From 044e141848d139149cef10a697676b460d4a588d Mon Sep 17 00:00:00 2001
From: Wojciech Figat <wojtek@figat.pl>
Date: Tue, 25 Oct 2022 15:06:52 +0200
Subject: [PATCH] Add `Render2D.DrawTexturedTriangles` with index buffer

---
 Source/Engine/Render2D/Render2D.cpp | 21 +++++++++++++++++++++
 Source/Engine/Render2D/Render2D.h   | 10 ++++++++++
 2 files changed, 31 insertions(+)

diff --git a/Source/Engine/Render2D/Render2D.cpp b/Source/Engine/Render2D/Render2D.cpp
index 1105920ba..d929bdb5c 100644
--- a/Source/Engine/Render2D/Render2D.cpp
+++ b/Source/Engine/Render2D/Render2D.cpp
@@ -1963,6 +1963,27 @@ void Render2D::DrawTexturedTriangles(GPUTexture* t, const Span<Float2>& vertices
         WriteTri(vertices[i], vertices[i + 1], vertices[i + 2], uvs[i], uvs[i + 1], uvs[i + 2], colors[i], colors[i + 1], colors[i + 2]);
 }
 
+void Render2D::DrawTexturedTriangles(GPUTexture* t, const Span<uint16>& indices, const Span<Float2>& vertices, const Span<Float2>& uvs, const Span<Color>& colors)
+{
+    RENDER2D_CHECK_RENDERING_STATE;
+    CHECK(vertices.Length() == uvs.Length());
+    CHECK(vertices.Length() == colors.Length());
+
+    Render2DDrawCall& drawCall = DrawCalls.AddOne();
+    drawCall.Type = DrawCallType::FillTexture;
+    drawCall.StartIB = IBIndex;
+    drawCall.CountIB = indices.Length();
+    drawCall.AsTexture.Ptr = t;
+    
+    for (int32 i = 0; i < indices.Length();)
+    {
+        const uint16 i0 = indices.Get()[i++];
+        const uint16 i1 = indices.Get()[i++];
+        const uint16 i2 = indices.Get()[i++];
+        WriteTri(vertices[i0], vertices[i1], vertices[i2], uvs[i0], uvs[i1], uvs[i2], colors[i0], colors[i1], colors[i2]);
+    }
+}
+
 void Render2D::FillTriangles(const Span<Float2>& vertices, const Span<Color>& colors, bool useAlpha)
 {
     CHECK(vertices.Length() == colors.Length());
diff --git a/Source/Engine/Render2D/Render2D.h b/Source/Engine/Render2D/Render2D.h
index 55f450e87..ba95c8a85 100644
--- a/Source/Engine/Render2D/Render2D.h
+++ b/Source/Engine/Render2D/Render2D.h
@@ -425,6 +425,16 @@ public:
     /// <param name="colors">The colors array.</param>
     API_FUNCTION() static void DrawTexturedTriangles(GPUTexture* t, const Span<Float2>& vertices, const Span<Float2>& uvs, const Span<Color>& colors);
 
+    /// <summary>
+    /// Draws indexed vertices array.
+    /// </summary>
+    /// <param name="t">The texture.</param>
+    /// <param name="indices">The indices array.</param>
+    /// <param name="vertices">The vertices array.</param>
+    /// <param name="uvs">The uvs array.</param>
+    /// <param name="colors">The colors array.</param>
+    API_FUNCTION() static void DrawTexturedTriangles(GPUTexture* t, const Span<uint16>& indices, const Span<Float2>& vertices, const Span<Float2>& uvs, const Span<Color>& colors);
+
     /// <summary>
     /// Draws vertices array.
     /// </summary>