rv3d->pixsize */
+uniform float pixelsize; /* U.pixelsize */
+uniform float pixfactor;
+
+float defaultpixsize = pixsize * pixelsize * (1000.0 / pixfactor);
+vec2 noffset = vec2(blur[0], blur[1]);
+
+out vec4 FragColor;
+
+void main()
+{
+	ivec2 uv = ivec2(gl_FragCoord.xy);
+
+	vec4 nloc = ProjectionMatrix * ViewMatrix * vec4(loc.xyz, 1.0);
+	
+	float dx = (ProjectionMatrix[3][3] == 0.0) ? (noffset[0] / (nloc.z * defaultpixsize)) : (noffset[0] / defaultpixsize);
+	float dy = (ProjectionMatrix[3][3] == 0.0) ? (noffset[1] / (nloc.z * defaultpixsize)) : (noffset[1] / defaultpixsize);
+	
+	/* apply blurring, using a 9-tap filter with predefined gaussian weights */
+	/* depth */
+	float outdepth = 0;
+    outdepth += texelFetch(strokeDepth, ivec2(uv.x - 1.0 * dx, uv.y + 1.0 * dy), 0).r * 0.0947416;
+    outdepth += texelFetch(strokeDepth, ivec2(uv.x - 0.0 * dx, uv.y + 1.0 * dy), 0).r * 0.118318;
+    outdepth += texelFetch(strokeDepth, ivec2(uv.x + 1.0 * dx, uv.y + 1.0 * dy), 0).r * 0.0947416;
+    outdepth += texelFetch(strokeDepth, ivec2(uv.x - 1.0 * dx, uv.y + 0.0 * dy), 0).r * 0.118318;
+
+    outdepth += texelFetch(strokeDepth, ivec2(uv.x, uv.y), 0).r * 0.147761;
+
+    outdepth += texelFetch(strokeDepth, ivec2(uv.x + 1.0 * dx, uv.y + 0.0 * dy), 0).r * 0.118318;
+    outdepth += texelFetch(strokeDepth, ivec2(uv.x - 1.0 * dx, uv.y - 1.0 * dy), 0).r * 0.0947416;
+    outdepth += texelFetch(strokeDepth, ivec2(uv.x + 0.0 * dx, uv.y - 1.0 * dy), 0).r * 0.118318;
+    outdepth += texelFetch(strokeDepth, ivec2(uv.x + 1.0 * dx, uv.y - 1.0 * dy), 0).r * 0.0947416;
+
+	gl_FragDepth = outdepth;
+
+	/* color */	
+	vec4 outcolor = vec4(0.0);
+    outcolor += texelFetch(strokeColor, ivec2(uv.x - 1.0 * dx, uv.y + 1.0 * dy), 0) * 0.0947416;
+    outcolor += texelFetch(strokeColor, ivec2(uv.x - 0.0 * dx, uv.y + 1.0 * dy), 0) * 0.118318;
+    outcolor += texelFetch(strokeColor, ivec2(uv.x + 1.0 * dx, uv.y + 1.0 * dy), 0) * 0.0947416;
+    outcolor += texelFetch(strokeColor, ivec2(uv.x - 1.0 * dx, uv.y + 0.0 * dy), 0) * 0.118318;
+
+    outcolor += texelFetch(strokeColor, ivec2(uv.x, uv.y), 0) * 0.147761;
+
+    outcolor += texelFetch(strokeColor, ivec2(uv.x + 1.0 * dx, uv.y + 0.0 * dy), 0) * 0.118318;
+    outcolor += texelFetch(strokeColor, ivec2(uv.x - 1.0 * dx, uv.y - 1.0 * dy), 0) * 0.0947416;
+    outcolor += texelFetch(strokeColor, ivec2(uv.x + 0.0 * dx, uv.y - 1.0 * dy), 0) * 0.118318;
+    outcolor += texelFetch(strokeColor, ivec2(uv.x + 1.0 * dx, uv.y - 1.0 * dy), 0) * 0.0947416;
+
+	FragColor = clamp(outcolor, 0, 1.0);
+}
diff --git a/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_colorize_frag.glsl b/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_colorize_frag.glsl
new file mode 100644
index 00000000000..7d0ce4a804e
--- /dev/null
+++ b/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_colorize_frag.glsl
@@ -0,0 +1,86 @@
+uniform sampler2D strokeColor;
+uniform sampler2D strokeDepth;
+
+uniform vec4 low_color;
+uniform vec4 high_color;
+uniform int mode;
+uniform float factor;
+
+out vec4 FragColor;
+
+#define MODE_GRAYSCALE   0
+#define MODE_SEPIA       1
+#define MODE_BITONE      2
+#define MODE_CUSTOM      3
+#define MODE_TRANSPARENT 4
+
+float get_luminance(vec4 color)
+{
