Draw 3d brush cursor procedurally

base/shaders/cursor.frag.glsl

@@ -1,15 +1,15 @@
 #version 450
 
 uniform vec3 tint;
-#ifdef SPIRV
-uniform sampler2D gbufferD; // vulkan unit align
-#endif
-uniform sampler2D tex;
 
 in vec2 tex_coord;
 out vec4 frag_color;
 
 void main() {
-	vec4 col = texture(tex, tex_coord);
-	frag_color = vec4((col.rgb / col.a) * tint, col.a);
+	float radius = 0.45;
+	float thickness = 0.03;
+	float dist = distance(tex_coord, vec2(0.5, 0.5));
+	float ring = smoothstep(radius - thickness, radius, dist) -
+				 smoothstep(radius, radius + thickness, dist);
+	frag_color = vec4(tint, min(ring, 0.6));
 }

base/shaders/cursor.vert.glsl

@@ -7,10 +7,6 @@ uniform vec2 tex_step;
 uniform float radius;
 uniform vec3 camera_right;
 uniform sampler2D gbufferD;
-#ifdef HLSL
-// direct3d12 unit align
-uniform sampler2D texa;
-#endif
 
 #ifdef HLSL
 in vec4 pos;
@@ -21,8 +17,7 @@ out vec2 tex_coord;
 
 vec3 get_pos(vec2 uv) {
 #ifdef HLSL
-	float keep = textureLod(texa, vec2(0.0, 0.0), 0.0).r; // direct3d12 unit align
-	float keep2 = pos.x + nor.x;
+	float keep = pos.x + nor.x;
 #endif
 
 #ifdef GLSL