From f6ca045735dc5a3da1c329434503ec37df940171 Mon Sep 17 00:00:00 2001
From: raysan5 <raysan5@gmail.com>
Date: Thu, 7 May 2020 12:46:45 +0200
Subject: [PATCH] ADDED: DrawTriangle3D() and DrawTriangleStrip3D()

Those functions could be very useful for custom triangle data drawing, using internal batch system.
---
 src/models.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 src/raylib.h |  3 ++-
 2 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/src/models.c b/src/models.c
index dfc070c66..00d3b5165 100644
--- a/src/models.c
+++ b/src/models.c
@@ -169,6 +169,48 @@ void DrawCircle3D(Vector3 center, float radius, Vector3 rotationAxis, float rota
     rlPopMatrix();
 }
 
+// Draw a color-filled triangle (vertex in counter-clockwise order!)
+void DrawTriangle3D(Vector3 v1, Vector3 v2, Vector3 v3, Color color)
+{
+    if (rlCheckBufferLimit(3)) rlglDraw();
+
+    rlBegin(RL_TRIANGLES);
+        rlColor4ub(color.r, color.g, color.b, color.a);
+        rlVertex3f(v1.x, v1.y, v1.z);
+        rlVertex3f(v2.x, v2.y, v2.z);
+        rlVertex3f(v3.x, v3.y, v3.z);
+    rlEnd();
+}
+
+// Draw a triangle strip defined by points
+void DrawTriangleStrip3D(Vector3 *points, int pointsCount, Color color)
+{
+    if (pointsCount >= 3)
+    {
+        if (rlCheckBufferLimit(3*(pointsCount - 2))) rlglDraw();
+
+        rlBegin(RL_TRIANGLES);
+            rlColor4ub(color.r, color.g, color.b, color.a);
+
+            for (int i = 2; i < pointsCount; i++)
+            {
+                if ((i%2) == 0)
+                {
+                    rlVertex3f(points[i].x, points[i].y, points[i].z);
+                    rlVertex3f(points[i - 2].x, points[i - 2].y, points[i - 2].z);
+                    rlVertex3f(points[i - 1].x, points[i - 1].y, points[i - 1].z);
+                }
+                else
+                {
+                    rlVertex3f(points[i].x, points[i].y, points[i].z);
+                    rlVertex3f(points[i - 1].x, points[i - 1].y, points[i - 1].z);
+                    rlVertex3f(points[i - 2].x, points[i - 2].y, points[i - 2].z);
+                }
+            }
+        rlEnd();
+    }
+}
+
 // Draw cube
 // NOTE: Cube position is the center position
 void DrawCube(Vector3 position, float width, float height, float length, Color color)
diff --git a/src/raylib.h b/src/raylib.h
index 4df397c8a..5289061fe 100644
--- a/src/raylib.h
+++ b/src/raylib.h
@@ -1259,6 +1259,8 @@ RLAPI const char *CodepointToUtf8(int codepoint, int *byteLength);    // Encode
 RLAPI void DrawLine3D(Vector3 startPos, Vector3 endPos, Color color);                                    // Draw a line in 3D world space
 RLAPI void DrawPoint3D(Vector3 position, Color color);                                                   // Draw a point in 3D space, actually a small line
 RLAPI void DrawCircle3D(Vector3 center, float radius, Vector3 rotationAxis, float rotationAngle, Color color); // Draw a circle in 3D world space
+RLAPI void DrawTriangle3D(Vector3 v1, Vector3 v2, Vector3 v3, Color color);                              // Draw a color-filled triangle (vertex in counter-clockwise order!)
+RLAPI void DrawTriangleStrip3D(Vector3 *points, int pointsCount, Color color);                           // Draw a triangle strip defined by points
 RLAPI void DrawCube(Vector3 position, float width, float height, float length, Color color);             // Draw cube
 RLAPI void DrawCubeV(Vector3 position, Vector3 size, Color color);                                       // Draw cube (Vector version)
 RLAPI void DrawCubeWires(Vector3 position, float width, float height, float length, Color color);        // Draw cube wires
@@ -1273,7 +1275,6 @@ RLAPI void DrawPlane(Vector3 centerPos, Vector2 size, Color color);
 RLAPI void DrawRay(Ray ray, Color color);                                                                // Draw a ray line
 RLAPI void DrawGrid(int slices, float spacing);                                                          // Draw a grid (centered at (0, 0, 0))
 RLAPI void DrawGizmo(Vector3 position);                                                                  // Draw simple gizmo
-//DrawTorus(), DrawTeapot() could be useful?
 
 //------------------------------------------------------------------------------------
 // Model 3d Loading and Drawing Functions (Module: models)