gg: filled arcs and circles

vlib/gg/gg.v

@@ -219,7 +219,15 @@ pub fn (ctx &GG) draw_rect(x, y, w, h f32, c gx.Color) {
 	ctx.draw_rect2(x, y, w, h, c)
 }
 
-pub fn (ctx &GG) draw_circle(x, y, radius int, c gx.Color) {
+// Useful for debugging meshes.
+pub fn set_mode_wireframe() {
+	C.glPolygonMode(C.GL_FRONT_AND_BACK, C.GL_LINE)
+}
+pub fn set_mode_point() {
+	C.glPolygonMode(C.GL_FRONT_AND_BACK, C.GL_POINT)
+}
+pub fn set_mode_fill() {
+	C.glPolygonMode(C.GL_FRONT_AND_BACK, C.GL_FILL)
 }
 
 /*
@@ -441,6 +449,38 @@ pub fn (ctx &GG) draw_arc(x, y, r, start_angle, end_angle f32, segments int, col
 	gl.draw_arrays(C.GL_LINE_STRIP, 0, segments + 1)
 }
 
+pub fn (ctx &GG) draw_filled_arc(x, y, r, start_angle, end_angle f32, segments int, color gx.Color) {
+	ctx.shader.set_int('has_texture', 0)
+	C.glDeleteBuffers(1, &ctx.vao)
+	C.glDeleteBuffers(1, &ctx.vbo)
+	ctx.shader.use()
+	ctx.shader.set_color('color', color)
+	start_rads := start_angle * 0.0174533 // deg -> rad approx
+	end_rads := end_angle * 0.0174533
+	rad_increment := end_rads / segments
+	mut vertices := []f32
+	mut i := 1
+	vertices << [x, y]
+	vertices << [x + f32(math.cos(start_angle)) * r, y + f32(math.sin(start_angle)) * r]
+	for i < segments {
+		theta := f32(i) * rad_increment
+		vertices << [x + f32(math.cos(theta)) * r, y + f32(math.sin(theta)) * r]
+		i++
+	}
+	// Add the last vertex at the final arc angle.
+	vertices << [x + f32(math.cos(end_rads)) * r, y + f32(math.sin(end_rads)) * r]
+	gl.bind_vao(ctx.vao)
+	gl.set_vbo(ctx.vbo, vertices, C.GL_STATIC_DRAW)
+	gl.vertex_attrib_pointer(0, 2, C.GL_FLOAT, false, 2, 0)
+	gl.enable_vertex_attrib_array(0)
+	gl.bind_vao(ctx.vao)
+	gl.draw_arrays(C.GL_TRIANGLE_FAN, 0, segments + 2)
+}
+
+pub fn (ctx &GG) draw_circle(x, y, r f32, color gx.Color) {
+	ctx.draw_filled_arc(x, y, r, 0, 360, 32 + int(r / 2), color)
+}
+
 /*
 pub fn (c &GG) draw_gray_line(x, y, x2, y2 f32) {
 	c.draw_line(x, y, x2, y2, gx.Gray)