+	float lum = (color.r * 0.2126) + (color.g * 0.7152) + (color.b * 0.723);
+	return lum;
+}
+
+void main()
+{
+	ivec2 uv = ivec2(gl_FragCoord.xy);
+
+	float stroke_depth = texelFetch(strokeDepth, uv.xy, 0).r;
+	vec4 src_pixel= texelFetch(strokeColor, uv.xy, 0);
+	float luminance = get_luminance(src_pixel);
+	vec4 outcolor;
+	
+	/* is transparent */ 
+	if (src_pixel.a == 0.0f) {
+		discard;
+	}
+	
+	switch(mode) {
+		case MODE_GRAYSCALE:
+			{
+			outcolor = vec4(luminance, luminance, luminance, src_pixel.a);
+			break;
+			}
+		case MODE_SEPIA:
+			{
+			float Red = (src_pixel.r * 0.393) + (src_pixel.g * 0.769) + (src_pixel.b * 0.189);
+			float Green = (src_pixel.r * 0.349) + (src_pixel.g * 0.686) + (src_pixel.b * 0.168);
+			float Blue = (src_pixel.r * 0.272) + (src_pixel.g * 0.534) + (src_pixel.b * 0.131);
+			outcolor = vec4(Red, Green, Blue, src_pixel.a);
+			break;
+			}
+		case MODE_BITONE:
+			{
+			if (luminance <= factor) {
+				outcolor = low_color;
+			}
+			else {
+				outcolor = high_color;
+			}
+			break;
+			}
+		case MODE_CUSTOM:
+			{
+			/* if below umbral, force custom color */
+			if (luminance <= factor) {
+				outcolor = low_color;
+			}
+			else {
+				outcolor = vec4(luminance * low_color.r, luminance * low_color.b, luminance * low_color.b, src_pixel.a);
+			}
+			break;
+			}
+		case MODE_TRANSPARENT:
+			{
+			outcolor = vec4(src_pixel.rgb, src_pixel.a * factor);
+			break;
+			}
+		default:
+			{
+			outcolor = src_pixel;
+			}
+	
+	}
+
+	gl_FragDepth = stroke_depth;
+	FragColor = outcolor;
+}
diff --git a/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_flip_frag.glsl b/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_flip_frag.glsl
new file mode 100644
index 00000000000..94fb3405c79
--- /dev/null
+++ b/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_flip_frag.glsl
@@ -0,0 +1,37 @@
+out vec4 FragColor;
+
+uniform sampler2D strokeColor;
+uniform sampler2D strokeDepth;
+uniform vec2 wsize;
+uniform int flipmode;
+
+void main()
+{
+	vec2 mode = vec2(0,0);
+	/* horz. */
+	if (flipmode >= 110) {
+		mode[0] = 1;
+	}
+	/* vert. */
+	if ((flipmode == 101) || (flipmode == 111)) {
+		mode[1] = 1;
+	}
+
+	vec2 uv = vec2(gl_FragCoord.xy);
+	float stroke_depth;
+	vec4 outcolor;
+
+	if (mode[0] > 0) {
+		uv.x = wsize.x - uv.x;
+	}
+	if (mode[1] > 0) {
+		uv.y = wsize.y - uv.y;
+	}
+	
+	ivec2 iuv = ivec2(uv.x, uv.y);
+	stroke_depth = texelFetch(strokeDepth, iuv, 0).r;
+	outcolor = texelFetch(strokeColor, iuv, 0);
+
+	gl_FragDepth = stroke_depth;
+	FragColor = outcolor;
+}
diff --git a/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_light_frag.glsl b/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_light_frag.glsl
new file mode 100644
index 00000000000..f3026c32fc8
--- /dev/null
+++ b/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_light_frag.glsl
@@ -0,0 +1,70 @@
+uniform mat4 ProjectionMatrix;
+uniform mat4 ViewMatrix;
+
+uniform sampler2D strokeColor;
+uniform sampler2D strokeDepth;
+uniform vec2 Viewport;
+uniform vec4 loc;
+uniform float energy;
+uniform float ambient;
+
+uniform float pixsize;   /* rv3d->pixsize */
+uniform float pixelsize; /* U.pixelsize */
+uniform float pixfactor;
+
+out vec4 FragColor;
+
+float defaultpixsize = pixsize * pixelsize * (1000.0 / pixfactor);
+
+#define height   loc.w
