1 files changed, 88 insertions, 0 deletions
diff --git a/source/blender/draw/modes/shaders/armature_stick_vert.glsl b/source/blender/draw/modes/shaders/armature_stick_vert.glsl
new file mode 100644
index 00000000000..58fc48e608e
--- /dev/null
+++ b/source/blender/draw/modes/shaders/armature_stick_vert.glsl
@@ -0,0 +1,88 @@
+
+uniform mat4 ProjectionMatrix;
+uniform mat4 ViewProjectionMatrix;
+uniform mat4 ViewMatrix;
+uniform vec2 viewportSize;
+
+/* ---- Instantiated Attribs ---- */
+in vec2 pos; /* bone aligned screen space */
+in uint flag;
+
+#define COL_WIRE 1u /* (1 << 0) */
+#define COL_HEAD 2u /* (1 << 1) */
+#define COL_TAIL 4u /* (1 << 2) */
+#define COL_BONE 8u /* (1 << 3) */
+
+#define POS_HEAD 16u /* (1 << 4) */
+#define POS_TAIL 32u /* (1 << 5) */ /* UNUSED */
+#define POS_BONE 64u /* (1 << 6) */
+
+/* ---- Per instance Attribs ---- */
+in vec3 boneStart;
+in vec3 boneEnd;
+in vec4 wireColor; /* alpha encode if we do wire. If 0.0 we dont. */
+in vec4 boneColor; /* alpha encode if we do bone. If 0.0 we dont. */
+in vec4 headColor; /* alpha encode if we do head. If 0.0 we dont. */
+in vec4 tailColor; /* alpha encode if we do tail. If 0.0 we dont. */
+
+#define do_wire (wireColor.a > 0.0)
+#define is_head bool(flag & POS_HEAD)
+#define is_bone bool(flag & POS_BONE)
+
+noperspective out float colorFac;
+flat out vec4 finalWireColor;
+flat out vec4 finalInnerColor;
+
+uniform float stickSize = 5.0; /* might be dependent on DPI setting in the future. */
+
+/* project to screen space */
+vec2 proj(vec4 pos)
+{
+	return (0.5 * (pos.xy / pos.w) + 0.5) * viewportSize;
+}
+
+void main()
+{
+	finalInnerColor = ((flag & COL_HEAD) != 0u) ? headColor : tailColor;
+	finalInnerColor = ((flag & COL_BONE) != 0u) ? boneColor : finalInnerColor;
+	finalWireColor = (do_wire) ? wireColor : finalInnerColor;
+	/* Make the color */
+	colorFac = ((flag & COL_WIRE) == 0u) ? ((flag & COL_BONE) != 0u) ? 1.0 : 2.0 : 0.0;
+
+	vec4 v0 = ViewMatrix * vec4(boneStart, 1.0);
+	vec4 v1 = ViewMatrix * vec4(boneEnd, 1.0);
+
+	/* Clip the bone to the camera origin plane (not the clip plane)
+	 * to avoid glitches if one end is behind the camera origin (in persp). */
+	float clip_dist = (ProjectionMatrix[3][3] == 0.0) ? -1e-7 : 1e20; /* hardcoded, -1e-8 is giving gliches. */
+	vec3 bvec = v1.xyz - v0.xyz;
+	vec3 clip_pt = v0.xyz + bvec * ((v0.z - clip_dist) / -bvec.z);
+	if (v0.z > clip_dist) {
+		v0.xyz = clip_pt;
+	}
+	else if (v1.z > clip_dist) {
+		v1.xyz = clip_pt;
+	}
+
+	vec4 p0 = ProjectionMatrix * v0;
+	vec4 p1 = ProjectionMatrix * v1;
+
+	float h = (is_head) ? p0.w : p1.w;
+
+	vec2 x_screen_vec = normalize(proj(p1) - proj(p0) + 1e-8);
+	vec2 y_screen_vec = vec2(x_screen_vec.y, -x_screen_vec.x);
+
+	/* 2D screen aligned pos at the point */
+	vec2 vpos = pos.x * x_screen_vec + pos.y * y_screen_vec;
+	vpos *= (ProjectionMatrix[3][3] == 0.0) ? h : 1.0;
+	vpos *= (do_wire) ? 1.0 : 0.5;
+
+	if (finalInnerColor.a > 0.0) {
+		gl_Position = (is_head) ? p0 : p1;
+		gl_Position.xy += stickSize * (vpos / viewportSize);
+		gl_Position.z += (is_bone) ? 0.0 : 1e-6; /* Avoid Z fighting of head/tails. */
+	}
+	else {
+		gl_Position = vec4(0.0);
+	}
+}