GPencil: Invert Texture for Line Strokes

Invert the texture of the stroke if the random UV is activated. Before, this parameter only affected to dot mode, but not to line strokes.

The texture is inverted vertically.

1 files changed, 17 insertions, 4 deletions

diff --git a/source/blender/draw/engines/gpencil/shaders/gpencil_stroke_geom.glsl b/source/blender/draw/engines/gpencil/shaders/gpencil_stroke_geom.glsl
index a3780a3dd4f..22096535289 100644
--- a/source/blender/draw/engines/gpencil/shaders/gpencil_stroke_geom.glsl
+++ b/source/blender/draw/engines/gpencil/shaders/gpencil_stroke_geom.glsl
@@ -182,24 +182,37 @@ void main(void)
 		EmitVertex();
 	}
 
+	float y_a = 0.0;
+	float y_b = 1.0;
+
+	/* invert uv (vertical) */
+	if (finaluvdata[2].x > 1.0) {
+		if ((finaluvdata[1].y != 0.0) && (finaluvdata[2].y != 0.0)) {
+			float d = ceil(finaluvdata[2].x) - 1.0;
+			if (floor(d / 2.0) == (d / 2.0)) {
+				y_a = 1.0;
+				y_b = 0.0;
+			}
+		}
+	}	
 	/* generate the triangle strip */
 	uvfac = vec2(0.0, 0.0);
-	mTexCoord = (color_type == GPENCIL_COLOR_SOLID) ? vec2(0, 0) : vec2(finaluvdata[1].x, 0);
+	mTexCoord = (color_type == GPENCIL_COLOR_SOLID) ? vec2(0, 0) : vec2(finaluvdata[1].x, y_a);
 	mColor = finalColor[1];
 	gl_Position = vec4((sp1 + length_a * miter_a) / Viewport, getZdepth(P1), 1.0);
 	EmitVertex();
 
-	mTexCoord = (color_type == GPENCIL_COLOR_SOLID) ? vec2(0, 1) : vec2(finaluvdata[1].x, 1);
+	mTexCoord = (color_type == GPENCIL_COLOR_SOLID) ? vec2(0, 1) : vec2(finaluvdata[1].x, y_b);
 	mColor = finalColor[1];
 	gl_Position = vec4((sp1 - length_a * miter_a) / Viewport, getZdepth(P1), 1.0);
 	EmitVertex();
 
-	mTexCoord = (color_type == GPENCIL_COLOR_SOLID) ? vec2(1, 0) : vec2(finaluvdata[2].x, 0);
+	mTexCoord = (color_type == GPENCIL_COLOR_SOLID) ? vec2(1, 0) : vec2(finaluvdata[2].x, y_a);
 	mColor = finalColor[2];
 	gl_Position = vec4((sp2 + length_b * miter_b) / Viewport, getZdepth(P2), 1.0);
 	EmitVertex();
 
-	mTexCoord = (color_type == GPENCIL_COLOR_SOLID) ? vec2(1, 1) : vec2(finaluvdata[2].x, 1);
+	mTexCoord = (color_type == GPENCIL_COLOR_SOLID) ? vec2(1, 1) : vec2(finaluvdata[2].x, y_b);
 	mColor = finalColor[2];
 	gl_Position = vec4((sp2 - length_b * miter_b) / Viewport, getZdepth(P2), 1.0);
 	EmitVertex();