+
+/* 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;
+}
+
+void main()
+{
+	float stroke_depth;
+	vec4 objcolor;
+	
+	vec4 light_loc = ProjectionMatrix * ViewMatrix * vec4(loc.xyz, 1.0); 
+	vec2 light2d = toScreenSpace(light_loc);
+
+	/* calc pixel scale */
+	float pxscale = (ProjectionMatrix[3][3] == 0.0) ? (10.0 / (light_loc.z * defaultpixsize)) : (10.0 / defaultpixsize);
+	pxscale = max(pxscale, 0.000001);
+
+	/* the height over plane is received in the w component of the loc 
+	 * and needs a factor to adapt to pixels
+	 */
+	float peak = height * 10.0 * pxscale;
+	vec3 light3d = vec3(light2d.x, light2d.y, peak); 
+	
+	vec2 uv = vec2(gl_FragCoord.xy);
+	vec3 frag_loc = vec3(uv.x, uv.y, 0);
+	vec3 norm = vec3(0, 0, 1.0); /* always z-up */
+
+	ivec2 iuv = ivec2(uv.x, uv.y);
+	stroke_depth = texelFetch(strokeDepth, iuv, 0).r;
+	objcolor = texelFetch(strokeColor, iuv, 0);
+	
+	/* diffuse light */
+	vec3 lightdir = normalize(light3d - frag_loc);
+	float diff = max(dot(norm, lightdir), 0.0);
+	float dist  = length(light3d - frag_loc) / pxscale;
+	float factor = diff * ((energy * 100.0) / (dist * dist));	
+	
+    vec3 result = factor * max(ambient, 0.1) * vec3(objcolor);
+	
+	gl_FragDepth = stroke_depth;
+	FragColor = vec4(result.r, result.g, result.b, objcolor.a);
+}
diff --git a/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_pixel_frag.glsl b/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_pixel_frag.glsl
new file mode 100644
index 00000000000..d1a57a9a1b6
--- /dev/null
+++ b/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_pixel_frag.glsl
@@ -0,0 +1,50 @@
+uniform mat4 ProjectionMatrix;
+uniform mat4 ViewMatrix;
+
+uniform sampler2D strokeColor;
+uniform sampler2D strokeDepth;
+
+uniform int size[3];
+uniform vec4 color;
+
+uniform vec3 loc;
+uniform float pixsize;   /* rv3d->pixsize */
+uniform float pixelsize; /* U.pixelsize */
+uniform float pixfactor;
+
+out vec4 FragColor;
+
+int uselines = size[2];
+float defaultpixsize = pixsize * pixelsize * (1000.0 / pixfactor);
+vec2 nsize = max(vec2(size[0], size[1]), 3.0);
+
+/* This pixelation shader is a modified version of original Geeks3d.com code */
+void main()
+{
+	vec2 uv = vec2(gl_FragCoord.xy);
+	vec4 nloc = ProjectionMatrix * ViewMatrix * vec4(loc.xyz, 1.0);
+	
+	float dx = (ProjectionMatrix[3][3] == 0.0) ? (nsize[0] / (nloc.z * defaultpixsize)) : (nsize[0] / defaultpixsize);
+	float dy = (ProjectionMatrix[3][3] == 0.0) ? (nsize[1] / (nloc.z * defaultpixsize)) : (nsize[1] / defaultpixsize);
+
+	dx = max(abs(dx), 3.0);
+	dy = max(abs(dy), 3.0);
+	
+	vec2 coord = vec2(dx * floor(uv.x / dx), dy * floor(uv.y / dy));
+	
+	float stroke_depth = texelFetch(strokeDepth, ivec2(coord), 0).r;
+	vec4 outcolor = texelFetch(strokeColor, ivec2(coord), 0);
+
+	if (uselines == 1) {
+		float difx = uv.x - (floor(uv.x / nsize[0]) * nsize[0]);
+		if ((difx == 0.5) && (outcolor.a > 0)) {
+			outcolor = color;
+		}
+		float dify = uv.y - (floor(uv.y / nsize[1]) * nsize[1]);
+		if ((dify == 0.5) && (outcolor.a > 0)) {
+			outcolor = color;
+		}
+	}
+	gl_FragDepth = stroke_depth;
+	FragColor = outcolor;
+}
diff --git a/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_rim_prepare_frag.glsl b/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_rim_prepare_frag.glsl
