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Wish the GPU compiles pipeline "fillTriangle" {
{vec2 p0 vec2 p1 vec2 p2 vec4 color} {
vec2 vertices[4] = vec2[4](p0, p1, p2, p0);
return vertices[gl_VertexIndex];
} {
return color;
}
}
When /someone/ wishes to draw a triangle with /...options/ {
dict with options {
Wish the GPU draws pipeline "fillTriangle" with arguments \
[list $p0 $p1 $p2 [getColor $color]]
}
}
When /someone/ wishes to draw a quad with /...options/ {
dict with options {
if {![info exists layer]} { set layer 0 }
Wish the GPU draws pipeline "fillTriangle" with arguments \
[list $p1 $p2 $p3 [getColor $color]] layer $layer
Wish the GPU draws pipeline "fillTriangle" with arguments \
[list $p0 $p1 $p3 [getColor $color]] layer $layer
}
}
When /someone/ wishes to draw a polygon with /...options/ {
set points [dict get $options points]
set color [dict get $options 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} {
Wish to draw a triangle with \
p0 [lindex $points 0] p1 [lindex $points 1] p2 [lindex $points 2] \
color $color
} elseif {$num_points == 4} {
Wish to draw a quad with \
p0 [lindex $points 0] p1 [lindex $points 1] p2 [lindex $points 2] p3 [lindex $points 3] \
color $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}]]
Wish the GPU draws pipeline "fillTriangle" with arguments \
[list $p0 $p1 $p2 [getColor $color]]
}
}
}
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