From a56ccb7392f9f7d0178c17fcef0bf60a1e7de705 Mon Sep 17 00:00:00 2001
From: Matthew Kosarek <mattkae@protonmail.com>
Date: Tue, 6 Jul 2021 20:24:05 -0400
Subject: (mkosarek) Done enough with SAT collisions for now

---
 2d/_collisions/polygon_polygon.html             |   5 +++++
 2d/_collisions/polygon_polygon.html.content     |   3 +++
 2d/_collisions/polygon_polygon/dist/output.wasm | Bin 57746 -> 58079 bytes
 2d/_collisions/polygon_polygon/main.cpp         |  23 ++++++++++++++++++++++-
 2d/_collisions/polygon_polygon/snippet2.cpp     |   2 ++
 5 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/2d/_collisions/polygon_polygon.html b/2d/_collisions/polygon_polygon.html
index 9826ba4..ace2c17 100644
--- a/2d/_collisions/polygon_polygon.html
+++ b/2d/_collisions/polygon_polygon.html
@@ -312,6 +312,8 @@
 <span class="code_comment">// the collision later.</span>
 ProjectionResult getProjection(Vector2* vertices, <span class="code_keyword">int</span> numVertices, <span class="code_keyword">Vector2</span> axis) {
     ProjectionResult pr;
+    pr.minVertex = vertices[0];
+    pr.maxVertex = vertices[0];
     <span class="code_keyword">float32</span> min = axis.dot(vertices[0]);
     <span class="code_keyword">float32</span> max = min;
 
@@ -404,6 +406,9 @@ IntersectionResult getIntersection(ConvexPolygon* first, ConvexPolygon* second)
 	<h2 id='live_example'>
 	  Live Example of Intersection Detection
 	</h2>
+    <p>
+      A live example of Separating Axis Theorem running with full collision detection. Click <button id='reverse_gravity'>this button</button>to reverse gravity on the simualtion.
+    </p>
     <div class="opengl_canvas_container">
       <canvas id="gl_canvas" width="800" height="600"></canvas>
       <button id="gl_canvas_play" class="play_button">
diff --git a/2d/_collisions/polygon_polygon.html.content b/2d/_collisions/polygon_polygon.html.content
index f2a9253..f2e6bfb 100644
--- a/2d/_collisions/polygon_polygon.html.content
+++ b/2d/_collisions/polygon_polygon.html.content
@@ -186,6 +186,9 @@
 	<h2 id='live_example'>
 	  Live Example of Intersection Detection
 	</h2>
+    <p>
+      A live example of Separating Axis Theorem running with full collision detection. Click <button id='reverse_gravity'>this button</button>to reverse gravity on the simualtion.
+    </p>
     <div class="opengl_canvas_container">
       <canvas id="gl_canvas" width="800" height="600"></canvas>
       <button id="gl_canvas_play" class="play_button">
diff --git a/2d/_collisions/polygon_polygon/dist/output.wasm b/2d/_collisions/polygon_polygon/dist/output.wasm
index f4ef9bb..a047d19 100755
Binary files a/2d/_collisions/polygon_polygon/dist/output.wasm and b/2d/_collisions/polygon_polygon/dist/output.wasm differ
diff --git a/2d/_collisions/polygon_polygon/main.cpp b/2d/_collisions/polygon_polygon/main.cpp
index e85cc25..620edaa 100644
--- a/2d/_collisions/polygon_polygon/main.cpp
+++ b/2d/_collisions/polygon_polygon/main.cpp
@@ -11,6 +11,8 @@
 #include <cmath>
 #include <cfloat>
 
+float32 gravityDirection = -1;
+
 struct Impulse {
     Vector2 force = { 0, 0 };
     float32 timeOfApplicationSeconds = 0.25f;
@@ -52,7 +54,7 @@ struct Rigidbody {
     }
 
     void applyGravity(float32 deltaTimeSeconds) {
-        velocity += (Vector2 { 0.f, -9.8f } * deltaTimeSeconds);
+        velocity += (Vector2 { 0.f, gravityDirection * 100.f } * deltaTimeSeconds);
     }
 
     void update(float32 deltaTimeSeconds) {
@@ -204,6 +206,7 @@ struct ConvexPolygon {
 
 EM_BOOL onPlayClicked(int eventType, const EmscriptenMouseEvent* mouseEvent, void* userData);
 EM_BOOL onStopClicked(int eventType, const EmscriptenMouseEvent* mouseEvent, void* userData);
+EM_BOOL onGravityReversed(int eventType, const EmscriptenMouseEvent* mouseEvent, void* userData);;
 
 void load();
 void update(float32 time, void* userData);
@@ -218,6 +221,7 @@ int main() {
 	context.init("#gl_canvas");
     emscripten_set_click_callback("#gl_canvas_play", NULL, false, onPlayClicked);
     emscripten_set_click_callback("#gl_canvas_stop", NULL, false, onStopClicked);
+    emscripten_set_click_callback("#reverse_gravity", NULL, false, onGravityReversed);
     return 0;
 }
 
@@ -269,12 +273,19 @@ struct SATResult {
 
 struct ProjectionResult {
     Vector2 minVertex;
+    Vector2 minAdjacent1;
+    Vector2 minAdjacent2;
+
     Vector2 maxVertex;
+    Vector2 maxAdjacent1;
+    Vector2 maxAdjacent2;
     Vector2 projection;
 };
 
 ProjectionResult getProjection(Vector2* vertices, int numVertices, Vector2 axis) {
     ProjectionResult pr;
+    pr.minVertex = vertices[0];
+    pr.maxVertex = vertices[0];
 	float32 min = axis.dot(vertices[0]);
 	float32 max = min;
 
@@ -334,6 +345,10 @@ bool runSatForShapesEdges(SATResult* result, ConvexPolygon* first, ConvexPolygon
             } else {
                 result->overlapPoint = secondProj.maxVertex;
             }
+
+            // Check if the normal from one of the edges of the overlap point is nearly perpendicular
+            // to the edge that you have intersected with. If so, let's call the point of intersection
+            // the middle of the edge.
 		}
 	}
 
@@ -497,3 +512,9 @@ EM_BOOL onStopClicked(int eventType, const EmscriptenMouseEvent* mouseEvent, voi
     unload();
     return true;
 }
+
+EM_BOOL onGravityReversed(int eventType, const EmscriptenMouseEvent* mouseEvent, void* userData) {
+    printf("Reversing gravity\n");
+    gravityDirection = -gravityDirection;
+    return true;
+}
diff --git a/2d/_collisions/polygon_polygon/snippet2.cpp b/2d/_collisions/polygon_polygon/snippet2.cpp
index a279f65..c182060 100644
--- a/2d/_collisions/polygon_polygon/snippet2.cpp
+++ b/2d/_collisions/polygon_polygon/snippet2.cpp
@@ -29,6 +29,8 @@ struct ProjectionResult {
 // the collision later.
 ProjectionResult getProjection(Vector2* vertices, int numVertices, Vector2 axis) {
     ProjectionResult pr;
+    pr.minVertex = vertices[0];
+    pr.maxVertex = vertices[0];
     float32 min = axis.dot(vertices[0]);
     float32 max = min;
 
-- 
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