new file mode 100644
index 00000000000..fe35d3832e1
--- /dev/null
+++ b/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_rim_prepare_frag.glsl
@@ -0,0 +1,64 @@
+uniform mat4 ProjectionMatrix;
+uniform mat4 ViewMatrix;
+
+/* ******************************************************************* */
+/* create rim and mask                                                 */
+/* ******************************************************************* */
+uniform sampler2D strokeColor;
+uniform sampler2D strokeDepth;
+uniform vec2 Viewport;
+
+uniform int offset[2];
+uniform vec3 rim_color;
+uniform vec3 mask_color;
+
+uniform vec3 loc;
+uniform float pixsize;   /* rv3d->pixsize */
+uniform float pixelsize; /* U.pixelsize */
+uniform float pixfactor;
+
+float defaultpixsize = pixsize * pixelsize * (1000.0 / pixfactor);
+vec2 noffset = vec2(offset[0], offset[1]);
+
+out vec4 FragColor;
+
+void main()
+{
+	vec2 uv = vec2(gl_FragCoord.xy);
+	vec4 nloc = ProjectionMatrix * ViewMatrix * vec4(loc.xyz, 1.0);
+	
+	float dx = (ProjectionMatrix[3][3] == 0.0) ? (noffset[0] / (nloc.z * defaultpixsize)) : (noffset[0] / defaultpixsize);
+	float dy = (ProjectionMatrix[3][3] == 0.0) ? (noffset[1] / (nloc.z * defaultpixsize)) : (noffset[1] / defaultpixsize);
+
+	float stroke_depth = texelFetch(strokeDepth, ivec2(uv.xy), 0).r;
+	vec4 src_pixel= texelFetch(strokeColor, ivec2(uv.xy), 0);
+	vec4 offset_pixel= texelFetch(strokeColor, ivec2(uv.x - dx, uv.y - dy), 0);
+	vec4 outcolor;
+
+	/* is transparent */ 
+	if (src_pixel.a == 0.0f) {
+		discard;
+	}
+	/* check inside viewport */
+	else if ((uv.x - dx < 0) || (uv.x - dx > Viewport[0])) {
+		discard;
+	}
+	else if ((uv.y - dy < 0) || (uv.y - dy > Viewport[1])) {
+		discard;
+	}
+	/* pixel is equal to mask color, keep */
+	else if (src_pixel.rgb == mask_color.rgb) {
+		discard;
+	}
+	else {
+		if ((src_pixel.a > 0) && (offset_pixel.a > 0)) {
+			discard;
+		}
+		else {
+			outcolor = vec4(rim_color, 1.0);
+		}	
+	}
+
+	gl_FragDepth = stroke_depth;
+	FragColor = outcolor;
+}
diff --git a/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_rim_resolve_frag.glsl b/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_rim_resolve_frag.glsl
new file mode 100644
index 00000000000..5e5edbd8325
--- /dev/null
+++ b/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_rim_resolve_frag.glsl
@@ -0,0 +1,101 @@
+/* ******************************************************************* */
+/* Resolve RIM pass and add blur if needed                                 */
+/* ******************************************************************* */
+uniform sampler2D strokeColor;
+uniform sampler2D strokeDepth;
+uniform sampler2D strokeRim;
+
+uniform vec3 mask_color;
+uniform int mode;
+
+out vec4 FragColor;
+
+#define MODE_NORMAL   0
+#define MODE_OVERLAY  1
+#define MODE_ADD      2
+#define MODE_SUB      3
+#define MODE_MULTIPLY 4
+#define MODE_DIVIDE   5
+
+float overlay_color(float a, float b)
+{
+	float rtn; 
+		if (a < 0.5) {
+			rtn = 2.0 * a * b;
+		}
+		else {
+			rtn = 1.0 - 2.0 * (1.0 - a) * (1.0 - b);
+		}
+	
+	return rtn;
+}
+
+vec4 get_blend_color(int mode, vec4 src_color, vec4 mix_color)
+{
+	vec4 outcolor;
+	if (mode == MODE_NORMAL) {
+		outcolor = mix_color;
+	}
