graph development

1 files changed, 37 insertions, 0 deletions

diff --git a/bezier.cpp b/bezier.cpp
index e5f9bf9..42ed04d 100644
--- a/bezier.cpp
+++ b/bezier.cpp
@@ -1,3 +1,39 @@
+static real32 Tau = 0.9; // tension
+
+static real32
+Bezier_SolveYForX(v2 Point_P0, v2 Point_P1, v2 Point_P2, v2 Point_P3, real32 TargetX) {
+
+    real32 Y = 0;
+
+    v2 m1 = (Point_P2 - Point_P0) / (2 * Tau);
+    v2 m2 = (Point_P3 - Point_P1) / (2 * Tau);
+
+    real32 Precision = 0.001;
+    real32 t = (TargetX - Point_P0.x) / (Point_P3.x - Point_P0.x);
+
+    for (;;) {
+        real32 t2 = t * t;
+        real32 t3 = t2 * t;
+        real32 mt = 1-t;
+        real32 mt2 = mt * mt;
+        real32 mt3 = mt2 * mt;
+        v2 Point = (Point_P0 * mt3) + (3 * Point_P1 * mt2 * t) + (3 * Point_P2 * mt * t2) + (Point_P3 * t3);
+
+        bool32 Cond1 = (Point.x <= (TargetX - Precision));
+        bool32 Cond2 = (Point.x >= (TargetX + Precision));
+
+        if (Cond1 || Cond2) {
+            t = t * TargetX / Point.x;
+        } else {
+            Y = Point.y;
+            break;
+        }
+    }
+
+    return Y;
+}
+
+#if 0
 // A modified version of the bezier code in ImGui with extra features for bitmap and path interaction.
 
 // Function to convert a ratio back into a point for the bezier handles.
@@ -307,3 +343,4 @@ void Mask_TriangulateAndRasterize(memory *Memory, project_layer *Layer, mask *Ma
 
     GL_RasterizeShape(Layer, Mask);
 }
+#endif