display: Implement fillTriangle; fillPolygon also seems to work.

1 files changed, 36 insertions, 3 deletions

diff --git a/virtual-programs/display.folk b/virtual-programs/display.folk
index fd30779b..fe0d883f 100644
--- a/virtual-programs/display.folk
+++ b/virtual-programs/display.folk
@@ -265,9 +265,42 @@ On process {
             }
         }
 
-        proc fillTriangle {args} {}
-        proc fillQuad {args} {}
-        proc fillPolygon {args} {}
+        variable fillTriangle [Gpu::pipeline {vec2 p0 vec2 p1 vec2 p2 vec4 color} {
+            vec2 vertices[4] = vec2[4](p0, p1, p2, p2);
+            return vertices[gl_VertexIndex];
+        } {
+            return color;
+        }]
+        proc fillTriangle {p0 p1 p2 color} {
+            variable fillTriangle
+            Gpu::draw $fillTriangle $p0 $p1 $p2 [getColor $color]
+        }
+        
+        proc fillQuad {p0 p1 p2 p3 color} {
+            fillTriangle $p1 $p2 $p3 $color
+            fillTriangle $p0 $p1 $p3 $color
+        }
+
+        proc fillPolygon {points color} {
+            set num_points [llength $points]
+            if {$num_points < 3} {
+                error "At least 3 points are required to form a polygon."
+            } elseif {$num_points == 3} {
+                eval fillTriangle $points $color
+            } elseif {$num_points == 4} {
+                eval fillQuad $points $color
+            } else {
+                # Get the first point in the list as the "base" point of the triangles
+                set p0 [lindex $points 0]
+
+                for {set i 1} {$i < $num_points - 1} {incr i} {
+                    set p1 [lindex $points $i]
+                    set p2 [lindex $points [expr {$i+1}]]
+                    fillTriangle $p0 $p1 $p2 $color
+                }
+            }
+        }
+
         proc image {x y im radians {scale 1.0}} {}
 
         proc end {} { Gpu::drawEnd; Gpu::poll }