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.

1 files changed, 70 insertions, 0 deletions

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);
+}