From 8b2d449b165f2214a088f8d0cd8a20b684e99787 Mon Sep 17 00:00:00 2001
From: thedmd <michcic@gmail.com>
Date: Sun, 19 Nov 2017 21:00:38 +0100
Subject: [PATCH] Add ShadeVertsLinearUV()

---
 imgui_draw.cpp   | 24 ++++++++++++++++++++++++
 imgui_internal.h |  2 ++
 2 files changed, 26 insertions(+)

diff --git a/imgui_draw.cpp b/imgui_draw.cpp
index 8718e978..5d8cc5d9 100644
--- a/imgui_draw.cpp
+++ b/imgui_draw.cpp
@@ -1226,6 +1226,30 @@ void ImGui::ShadeVertsLinearAlphaGradientForLeftToRightText(ImDrawVert* vert_sta
     }
 }
 
+// Distribute UV over (a, b) rectangle
+void ImGui::ShadeVertsLinearUV(ImDrawVert* vert_start, ImDrawVert* vert_end, const ImVec2& a, const ImVec2& b, const ImVec2& uv_a, const ImVec2& uv_b, bool clamp)
+{
+    const ImVec2 size = b - a;
+    const ImVec2 uv_size = uv_b - uv_a;
+    const ImVec2 scale = ImVec2(
+        size.x ? (uv_size.x / size.x) : 0.0f,
+        size.y ? (uv_size.y / size.y) : 0.0f);
+
+    if (clamp)
+    {
+        const ImVec2 min = ImMin(uv_a, uv_b);
+        const ImVec2 max = ImMax(uv_a, uv_b);
+
+        for (ImDrawVert* vertex = vert_start; vertex < vert_end; ++vertex)
+            vertex->uv = ImClamp(uv_a + ImMul(ImVec2(vertex->pos.x, vertex->pos.y) - a, scale), min, max);
+    }
+    else
+    {
+        for (ImDrawVert* vertex = vert_start; vertex < vert_end; ++vertex)
+            vertex->uv = uv_a + ImMul(ImVec2(vertex->pos.x, vertex->pos.y) - a, scale);
+    }
+}
+
 //-----------------------------------------------------------------------------
 // ImFontConfig
 //-----------------------------------------------------------------------------
diff --git a/imgui_internal.h b/imgui_internal.h
index 6a5c24aa..f9c9a7d4 100644
--- a/imgui_internal.h
+++ b/imgui_internal.h
@@ -155,6 +155,7 @@ static inline ImVec2 ImFloor(const ImVec2& v)
 static inline float  ImDot(const ImVec2& a, const ImVec2& b)                    { return a.x * b.x + a.y * b.y; }
 static inline ImVec2 ImRotate(const ImVec2& v, float cos_a, float sin_a)        { return ImVec2(v.x * cos_a - v.y * sin_a, v.x * sin_a + v.y * cos_a); }
 static inline float  ImLinearSweep(float current, float target, float speed)    { if (current < target) return ImMin(current + speed, target); if (current > target) return ImMax(current - speed, target); return current; }
+static inline ImVec2 ImMul(const ImVec2& lhs, const ImVec2& rhs)                { return ImVec2(lhs.x * rhs.x, lhs.y * rhs.y); }
 
 // We call C++ constructor on own allocated memory via the placement "new(ptr) Type()" syntax.
 // Defining a custom placement new() with a dummy parameter allows us to bypass including <new> which on some platforms complains when user has disabled exceptions.
@@ -873,6 +874,7 @@ namespace ImGui
     // Shade functions
     IMGUI_API void          ShadeVertsLinearColorGradientKeepAlpha(ImDrawVert* vert_start, ImDrawVert* vert_end, ImVec2 gradient_p0, ImVec2 gradient_p1, ImU32 col0, ImU32 col1);
     IMGUI_API void          ShadeVertsLinearAlphaGradientForLeftToRightText(ImDrawVert* vert_start, ImDrawVert* vert_end, float gradient_p0_x, float gradient_p1_x);
+    IMGUI_API void          ShadeVertsLinearUV(ImDrawVert* vert_start, ImDrawVert* vert_end, const ImVec2& a, const ImVec2& b, const ImVec2& uv_a, const ImVec2& uv_b, bool clamp);
 
 } // namespace ImGui