+	else if (mode == MODE_OVERLAY) {
+		outcolor.r = overlay_color(src_color.r, mix_color.r);
+		outcolor.g = overlay_color(src_color.g, mix_color.g);
+		outcolor.b = overlay_color(src_color.b, mix_color.b);
+	}
+	else if (mode == MODE_ADD){
+		outcolor = src_color + mix_color;
+	}
+	else if (mode == MODE_SUB){
+		outcolor = src_color - mix_color;
+	}
+	else if (mode == MODE_MULTIPLY)	{
+		outcolor = src_color * mix_color;
+	}
+	else if (mode == MODE_DIVIDE) {
+		outcolor = src_color / mix_color;
+	}
+	else {	
+		outcolor = mix_color;
+	}
+		
+	/* use always the alpha of source color */
+	
+	outcolor.a = src_color.a;
+	/* use alpha to calculate the weight of the mixed color */
+	outcolor = mix(src_color, outcolor, mix_color.a);
+	
+	return outcolor;
+}
+
+void main()
+{
+	ivec2 uv = ivec2(gl_FragCoord.xy);
+
+	float stroke_depth = texelFetch(strokeDepth, uv.xy, 0).r;
+	vec4 src_pixel= texelFetch(strokeColor, uv.xy, 0);
+	vec4 rim_pixel= texelFetch(strokeRim, uv.xy, 0);
+
+	vec4 outcolor = src_pixel;
+	
+	/* is transparent */ 
+	if (src_pixel.a == 0.0f) {
+		discard;
+	}
+	/* pixel is equal to mask color, keep */
+	else if (src_pixel.rgb == mask_color.rgb) {
+		outcolor = src_pixel;
+	}
+	else {
+		if (rim_pixel.a == 0.0f) {
+			outcolor = src_pixel;
+		}
+		else {
+			outcolor = get_blend_color(mode, src_pixel, rim_pixel);
+		}
+	}
+	
+	gl_FragDepth = stroke_depth;
+	FragColor = outcolor;
+}
+
+
+
diff --git a/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_swirl_frag.glsl b/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_swirl_frag.glsl
new file mode 100644
index 00000000000..6ce64350b3d
--- /dev/null
+++ b/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_swirl_frag.glsl
@@ -0,0 +1,70 @@
+uniform mat4 ProjectionMatrix;
+uniform mat4 ViewMatrix;
+
+uniform sampler2D strokeColor;
+uniform sampler2D strokeDepth;
+
+uniform vec2 Viewport;
+uniform vec3 loc;
+uniform int 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;
+}
diff --git a/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_wave_frag.glsl b/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_wave_frag.glsl
new file mode 100644
index 00000000000..882b2cf59f1
--- /dev/null
+++ b/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_wave_frag.glsl
@@ -0,0 +1,40 @@
+
+out vec4 FragColor;
+
+uniform sampler2D strokeColor;
+uniform sampler2D strokeDepth;
+
+uniform float amplitude;
+uniform float period;
+uniform float phase;
+uniform int orientation;
+uniform vec2 wsize;
+
+#define M_PI 3.1415926535897932384626433832795
+
+#define HORIZONTAL 0
+#define VERTICAL 1
+
+void main()
+{
+	vec4 outcolor;
+	ivec2 uv = ivec2(gl_FragCoord.xy);
+	float stroke_depth;
+
+	float value;
+	if (orientation == HORIZONTAL) {
+		float pval = (uv.x * M_PI) / wsize[0];
+		value = amplitude * sin((period * pval) + phase);
+		outcolor = texelFetch(strokeColor, ivec2(uv.x, uv.y + value), 0);
+		stroke_depth = texelFetch(strokeDepth, ivec2(uv.x, uv.y + value), 0).r;
+	}
+	else {
+		float pval = (uv.y * M_PI) / wsize[1];
+		value = amplitude * sin((period * pval) + phase);
+		outcolor = texelFetch(strokeColor, ivec2(uv.x + value, uv.y), 0);
+		stroke_depth = texelFetch(strokeDepth, ivec2(uv.x + value, uv.y), 0).r;
+	}
+
+	FragColor = outcolor;
+	gl_FragDepth = stroke_depth;
+}